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34dc7c2f BB |
1 | /* |
2 | * CDDL HEADER START | |
3 | * | |
4 | * The contents of this file are subject to the terms of the | |
5 | * Common Development and Distribution License (the "License"). | |
6 | * You may not use this file except in compliance with the License. | |
7 | * | |
8 | * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE | |
9 | * or http://www.opensolaris.org/os/licensing. | |
10 | * See the License for the specific language governing permissions | |
11 | * and limitations under the License. | |
12 | * | |
13 | * When distributing Covered Code, include this CDDL HEADER in each | |
14 | * file and include the License file at usr/src/OPENSOLARIS.LICENSE. | |
15 | * If applicable, add the following below this CDDL HEADER, with the | |
16 | * fields enclosed by brackets "[]" replaced with your own identifying | |
17 | * information: Portions Copyright [yyyy] [name of copyright owner] | |
18 | * | |
19 | * CDDL HEADER END | |
20 | */ | |
21 | /* | |
428870ff | 22 | * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. |
3541dc6d GA |
23 | * Copyright 2011 Nexenta Systems, Inc. All rights reserved. |
24 | * Copyright (c) 2011 by Delphix. All rights reserved. | |
c06d4368 | 25 | * Copyright (c) 2013 by Saso Kiselkov. All rights reserved. |
34dc7c2f BB |
26 | */ |
27 | ||
34dc7c2f BB |
28 | /* |
29 | * DVA-based Adjustable Replacement Cache | |
30 | * | |
31 | * While much of the theory of operation used here is | |
32 | * based on the self-tuning, low overhead replacement cache | |
33 | * presented by Megiddo and Modha at FAST 2003, there are some | |
34 | * significant differences: | |
35 | * | |
36 | * 1. The Megiddo and Modha model assumes any page is evictable. | |
37 | * Pages in its cache cannot be "locked" into memory. This makes | |
38 | * the eviction algorithm simple: evict the last page in the list. | |
39 | * This also make the performance characteristics easy to reason | |
40 | * about. Our cache is not so simple. At any given moment, some | |
41 | * subset of the blocks in the cache are un-evictable because we | |
42 | * have handed out a reference to them. Blocks are only evictable | |
43 | * when there are no external references active. This makes | |
44 | * eviction far more problematic: we choose to evict the evictable | |
45 | * blocks that are the "lowest" in the list. | |
46 | * | |
47 | * There are times when it is not possible to evict the requested | |
48 | * space. In these circumstances we are unable to adjust the cache | |
49 | * size. To prevent the cache growing unbounded at these times we | |
50 | * implement a "cache throttle" that slows the flow of new data | |
51 | * into the cache until we can make space available. | |
52 | * | |
53 | * 2. The Megiddo and Modha model assumes a fixed cache size. | |
54 | * Pages are evicted when the cache is full and there is a cache | |
55 | * miss. Our model has a variable sized cache. It grows with | |
56 | * high use, but also tries to react to memory pressure from the | |
57 | * operating system: decreasing its size when system memory is | |
58 | * tight. | |
59 | * | |
60 | * 3. The Megiddo and Modha model assumes a fixed page size. All | |
61 | * elements of the cache are therefor exactly the same size. So | |
62 | * when adjusting the cache size following a cache miss, its simply | |
63 | * a matter of choosing a single page to evict. In our model, we | |
64 | * have variable sized cache blocks (rangeing from 512 bytes to | |
65 | * 128K bytes). We therefor choose a set of blocks to evict to make | |
66 | * space for a cache miss that approximates as closely as possible | |
67 | * the space used by the new block. | |
68 | * | |
69 | * See also: "ARC: A Self-Tuning, Low Overhead Replacement Cache" | |
70 | * by N. Megiddo & D. Modha, FAST 2003 | |
71 | */ | |
72 | ||
73 | /* | |
74 | * The locking model: | |
75 | * | |
76 | * A new reference to a cache buffer can be obtained in two | |
77 | * ways: 1) via a hash table lookup using the DVA as a key, | |
78 | * or 2) via one of the ARC lists. The arc_read() interface | |
79 | * uses method 1, while the internal arc algorithms for | |
80 | * adjusting the cache use method 2. We therefor provide two | |
81 | * types of locks: 1) the hash table lock array, and 2) the | |
82 | * arc list locks. | |
83 | * | |
5c839890 BC |
84 | * Buffers do not have their own mutexes, rather they rely on the |
85 | * hash table mutexes for the bulk of their protection (i.e. most | |
86 | * fields in the arc_buf_hdr_t are protected by these mutexes). | |
34dc7c2f BB |
87 | * |
88 | * buf_hash_find() returns the appropriate mutex (held) when it | |
89 | * locates the requested buffer in the hash table. It returns | |
90 | * NULL for the mutex if the buffer was not in the table. | |
91 | * | |
92 | * buf_hash_remove() expects the appropriate hash mutex to be | |
93 | * already held before it is invoked. | |
94 | * | |
95 | * Each arc state also has a mutex which is used to protect the | |
96 | * buffer list associated with the state. When attempting to | |
97 | * obtain a hash table lock while holding an arc list lock you | |
98 | * must use: mutex_tryenter() to avoid deadlock. Also note that | |
99 | * the active state mutex must be held before the ghost state mutex. | |
100 | * | |
101 | * Arc buffers may have an associated eviction callback function. | |
102 | * This function will be invoked prior to removing the buffer (e.g. | |
103 | * in arc_do_user_evicts()). Note however that the data associated | |
104 | * with the buffer may be evicted prior to the callback. The callback | |
105 | * must be made with *no locks held* (to prevent deadlock). Additionally, | |
106 | * the users of callbacks must ensure that their private data is | |
107 | * protected from simultaneous callbacks from arc_buf_evict() | |
108 | * and arc_do_user_evicts(). | |
109 | * | |
ab26409d BB |
110 | * It as also possible to register a callback which is run when the |
111 | * arc_meta_limit is reached and no buffers can be safely evicted. In | |
112 | * this case the arc user should drop a reference on some arc buffers so | |
113 | * they can be reclaimed and the arc_meta_limit honored. For example, | |
114 | * when using the ZPL each dentry holds a references on a znode. These | |
115 | * dentries must be pruned before the arc buffer holding the znode can | |
116 | * be safely evicted. | |
117 | * | |
34dc7c2f BB |
118 | * Note that the majority of the performance stats are manipulated |
119 | * with atomic operations. | |
120 | * | |
121 | * The L2ARC uses the l2arc_buflist_mtx global mutex for the following: | |
122 | * | |
123 | * - L2ARC buflist creation | |
124 | * - L2ARC buflist eviction | |
125 | * - L2ARC write completion, which walks L2ARC buflists | |
126 | * - ARC header destruction, as it removes from L2ARC buflists | |
127 | * - ARC header release, as it removes from L2ARC buflists | |
128 | */ | |
129 | ||
130 | #include <sys/spa.h> | |
131 | #include <sys/zio.h> | |
c06d4368 | 132 | #include <sys/zio_compress.h> |
34dc7c2f BB |
133 | #include <sys/zfs_context.h> |
134 | #include <sys/arc.h> | |
b128c09f | 135 | #include <sys/vdev.h> |
9babb374 | 136 | #include <sys/vdev_impl.h> |
34dc7c2f BB |
137 | #ifdef _KERNEL |
138 | #include <sys/vmsystm.h> | |
139 | #include <vm/anon.h> | |
140 | #include <sys/fs/swapnode.h> | |
ab26409d | 141 | #include <sys/zpl.h> |
34dc7c2f BB |
142 | #endif |
143 | #include <sys/callb.h> | |
144 | #include <sys/kstat.h> | |
570827e1 | 145 | #include <sys/dmu_tx.h> |
428870ff | 146 | #include <zfs_fletcher.h> |
34dc7c2f BB |
147 | |
148 | static kmutex_t arc_reclaim_thr_lock; | |
149 | static kcondvar_t arc_reclaim_thr_cv; /* used to signal reclaim thr */ | |
150 | static uint8_t arc_thread_exit; | |
151 | ||
ab26409d | 152 | /* number of bytes to prune from caches when at arc_meta_limit is reached */ |
c06d4368 | 153 | int zfs_arc_meta_prune = 1048576; |
34dc7c2f BB |
154 | |
155 | typedef enum arc_reclaim_strategy { | |
156 | ARC_RECLAIM_AGGR, /* Aggressive reclaim strategy */ | |
157 | ARC_RECLAIM_CONS /* Conservative reclaim strategy */ | |
158 | } arc_reclaim_strategy_t; | |
159 | ||
160 | /* number of seconds before growing cache again */ | |
c06d4368 | 161 | int zfs_arc_grow_retry = 5; |
34dc7c2f | 162 | |
d164b209 | 163 | /* shift of arc_c for calculating both min and max arc_p */ |
c06d4368 | 164 | int zfs_arc_p_min_shift = 4; |
d164b209 BB |
165 | |
166 | /* log2(fraction of arc to reclaim) */ | |
c06d4368 | 167 | int zfs_arc_shrink_shift = 5; |
d164b209 | 168 | |
34dc7c2f BB |
169 | /* |
170 | * minimum lifespan of a prefetch block in clock ticks | |
171 | * (initialized in arc_init()) | |
172 | */ | |
c06d4368 AX |
173 | int zfs_arc_min_prefetch_lifespan = HZ; |
174 | ||
175 | /* disable arc proactive arc throttle due to low memory */ | |
176 | int zfs_arc_memory_throttle_disable = 1; | |
177 | ||
178 | /* disable duplicate buffer eviction */ | |
179 | int zfs_disable_dup_eviction = 0; | |
34dc7c2f BB |
180 | |
181 | static int arc_dead; | |
182 | ||
c06d4368 AX |
183 | /* expiration time for arc_no_grow */ |
184 | static clock_t arc_grow_time = 0; | |
185 | ||
b128c09f BB |
186 | /* |
187 | * The arc has filled available memory and has now warmed up. | |
188 | */ | |
189 | static boolean_t arc_warm; | |
190 | ||
34dc7c2f BB |
191 | /* |
192 | * These tunables are for performance analysis. | |
193 | */ | |
c28b2279 BB |
194 | unsigned long zfs_arc_max = 0; |
195 | unsigned long zfs_arc_min = 0; | |
196 | unsigned long zfs_arc_meta_limit = 0; | |
34dc7c2f BB |
197 | |
198 | /* | |
199 | * Note that buffers can be in one of 6 states: | |
200 | * ARC_anon - anonymous (discussed below) | |
201 | * ARC_mru - recently used, currently cached | |
202 | * ARC_mru_ghost - recentely used, no longer in cache | |
203 | * ARC_mfu - frequently used, currently cached | |
204 | * ARC_mfu_ghost - frequently used, no longer in cache | |
205 | * ARC_l2c_only - exists in L2ARC but not other states | |
206 | * When there are no active references to the buffer, they are | |
207 | * are linked onto a list in one of these arc states. These are | |
208 | * the only buffers that can be evicted or deleted. Within each | |
209 | * state there are multiple lists, one for meta-data and one for | |
210 | * non-meta-data. Meta-data (indirect blocks, blocks of dnodes, | |
211 | * etc.) is tracked separately so that it can be managed more | |
212 | * explicitly: favored over data, limited explicitly. | |
213 | * | |
214 | * Anonymous buffers are buffers that are not associated with | |
215 | * a DVA. These are buffers that hold dirty block copies | |
216 | * before they are written to stable storage. By definition, | |
217 | * they are "ref'd" and are considered part of arc_mru | |
218 | * that cannot be freed. Generally, they will aquire a DVA | |
219 | * as they are written and migrate onto the arc_mru list. | |
220 | * | |
221 | * The ARC_l2c_only state is for buffers that are in the second | |
222 | * level ARC but no longer in any of the ARC_m* lists. The second | |
223 | * level ARC itself may also contain buffers that are in any of | |
224 | * the ARC_m* states - meaning that a buffer can exist in two | |
225 | * places. The reason for the ARC_l2c_only state is to keep the | |
226 | * buffer header in the hash table, so that reads that hit the | |
227 | * second level ARC benefit from these fast lookups. | |
228 | */ | |
229 | ||
230 | typedef struct arc_state { | |
231 | list_t arcs_list[ARC_BUFC_NUMTYPES]; /* list of evictable buffers */ | |
232 | uint64_t arcs_lsize[ARC_BUFC_NUMTYPES]; /* amount of evictable data */ | |
233 | uint64_t arcs_size; /* total amount of data in this state */ | |
234 | kmutex_t arcs_mtx; | |
235 | } arc_state_t; | |
236 | ||
237 | /* The 6 states: */ | |
238 | static arc_state_t ARC_anon; | |
239 | static arc_state_t ARC_mru; | |
240 | static arc_state_t ARC_mru_ghost; | |
241 | static arc_state_t ARC_mfu; | |
242 | static arc_state_t ARC_mfu_ghost; | |
243 | static arc_state_t ARC_l2c_only; | |
244 | ||
245 | typedef struct arc_stats { | |
246 | kstat_named_t arcstat_hits; | |
247 | kstat_named_t arcstat_misses; | |
248 | kstat_named_t arcstat_demand_data_hits; | |
249 | kstat_named_t arcstat_demand_data_misses; | |
250 | kstat_named_t arcstat_demand_metadata_hits; | |
251 | kstat_named_t arcstat_demand_metadata_misses; | |
252 | kstat_named_t arcstat_prefetch_data_hits; | |
253 | kstat_named_t arcstat_prefetch_data_misses; | |
254 | kstat_named_t arcstat_prefetch_metadata_hits; | |
255 | kstat_named_t arcstat_prefetch_metadata_misses; | |
256 | kstat_named_t arcstat_mru_hits; | |
257 | kstat_named_t arcstat_mru_ghost_hits; | |
258 | kstat_named_t arcstat_mfu_hits; | |
259 | kstat_named_t arcstat_mfu_ghost_hits; | |
260 | kstat_named_t arcstat_deleted; | |
261 | kstat_named_t arcstat_recycle_miss; | |
262 | kstat_named_t arcstat_mutex_miss; | |
263 | kstat_named_t arcstat_evict_skip; | |
428870ff BB |
264 | kstat_named_t arcstat_evict_l2_cached; |
265 | kstat_named_t arcstat_evict_l2_eligible; | |
266 | kstat_named_t arcstat_evict_l2_ineligible; | |
34dc7c2f BB |
267 | kstat_named_t arcstat_hash_elements; |
268 | kstat_named_t arcstat_hash_elements_max; | |
269 | kstat_named_t arcstat_hash_collisions; | |
270 | kstat_named_t arcstat_hash_chains; | |
271 | kstat_named_t arcstat_hash_chain_max; | |
272 | kstat_named_t arcstat_p; | |
273 | kstat_named_t arcstat_c; | |
274 | kstat_named_t arcstat_c_min; | |
275 | kstat_named_t arcstat_c_max; | |
276 | kstat_named_t arcstat_size; | |
277 | kstat_named_t arcstat_hdr_size; | |
d164b209 BB |
278 | kstat_named_t arcstat_data_size; |
279 | kstat_named_t arcstat_other_size; | |
13be560d BB |
280 | kstat_named_t arcstat_anon_size; |
281 | kstat_named_t arcstat_anon_evict_data; | |
282 | kstat_named_t arcstat_anon_evict_metadata; | |
283 | kstat_named_t arcstat_mru_size; | |
284 | kstat_named_t arcstat_mru_evict_data; | |
285 | kstat_named_t arcstat_mru_evict_metadata; | |
286 | kstat_named_t arcstat_mru_ghost_size; | |
287 | kstat_named_t arcstat_mru_ghost_evict_data; | |
288 | kstat_named_t arcstat_mru_ghost_evict_metadata; | |
289 | kstat_named_t arcstat_mfu_size; | |
290 | kstat_named_t arcstat_mfu_evict_data; | |
291 | kstat_named_t arcstat_mfu_evict_metadata; | |
292 | kstat_named_t arcstat_mfu_ghost_size; | |
293 | kstat_named_t arcstat_mfu_ghost_evict_data; | |
294 | kstat_named_t arcstat_mfu_ghost_evict_metadata; | |
34dc7c2f BB |
295 | kstat_named_t arcstat_l2_hits; |
296 | kstat_named_t arcstat_l2_misses; | |
297 | kstat_named_t arcstat_l2_feeds; | |
298 | kstat_named_t arcstat_l2_rw_clash; | |
d164b209 BB |
299 | kstat_named_t arcstat_l2_read_bytes; |
300 | kstat_named_t arcstat_l2_write_bytes; | |
34dc7c2f BB |
301 | kstat_named_t arcstat_l2_writes_sent; |
302 | kstat_named_t arcstat_l2_writes_done; | |
303 | kstat_named_t arcstat_l2_writes_error; | |
304 | kstat_named_t arcstat_l2_writes_hdr_miss; | |
305 | kstat_named_t arcstat_l2_evict_lock_retry; | |
306 | kstat_named_t arcstat_l2_evict_reading; | |
307 | kstat_named_t arcstat_l2_free_on_write; | |
308 | kstat_named_t arcstat_l2_abort_lowmem; | |
309 | kstat_named_t arcstat_l2_cksum_bad; | |
310 | kstat_named_t arcstat_l2_io_error; | |
311 | kstat_named_t arcstat_l2_size; | |
c06d4368 | 312 | kstat_named_t arcstat_l2_asize; |
34dc7c2f | 313 | kstat_named_t arcstat_l2_hdr_size; |
c06d4368 AX |
314 | kstat_named_t arcstat_l2_compress_successes; |
315 | kstat_named_t arcstat_l2_compress_zeros; | |
316 | kstat_named_t arcstat_l2_compress_failures; | |
34dc7c2f | 317 | kstat_named_t arcstat_memory_throttle_count; |
1eb5bfa3 GW |
318 | kstat_named_t arcstat_duplicate_buffers; |
319 | kstat_named_t arcstat_duplicate_buffers_size; | |
320 | kstat_named_t arcstat_duplicate_reads; | |
7cb67b45 BB |
321 | kstat_named_t arcstat_memory_direct_count; |
322 | kstat_named_t arcstat_memory_indirect_count; | |
1834f2d8 BB |
323 | kstat_named_t arcstat_no_grow; |
324 | kstat_named_t arcstat_tempreserve; | |
325 | kstat_named_t arcstat_loaned_bytes; | |
ab26409d | 326 | kstat_named_t arcstat_prune; |
1834f2d8 BB |
327 | kstat_named_t arcstat_meta_used; |
328 | kstat_named_t arcstat_meta_limit; | |
329 | kstat_named_t arcstat_meta_max; | |
34dc7c2f BB |
330 | } arc_stats_t; |
331 | ||
332 | static arc_stats_t arc_stats = { | |
333 | { "hits", KSTAT_DATA_UINT64 }, | |
334 | { "misses", KSTAT_DATA_UINT64 }, | |
335 | { "demand_data_hits", KSTAT_DATA_UINT64 }, | |
336 | { "demand_data_misses", KSTAT_DATA_UINT64 }, | |
337 | { "demand_metadata_hits", KSTAT_DATA_UINT64 }, | |
338 | { "demand_metadata_misses", KSTAT_DATA_UINT64 }, | |
339 | { "prefetch_data_hits", KSTAT_DATA_UINT64 }, | |
340 | { "prefetch_data_misses", KSTAT_DATA_UINT64 }, | |
341 | { "prefetch_metadata_hits", KSTAT_DATA_UINT64 }, | |
342 | { "prefetch_metadata_misses", KSTAT_DATA_UINT64 }, | |
343 | { "mru_hits", KSTAT_DATA_UINT64 }, | |
344 | { "mru_ghost_hits", KSTAT_DATA_UINT64 }, | |
345 | { "mfu_hits", KSTAT_DATA_UINT64 }, | |
346 | { "mfu_ghost_hits", KSTAT_DATA_UINT64 }, | |
347 | { "deleted", KSTAT_DATA_UINT64 }, | |
348 | { "recycle_miss", KSTAT_DATA_UINT64 }, | |
349 | { "mutex_miss", KSTAT_DATA_UINT64 }, | |
350 | { "evict_skip", KSTAT_DATA_UINT64 }, | |
428870ff BB |
351 | { "evict_l2_cached", KSTAT_DATA_UINT64 }, |
352 | { "evict_l2_eligible", KSTAT_DATA_UINT64 }, | |
353 | { "evict_l2_ineligible", KSTAT_DATA_UINT64 }, | |
34dc7c2f BB |
354 | { "hash_elements", KSTAT_DATA_UINT64 }, |
355 | { "hash_elements_max", KSTAT_DATA_UINT64 }, | |
356 | { "hash_collisions", KSTAT_DATA_UINT64 }, | |
357 | { "hash_chains", KSTAT_DATA_UINT64 }, | |
358 | { "hash_chain_max", KSTAT_DATA_UINT64 }, | |
359 | { "p", KSTAT_DATA_UINT64 }, | |
360 | { "c", KSTAT_DATA_UINT64 }, | |
361 | { "c_min", KSTAT_DATA_UINT64 }, | |
362 | { "c_max", KSTAT_DATA_UINT64 }, | |
363 | { "size", KSTAT_DATA_UINT64 }, | |
364 | { "hdr_size", KSTAT_DATA_UINT64 }, | |
d164b209 BB |
365 | { "data_size", KSTAT_DATA_UINT64 }, |
366 | { "other_size", KSTAT_DATA_UINT64 }, | |
13be560d BB |
367 | { "anon_size", KSTAT_DATA_UINT64 }, |
368 | { "anon_evict_data", KSTAT_DATA_UINT64 }, | |
369 | { "anon_evict_metadata", KSTAT_DATA_UINT64 }, | |
370 | { "mru_size", KSTAT_DATA_UINT64 }, | |
371 | { "mru_evict_data", KSTAT_DATA_UINT64 }, | |
372 | { "mru_evict_metadata", KSTAT_DATA_UINT64 }, | |
373 | { "mru_ghost_size", KSTAT_DATA_UINT64 }, | |
374 | { "mru_ghost_evict_data", KSTAT_DATA_UINT64 }, | |
375 | { "mru_ghost_evict_metadata", KSTAT_DATA_UINT64 }, | |
376 | { "mfu_size", KSTAT_DATA_UINT64 }, | |
377 | { "mfu_evict_data", KSTAT_DATA_UINT64 }, | |
378 | { "mfu_evict_metadata", KSTAT_DATA_UINT64 }, | |
379 | { "mfu_ghost_size", KSTAT_DATA_UINT64 }, | |
380 | { "mfu_ghost_evict_data", KSTAT_DATA_UINT64 }, | |
381 | { "mfu_ghost_evict_metadata", KSTAT_DATA_UINT64 }, | |
34dc7c2f BB |
382 | { "l2_hits", KSTAT_DATA_UINT64 }, |
383 | { "l2_misses", KSTAT_DATA_UINT64 }, | |
384 | { "l2_feeds", KSTAT_DATA_UINT64 }, | |
385 | { "l2_rw_clash", KSTAT_DATA_UINT64 }, | |
d164b209 BB |
386 | { "l2_read_bytes", KSTAT_DATA_UINT64 }, |
387 | { "l2_write_bytes", KSTAT_DATA_UINT64 }, | |
34dc7c2f BB |
388 | { "l2_writes_sent", KSTAT_DATA_UINT64 }, |
389 | { "l2_writes_done", KSTAT_DATA_UINT64 }, | |
390 | { "l2_writes_error", KSTAT_DATA_UINT64 }, | |
391 | { "l2_writes_hdr_miss", KSTAT_DATA_UINT64 }, | |
392 | { "l2_evict_lock_retry", KSTAT_DATA_UINT64 }, | |
393 | { "l2_evict_reading", KSTAT_DATA_UINT64 }, | |
394 | { "l2_free_on_write", KSTAT_DATA_UINT64 }, | |
395 | { "l2_abort_lowmem", KSTAT_DATA_UINT64 }, | |
396 | { "l2_cksum_bad", KSTAT_DATA_UINT64 }, | |
397 | { "l2_io_error", KSTAT_DATA_UINT64 }, | |
398 | { "l2_size", KSTAT_DATA_UINT64 }, | |
c06d4368 | 399 | { "l2_asize", KSTAT_DATA_UINT64 }, |
34dc7c2f | 400 | { "l2_hdr_size", KSTAT_DATA_UINT64 }, |
c06d4368 AX |
401 | { "l2_compress_successes", KSTAT_DATA_UINT64 }, |
402 | { "l2_compress_zeros", KSTAT_DATA_UINT64 }, | |
403 | { "l2_compress_failures", KSTAT_DATA_UINT64 }, | |
1834f2d8 | 404 | { "memory_throttle_count", KSTAT_DATA_UINT64 }, |
1eb5bfa3 GW |
405 | { "duplicate_buffers", KSTAT_DATA_UINT64 }, |
406 | { "duplicate_buffers_size", KSTAT_DATA_UINT64 }, | |
407 | { "duplicate_reads", KSTAT_DATA_UINT64 }, | |
7cb67b45 BB |
408 | { "memory_direct_count", KSTAT_DATA_UINT64 }, |
409 | { "memory_indirect_count", KSTAT_DATA_UINT64 }, | |
1834f2d8 BB |
410 | { "arc_no_grow", KSTAT_DATA_UINT64 }, |
411 | { "arc_tempreserve", KSTAT_DATA_UINT64 }, | |
412 | { "arc_loaned_bytes", KSTAT_DATA_UINT64 }, | |
ab26409d | 413 | { "arc_prune", KSTAT_DATA_UINT64 }, |
1834f2d8 BB |
414 | { "arc_meta_used", KSTAT_DATA_UINT64 }, |
415 | { "arc_meta_limit", KSTAT_DATA_UINT64 }, | |
416 | { "arc_meta_max", KSTAT_DATA_UINT64 }, | |
34dc7c2f BB |
417 | }; |
418 | ||
419 | #define ARCSTAT(stat) (arc_stats.stat.value.ui64) | |
420 | ||
421 | #define ARCSTAT_INCR(stat, val) \ | |
422 | atomic_add_64(&arc_stats.stat.value.ui64, (val)); | |
423 | ||
428870ff | 424 | #define ARCSTAT_BUMP(stat) ARCSTAT_INCR(stat, 1) |
34dc7c2f BB |
425 | #define ARCSTAT_BUMPDOWN(stat) ARCSTAT_INCR(stat, -1) |
426 | ||
427 | #define ARCSTAT_MAX(stat, val) { \ | |
428 | uint64_t m; \ | |
429 | while ((val) > (m = arc_stats.stat.value.ui64) && \ | |
430 | (m != atomic_cas_64(&arc_stats.stat.value.ui64, m, (val)))) \ | |
431 | continue; \ | |
432 | } | |
433 | ||
434 | #define ARCSTAT_MAXSTAT(stat) \ | |
435 | ARCSTAT_MAX(stat##_max, arc_stats.stat.value.ui64) | |
436 | ||
437 | /* | |
438 | * We define a macro to allow ARC hits/misses to be easily broken down by | |
439 | * two separate conditions, giving a total of four different subtypes for | |
440 | * each of hits and misses (so eight statistics total). | |
441 | */ | |
442 | #define ARCSTAT_CONDSTAT(cond1, stat1, notstat1, cond2, stat2, notstat2, stat) \ | |
443 | if (cond1) { \ | |
444 | if (cond2) { \ | |
445 | ARCSTAT_BUMP(arcstat_##stat1##_##stat2##_##stat); \ | |
446 | } else { \ | |
447 | ARCSTAT_BUMP(arcstat_##stat1##_##notstat2##_##stat); \ | |
448 | } \ | |
449 | } else { \ | |
450 | if (cond2) { \ | |
451 | ARCSTAT_BUMP(arcstat_##notstat1##_##stat2##_##stat); \ | |
452 | } else { \ | |
453 | ARCSTAT_BUMP(arcstat_##notstat1##_##notstat2##_##stat);\ | |
454 | } \ | |
455 | } | |
456 | ||
457 | kstat_t *arc_ksp; | |
428870ff | 458 | static arc_state_t *arc_anon; |
34dc7c2f BB |
459 | static arc_state_t *arc_mru; |
460 | static arc_state_t *arc_mru_ghost; | |
461 | static arc_state_t *arc_mfu; | |
462 | static arc_state_t *arc_mfu_ghost; | |
463 | static arc_state_t *arc_l2c_only; | |
464 | ||
465 | /* | |
466 | * There are several ARC variables that are critical to export as kstats -- | |
467 | * but we don't want to have to grovel around in the kstat whenever we wish to | |
468 | * manipulate them. For these variables, we therefore define them to be in | |
469 | * terms of the statistic variable. This assures that we are not introducing | |
470 | * the possibility of inconsistency by having shadow copies of the variables, | |
471 | * while still allowing the code to be readable. | |
472 | */ | |
473 | #define arc_size ARCSTAT(arcstat_size) /* actual total arc size */ | |
474 | #define arc_p ARCSTAT(arcstat_p) /* target size of MRU */ | |
475 | #define arc_c ARCSTAT(arcstat_c) /* target size of cache */ | |
476 | #define arc_c_min ARCSTAT(arcstat_c_min) /* min target cache size */ | |
477 | #define arc_c_max ARCSTAT(arcstat_c_max) /* max target cache size */ | |
1834f2d8 BB |
478 | #define arc_no_grow ARCSTAT(arcstat_no_grow) |
479 | #define arc_tempreserve ARCSTAT(arcstat_tempreserve) | |
480 | #define arc_loaned_bytes ARCSTAT(arcstat_loaned_bytes) | |
481 | #define arc_meta_used ARCSTAT(arcstat_meta_used) | |
482 | #define arc_meta_limit ARCSTAT(arcstat_meta_limit) | |
483 | #define arc_meta_max ARCSTAT(arcstat_meta_max) | |
34dc7c2f | 484 | |
c06d4368 AX |
485 | #define L2ARC_IS_VALID_COMPRESS(_c_) \ |
486 | ((_c_) == ZIO_COMPRESS_LZ4 || (_c_) == ZIO_COMPRESS_EMPTY) | |
487 | ||
34dc7c2f BB |
488 | typedef struct l2arc_buf_hdr l2arc_buf_hdr_t; |
489 | ||
490 | typedef struct arc_callback arc_callback_t; | |
491 | ||
492 | struct arc_callback { | |
493 | void *acb_private; | |
494 | arc_done_func_t *acb_done; | |
34dc7c2f BB |
495 | arc_buf_t *acb_buf; |
496 | zio_t *acb_zio_dummy; | |
497 | arc_callback_t *acb_next; | |
498 | }; | |
499 | ||
500 | typedef struct arc_write_callback arc_write_callback_t; | |
501 | ||
502 | struct arc_write_callback { | |
503 | void *awcb_private; | |
504 | arc_done_func_t *awcb_ready; | |
505 | arc_done_func_t *awcb_done; | |
506 | arc_buf_t *awcb_buf; | |
507 | }; | |
508 | ||
509 | struct arc_buf_hdr { | |
510 | /* protected by hash lock */ | |
511 | dva_t b_dva; | |
512 | uint64_t b_birth; | |
513 | uint64_t b_cksum0; | |
514 | ||
515 | kmutex_t b_freeze_lock; | |
516 | zio_cksum_t *b_freeze_cksum; | |
517 | ||
518 | arc_buf_hdr_t *b_hash_next; | |
519 | arc_buf_t *b_buf; | |
520 | uint32_t b_flags; | |
521 | uint32_t b_datacnt; | |
522 | ||
523 | arc_callback_t *b_acb; | |
524 | kcondvar_t b_cv; | |
525 | ||
526 | /* immutable */ | |
527 | arc_buf_contents_t b_type; | |
528 | uint64_t b_size; | |
d164b209 | 529 | uint64_t b_spa; |
34dc7c2f BB |
530 | |
531 | /* protected by arc state mutex */ | |
532 | arc_state_t *b_state; | |
533 | list_node_t b_arc_node; | |
534 | ||
535 | /* updated atomically */ | |
536 | clock_t b_arc_access; | |
537 | ||
538 | /* self protecting */ | |
539 | refcount_t b_refcnt; | |
540 | ||
541 | l2arc_buf_hdr_t *b_l2hdr; | |
542 | list_node_t b_l2node; | |
543 | }; | |
544 | ||
ab26409d BB |
545 | static list_t arc_prune_list; |
546 | static kmutex_t arc_prune_mtx; | |
34dc7c2f BB |
547 | static arc_buf_t *arc_eviction_list; |
548 | static kmutex_t arc_eviction_mtx; | |
549 | static arc_buf_hdr_t arc_eviction_hdr; | |
550 | static void arc_get_data_buf(arc_buf_t *buf); | |
551 | static void arc_access(arc_buf_hdr_t *buf, kmutex_t *hash_lock); | |
552 | static int arc_evict_needed(arc_buf_contents_t type); | |
c06d4368 AX |
553 | static void arc_evict_ghost(arc_state_t *state, uint64_t spa, int64_t bytes, |
554 | arc_buf_contents_t type); | |
34dc7c2f | 555 | |
428870ff BB |
556 | static boolean_t l2arc_write_eligible(uint64_t spa_guid, arc_buf_hdr_t *ab); |
557 | ||
34dc7c2f BB |
558 | #define GHOST_STATE(state) \ |
559 | ((state) == arc_mru_ghost || (state) == arc_mfu_ghost || \ | |
560 | (state) == arc_l2c_only) | |
561 | ||
562 | /* | |
563 | * Private ARC flags. These flags are private ARC only flags that will show up | |
564 | * in b_flags in the arc_hdr_buf_t. Some flags are publicly declared, and can | |
565 | * be passed in as arc_flags in things like arc_read. However, these flags | |
566 | * should never be passed and should only be set by ARC code. When adding new | |
567 | * public flags, make sure not to smash the private ones. | |
568 | */ | |
569 | ||
570 | #define ARC_IN_HASH_TABLE (1 << 9) /* this buffer is hashed */ | |
571 | #define ARC_IO_IN_PROGRESS (1 << 10) /* I/O in progress for buf */ | |
572 | #define ARC_IO_ERROR (1 << 11) /* I/O failed for buf */ | |
573 | #define ARC_FREED_IN_READ (1 << 12) /* buf freed while in read */ | |
574 | #define ARC_BUF_AVAILABLE (1 << 13) /* block not in active use */ | |
575 | #define ARC_INDIRECT (1 << 14) /* this is an indirect block */ | |
576 | #define ARC_FREE_IN_PROGRESS (1 << 15) /* hdr about to be freed */ | |
b128c09f BB |
577 | #define ARC_L2_WRITING (1 << 16) /* L2ARC write in progress */ |
578 | #define ARC_L2_EVICTED (1 << 17) /* evicted during I/O */ | |
579 | #define ARC_L2_WRITE_HEAD (1 << 18) /* head of write list */ | |
34dc7c2f BB |
580 | |
581 | #define HDR_IN_HASH_TABLE(hdr) ((hdr)->b_flags & ARC_IN_HASH_TABLE) | |
582 | #define HDR_IO_IN_PROGRESS(hdr) ((hdr)->b_flags & ARC_IO_IN_PROGRESS) | |
583 | #define HDR_IO_ERROR(hdr) ((hdr)->b_flags & ARC_IO_ERROR) | |
d164b209 | 584 | #define HDR_PREFETCH(hdr) ((hdr)->b_flags & ARC_PREFETCH) |
34dc7c2f BB |
585 | #define HDR_FREED_IN_READ(hdr) ((hdr)->b_flags & ARC_FREED_IN_READ) |
586 | #define HDR_BUF_AVAILABLE(hdr) ((hdr)->b_flags & ARC_BUF_AVAILABLE) | |
587 | #define HDR_FREE_IN_PROGRESS(hdr) ((hdr)->b_flags & ARC_FREE_IN_PROGRESS) | |
b128c09f BB |
588 | #define HDR_L2CACHE(hdr) ((hdr)->b_flags & ARC_L2CACHE) |
589 | #define HDR_L2_READING(hdr) ((hdr)->b_flags & ARC_IO_IN_PROGRESS && \ | |
590 | (hdr)->b_l2hdr != NULL) | |
34dc7c2f BB |
591 | #define HDR_L2_WRITING(hdr) ((hdr)->b_flags & ARC_L2_WRITING) |
592 | #define HDR_L2_EVICTED(hdr) ((hdr)->b_flags & ARC_L2_EVICTED) | |
593 | #define HDR_L2_WRITE_HEAD(hdr) ((hdr)->b_flags & ARC_L2_WRITE_HEAD) | |
594 | ||
595 | /* | |
596 | * Other sizes | |
597 | */ | |
598 | ||
599 | #define HDR_SIZE ((int64_t)sizeof (arc_buf_hdr_t)) | |
600 | #define L2HDR_SIZE ((int64_t)sizeof (l2arc_buf_hdr_t)) | |
601 | ||
602 | /* | |
603 | * Hash table routines | |
604 | */ | |
605 | ||
00b46022 BB |
606 | #define HT_LOCK_ALIGN 64 |
607 | #define HT_LOCK_PAD (P2NPHASE(sizeof (kmutex_t), (HT_LOCK_ALIGN))) | |
34dc7c2f BB |
608 | |
609 | struct ht_lock { | |
610 | kmutex_t ht_lock; | |
611 | #ifdef _KERNEL | |
00b46022 | 612 | unsigned char pad[HT_LOCK_PAD]; |
34dc7c2f BB |
613 | #endif |
614 | }; | |
615 | ||
616 | #define BUF_LOCKS 256 | |
617 | typedef struct buf_hash_table { | |
618 | uint64_t ht_mask; | |
619 | arc_buf_hdr_t **ht_table; | |
620 | struct ht_lock ht_locks[BUF_LOCKS]; | |
621 | } buf_hash_table_t; | |
622 | ||
623 | static buf_hash_table_t buf_hash_table; | |
624 | ||
625 | #define BUF_HASH_INDEX(spa, dva, birth) \ | |
626 | (buf_hash(spa, dva, birth) & buf_hash_table.ht_mask) | |
627 | #define BUF_HASH_LOCK_NTRY(idx) (buf_hash_table.ht_locks[idx & (BUF_LOCKS-1)]) | |
628 | #define BUF_HASH_LOCK(idx) (&(BUF_HASH_LOCK_NTRY(idx).ht_lock)) | |
428870ff BB |
629 | #define HDR_LOCK(hdr) \ |
630 | (BUF_HASH_LOCK(BUF_HASH_INDEX(hdr->b_spa, &hdr->b_dva, hdr->b_birth))) | |
34dc7c2f BB |
631 | |
632 | uint64_t zfs_crc64_table[256]; | |
633 | ||
634 | /* | |
635 | * Level 2 ARC | |
636 | */ | |
637 | ||
638 | #define L2ARC_WRITE_SIZE (8 * 1024 * 1024) /* initial write max */ | |
c06d4368 AX |
639 | #define L2ARC_HEADROOM 2 /* num of writes */ |
640 | /* | |
641 | * If we discover during ARC scan any buffers to be compressed, we boost | |
642 | * our headroom for the next scanning cycle by this percentage multiple. | |
643 | */ | |
644 | #define L2ARC_HEADROOM_BOOST 200 | |
d164b209 BB |
645 | #define L2ARC_FEED_SECS 1 /* caching interval secs */ |
646 | #define L2ARC_FEED_MIN_MS 200 /* min caching interval ms */ | |
34dc7c2f BB |
647 | |
648 | #define l2arc_writes_sent ARCSTAT(arcstat_l2_writes_sent) | |
649 | #define l2arc_writes_done ARCSTAT(arcstat_l2_writes_done) | |
650 | ||
651 | /* | |
652 | * L2ARC Performance Tunables | |
653 | */ | |
abd8610c BB |
654 | unsigned long l2arc_write_max = L2ARC_WRITE_SIZE; /* def max write size */ |
655 | unsigned long l2arc_write_boost = L2ARC_WRITE_SIZE; /* extra warmup write */ | |
656 | unsigned long l2arc_headroom = L2ARC_HEADROOM; /* # of dev writes */ | |
c06d4368 | 657 | unsigned long l2arc_headroom_boost = L2ARC_HEADROOM_BOOST; |
abd8610c BB |
658 | unsigned long l2arc_feed_secs = L2ARC_FEED_SECS; /* interval seconds */ |
659 | unsigned long l2arc_feed_min_ms = L2ARC_FEED_MIN_MS; /* min interval msecs */ | |
660 | int l2arc_noprefetch = B_TRUE; /* don't cache prefetch bufs */ | |
c06d4368 | 661 | int l2arc_nocompress = B_FALSE; /* don't compress bufs */ |
abd8610c | 662 | int l2arc_feed_again = B_TRUE; /* turbo warmup */ |
c06d4368 | 663 | int l2arc_norw = B_FALSE; /* no reads during writes */ |
34dc7c2f BB |
664 | |
665 | /* | |
666 | * L2ARC Internals | |
667 | */ | |
668 | typedef struct l2arc_dev { | |
669 | vdev_t *l2ad_vdev; /* vdev */ | |
670 | spa_t *l2ad_spa; /* spa */ | |
671 | uint64_t l2ad_hand; /* next write location */ | |
34dc7c2f BB |
672 | uint64_t l2ad_start; /* first addr on device */ |
673 | uint64_t l2ad_end; /* last addr on device */ | |
674 | uint64_t l2ad_evict; /* last addr eviction reached */ | |
675 | boolean_t l2ad_first; /* first sweep through */ | |
d164b209 | 676 | boolean_t l2ad_writing; /* currently writing */ |
34dc7c2f BB |
677 | list_t *l2ad_buflist; /* buffer list */ |
678 | list_node_t l2ad_node; /* device list node */ | |
679 | } l2arc_dev_t; | |
680 | ||
681 | static list_t L2ARC_dev_list; /* device list */ | |
682 | static list_t *l2arc_dev_list; /* device list pointer */ | |
683 | static kmutex_t l2arc_dev_mtx; /* device list mutex */ | |
684 | static l2arc_dev_t *l2arc_dev_last; /* last device used */ | |
685 | static kmutex_t l2arc_buflist_mtx; /* mutex for all buflists */ | |
686 | static list_t L2ARC_free_on_write; /* free after write buf list */ | |
687 | static list_t *l2arc_free_on_write; /* free after write list ptr */ | |
688 | static kmutex_t l2arc_free_on_write_mtx; /* mutex for list */ | |
689 | static uint64_t l2arc_ndev; /* number of devices */ | |
690 | ||
691 | typedef struct l2arc_read_callback { | |
c06d4368 AX |
692 | arc_buf_t *l2rcb_buf; /* read buffer */ |
693 | spa_t *l2rcb_spa; /* spa */ | |
694 | blkptr_t l2rcb_bp; /* original blkptr */ | |
695 | zbookmark_t l2rcb_zb; /* original bookmark */ | |
696 | int l2rcb_flags; /* original flags */ | |
697 | enum zio_compress l2rcb_compress; /* applied compress */ | |
34dc7c2f BB |
698 | } l2arc_read_callback_t; |
699 | ||
700 | typedef struct l2arc_write_callback { | |
701 | l2arc_dev_t *l2wcb_dev; /* device info */ | |
702 | arc_buf_hdr_t *l2wcb_head; /* head of write buflist */ | |
703 | } l2arc_write_callback_t; | |
704 | ||
705 | struct l2arc_buf_hdr { | |
706 | /* protected by arc_buf_hdr mutex */ | |
c06d4368 AX |
707 | l2arc_dev_t *b_dev; /* L2ARC device */ |
708 | uint64_t b_daddr; /* disk address, offset byte */ | |
709 | /* compression applied to buffer data */ | |
710 | enum zio_compress b_compress; | |
711 | /* real alloc'd buffer size depending on b_compress applied */ | |
712 | int b_asize; | |
713 | /* temporary buffer holder for in-flight compressed data */ | |
714 | void *b_tmp_cdata; | |
34dc7c2f BB |
715 | }; |
716 | ||
717 | typedef struct l2arc_data_free { | |
718 | /* protected by l2arc_free_on_write_mtx */ | |
719 | void *l2df_data; | |
720 | size_t l2df_size; | |
721 | void (*l2df_func)(void *, size_t); | |
722 | list_node_t l2df_list_node; | |
723 | } l2arc_data_free_t; | |
724 | ||
725 | static kmutex_t l2arc_feed_thr_lock; | |
726 | static kcondvar_t l2arc_feed_thr_cv; | |
727 | static uint8_t l2arc_thread_exit; | |
728 | ||
729 | static void l2arc_read_done(zio_t *zio); | |
730 | static void l2arc_hdr_stat_add(void); | |
731 | static void l2arc_hdr_stat_remove(void); | |
732 | ||
c06d4368 AX |
733 | static boolean_t l2arc_compress_buf(l2arc_buf_hdr_t *l2hdr); |
734 | static void l2arc_decompress_zio(zio_t *zio, arc_buf_hdr_t *hdr, | |
735 | enum zio_compress c); | |
736 | static void l2arc_release_cdata_buf(arc_buf_hdr_t *ab); | |
737 | ||
34dc7c2f | 738 | static uint64_t |
d164b209 | 739 | buf_hash(uint64_t spa, const dva_t *dva, uint64_t birth) |
34dc7c2f | 740 | { |
34dc7c2f BB |
741 | uint8_t *vdva = (uint8_t *)dva; |
742 | uint64_t crc = -1ULL; | |
743 | int i; | |
744 | ||
745 | ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY); | |
746 | ||
747 | for (i = 0; i < sizeof (dva_t); i++) | |
748 | crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ vdva[i]) & 0xFF]; | |
749 | ||
d164b209 | 750 | crc ^= (spa>>8) ^ birth; |
34dc7c2f BB |
751 | |
752 | return (crc); | |
753 | } | |
754 | ||
755 | #define BUF_EMPTY(buf) \ | |
756 | ((buf)->b_dva.dva_word[0] == 0 && \ | |
757 | (buf)->b_dva.dva_word[1] == 0 && \ | |
758 | (buf)->b_birth == 0) | |
759 | ||
760 | #define BUF_EQUAL(spa, dva, birth, buf) \ | |
761 | ((buf)->b_dva.dva_word[0] == (dva)->dva_word[0]) && \ | |
762 | ((buf)->b_dva.dva_word[1] == (dva)->dva_word[1]) && \ | |
763 | ((buf)->b_birth == birth) && ((buf)->b_spa == spa) | |
764 | ||
428870ff BB |
765 | static void |
766 | buf_discard_identity(arc_buf_hdr_t *hdr) | |
767 | { | |
768 | hdr->b_dva.dva_word[0] = 0; | |
769 | hdr->b_dva.dva_word[1] = 0; | |
770 | hdr->b_birth = 0; | |
771 | hdr->b_cksum0 = 0; | |
772 | } | |
773 | ||
34dc7c2f | 774 | static arc_buf_hdr_t * |
d164b209 | 775 | buf_hash_find(uint64_t spa, const dva_t *dva, uint64_t birth, kmutex_t **lockp) |
34dc7c2f BB |
776 | { |
777 | uint64_t idx = BUF_HASH_INDEX(spa, dva, birth); | |
778 | kmutex_t *hash_lock = BUF_HASH_LOCK(idx); | |
779 | arc_buf_hdr_t *buf; | |
780 | ||
781 | mutex_enter(hash_lock); | |
782 | for (buf = buf_hash_table.ht_table[idx]; buf != NULL; | |
783 | buf = buf->b_hash_next) { | |
784 | if (BUF_EQUAL(spa, dva, birth, buf)) { | |
785 | *lockp = hash_lock; | |
786 | return (buf); | |
787 | } | |
788 | } | |
789 | mutex_exit(hash_lock); | |
790 | *lockp = NULL; | |
791 | return (NULL); | |
792 | } | |
793 | ||
794 | /* | |
795 | * Insert an entry into the hash table. If there is already an element | |
796 | * equal to elem in the hash table, then the already existing element | |
797 | * will be returned and the new element will not be inserted. | |
798 | * Otherwise returns NULL. | |
799 | */ | |
800 | static arc_buf_hdr_t * | |
801 | buf_hash_insert(arc_buf_hdr_t *buf, kmutex_t **lockp) | |
802 | { | |
803 | uint64_t idx = BUF_HASH_INDEX(buf->b_spa, &buf->b_dva, buf->b_birth); | |
804 | kmutex_t *hash_lock = BUF_HASH_LOCK(idx); | |
805 | arc_buf_hdr_t *fbuf; | |
806 | uint32_t i; | |
807 | ||
808 | ASSERT(!HDR_IN_HASH_TABLE(buf)); | |
809 | *lockp = hash_lock; | |
810 | mutex_enter(hash_lock); | |
811 | for (fbuf = buf_hash_table.ht_table[idx], i = 0; fbuf != NULL; | |
812 | fbuf = fbuf->b_hash_next, i++) { | |
813 | if (BUF_EQUAL(buf->b_spa, &buf->b_dva, buf->b_birth, fbuf)) | |
814 | return (fbuf); | |
815 | } | |
816 | ||
817 | buf->b_hash_next = buf_hash_table.ht_table[idx]; | |
818 | buf_hash_table.ht_table[idx] = buf; | |
819 | buf->b_flags |= ARC_IN_HASH_TABLE; | |
820 | ||
821 | /* collect some hash table performance data */ | |
822 | if (i > 0) { | |
823 | ARCSTAT_BUMP(arcstat_hash_collisions); | |
824 | if (i == 1) | |
825 | ARCSTAT_BUMP(arcstat_hash_chains); | |
826 | ||
827 | ARCSTAT_MAX(arcstat_hash_chain_max, i); | |
828 | } | |
829 | ||
830 | ARCSTAT_BUMP(arcstat_hash_elements); | |
831 | ARCSTAT_MAXSTAT(arcstat_hash_elements); | |
832 | ||
833 | return (NULL); | |
834 | } | |
835 | ||
836 | static void | |
837 | buf_hash_remove(arc_buf_hdr_t *buf) | |
838 | { | |
839 | arc_buf_hdr_t *fbuf, **bufp; | |
840 | uint64_t idx = BUF_HASH_INDEX(buf->b_spa, &buf->b_dva, buf->b_birth); | |
841 | ||
842 | ASSERT(MUTEX_HELD(BUF_HASH_LOCK(idx))); | |
843 | ASSERT(HDR_IN_HASH_TABLE(buf)); | |
844 | ||
845 | bufp = &buf_hash_table.ht_table[idx]; | |
846 | while ((fbuf = *bufp) != buf) { | |
847 | ASSERT(fbuf != NULL); | |
848 | bufp = &fbuf->b_hash_next; | |
849 | } | |
850 | *bufp = buf->b_hash_next; | |
851 | buf->b_hash_next = NULL; | |
852 | buf->b_flags &= ~ARC_IN_HASH_TABLE; | |
853 | ||
854 | /* collect some hash table performance data */ | |
855 | ARCSTAT_BUMPDOWN(arcstat_hash_elements); | |
856 | ||
857 | if (buf_hash_table.ht_table[idx] && | |
858 | buf_hash_table.ht_table[idx]->b_hash_next == NULL) | |
859 | ARCSTAT_BUMPDOWN(arcstat_hash_chains); | |
860 | } | |
861 | ||
862 | /* | |
863 | * Global data structures and functions for the buf kmem cache. | |
864 | */ | |
865 | static kmem_cache_t *hdr_cache; | |
866 | static kmem_cache_t *buf_cache; | |
867 | ||
868 | static void | |
869 | buf_fini(void) | |
870 | { | |
871 | int i; | |
872 | ||
00b46022 BB |
873 | #if defined(_KERNEL) && defined(HAVE_SPL) |
874 | /* Large allocations which do not require contiguous pages | |
875 | * should be using vmem_free() in the linux kernel */ | |
876 | vmem_free(buf_hash_table.ht_table, | |
877 | (buf_hash_table.ht_mask + 1) * sizeof (void *)); | |
878 | #else | |
34dc7c2f BB |
879 | kmem_free(buf_hash_table.ht_table, |
880 | (buf_hash_table.ht_mask + 1) * sizeof (void *)); | |
00b46022 | 881 | #endif |
34dc7c2f BB |
882 | for (i = 0; i < BUF_LOCKS; i++) |
883 | mutex_destroy(&buf_hash_table.ht_locks[i].ht_lock); | |
884 | kmem_cache_destroy(hdr_cache); | |
885 | kmem_cache_destroy(buf_cache); | |
886 | } | |
887 | ||
888 | /* | |
889 | * Constructor callback - called when the cache is empty | |
890 | * and a new buf is requested. | |
891 | */ | |
892 | /* ARGSUSED */ | |
893 | static int | |
894 | hdr_cons(void *vbuf, void *unused, int kmflag) | |
895 | { | |
896 | arc_buf_hdr_t *buf = vbuf; | |
897 | ||
898 | bzero(buf, sizeof (arc_buf_hdr_t)); | |
899 | refcount_create(&buf->b_refcnt); | |
900 | cv_init(&buf->b_cv, NULL, CV_DEFAULT, NULL); | |
901 | mutex_init(&buf->b_freeze_lock, NULL, MUTEX_DEFAULT, NULL); | |
98f72a53 BB |
902 | list_link_init(&buf->b_arc_node); |
903 | list_link_init(&buf->b_l2node); | |
d164b209 | 904 | arc_space_consume(sizeof (arc_buf_hdr_t), ARC_SPACE_HDRS); |
34dc7c2f | 905 | |
34dc7c2f BB |
906 | return (0); |
907 | } | |
908 | ||
b128c09f BB |
909 | /* ARGSUSED */ |
910 | static int | |
911 | buf_cons(void *vbuf, void *unused, int kmflag) | |
912 | { | |
913 | arc_buf_t *buf = vbuf; | |
914 | ||
915 | bzero(buf, sizeof (arc_buf_t)); | |
428870ff | 916 | mutex_init(&buf->b_evict_lock, NULL, MUTEX_DEFAULT, NULL); |
d164b209 BB |
917 | arc_space_consume(sizeof (arc_buf_t), ARC_SPACE_HDRS); |
918 | ||
b128c09f BB |
919 | return (0); |
920 | } | |
921 | ||
34dc7c2f BB |
922 | /* |
923 | * Destructor callback - called when a cached buf is | |
924 | * no longer required. | |
925 | */ | |
926 | /* ARGSUSED */ | |
927 | static void | |
928 | hdr_dest(void *vbuf, void *unused) | |
929 | { | |
930 | arc_buf_hdr_t *buf = vbuf; | |
931 | ||
428870ff | 932 | ASSERT(BUF_EMPTY(buf)); |
34dc7c2f BB |
933 | refcount_destroy(&buf->b_refcnt); |
934 | cv_destroy(&buf->b_cv); | |
935 | mutex_destroy(&buf->b_freeze_lock); | |
d164b209 | 936 | arc_space_return(sizeof (arc_buf_hdr_t), ARC_SPACE_HDRS); |
34dc7c2f BB |
937 | } |
938 | ||
b128c09f BB |
939 | /* ARGSUSED */ |
940 | static void | |
941 | buf_dest(void *vbuf, void *unused) | |
942 | { | |
943 | arc_buf_t *buf = vbuf; | |
944 | ||
428870ff | 945 | mutex_destroy(&buf->b_evict_lock); |
d164b209 | 946 | arc_space_return(sizeof (arc_buf_t), ARC_SPACE_HDRS); |
b128c09f BB |
947 | } |
948 | ||
34dc7c2f BB |
949 | static void |
950 | buf_init(void) | |
951 | { | |
952 | uint64_t *ct; | |
953 | uint64_t hsize = 1ULL << 12; | |
954 | int i, j; | |
955 | ||
956 | /* | |
957 | * The hash table is big enough to fill all of physical memory | |
958 | * with an average 64K block size. The table will take up | |
959 | * totalmem*sizeof(void*)/64K (eg. 128KB/GB with 8-byte pointers). | |
960 | */ | |
961 | while (hsize * 65536 < physmem * PAGESIZE) | |
962 | hsize <<= 1; | |
963 | retry: | |
964 | buf_hash_table.ht_mask = hsize - 1; | |
00b46022 BB |
965 | #if defined(_KERNEL) && defined(HAVE_SPL) |
966 | /* Large allocations which do not require contiguous pages | |
967 | * should be using vmem_alloc() in the linux kernel */ | |
968 | buf_hash_table.ht_table = | |
969 | vmem_zalloc(hsize * sizeof (void*), KM_SLEEP); | |
970 | #else | |
34dc7c2f BB |
971 | buf_hash_table.ht_table = |
972 | kmem_zalloc(hsize * sizeof (void*), KM_NOSLEEP); | |
00b46022 | 973 | #endif |
34dc7c2f BB |
974 | if (buf_hash_table.ht_table == NULL) { |
975 | ASSERT(hsize > (1ULL << 8)); | |
976 | hsize >>= 1; | |
977 | goto retry; | |
978 | } | |
979 | ||
980 | hdr_cache = kmem_cache_create("arc_buf_hdr_t", sizeof (arc_buf_hdr_t), | |
302f753f | 981 | 0, hdr_cons, hdr_dest, NULL, NULL, NULL, 0); |
34dc7c2f | 982 | buf_cache = kmem_cache_create("arc_buf_t", sizeof (arc_buf_t), |
b128c09f | 983 | 0, buf_cons, buf_dest, NULL, NULL, NULL, 0); |
34dc7c2f BB |
984 | |
985 | for (i = 0; i < 256; i++) | |
986 | for (ct = zfs_crc64_table + i, *ct = i, j = 8; j > 0; j--) | |
987 | *ct = (*ct >> 1) ^ (-(*ct & 1) & ZFS_CRC64_POLY); | |
988 | ||
989 | for (i = 0; i < BUF_LOCKS; i++) { | |
990 | mutex_init(&buf_hash_table.ht_locks[i].ht_lock, | |
991 | NULL, MUTEX_DEFAULT, NULL); | |
992 | } | |
993 | } | |
994 | ||
995 | #define ARC_MINTIME (hz>>4) /* 62 ms */ | |
996 | ||
997 | static void | |
998 | arc_cksum_verify(arc_buf_t *buf) | |
999 | { | |
1000 | zio_cksum_t zc; | |
1001 | ||
1002 | if (!(zfs_flags & ZFS_DEBUG_MODIFY)) | |
1003 | return; | |
1004 | ||
1005 | mutex_enter(&buf->b_hdr->b_freeze_lock); | |
1006 | if (buf->b_hdr->b_freeze_cksum == NULL || | |
1007 | (buf->b_hdr->b_flags & ARC_IO_ERROR)) { | |
1008 | mutex_exit(&buf->b_hdr->b_freeze_lock); | |
1009 | return; | |
1010 | } | |
1011 | fletcher_2_native(buf->b_data, buf->b_hdr->b_size, &zc); | |
1012 | if (!ZIO_CHECKSUM_EQUAL(*buf->b_hdr->b_freeze_cksum, zc)) | |
1013 | panic("buffer modified while frozen!"); | |
1014 | mutex_exit(&buf->b_hdr->b_freeze_lock); | |
1015 | } | |
1016 | ||
1017 | static int | |
1018 | arc_cksum_equal(arc_buf_t *buf) | |
1019 | { | |
1020 | zio_cksum_t zc; | |
1021 | int equal; | |
1022 | ||
1023 | mutex_enter(&buf->b_hdr->b_freeze_lock); | |
1024 | fletcher_2_native(buf->b_data, buf->b_hdr->b_size, &zc); | |
1025 | equal = ZIO_CHECKSUM_EQUAL(*buf->b_hdr->b_freeze_cksum, zc); | |
1026 | mutex_exit(&buf->b_hdr->b_freeze_lock); | |
1027 | ||
1028 | return (equal); | |
1029 | } | |
1030 | ||
1031 | static void | |
1032 | arc_cksum_compute(arc_buf_t *buf, boolean_t force) | |
1033 | { | |
1034 | if (!force && !(zfs_flags & ZFS_DEBUG_MODIFY)) | |
1035 | return; | |
1036 | ||
1037 | mutex_enter(&buf->b_hdr->b_freeze_lock); | |
1038 | if (buf->b_hdr->b_freeze_cksum != NULL) { | |
1039 | mutex_exit(&buf->b_hdr->b_freeze_lock); | |
1040 | return; | |
1041 | } | |
409dc1a5 PS |
1042 | buf->b_hdr->b_freeze_cksum = kmem_alloc(sizeof (zio_cksum_t), |
1043 | KM_PUSHPAGE); | |
34dc7c2f BB |
1044 | fletcher_2_native(buf->b_data, buf->b_hdr->b_size, |
1045 | buf->b_hdr->b_freeze_cksum); | |
1046 | mutex_exit(&buf->b_hdr->b_freeze_lock); | |
1047 | } | |
1048 | ||
1049 | void | |
1050 | arc_buf_thaw(arc_buf_t *buf) | |
1051 | { | |
1052 | if (zfs_flags & ZFS_DEBUG_MODIFY) { | |
1053 | if (buf->b_hdr->b_state != arc_anon) | |
1054 | panic("modifying non-anon buffer!"); | |
1055 | if (buf->b_hdr->b_flags & ARC_IO_IN_PROGRESS) | |
1056 | panic("modifying buffer while i/o in progress!"); | |
1057 | arc_cksum_verify(buf); | |
1058 | } | |
1059 | ||
1060 | mutex_enter(&buf->b_hdr->b_freeze_lock); | |
1061 | if (buf->b_hdr->b_freeze_cksum != NULL) { | |
1062 | kmem_free(buf->b_hdr->b_freeze_cksum, sizeof (zio_cksum_t)); | |
1063 | buf->b_hdr->b_freeze_cksum = NULL; | |
1064 | } | |
428870ff | 1065 | |
34dc7c2f BB |
1066 | mutex_exit(&buf->b_hdr->b_freeze_lock); |
1067 | } | |
1068 | ||
1069 | void | |
1070 | arc_buf_freeze(arc_buf_t *buf) | |
1071 | { | |
428870ff BB |
1072 | kmutex_t *hash_lock; |
1073 | ||
34dc7c2f BB |
1074 | if (!(zfs_flags & ZFS_DEBUG_MODIFY)) |
1075 | return; | |
1076 | ||
428870ff BB |
1077 | hash_lock = HDR_LOCK(buf->b_hdr); |
1078 | mutex_enter(hash_lock); | |
1079 | ||
34dc7c2f BB |
1080 | ASSERT(buf->b_hdr->b_freeze_cksum != NULL || |
1081 | buf->b_hdr->b_state == arc_anon); | |
1082 | arc_cksum_compute(buf, B_FALSE); | |
428870ff | 1083 | mutex_exit(hash_lock); |
34dc7c2f BB |
1084 | } |
1085 | ||
1086 | static void | |
1087 | add_reference(arc_buf_hdr_t *ab, kmutex_t *hash_lock, void *tag) | |
1088 | { | |
1089 | ASSERT(MUTEX_HELD(hash_lock)); | |
1090 | ||
1091 | if ((refcount_add(&ab->b_refcnt, tag) == 1) && | |
1092 | (ab->b_state != arc_anon)) { | |
1093 | uint64_t delta = ab->b_size * ab->b_datacnt; | |
1094 | list_t *list = &ab->b_state->arcs_list[ab->b_type]; | |
1095 | uint64_t *size = &ab->b_state->arcs_lsize[ab->b_type]; | |
1096 | ||
1097 | ASSERT(!MUTEX_HELD(&ab->b_state->arcs_mtx)); | |
1098 | mutex_enter(&ab->b_state->arcs_mtx); | |
1099 | ASSERT(list_link_active(&ab->b_arc_node)); | |
1100 | list_remove(list, ab); | |
1101 | if (GHOST_STATE(ab->b_state)) { | |
c06d4368 | 1102 | ASSERT0(ab->b_datacnt); |
34dc7c2f BB |
1103 | ASSERT3P(ab->b_buf, ==, NULL); |
1104 | delta = ab->b_size; | |
1105 | } | |
1106 | ASSERT(delta > 0); | |
1107 | ASSERT3U(*size, >=, delta); | |
1108 | atomic_add_64(size, -delta); | |
1109 | mutex_exit(&ab->b_state->arcs_mtx); | |
b128c09f | 1110 | /* remove the prefetch flag if we get a reference */ |
34dc7c2f BB |
1111 | if (ab->b_flags & ARC_PREFETCH) |
1112 | ab->b_flags &= ~ARC_PREFETCH; | |
1113 | } | |
1114 | } | |
1115 | ||
1116 | static int | |
1117 | remove_reference(arc_buf_hdr_t *ab, kmutex_t *hash_lock, void *tag) | |
1118 | { | |
1119 | int cnt; | |
1120 | arc_state_t *state = ab->b_state; | |
1121 | ||
1122 | ASSERT(state == arc_anon || MUTEX_HELD(hash_lock)); | |
1123 | ASSERT(!GHOST_STATE(state)); | |
1124 | ||
1125 | if (((cnt = refcount_remove(&ab->b_refcnt, tag)) == 0) && | |
1126 | (state != arc_anon)) { | |
1127 | uint64_t *size = &state->arcs_lsize[ab->b_type]; | |
1128 | ||
1129 | ASSERT(!MUTEX_HELD(&state->arcs_mtx)); | |
1130 | mutex_enter(&state->arcs_mtx); | |
1131 | ASSERT(!list_link_active(&ab->b_arc_node)); | |
1132 | list_insert_head(&state->arcs_list[ab->b_type], ab); | |
1133 | ASSERT(ab->b_datacnt > 0); | |
1134 | atomic_add_64(size, ab->b_size * ab->b_datacnt); | |
1135 | mutex_exit(&state->arcs_mtx); | |
1136 | } | |
1137 | return (cnt); | |
1138 | } | |
1139 | ||
1140 | /* | |
1141 | * Move the supplied buffer to the indicated state. The mutex | |
1142 | * for the buffer must be held by the caller. | |
1143 | */ | |
1144 | static void | |
1145 | arc_change_state(arc_state_t *new_state, arc_buf_hdr_t *ab, kmutex_t *hash_lock) | |
1146 | { | |
1147 | arc_state_t *old_state = ab->b_state; | |
1148 | int64_t refcnt = refcount_count(&ab->b_refcnt); | |
1149 | uint64_t from_delta, to_delta; | |
1150 | ||
1151 | ASSERT(MUTEX_HELD(hash_lock)); | |
1152 | ASSERT(new_state != old_state); | |
1153 | ASSERT(refcnt == 0 || ab->b_datacnt > 0); | |
1154 | ASSERT(ab->b_datacnt == 0 || !GHOST_STATE(new_state)); | |
428870ff | 1155 | ASSERT(ab->b_datacnt <= 1 || old_state != arc_anon); |
34dc7c2f BB |
1156 | |
1157 | from_delta = to_delta = ab->b_datacnt * ab->b_size; | |
1158 | ||
1159 | /* | |
1160 | * If this buffer is evictable, transfer it from the | |
1161 | * old state list to the new state list. | |
1162 | */ | |
1163 | if (refcnt == 0) { | |
1164 | if (old_state != arc_anon) { | |
1165 | int use_mutex = !MUTEX_HELD(&old_state->arcs_mtx); | |
1166 | uint64_t *size = &old_state->arcs_lsize[ab->b_type]; | |
1167 | ||
1168 | if (use_mutex) | |
1169 | mutex_enter(&old_state->arcs_mtx); | |
1170 | ||
1171 | ASSERT(list_link_active(&ab->b_arc_node)); | |
1172 | list_remove(&old_state->arcs_list[ab->b_type], ab); | |
1173 | ||
1174 | /* | |
1175 | * If prefetching out of the ghost cache, | |
428870ff | 1176 | * we will have a non-zero datacnt. |
34dc7c2f BB |
1177 | */ |
1178 | if (GHOST_STATE(old_state) && ab->b_datacnt == 0) { | |
1179 | /* ghost elements have a ghost size */ | |
1180 | ASSERT(ab->b_buf == NULL); | |
1181 | from_delta = ab->b_size; | |
1182 | } | |
1183 | ASSERT3U(*size, >=, from_delta); | |
1184 | atomic_add_64(size, -from_delta); | |
1185 | ||
1186 | if (use_mutex) | |
1187 | mutex_exit(&old_state->arcs_mtx); | |
1188 | } | |
1189 | if (new_state != arc_anon) { | |
1190 | int use_mutex = !MUTEX_HELD(&new_state->arcs_mtx); | |
1191 | uint64_t *size = &new_state->arcs_lsize[ab->b_type]; | |
1192 | ||
1193 | if (use_mutex) | |
1194 | mutex_enter(&new_state->arcs_mtx); | |
1195 | ||
1196 | list_insert_head(&new_state->arcs_list[ab->b_type], ab); | |
1197 | ||
1198 | /* ghost elements have a ghost size */ | |
1199 | if (GHOST_STATE(new_state)) { | |
1200 | ASSERT(ab->b_datacnt == 0); | |
1201 | ASSERT(ab->b_buf == NULL); | |
1202 | to_delta = ab->b_size; | |
1203 | } | |
1204 | atomic_add_64(size, to_delta); | |
1205 | ||
1206 | if (use_mutex) | |
1207 | mutex_exit(&new_state->arcs_mtx); | |
1208 | } | |
1209 | } | |
1210 | ||
1211 | ASSERT(!BUF_EMPTY(ab)); | |
428870ff | 1212 | if (new_state == arc_anon && HDR_IN_HASH_TABLE(ab)) |
34dc7c2f | 1213 | buf_hash_remove(ab); |
34dc7c2f BB |
1214 | |
1215 | /* adjust state sizes */ | |
1216 | if (to_delta) | |
1217 | atomic_add_64(&new_state->arcs_size, to_delta); | |
1218 | if (from_delta) { | |
1219 | ASSERT3U(old_state->arcs_size, >=, from_delta); | |
1220 | atomic_add_64(&old_state->arcs_size, -from_delta); | |
1221 | } | |
1222 | ab->b_state = new_state; | |
1223 | ||
1224 | /* adjust l2arc hdr stats */ | |
1225 | if (new_state == arc_l2c_only) | |
1226 | l2arc_hdr_stat_add(); | |
1227 | else if (old_state == arc_l2c_only) | |
1228 | l2arc_hdr_stat_remove(); | |
1229 | } | |
1230 | ||
1231 | void | |
d164b209 | 1232 | arc_space_consume(uint64_t space, arc_space_type_t type) |
34dc7c2f | 1233 | { |
d164b209 BB |
1234 | ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES); |
1235 | ||
1236 | switch (type) { | |
e75c13c3 BB |
1237 | default: |
1238 | break; | |
d164b209 BB |
1239 | case ARC_SPACE_DATA: |
1240 | ARCSTAT_INCR(arcstat_data_size, space); | |
1241 | break; | |
1242 | case ARC_SPACE_OTHER: | |
1243 | ARCSTAT_INCR(arcstat_other_size, space); | |
1244 | break; | |
1245 | case ARC_SPACE_HDRS: | |
1246 | ARCSTAT_INCR(arcstat_hdr_size, space); | |
1247 | break; | |
1248 | case ARC_SPACE_L2HDRS: | |
1249 | ARCSTAT_INCR(arcstat_l2_hdr_size, space); | |
1250 | break; | |
1251 | } | |
1252 | ||
34dc7c2f BB |
1253 | atomic_add_64(&arc_meta_used, space); |
1254 | atomic_add_64(&arc_size, space); | |
1255 | } | |
1256 | ||
1257 | void | |
d164b209 | 1258 | arc_space_return(uint64_t space, arc_space_type_t type) |
34dc7c2f | 1259 | { |
d164b209 BB |
1260 | ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES); |
1261 | ||
1262 | switch (type) { | |
e75c13c3 BB |
1263 | default: |
1264 | break; | |
d164b209 BB |
1265 | case ARC_SPACE_DATA: |
1266 | ARCSTAT_INCR(arcstat_data_size, -space); | |
1267 | break; | |
1268 | case ARC_SPACE_OTHER: | |
1269 | ARCSTAT_INCR(arcstat_other_size, -space); | |
1270 | break; | |
1271 | case ARC_SPACE_HDRS: | |
1272 | ARCSTAT_INCR(arcstat_hdr_size, -space); | |
1273 | break; | |
1274 | case ARC_SPACE_L2HDRS: | |
1275 | ARCSTAT_INCR(arcstat_l2_hdr_size, -space); | |
1276 | break; | |
1277 | } | |
1278 | ||
34dc7c2f BB |
1279 | ASSERT(arc_meta_used >= space); |
1280 | if (arc_meta_max < arc_meta_used) | |
1281 | arc_meta_max = arc_meta_used; | |
1282 | atomic_add_64(&arc_meta_used, -space); | |
1283 | ASSERT(arc_size >= space); | |
1284 | atomic_add_64(&arc_size, -space); | |
1285 | } | |
1286 | ||
34dc7c2f BB |
1287 | arc_buf_t * |
1288 | arc_buf_alloc(spa_t *spa, int size, void *tag, arc_buf_contents_t type) | |
1289 | { | |
1290 | arc_buf_hdr_t *hdr; | |
1291 | arc_buf_t *buf; | |
1292 | ||
1293 | ASSERT3U(size, >, 0); | |
1294 | hdr = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); | |
1295 | ASSERT(BUF_EMPTY(hdr)); | |
1296 | hdr->b_size = size; | |
1297 | hdr->b_type = type; | |
3541dc6d | 1298 | hdr->b_spa = spa_load_guid(spa); |
34dc7c2f BB |
1299 | hdr->b_state = arc_anon; |
1300 | hdr->b_arc_access = 0; | |
1301 | buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); | |
1302 | buf->b_hdr = hdr; | |
1303 | buf->b_data = NULL; | |
1304 | buf->b_efunc = NULL; | |
1305 | buf->b_private = NULL; | |
1306 | buf->b_next = NULL; | |
1307 | hdr->b_buf = buf; | |
1308 | arc_get_data_buf(buf); | |
1309 | hdr->b_datacnt = 1; | |
1310 | hdr->b_flags = 0; | |
1311 | ASSERT(refcount_is_zero(&hdr->b_refcnt)); | |
1312 | (void) refcount_add(&hdr->b_refcnt, tag); | |
1313 | ||
1314 | return (buf); | |
1315 | } | |
1316 | ||
9babb374 BB |
1317 | static char *arc_onloan_tag = "onloan"; |
1318 | ||
1319 | /* | |
1320 | * Loan out an anonymous arc buffer. Loaned buffers are not counted as in | |
1321 | * flight data by arc_tempreserve_space() until they are "returned". Loaned | |
1322 | * buffers must be returned to the arc before they can be used by the DMU or | |
1323 | * freed. | |
1324 | */ | |
1325 | arc_buf_t * | |
1326 | arc_loan_buf(spa_t *spa, int size) | |
1327 | { | |
1328 | arc_buf_t *buf; | |
1329 | ||
1330 | buf = arc_buf_alloc(spa, size, arc_onloan_tag, ARC_BUFC_DATA); | |
1331 | ||
1332 | atomic_add_64(&arc_loaned_bytes, size); | |
1333 | return (buf); | |
1334 | } | |
1335 | ||
1336 | /* | |
1337 | * Return a loaned arc buffer to the arc. | |
1338 | */ | |
1339 | void | |
1340 | arc_return_buf(arc_buf_t *buf, void *tag) | |
1341 | { | |
1342 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
1343 | ||
9babb374 | 1344 | ASSERT(buf->b_data != NULL); |
428870ff BB |
1345 | (void) refcount_add(&hdr->b_refcnt, tag); |
1346 | (void) refcount_remove(&hdr->b_refcnt, arc_onloan_tag); | |
9babb374 BB |
1347 | |
1348 | atomic_add_64(&arc_loaned_bytes, -hdr->b_size); | |
1349 | } | |
1350 | ||
428870ff BB |
1351 | /* Detach an arc_buf from a dbuf (tag) */ |
1352 | void | |
1353 | arc_loan_inuse_buf(arc_buf_t *buf, void *tag) | |
1354 | { | |
1355 | arc_buf_hdr_t *hdr; | |
1356 | ||
1357 | ASSERT(buf->b_data != NULL); | |
1358 | hdr = buf->b_hdr; | |
1359 | (void) refcount_add(&hdr->b_refcnt, arc_onloan_tag); | |
1360 | (void) refcount_remove(&hdr->b_refcnt, tag); | |
1361 | buf->b_efunc = NULL; | |
1362 | buf->b_private = NULL; | |
1363 | ||
1364 | atomic_add_64(&arc_loaned_bytes, hdr->b_size); | |
1365 | } | |
1366 | ||
34dc7c2f BB |
1367 | static arc_buf_t * |
1368 | arc_buf_clone(arc_buf_t *from) | |
1369 | { | |
1370 | arc_buf_t *buf; | |
1371 | arc_buf_hdr_t *hdr = from->b_hdr; | |
1372 | uint64_t size = hdr->b_size; | |
1373 | ||
428870ff BB |
1374 | ASSERT(hdr->b_state != arc_anon); |
1375 | ||
34dc7c2f BB |
1376 | buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); |
1377 | buf->b_hdr = hdr; | |
1378 | buf->b_data = NULL; | |
1379 | buf->b_efunc = NULL; | |
1380 | buf->b_private = NULL; | |
1381 | buf->b_next = hdr->b_buf; | |
1382 | hdr->b_buf = buf; | |
1383 | arc_get_data_buf(buf); | |
1384 | bcopy(from->b_data, buf->b_data, size); | |
1eb5bfa3 GW |
1385 | |
1386 | /* | |
1387 | * This buffer already exists in the arc so create a duplicate | |
1388 | * copy for the caller. If the buffer is associated with user data | |
1389 | * then track the size and number of duplicates. These stats will be | |
1390 | * updated as duplicate buffers are created and destroyed. | |
1391 | */ | |
1392 | if (hdr->b_type == ARC_BUFC_DATA) { | |
1393 | ARCSTAT_BUMP(arcstat_duplicate_buffers); | |
1394 | ARCSTAT_INCR(arcstat_duplicate_buffers_size, size); | |
1395 | } | |
34dc7c2f BB |
1396 | hdr->b_datacnt += 1; |
1397 | return (buf); | |
1398 | } | |
1399 | ||
1400 | void | |
1401 | arc_buf_add_ref(arc_buf_t *buf, void* tag) | |
1402 | { | |
1403 | arc_buf_hdr_t *hdr; | |
1404 | kmutex_t *hash_lock; | |
1405 | ||
1406 | /* | |
b128c09f BB |
1407 | * Check to see if this buffer is evicted. Callers |
1408 | * must verify b_data != NULL to know if the add_ref | |
1409 | * was successful. | |
34dc7c2f | 1410 | */ |
428870ff | 1411 | mutex_enter(&buf->b_evict_lock); |
b128c09f | 1412 | if (buf->b_data == NULL) { |
428870ff | 1413 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
1414 | return; |
1415 | } | |
428870ff | 1416 | hash_lock = HDR_LOCK(buf->b_hdr); |
34dc7c2f | 1417 | mutex_enter(hash_lock); |
428870ff BB |
1418 | hdr = buf->b_hdr; |
1419 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
1420 | mutex_exit(&buf->b_evict_lock); | |
34dc7c2f | 1421 | |
34dc7c2f BB |
1422 | ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); |
1423 | add_reference(hdr, hash_lock, tag); | |
d164b209 | 1424 | DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr); |
34dc7c2f BB |
1425 | arc_access(hdr, hash_lock); |
1426 | mutex_exit(hash_lock); | |
1427 | ARCSTAT_BUMP(arcstat_hits); | |
1428 | ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), | |
1429 | demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, | |
1430 | data, metadata, hits); | |
1431 | } | |
1432 | ||
1433 | /* | |
1434 | * Free the arc data buffer. If it is an l2arc write in progress, | |
1435 | * the buffer is placed on l2arc_free_on_write to be freed later. | |
1436 | */ | |
1437 | static void | |
1438 | arc_buf_data_free(arc_buf_hdr_t *hdr, void (*free_func)(void *, size_t), | |
1439 | void *data, size_t size) | |
1440 | { | |
1441 | if (HDR_L2_WRITING(hdr)) { | |
1442 | l2arc_data_free_t *df; | |
594b4dd8 | 1443 | df = kmem_alloc(sizeof (l2arc_data_free_t), KM_PUSHPAGE); |
34dc7c2f BB |
1444 | df->l2df_data = data; |
1445 | df->l2df_size = size; | |
1446 | df->l2df_func = free_func; | |
1447 | mutex_enter(&l2arc_free_on_write_mtx); | |
1448 | list_insert_head(l2arc_free_on_write, df); | |
1449 | mutex_exit(&l2arc_free_on_write_mtx); | |
1450 | ARCSTAT_BUMP(arcstat_l2_free_on_write); | |
1451 | } else { | |
1452 | free_func(data, size); | |
1453 | } | |
1454 | } | |
1455 | ||
1456 | static void | |
1457 | arc_buf_destroy(arc_buf_t *buf, boolean_t recycle, boolean_t all) | |
1458 | { | |
1459 | arc_buf_t **bufp; | |
1460 | ||
1461 | /* free up data associated with the buf */ | |
1462 | if (buf->b_data) { | |
1463 | arc_state_t *state = buf->b_hdr->b_state; | |
1464 | uint64_t size = buf->b_hdr->b_size; | |
1465 | arc_buf_contents_t type = buf->b_hdr->b_type; | |
1466 | ||
1467 | arc_cksum_verify(buf); | |
428870ff | 1468 | |
34dc7c2f BB |
1469 | if (!recycle) { |
1470 | if (type == ARC_BUFC_METADATA) { | |
1471 | arc_buf_data_free(buf->b_hdr, zio_buf_free, | |
1472 | buf->b_data, size); | |
d164b209 | 1473 | arc_space_return(size, ARC_SPACE_DATA); |
34dc7c2f BB |
1474 | } else { |
1475 | ASSERT(type == ARC_BUFC_DATA); | |
1476 | arc_buf_data_free(buf->b_hdr, | |
1477 | zio_data_buf_free, buf->b_data, size); | |
d164b209 | 1478 | ARCSTAT_INCR(arcstat_data_size, -size); |
34dc7c2f BB |
1479 | atomic_add_64(&arc_size, -size); |
1480 | } | |
1481 | } | |
1482 | if (list_link_active(&buf->b_hdr->b_arc_node)) { | |
1483 | uint64_t *cnt = &state->arcs_lsize[type]; | |
1484 | ||
1485 | ASSERT(refcount_is_zero(&buf->b_hdr->b_refcnt)); | |
1486 | ASSERT(state != arc_anon); | |
1487 | ||
1488 | ASSERT3U(*cnt, >=, size); | |
1489 | atomic_add_64(cnt, -size); | |
1490 | } | |
1491 | ASSERT3U(state->arcs_size, >=, size); | |
1492 | atomic_add_64(&state->arcs_size, -size); | |
1493 | buf->b_data = NULL; | |
1eb5bfa3 GW |
1494 | |
1495 | /* | |
1496 | * If we're destroying a duplicate buffer make sure | |
1497 | * that the appropriate statistics are updated. | |
1498 | */ | |
1499 | if (buf->b_hdr->b_datacnt > 1 && | |
1500 | buf->b_hdr->b_type == ARC_BUFC_DATA) { | |
1501 | ARCSTAT_BUMPDOWN(arcstat_duplicate_buffers); | |
1502 | ARCSTAT_INCR(arcstat_duplicate_buffers_size, -size); | |
1503 | } | |
34dc7c2f BB |
1504 | ASSERT(buf->b_hdr->b_datacnt > 0); |
1505 | buf->b_hdr->b_datacnt -= 1; | |
1506 | } | |
1507 | ||
1508 | /* only remove the buf if requested */ | |
1509 | if (!all) | |
1510 | return; | |
1511 | ||
1512 | /* remove the buf from the hdr list */ | |
1513 | for (bufp = &buf->b_hdr->b_buf; *bufp != buf; bufp = &(*bufp)->b_next) | |
1514 | continue; | |
1515 | *bufp = buf->b_next; | |
428870ff | 1516 | buf->b_next = NULL; |
34dc7c2f BB |
1517 | |
1518 | ASSERT(buf->b_efunc == NULL); | |
1519 | ||
1520 | /* clean up the buf */ | |
1521 | buf->b_hdr = NULL; | |
1522 | kmem_cache_free(buf_cache, buf); | |
1523 | } | |
1524 | ||
1525 | static void | |
1526 | arc_hdr_destroy(arc_buf_hdr_t *hdr) | |
1527 | { | |
d6320ddb BB |
1528 | l2arc_buf_hdr_t *l2hdr = hdr->b_l2hdr; |
1529 | ||
34dc7c2f BB |
1530 | ASSERT(refcount_is_zero(&hdr->b_refcnt)); |
1531 | ASSERT3P(hdr->b_state, ==, arc_anon); | |
1532 | ASSERT(!HDR_IO_IN_PROGRESS(hdr)); | |
1533 | ||
428870ff BB |
1534 | if (l2hdr != NULL) { |
1535 | boolean_t buflist_held = MUTEX_HELD(&l2arc_buflist_mtx); | |
1536 | /* | |
1537 | * To prevent arc_free() and l2arc_evict() from | |
1538 | * attempting to free the same buffer at the same time, | |
1539 | * a FREE_IN_PROGRESS flag is given to arc_free() to | |
1540 | * give it priority. l2arc_evict() can't destroy this | |
1541 | * header while we are waiting on l2arc_buflist_mtx. | |
1542 | * | |
1543 | * The hdr may be removed from l2ad_buflist before we | |
1544 | * grab l2arc_buflist_mtx, so b_l2hdr is rechecked. | |
1545 | */ | |
1546 | if (!buflist_held) { | |
34dc7c2f | 1547 | mutex_enter(&l2arc_buflist_mtx); |
428870ff | 1548 | l2hdr = hdr->b_l2hdr; |
34dc7c2f | 1549 | } |
428870ff BB |
1550 | |
1551 | if (l2hdr != NULL) { | |
1552 | list_remove(l2hdr->b_dev->l2ad_buflist, hdr); | |
1553 | ARCSTAT_INCR(arcstat_l2_size, -hdr->b_size); | |
c06d4368 | 1554 | ARCSTAT_INCR(arcstat_l2_asize, -l2hdr->b_asize); |
428870ff | 1555 | kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t)); |
c06d4368 | 1556 | arc_space_return(L2HDR_SIZE, ARC_SPACE_L2HDRS); |
428870ff BB |
1557 | if (hdr->b_state == arc_l2c_only) |
1558 | l2arc_hdr_stat_remove(); | |
1559 | hdr->b_l2hdr = NULL; | |
1560 | } | |
1561 | ||
1562 | if (!buflist_held) | |
1563 | mutex_exit(&l2arc_buflist_mtx); | |
34dc7c2f BB |
1564 | } |
1565 | ||
1566 | if (!BUF_EMPTY(hdr)) { | |
1567 | ASSERT(!HDR_IN_HASH_TABLE(hdr)); | |
428870ff | 1568 | buf_discard_identity(hdr); |
34dc7c2f BB |
1569 | } |
1570 | while (hdr->b_buf) { | |
1571 | arc_buf_t *buf = hdr->b_buf; | |
1572 | ||
1573 | if (buf->b_efunc) { | |
1574 | mutex_enter(&arc_eviction_mtx); | |
428870ff | 1575 | mutex_enter(&buf->b_evict_lock); |
34dc7c2f BB |
1576 | ASSERT(buf->b_hdr != NULL); |
1577 | arc_buf_destroy(hdr->b_buf, FALSE, FALSE); | |
1578 | hdr->b_buf = buf->b_next; | |
1579 | buf->b_hdr = &arc_eviction_hdr; | |
1580 | buf->b_next = arc_eviction_list; | |
1581 | arc_eviction_list = buf; | |
428870ff | 1582 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
1583 | mutex_exit(&arc_eviction_mtx); |
1584 | } else { | |
1585 | arc_buf_destroy(hdr->b_buf, FALSE, TRUE); | |
1586 | } | |
1587 | } | |
1588 | if (hdr->b_freeze_cksum != NULL) { | |
1589 | kmem_free(hdr->b_freeze_cksum, sizeof (zio_cksum_t)); | |
1590 | hdr->b_freeze_cksum = NULL; | |
1591 | } | |
1592 | ||
1593 | ASSERT(!list_link_active(&hdr->b_arc_node)); | |
1594 | ASSERT3P(hdr->b_hash_next, ==, NULL); | |
1595 | ASSERT3P(hdr->b_acb, ==, NULL); | |
1596 | kmem_cache_free(hdr_cache, hdr); | |
1597 | } | |
1598 | ||
1599 | void | |
1600 | arc_buf_free(arc_buf_t *buf, void *tag) | |
1601 | { | |
1602 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
1603 | int hashed = hdr->b_state != arc_anon; | |
1604 | ||
1605 | ASSERT(buf->b_efunc == NULL); | |
1606 | ASSERT(buf->b_data != NULL); | |
1607 | ||
1608 | if (hashed) { | |
1609 | kmutex_t *hash_lock = HDR_LOCK(hdr); | |
1610 | ||
1611 | mutex_enter(hash_lock); | |
428870ff BB |
1612 | hdr = buf->b_hdr; |
1613 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
1614 | ||
34dc7c2f | 1615 | (void) remove_reference(hdr, hash_lock, tag); |
428870ff | 1616 | if (hdr->b_datacnt > 1) { |
34dc7c2f | 1617 | arc_buf_destroy(buf, FALSE, TRUE); |
428870ff BB |
1618 | } else { |
1619 | ASSERT(buf == hdr->b_buf); | |
1620 | ASSERT(buf->b_efunc == NULL); | |
34dc7c2f | 1621 | hdr->b_flags |= ARC_BUF_AVAILABLE; |
428870ff | 1622 | } |
34dc7c2f BB |
1623 | mutex_exit(hash_lock); |
1624 | } else if (HDR_IO_IN_PROGRESS(hdr)) { | |
1625 | int destroy_hdr; | |
1626 | /* | |
1627 | * We are in the middle of an async write. Don't destroy | |
1628 | * this buffer unless the write completes before we finish | |
1629 | * decrementing the reference count. | |
1630 | */ | |
1631 | mutex_enter(&arc_eviction_mtx); | |
1632 | (void) remove_reference(hdr, NULL, tag); | |
1633 | ASSERT(refcount_is_zero(&hdr->b_refcnt)); | |
1634 | destroy_hdr = !HDR_IO_IN_PROGRESS(hdr); | |
1635 | mutex_exit(&arc_eviction_mtx); | |
1636 | if (destroy_hdr) | |
1637 | arc_hdr_destroy(hdr); | |
1638 | } else { | |
428870ff | 1639 | if (remove_reference(hdr, NULL, tag) > 0) |
34dc7c2f | 1640 | arc_buf_destroy(buf, FALSE, TRUE); |
428870ff | 1641 | else |
34dc7c2f | 1642 | arc_hdr_destroy(hdr); |
34dc7c2f BB |
1643 | } |
1644 | } | |
1645 | ||
1646 | int | |
1647 | arc_buf_remove_ref(arc_buf_t *buf, void* tag) | |
1648 | { | |
1649 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
c06d4368 | 1650 | kmutex_t *hash_lock = NULL; |
34dc7c2f BB |
1651 | int no_callback = (buf->b_efunc == NULL); |
1652 | ||
1653 | if (hdr->b_state == arc_anon) { | |
428870ff | 1654 | ASSERT(hdr->b_datacnt == 1); |
34dc7c2f BB |
1655 | arc_buf_free(buf, tag); |
1656 | return (no_callback); | |
1657 | } | |
1658 | ||
c06d4368 | 1659 | hash_lock = HDR_LOCK(hdr); |
34dc7c2f | 1660 | mutex_enter(hash_lock); |
428870ff BB |
1661 | hdr = buf->b_hdr; |
1662 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
34dc7c2f BB |
1663 | ASSERT(hdr->b_state != arc_anon); |
1664 | ASSERT(buf->b_data != NULL); | |
1665 | ||
1666 | (void) remove_reference(hdr, hash_lock, tag); | |
1667 | if (hdr->b_datacnt > 1) { | |
1668 | if (no_callback) | |
1669 | arc_buf_destroy(buf, FALSE, TRUE); | |
1670 | } else if (no_callback) { | |
1671 | ASSERT(hdr->b_buf == buf && buf->b_next == NULL); | |
428870ff | 1672 | ASSERT(buf->b_efunc == NULL); |
34dc7c2f BB |
1673 | hdr->b_flags |= ARC_BUF_AVAILABLE; |
1674 | } | |
1675 | ASSERT(no_callback || hdr->b_datacnt > 1 || | |
1676 | refcount_is_zero(&hdr->b_refcnt)); | |
1677 | mutex_exit(hash_lock); | |
1678 | return (no_callback); | |
1679 | } | |
1680 | ||
1681 | int | |
1682 | arc_buf_size(arc_buf_t *buf) | |
1683 | { | |
1684 | return (buf->b_hdr->b_size); | |
1685 | } | |
1686 | ||
1eb5bfa3 GW |
1687 | /* |
1688 | * Called from the DMU to determine if the current buffer should be | |
1689 | * evicted. In order to ensure proper locking, the eviction must be initiated | |
1690 | * from the DMU. Return true if the buffer is associated with user data and | |
1691 | * duplicate buffers still exist. | |
1692 | */ | |
1693 | boolean_t | |
1694 | arc_buf_eviction_needed(arc_buf_t *buf) | |
1695 | { | |
1696 | arc_buf_hdr_t *hdr; | |
1697 | boolean_t evict_needed = B_FALSE; | |
1698 | ||
1699 | if (zfs_disable_dup_eviction) | |
1700 | return (B_FALSE); | |
1701 | ||
1702 | mutex_enter(&buf->b_evict_lock); | |
1703 | hdr = buf->b_hdr; | |
1704 | if (hdr == NULL) { | |
1705 | /* | |
1706 | * We are in arc_do_user_evicts(); let that function | |
1707 | * perform the eviction. | |
1708 | */ | |
1709 | ASSERT(buf->b_data == NULL); | |
1710 | mutex_exit(&buf->b_evict_lock); | |
1711 | return (B_FALSE); | |
1712 | } else if (buf->b_data == NULL) { | |
1713 | /* | |
1714 | * We have already been added to the arc eviction list; | |
1715 | * recommend eviction. | |
1716 | */ | |
1717 | ASSERT3P(hdr, ==, &arc_eviction_hdr); | |
1718 | mutex_exit(&buf->b_evict_lock); | |
1719 | return (B_TRUE); | |
1720 | } | |
1721 | ||
1722 | if (hdr->b_datacnt > 1 && hdr->b_type == ARC_BUFC_DATA) | |
1723 | evict_needed = B_TRUE; | |
1724 | ||
1725 | mutex_exit(&buf->b_evict_lock); | |
1726 | return (evict_needed); | |
1727 | } | |
1728 | ||
34dc7c2f BB |
1729 | /* |
1730 | * Evict buffers from list until we've removed the specified number of | |
1731 | * bytes. Move the removed buffers to the appropriate evict state. | |
1732 | * If the recycle flag is set, then attempt to "recycle" a buffer: | |
1733 | * - look for a buffer to evict that is `bytes' long. | |
1734 | * - return the data block from this buffer rather than freeing it. | |
1735 | * This flag is used by callers that are trying to make space for a | |
1736 | * new buffer in a full arc cache. | |
1737 | * | |
1738 | * This function makes a "best effort". It skips over any buffers | |
1739 | * it can't get a hash_lock on, and so may not catch all candidates. | |
1740 | * It may also return without evicting as much space as requested. | |
1741 | */ | |
1742 | static void * | |
d164b209 | 1743 | arc_evict(arc_state_t *state, uint64_t spa, int64_t bytes, boolean_t recycle, |
34dc7c2f BB |
1744 | arc_buf_contents_t type) |
1745 | { | |
1746 | arc_state_t *evicted_state; | |
1747 | uint64_t bytes_evicted = 0, skipped = 0, missed = 0; | |
1748 | arc_buf_hdr_t *ab, *ab_prev = NULL; | |
1749 | list_t *list = &state->arcs_list[type]; | |
1750 | kmutex_t *hash_lock; | |
1751 | boolean_t have_lock; | |
1752 | void *stolen = NULL; | |
1753 | ||
1754 | ASSERT(state == arc_mru || state == arc_mfu); | |
1755 | ||
1756 | evicted_state = (state == arc_mru) ? arc_mru_ghost : arc_mfu_ghost; | |
1757 | ||
1758 | mutex_enter(&state->arcs_mtx); | |
1759 | mutex_enter(&evicted_state->arcs_mtx); | |
1760 | ||
1761 | for (ab = list_tail(list); ab; ab = ab_prev) { | |
1762 | ab_prev = list_prev(list, ab); | |
1763 | /* prefetch buffers have a minimum lifespan */ | |
1764 | if (HDR_IO_IN_PROGRESS(ab) || | |
1765 | (spa && ab->b_spa != spa) || | |
1766 | (ab->b_flags & (ARC_PREFETCH|ARC_INDIRECT) && | |
428870ff | 1767 | ddi_get_lbolt() - ab->b_arc_access < |
c06d4368 | 1768 | zfs_arc_min_prefetch_lifespan)) { |
34dc7c2f BB |
1769 | skipped++; |
1770 | continue; | |
1771 | } | |
1772 | /* "lookahead" for better eviction candidate */ | |
1773 | if (recycle && ab->b_size != bytes && | |
1774 | ab_prev && ab_prev->b_size == bytes) | |
1775 | continue; | |
1776 | hash_lock = HDR_LOCK(ab); | |
1777 | have_lock = MUTEX_HELD(hash_lock); | |
1778 | if (have_lock || mutex_tryenter(hash_lock)) { | |
c06d4368 | 1779 | ASSERT0(refcount_count(&ab->b_refcnt)); |
34dc7c2f BB |
1780 | ASSERT(ab->b_datacnt > 0); |
1781 | while (ab->b_buf) { | |
1782 | arc_buf_t *buf = ab->b_buf; | |
428870ff | 1783 | if (!mutex_tryenter(&buf->b_evict_lock)) { |
b128c09f BB |
1784 | missed += 1; |
1785 | break; | |
1786 | } | |
34dc7c2f BB |
1787 | if (buf->b_data) { |
1788 | bytes_evicted += ab->b_size; | |
1789 | if (recycle && ab->b_type == type && | |
1790 | ab->b_size == bytes && | |
1791 | !HDR_L2_WRITING(ab)) { | |
1792 | stolen = buf->b_data; | |
1793 | recycle = FALSE; | |
1794 | } | |
1795 | } | |
1796 | if (buf->b_efunc) { | |
1797 | mutex_enter(&arc_eviction_mtx); | |
1798 | arc_buf_destroy(buf, | |
1799 | buf->b_data == stolen, FALSE); | |
1800 | ab->b_buf = buf->b_next; | |
1801 | buf->b_hdr = &arc_eviction_hdr; | |
1802 | buf->b_next = arc_eviction_list; | |
1803 | arc_eviction_list = buf; | |
1804 | mutex_exit(&arc_eviction_mtx); | |
428870ff | 1805 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f | 1806 | } else { |
428870ff | 1807 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
1808 | arc_buf_destroy(buf, |
1809 | buf->b_data == stolen, TRUE); | |
1810 | } | |
1811 | } | |
428870ff BB |
1812 | |
1813 | if (ab->b_l2hdr) { | |
1814 | ARCSTAT_INCR(arcstat_evict_l2_cached, | |
1815 | ab->b_size); | |
1816 | } else { | |
1817 | if (l2arc_write_eligible(ab->b_spa, ab)) { | |
1818 | ARCSTAT_INCR(arcstat_evict_l2_eligible, | |
1819 | ab->b_size); | |
1820 | } else { | |
1821 | ARCSTAT_INCR( | |
1822 | arcstat_evict_l2_ineligible, | |
1823 | ab->b_size); | |
1824 | } | |
1825 | } | |
1826 | ||
b128c09f BB |
1827 | if (ab->b_datacnt == 0) { |
1828 | arc_change_state(evicted_state, ab, hash_lock); | |
1829 | ASSERT(HDR_IN_HASH_TABLE(ab)); | |
1830 | ab->b_flags |= ARC_IN_HASH_TABLE; | |
1831 | ab->b_flags &= ~ARC_BUF_AVAILABLE; | |
1832 | DTRACE_PROBE1(arc__evict, arc_buf_hdr_t *, ab); | |
1833 | } | |
34dc7c2f BB |
1834 | if (!have_lock) |
1835 | mutex_exit(hash_lock); | |
1836 | if (bytes >= 0 && bytes_evicted >= bytes) | |
1837 | break; | |
1838 | } else { | |
1839 | missed += 1; | |
1840 | } | |
1841 | } | |
1842 | ||
1843 | mutex_exit(&evicted_state->arcs_mtx); | |
1844 | mutex_exit(&state->arcs_mtx); | |
1845 | ||
1846 | if (bytes_evicted < bytes) | |
3f504482 | 1847 | dprintf("only evicted %lld bytes from %x\n", |
34dc7c2f BB |
1848 | (longlong_t)bytes_evicted, state); |
1849 | ||
1850 | if (skipped) | |
1851 | ARCSTAT_INCR(arcstat_evict_skip, skipped); | |
1852 | ||
1853 | if (missed) | |
1854 | ARCSTAT_INCR(arcstat_mutex_miss, missed); | |
1855 | ||
1856 | /* | |
1857 | * We have just evicted some date into the ghost state, make | |
1858 | * sure we also adjust the ghost state size if necessary. | |
1859 | */ | |
1860 | if (arc_no_grow && | |
1861 | arc_mru_ghost->arcs_size + arc_mfu_ghost->arcs_size > arc_c) { | |
1862 | int64_t mru_over = arc_anon->arcs_size + arc_mru->arcs_size + | |
1863 | arc_mru_ghost->arcs_size - arc_c; | |
1864 | ||
1865 | if (mru_over > 0 && arc_mru_ghost->arcs_lsize[type] > 0) { | |
1866 | int64_t todelete = | |
1867 | MIN(arc_mru_ghost->arcs_lsize[type], mru_over); | |
c06d4368 AX |
1868 | arc_evict_ghost(arc_mru_ghost, 0, todelete, |
1869 | ARC_BUFC_DATA); | |
34dc7c2f BB |
1870 | } else if (arc_mfu_ghost->arcs_lsize[type] > 0) { |
1871 | int64_t todelete = MIN(arc_mfu_ghost->arcs_lsize[type], | |
1872 | arc_mru_ghost->arcs_size + | |
1873 | arc_mfu_ghost->arcs_size - arc_c); | |
c06d4368 AX |
1874 | arc_evict_ghost(arc_mfu_ghost, 0, todelete, |
1875 | ARC_BUFC_DATA); | |
34dc7c2f BB |
1876 | } |
1877 | } | |
1878 | ||
1879 | return (stolen); | |
1880 | } | |
1881 | ||
1882 | /* | |
1883 | * Remove buffers from list until we've removed the specified number of | |
1884 | * bytes. Destroy the buffers that are removed. | |
1885 | */ | |
1886 | static void | |
c06d4368 AX |
1887 | arc_evict_ghost(arc_state_t *state, uint64_t spa, int64_t bytes, |
1888 | arc_buf_contents_t type) | |
34dc7c2f BB |
1889 | { |
1890 | arc_buf_hdr_t *ab, *ab_prev; | |
2598c001 | 1891 | arc_buf_hdr_t marker; |
c06d4368 | 1892 | list_t *list = &state->arcs_list[type]; |
34dc7c2f BB |
1893 | kmutex_t *hash_lock; |
1894 | uint64_t bytes_deleted = 0; | |
1895 | uint64_t bufs_skipped = 0; | |
1896 | ||
1897 | ASSERT(GHOST_STATE(state)); | |
2598c001 | 1898 | bzero(&marker, sizeof(marker)); |
34dc7c2f BB |
1899 | top: |
1900 | mutex_enter(&state->arcs_mtx); | |
1901 | for (ab = list_tail(list); ab; ab = ab_prev) { | |
1902 | ab_prev = list_prev(list, ab); | |
1903 | if (spa && ab->b_spa != spa) | |
1904 | continue; | |
572e2857 BB |
1905 | |
1906 | /* ignore markers */ | |
1907 | if (ab->b_spa == 0) | |
1908 | continue; | |
1909 | ||
34dc7c2f | 1910 | hash_lock = HDR_LOCK(ab); |
428870ff BB |
1911 | /* caller may be trying to modify this buffer, skip it */ |
1912 | if (MUTEX_HELD(hash_lock)) | |
1913 | continue; | |
34dc7c2f BB |
1914 | if (mutex_tryenter(hash_lock)) { |
1915 | ASSERT(!HDR_IO_IN_PROGRESS(ab)); | |
1916 | ASSERT(ab->b_buf == NULL); | |
1917 | ARCSTAT_BUMP(arcstat_deleted); | |
1918 | bytes_deleted += ab->b_size; | |
1919 | ||
1920 | if (ab->b_l2hdr != NULL) { | |
1921 | /* | |
1922 | * This buffer is cached on the 2nd Level ARC; | |
1923 | * don't destroy the header. | |
1924 | */ | |
1925 | arc_change_state(arc_l2c_only, ab, hash_lock); | |
1926 | mutex_exit(hash_lock); | |
1927 | } else { | |
1928 | arc_change_state(arc_anon, ab, hash_lock); | |
1929 | mutex_exit(hash_lock); | |
1930 | arc_hdr_destroy(ab); | |
1931 | } | |
1932 | ||
1933 | DTRACE_PROBE1(arc__delete, arc_buf_hdr_t *, ab); | |
1934 | if (bytes >= 0 && bytes_deleted >= bytes) | |
1935 | break; | |
572e2857 BB |
1936 | } else if (bytes < 0) { |
1937 | /* | |
1938 | * Insert a list marker and then wait for the | |
1939 | * hash lock to become available. Once its | |
1940 | * available, restart from where we left off. | |
1941 | */ | |
1942 | list_insert_after(list, ab, &marker); | |
1943 | mutex_exit(&state->arcs_mtx); | |
1944 | mutex_enter(hash_lock); | |
1945 | mutex_exit(hash_lock); | |
1946 | mutex_enter(&state->arcs_mtx); | |
1947 | ab_prev = list_prev(list, &marker); | |
1948 | list_remove(list, &marker); | |
1949 | } else | |
34dc7c2f | 1950 | bufs_skipped += 1; |
34dc7c2f BB |
1951 | } |
1952 | mutex_exit(&state->arcs_mtx); | |
1953 | ||
1954 | if (list == &state->arcs_list[ARC_BUFC_DATA] && | |
1955 | (bytes < 0 || bytes_deleted < bytes)) { | |
1956 | list = &state->arcs_list[ARC_BUFC_METADATA]; | |
1957 | goto top; | |
1958 | } | |
1959 | ||
1960 | if (bufs_skipped) { | |
1961 | ARCSTAT_INCR(arcstat_mutex_miss, bufs_skipped); | |
1962 | ASSERT(bytes >= 0); | |
1963 | } | |
1964 | ||
1965 | if (bytes_deleted < bytes) | |
3f504482 | 1966 | dprintf("only deleted %lld bytes from %p\n", |
34dc7c2f BB |
1967 | (longlong_t)bytes_deleted, state); |
1968 | } | |
1969 | ||
1970 | static void | |
1971 | arc_adjust(void) | |
1972 | { | |
d164b209 BB |
1973 | int64_t adjustment, delta; |
1974 | ||
1975 | /* | |
1976 | * Adjust MRU size | |
1977 | */ | |
34dc7c2f | 1978 | |
572e2857 BB |
1979 | adjustment = MIN((int64_t)(arc_size - arc_c), |
1980 | (int64_t)(arc_anon->arcs_size + arc_mru->arcs_size + arc_meta_used - | |
1981 | arc_p)); | |
34dc7c2f | 1982 | |
d164b209 BB |
1983 | if (adjustment > 0 && arc_mru->arcs_lsize[ARC_BUFC_DATA] > 0) { |
1984 | delta = MIN(arc_mru->arcs_lsize[ARC_BUFC_DATA], adjustment); | |
b8864a23 | 1985 | (void) arc_evict(arc_mru, 0, delta, FALSE, ARC_BUFC_DATA); |
d164b209 | 1986 | adjustment -= delta; |
34dc7c2f BB |
1987 | } |
1988 | ||
d164b209 BB |
1989 | if (adjustment > 0 && arc_mru->arcs_lsize[ARC_BUFC_METADATA] > 0) { |
1990 | delta = MIN(arc_mru->arcs_lsize[ARC_BUFC_METADATA], adjustment); | |
b8864a23 | 1991 | (void) arc_evict(arc_mru, 0, delta, FALSE, |
34dc7c2f | 1992 | ARC_BUFC_METADATA); |
34dc7c2f BB |
1993 | } |
1994 | ||
d164b209 BB |
1995 | /* |
1996 | * Adjust MFU size | |
1997 | */ | |
34dc7c2f | 1998 | |
d164b209 BB |
1999 | adjustment = arc_size - arc_c; |
2000 | ||
2001 | if (adjustment > 0 && arc_mfu->arcs_lsize[ARC_BUFC_DATA] > 0) { | |
2002 | delta = MIN(adjustment, arc_mfu->arcs_lsize[ARC_BUFC_DATA]); | |
b8864a23 | 2003 | (void) arc_evict(arc_mfu, 0, delta, FALSE, ARC_BUFC_DATA); |
d164b209 | 2004 | adjustment -= delta; |
34dc7c2f BB |
2005 | } |
2006 | ||
d164b209 BB |
2007 | if (adjustment > 0 && arc_mfu->arcs_lsize[ARC_BUFC_METADATA] > 0) { |
2008 | int64_t delta = MIN(adjustment, | |
2009 | arc_mfu->arcs_lsize[ARC_BUFC_METADATA]); | |
b8864a23 | 2010 | (void) arc_evict(arc_mfu, 0, delta, FALSE, |
d164b209 BB |
2011 | ARC_BUFC_METADATA); |
2012 | } | |
34dc7c2f | 2013 | |
d164b209 BB |
2014 | /* |
2015 | * Adjust ghost lists | |
2016 | */ | |
34dc7c2f | 2017 | |
d164b209 BB |
2018 | adjustment = arc_mru->arcs_size + arc_mru_ghost->arcs_size - arc_c; |
2019 | ||
2020 | if (adjustment > 0 && arc_mru_ghost->arcs_size > 0) { | |
2021 | delta = MIN(arc_mru_ghost->arcs_size, adjustment); | |
c06d4368 | 2022 | arc_evict_ghost(arc_mru_ghost, 0, delta, ARC_BUFC_DATA); |
d164b209 | 2023 | } |
34dc7c2f | 2024 | |
d164b209 BB |
2025 | adjustment = |
2026 | arc_mru_ghost->arcs_size + arc_mfu_ghost->arcs_size - arc_c; | |
34dc7c2f | 2027 | |
d164b209 BB |
2028 | if (adjustment > 0 && arc_mfu_ghost->arcs_size > 0) { |
2029 | delta = MIN(arc_mfu_ghost->arcs_size, adjustment); | |
c06d4368 | 2030 | arc_evict_ghost(arc_mfu_ghost, 0, delta, ARC_BUFC_DATA); |
34dc7c2f BB |
2031 | } |
2032 | } | |
2033 | ||
ab26409d BB |
2034 | /* |
2035 | * Request that arc user drop references so that N bytes can be released | |
2036 | * from the cache. This provides a mechanism to ensure the arc can honor | |
2037 | * the arc_meta_limit and reclaim buffers which are pinned in the cache | |
2038 | * by higher layers. (i.e. the zpl) | |
2039 | */ | |
2040 | static void | |
2041 | arc_do_user_prune(int64_t adjustment) | |
2042 | { | |
2043 | arc_prune_func_t *func; | |
2044 | void *private; | |
2045 | arc_prune_t *cp, *np; | |
2046 | ||
2047 | mutex_enter(&arc_prune_mtx); | |
2048 | ||
2049 | cp = list_head(&arc_prune_list); | |
2050 | while (cp != NULL) { | |
2051 | func = cp->p_pfunc; | |
2052 | private = cp->p_private; | |
2053 | np = list_next(&arc_prune_list, cp); | |
2054 | refcount_add(&cp->p_refcnt, func); | |
2055 | mutex_exit(&arc_prune_mtx); | |
2056 | ||
2057 | if (func != NULL) | |
2058 | func(adjustment, private); | |
2059 | ||
2060 | mutex_enter(&arc_prune_mtx); | |
2061 | ||
2062 | /* User removed prune callback concurrently with execution */ | |
2063 | if (refcount_remove(&cp->p_refcnt, func) == 0) { | |
2064 | ASSERT(!list_link_active(&cp->p_node)); | |
2065 | refcount_destroy(&cp->p_refcnt); | |
2066 | kmem_free(cp, sizeof (*cp)); | |
2067 | } | |
2068 | ||
2069 | cp = np; | |
2070 | } | |
2071 | ||
2072 | ARCSTAT_BUMP(arcstat_prune); | |
2073 | mutex_exit(&arc_prune_mtx); | |
2074 | } | |
2075 | ||
34dc7c2f BB |
2076 | static void |
2077 | arc_do_user_evicts(void) | |
2078 | { | |
2079 | mutex_enter(&arc_eviction_mtx); | |
2080 | while (arc_eviction_list != NULL) { | |
2081 | arc_buf_t *buf = arc_eviction_list; | |
2082 | arc_eviction_list = buf->b_next; | |
428870ff | 2083 | mutex_enter(&buf->b_evict_lock); |
34dc7c2f | 2084 | buf->b_hdr = NULL; |
428870ff | 2085 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
2086 | mutex_exit(&arc_eviction_mtx); |
2087 | ||
2088 | if (buf->b_efunc != NULL) | |
2089 | VERIFY(buf->b_efunc(buf) == 0); | |
2090 | ||
2091 | buf->b_efunc = NULL; | |
2092 | buf->b_private = NULL; | |
2093 | kmem_cache_free(buf_cache, buf); | |
2094 | mutex_enter(&arc_eviction_mtx); | |
2095 | } | |
2096 | mutex_exit(&arc_eviction_mtx); | |
2097 | } | |
2098 | ||
ab26409d BB |
2099 | /* |
2100 | * Evict only meta data objects from the cache leaving the data objects. | |
2101 | * This is only used to enforce the tunable arc_meta_limit, if we are | |
2102 | * unable to evict enough buffers notify the user via the prune callback. | |
2103 | */ | |
2104 | void | |
2105 | arc_adjust_meta(int64_t adjustment, boolean_t may_prune) | |
2106 | { | |
2107 | int64_t delta; | |
2108 | ||
2109 | if (adjustment > 0 && arc_mru->arcs_lsize[ARC_BUFC_METADATA] > 0) { | |
2110 | delta = MIN(arc_mru->arcs_lsize[ARC_BUFC_METADATA], adjustment); | |
2111 | arc_evict(arc_mru, 0, delta, FALSE, ARC_BUFC_METADATA); | |
2112 | adjustment -= delta; | |
2113 | } | |
2114 | ||
2115 | if (adjustment > 0 && arc_mfu->arcs_lsize[ARC_BUFC_METADATA] > 0) { | |
2116 | delta = MIN(arc_mfu->arcs_lsize[ARC_BUFC_METADATA], adjustment); | |
2117 | arc_evict(arc_mfu, 0, delta, FALSE, ARC_BUFC_METADATA); | |
2118 | adjustment -= delta; | |
2119 | } | |
2120 | ||
2121 | if (may_prune && (adjustment > 0) && (arc_meta_used > arc_meta_limit)) | |
c06d4368 | 2122 | arc_do_user_prune(zfs_arc_meta_prune); |
ab26409d BB |
2123 | } |
2124 | ||
34dc7c2f BB |
2125 | /* |
2126 | * Flush all *evictable* data from the cache for the given spa. | |
2127 | * NOTE: this will not touch "active" (i.e. referenced) data. | |
2128 | */ | |
2129 | void | |
2130 | arc_flush(spa_t *spa) | |
2131 | { | |
d164b209 BB |
2132 | uint64_t guid = 0; |
2133 | ||
2134 | if (spa) | |
3541dc6d | 2135 | guid = spa_load_guid(spa); |
d164b209 | 2136 | |
34dc7c2f | 2137 | while (list_head(&arc_mru->arcs_list[ARC_BUFC_DATA])) { |
d164b209 | 2138 | (void) arc_evict(arc_mru, guid, -1, FALSE, ARC_BUFC_DATA); |
34dc7c2f BB |
2139 | if (spa) |
2140 | break; | |
2141 | } | |
2142 | while (list_head(&arc_mru->arcs_list[ARC_BUFC_METADATA])) { | |
d164b209 | 2143 | (void) arc_evict(arc_mru, guid, -1, FALSE, ARC_BUFC_METADATA); |
34dc7c2f BB |
2144 | if (spa) |
2145 | break; | |
2146 | } | |
2147 | while (list_head(&arc_mfu->arcs_list[ARC_BUFC_DATA])) { | |
d164b209 | 2148 | (void) arc_evict(arc_mfu, guid, -1, FALSE, ARC_BUFC_DATA); |
34dc7c2f BB |
2149 | if (spa) |
2150 | break; | |
2151 | } | |
2152 | while (list_head(&arc_mfu->arcs_list[ARC_BUFC_METADATA])) { | |
d164b209 | 2153 | (void) arc_evict(arc_mfu, guid, -1, FALSE, ARC_BUFC_METADATA); |
34dc7c2f BB |
2154 | if (spa) |
2155 | break; | |
2156 | } | |
2157 | ||
c06d4368 AX |
2158 | arc_evict_ghost(arc_mru_ghost, guid, -1, ARC_BUFC_DATA); |
2159 | arc_evict_ghost(arc_mfu_ghost, guid, -1, ARC_BUFC_DATA); | |
34dc7c2f BB |
2160 | |
2161 | mutex_enter(&arc_reclaim_thr_lock); | |
2162 | arc_do_user_evicts(); | |
2163 | mutex_exit(&arc_reclaim_thr_lock); | |
2164 | ASSERT(spa || arc_eviction_list == NULL); | |
2165 | } | |
2166 | ||
34dc7c2f | 2167 | void |
302f753f | 2168 | arc_shrink(uint64_t bytes) |
34dc7c2f BB |
2169 | { |
2170 | if (arc_c > arc_c_min) { | |
2171 | uint64_t to_free; | |
2172 | ||
c06d4368 | 2173 | to_free = bytes ? bytes : arc_c >> zfs_arc_shrink_shift; |
302f753f | 2174 | |
34dc7c2f BB |
2175 | if (arc_c > arc_c_min + to_free) |
2176 | atomic_add_64(&arc_c, -to_free); | |
2177 | else | |
2178 | arc_c = arc_c_min; | |
2179 | ||
c06d4368 | 2180 | atomic_add_64(&arc_p, -(arc_p >> zfs_arc_shrink_shift)); |
34dc7c2f BB |
2181 | if (arc_c > arc_size) |
2182 | arc_c = MAX(arc_size, arc_c_min); | |
2183 | if (arc_p > arc_c) | |
2184 | arc_p = (arc_c >> 1); | |
2185 | ASSERT(arc_c >= arc_c_min); | |
2186 | ASSERT((int64_t)arc_p >= 0); | |
2187 | } | |
2188 | ||
2189 | if (arc_size > arc_c) | |
2190 | arc_adjust(); | |
2191 | } | |
2192 | ||
34dc7c2f | 2193 | static void |
302f753f | 2194 | arc_kmem_reap_now(arc_reclaim_strategy_t strat, uint64_t bytes) |
34dc7c2f BB |
2195 | { |
2196 | size_t i; | |
2197 | kmem_cache_t *prev_cache = NULL; | |
2198 | kmem_cache_t *prev_data_cache = NULL; | |
2199 | extern kmem_cache_t *zio_buf_cache[]; | |
2200 | extern kmem_cache_t *zio_data_buf_cache[]; | |
34dc7c2f BB |
2201 | |
2202 | /* | |
2203 | * An aggressive reclamation will shrink the cache size as well as | |
2204 | * reap free buffers from the arc kmem caches. | |
2205 | */ | |
2206 | if (strat == ARC_RECLAIM_AGGR) | |
302f753f | 2207 | arc_shrink(bytes); |
34dc7c2f BB |
2208 | |
2209 | for (i = 0; i < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; i++) { | |
2210 | if (zio_buf_cache[i] != prev_cache) { | |
2211 | prev_cache = zio_buf_cache[i]; | |
2212 | kmem_cache_reap_now(zio_buf_cache[i]); | |
2213 | } | |
2214 | if (zio_data_buf_cache[i] != prev_data_cache) { | |
2215 | prev_data_cache = zio_data_buf_cache[i]; | |
2216 | kmem_cache_reap_now(zio_data_buf_cache[i]); | |
2217 | } | |
2218 | } | |
ab26409d | 2219 | |
34dc7c2f BB |
2220 | kmem_cache_reap_now(buf_cache); |
2221 | kmem_cache_reap_now(hdr_cache); | |
2222 | } | |
2223 | ||
302f753f BB |
2224 | /* |
2225 | * Unlike other ZFS implementations this thread is only responsible for | |
2226 | * adapting the target ARC size on Linux. The responsibility for memory | |
2227 | * reclamation has been entirely delegated to the arc_shrinker_func() | |
2228 | * which is registered with the VM. To reflect this change in behavior | |
2229 | * the arc_reclaim thread has been renamed to arc_adapt. | |
2230 | */ | |
34dc7c2f | 2231 | static void |
302f753f | 2232 | arc_adapt_thread(void) |
34dc7c2f | 2233 | { |
34dc7c2f | 2234 | callb_cpr_t cpr; |
ab26409d | 2235 | int64_t prune; |
34dc7c2f BB |
2236 | |
2237 | CALLB_CPR_INIT(&cpr, &arc_reclaim_thr_lock, callb_generic_cpr, FTAG); | |
2238 | ||
2239 | mutex_enter(&arc_reclaim_thr_lock); | |
2240 | while (arc_thread_exit == 0) { | |
302f753f BB |
2241 | #ifndef _KERNEL |
2242 | arc_reclaim_strategy_t last_reclaim = ARC_RECLAIM_CONS; | |
2243 | ||
2244 | if (spa_get_random(100) == 0) { | |
34dc7c2f BB |
2245 | |
2246 | if (arc_no_grow) { | |
2247 | if (last_reclaim == ARC_RECLAIM_CONS) { | |
2248 | last_reclaim = ARC_RECLAIM_AGGR; | |
2249 | } else { | |
2250 | last_reclaim = ARC_RECLAIM_CONS; | |
2251 | } | |
2252 | } else { | |
2253 | arc_no_grow = TRUE; | |
2254 | last_reclaim = ARC_RECLAIM_AGGR; | |
2255 | membar_producer(); | |
2256 | } | |
2257 | ||
2258 | /* reset the growth delay for every reclaim */ | |
c06d4368 | 2259 | arc_grow_time = ddi_get_lbolt()+(zfs_arc_grow_retry * hz); |
34dc7c2f | 2260 | |
302f753f | 2261 | arc_kmem_reap_now(last_reclaim, 0); |
b128c09f | 2262 | arc_warm = B_TRUE; |
302f753f BB |
2263 | } |
2264 | #endif /* !_KERNEL */ | |
34dc7c2f | 2265 | |
302f753f BB |
2266 | /* No recent memory pressure allow the ARC to grow. */ |
2267 | if (arc_no_grow && ddi_get_lbolt() >= arc_grow_time) | |
34dc7c2f | 2268 | arc_no_grow = FALSE; |
34dc7c2f | 2269 | |
ab26409d BB |
2270 | /* |
2271 | * Keep meta data usage within limits, arc_shrink() is not | |
2272 | * used to avoid collapsing the arc_c value when only the | |
2273 | * arc_meta_limit is being exceeded. | |
2274 | */ | |
2275 | prune = (int64_t)arc_meta_used - (int64_t)arc_meta_limit; | |
2276 | if (prune > 0) | |
2277 | arc_adjust_meta(prune, B_TRUE); | |
6a8f9b6b | 2278 | |
572e2857 | 2279 | arc_adjust(); |
34dc7c2f BB |
2280 | |
2281 | if (arc_eviction_list != NULL) | |
2282 | arc_do_user_evicts(); | |
2283 | ||
2284 | /* block until needed, or one second, whichever is shorter */ | |
2285 | CALLB_CPR_SAFE_BEGIN(&cpr); | |
5b63b3eb | 2286 | (void) cv_timedwait_interruptible(&arc_reclaim_thr_cv, |
428870ff | 2287 | &arc_reclaim_thr_lock, (ddi_get_lbolt() + hz)); |
34dc7c2f | 2288 | CALLB_CPR_SAFE_END(&cpr, &arc_reclaim_thr_lock); |
c06d4368 AX |
2289 | |
2290 | ||
2291 | /* Allow the module options to be changed */ | |
2292 | if (zfs_arc_max > 64 << 20 && | |
2293 | zfs_arc_max < physmem * PAGESIZE && | |
2294 | zfs_arc_max != arc_c_max) | |
2295 | arc_c_max = zfs_arc_max; | |
2296 | ||
2297 | if (zfs_arc_min > 0 && | |
2298 | zfs_arc_min < arc_c_max && | |
2299 | zfs_arc_min != arc_c_min) | |
2300 | arc_c_min = zfs_arc_min; | |
2301 | ||
2302 | if (zfs_arc_meta_limit > 0 && | |
2303 | zfs_arc_meta_limit <= arc_c_max && | |
2304 | zfs_arc_meta_limit != arc_meta_limit) | |
2305 | arc_meta_limit = zfs_arc_meta_limit; | |
2306 | ||
2307 | ||
2308 | ||
34dc7c2f BB |
2309 | } |
2310 | ||
2311 | arc_thread_exit = 0; | |
2312 | cv_broadcast(&arc_reclaim_thr_cv); | |
2313 | CALLB_CPR_EXIT(&cpr); /* drops arc_reclaim_thr_lock */ | |
2314 | thread_exit(); | |
2315 | } | |
2316 | ||
7cb67b45 BB |
2317 | #ifdef _KERNEL |
2318 | /* | |
302f753f BB |
2319 | * Determine the amount of memory eligible for eviction contained in the |
2320 | * ARC. All clean data reported by the ghost lists can always be safely | |
2321 | * evicted. Due to arc_c_min, the same does not hold for all clean data | |
2322 | * contained by the regular mru and mfu lists. | |
2323 | * | |
2324 | * In the case of the regular mru and mfu lists, we need to report as | |
2325 | * much clean data as possible, such that evicting that same reported | |
2326 | * data will not bring arc_size below arc_c_min. Thus, in certain | |
2327 | * circumstances, the total amount of clean data in the mru and mfu | |
2328 | * lists might not actually be evictable. | |
2329 | * | |
2330 | * The following two distinct cases are accounted for: | |
2331 | * | |
2332 | * 1. The sum of the amount of dirty data contained by both the mru and | |
2333 | * mfu lists, plus the ARC's other accounting (e.g. the anon list), | |
2334 | * is greater than or equal to arc_c_min. | |
2335 | * (i.e. amount of dirty data >= arc_c_min) | |
2336 | * | |
2337 | * This is the easy case; all clean data contained by the mru and mfu | |
2338 | * lists is evictable. Evicting all clean data can only drop arc_size | |
2339 | * to the amount of dirty data, which is greater than arc_c_min. | |
2340 | * | |
2341 | * 2. The sum of the amount of dirty data contained by both the mru and | |
2342 | * mfu lists, plus the ARC's other accounting (e.g. the anon list), | |
2343 | * is less than arc_c_min. | |
2344 | * (i.e. arc_c_min > amount of dirty data) | |
2345 | * | |
2346 | * 2.1. arc_size is greater than or equal arc_c_min. | |
2347 | * (i.e. arc_size >= arc_c_min > amount of dirty data) | |
2348 | * | |
2349 | * In this case, not all clean data from the regular mru and mfu | |
2350 | * lists is actually evictable; we must leave enough clean data | |
2351 | * to keep arc_size above arc_c_min. Thus, the maximum amount of | |
2352 | * evictable data from the two lists combined, is exactly the | |
2353 | * difference between arc_size and arc_c_min. | |
2354 | * | |
2355 | * 2.2. arc_size is less than arc_c_min | |
2356 | * (i.e. arc_c_min > arc_size > amount of dirty data) | |
2357 | * | |
2358 | * In this case, none of the data contained in the mru and mfu | |
2359 | * lists is evictable, even if it's clean. Since arc_size is | |
2360 | * already below arc_c_min, evicting any more would only | |
2361 | * increase this negative difference. | |
7cb67b45 | 2362 | */ |
302f753f BB |
2363 | static uint64_t |
2364 | arc_evictable_memory(void) { | |
2365 | uint64_t arc_clean = | |
2366 | arc_mru->arcs_lsize[ARC_BUFC_DATA] + | |
2367 | arc_mru->arcs_lsize[ARC_BUFC_METADATA] + | |
2368 | arc_mfu->arcs_lsize[ARC_BUFC_DATA] + | |
2369 | arc_mfu->arcs_lsize[ARC_BUFC_METADATA]; | |
2370 | uint64_t ghost_clean = | |
2371 | arc_mru_ghost->arcs_lsize[ARC_BUFC_DATA] + | |
2372 | arc_mru_ghost->arcs_lsize[ARC_BUFC_METADATA] + | |
2373 | arc_mfu_ghost->arcs_lsize[ARC_BUFC_DATA] + | |
2374 | arc_mfu_ghost->arcs_lsize[ARC_BUFC_METADATA]; | |
2375 | uint64_t arc_dirty = MAX((int64_t)arc_size - (int64_t)arc_clean, 0); | |
2376 | ||
2377 | if (arc_dirty >= arc_c_min) | |
2378 | return (ghost_clean + arc_clean); | |
2379 | ||
2380 | return (ghost_clean + MAX((int64_t)arc_size - (int64_t)arc_c_min, 0)); | |
2381 | } | |
2382 | ||
7e7baeca BB |
2383 | static int |
2384 | __arc_shrinker_func(struct shrinker *shrink, struct shrink_control *sc) | |
7cb67b45 | 2385 | { |
302f753f | 2386 | uint64_t pages; |
7cb67b45 | 2387 | |
302f753f BB |
2388 | /* The arc is considered warm once reclaim has occurred */ |
2389 | if (unlikely(arc_warm == B_FALSE)) | |
2390 | arc_warm = B_TRUE; | |
7cb67b45 | 2391 | |
302f753f BB |
2392 | /* Return the potential number of reclaimable pages */ |
2393 | pages = btop(arc_evictable_memory()); | |
2394 | if (sc->nr_to_scan == 0) | |
2395 | return (pages); | |
3fd70ee6 BB |
2396 | |
2397 | /* Not allowed to perform filesystem reclaim */ | |
7e7baeca | 2398 | if (!(sc->gfp_mask & __GFP_FS)) |
3fd70ee6 BB |
2399 | return (-1); |
2400 | ||
7cb67b45 BB |
2401 | /* Reclaim in progress */ |
2402 | if (mutex_tryenter(&arc_reclaim_thr_lock) == 0) | |
2403 | return (-1); | |
2404 | ||
302f753f BB |
2405 | /* |
2406 | * Evict the requested number of pages by shrinking arc_c the | |
2407 | * requested amount. If there is nothing left to evict just | |
2408 | * reap whatever we can from the various arc slabs. | |
2409 | */ | |
2410 | if (pages > 0) { | |
2411 | arc_kmem_reap_now(ARC_RECLAIM_AGGR, ptob(sc->nr_to_scan)); | |
302f753f BB |
2412 | } else { |
2413 | arc_kmem_reap_now(ARC_RECLAIM_CONS, ptob(sc->nr_to_scan)); | |
302f753f BB |
2414 | } |
2415 | ||
2416 | /* | |
2417 | * When direct reclaim is observed it usually indicates a rapid | |
2418 | * increase in memory pressure. This occurs because the kswapd | |
2419 | * threads were unable to asynchronously keep enough free memory | |
2420 | * available. In this case set arc_no_grow to briefly pause arc | |
2421 | * growth to avoid compounding the memory pressure. | |
2422 | */ | |
7cb67b45 | 2423 | if (current_is_kswapd()) { |
302f753f | 2424 | ARCSTAT_BUMP(arcstat_memory_indirect_count); |
7cb67b45 | 2425 | } else { |
302f753f | 2426 | arc_no_grow = B_TRUE; |
c06d4368 | 2427 | arc_grow_time = ddi_get_lbolt() + (zfs_arc_grow_retry * hz); |
302f753f | 2428 | ARCSTAT_BUMP(arcstat_memory_direct_count); |
7cb67b45 BB |
2429 | } |
2430 | ||
7cb67b45 BB |
2431 | mutex_exit(&arc_reclaim_thr_lock); |
2432 | ||
c06d4368 | 2433 | return (-1); |
7cb67b45 | 2434 | } |
7e7baeca | 2435 | SPL_SHRINKER_CALLBACK_WRAPPER(arc_shrinker_func); |
7cb67b45 BB |
2436 | |
2437 | SPL_SHRINKER_DECLARE(arc_shrinker, arc_shrinker_func, DEFAULT_SEEKS); | |
2438 | #endif /* _KERNEL */ | |
2439 | ||
34dc7c2f BB |
2440 | /* |
2441 | * Adapt arc info given the number of bytes we are trying to add and | |
2442 | * the state that we are comming from. This function is only called | |
2443 | * when we are adding new content to the cache. | |
2444 | */ | |
2445 | static void | |
2446 | arc_adapt(int bytes, arc_state_t *state) | |
2447 | { | |
2448 | int mult; | |
c06d4368 | 2449 | uint64_t arc_p_min = (arc_c >> zfs_arc_p_min_shift); |
34dc7c2f BB |
2450 | |
2451 | if (state == arc_l2c_only) | |
2452 | return; | |
2453 | ||
2454 | ASSERT(bytes > 0); | |
2455 | /* | |
2456 | * Adapt the target size of the MRU list: | |
2457 | * - if we just hit in the MRU ghost list, then increase | |
2458 | * the target size of the MRU list. | |
2459 | * - if we just hit in the MFU ghost list, then increase | |
2460 | * the target size of the MFU list by decreasing the | |
2461 | * target size of the MRU list. | |
2462 | */ | |
2463 | if (state == arc_mru_ghost) { | |
2464 | mult = ((arc_mru_ghost->arcs_size >= arc_mfu_ghost->arcs_size) ? | |
2465 | 1 : (arc_mfu_ghost->arcs_size/arc_mru_ghost->arcs_size)); | |
572e2857 | 2466 | mult = MIN(mult, 10); /* avoid wild arc_p adjustment */ |
34dc7c2f | 2467 | |
d164b209 | 2468 | arc_p = MIN(arc_c - arc_p_min, arc_p + bytes * mult); |
34dc7c2f | 2469 | } else if (state == arc_mfu_ghost) { |
d164b209 BB |
2470 | uint64_t delta; |
2471 | ||
34dc7c2f BB |
2472 | mult = ((arc_mfu_ghost->arcs_size >= arc_mru_ghost->arcs_size) ? |
2473 | 1 : (arc_mru_ghost->arcs_size/arc_mfu_ghost->arcs_size)); | |
572e2857 | 2474 | mult = MIN(mult, 10); |
34dc7c2f | 2475 | |
d164b209 BB |
2476 | delta = MIN(bytes * mult, arc_p); |
2477 | arc_p = MAX(arc_p_min, arc_p - delta); | |
34dc7c2f BB |
2478 | } |
2479 | ASSERT((int64_t)arc_p >= 0); | |
2480 | ||
34dc7c2f BB |
2481 | if (arc_no_grow) |
2482 | return; | |
2483 | ||
2484 | if (arc_c >= arc_c_max) | |
2485 | return; | |
2486 | ||
2487 | /* | |
2488 | * If we're within (2 * maxblocksize) bytes of the target | |
2489 | * cache size, increment the target cache size | |
2490 | */ | |
2491 | if (arc_size > arc_c - (2ULL << SPA_MAXBLOCKSHIFT)) { | |
2492 | atomic_add_64(&arc_c, (int64_t)bytes); | |
2493 | if (arc_c > arc_c_max) | |
2494 | arc_c = arc_c_max; | |
2495 | else if (state == arc_anon) | |
2496 | atomic_add_64(&arc_p, (int64_t)bytes); | |
2497 | if (arc_p > arc_c) | |
2498 | arc_p = arc_c; | |
2499 | } | |
2500 | ASSERT((int64_t)arc_p >= 0); | |
2501 | } | |
2502 | ||
2503 | /* | |
2504 | * Check if the cache has reached its limits and eviction is required | |
2505 | * prior to insert. | |
2506 | */ | |
2507 | static int | |
2508 | arc_evict_needed(arc_buf_contents_t type) | |
2509 | { | |
2510 | if (type == ARC_BUFC_METADATA && arc_meta_used >= arc_meta_limit) | |
2511 | return (1); | |
2512 | ||
302f753f | 2513 | if (arc_no_grow) |
34dc7c2f BB |
2514 | return (1); |
2515 | ||
2516 | return (arc_size > arc_c); | |
2517 | } | |
2518 | ||
2519 | /* | |
2520 | * The buffer, supplied as the first argument, needs a data block. | |
2521 | * So, if we are at cache max, determine which cache should be victimized. | |
2522 | * We have the following cases: | |
2523 | * | |
2524 | * 1. Insert for MRU, p > sizeof(arc_anon + arc_mru) -> | |
2525 | * In this situation if we're out of space, but the resident size of the MFU is | |
2526 | * under the limit, victimize the MFU cache to satisfy this insertion request. | |
2527 | * | |
2528 | * 2. Insert for MRU, p <= sizeof(arc_anon + arc_mru) -> | |
2529 | * Here, we've used up all of the available space for the MRU, so we need to | |
2530 | * evict from our own cache instead. Evict from the set of resident MRU | |
2531 | * entries. | |
2532 | * | |
2533 | * 3. Insert for MFU (c - p) > sizeof(arc_mfu) -> | |
2534 | * c minus p represents the MFU space in the cache, since p is the size of the | |
2535 | * cache that is dedicated to the MRU. In this situation there's still space on | |
2536 | * the MFU side, so the MRU side needs to be victimized. | |
2537 | * | |
2538 | * 4. Insert for MFU (c - p) < sizeof(arc_mfu) -> | |
2539 | * MFU's resident set is consuming more space than it has been allotted. In | |
2540 | * this situation, we must victimize our own cache, the MFU, for this insertion. | |
2541 | */ | |
2542 | static void | |
2543 | arc_get_data_buf(arc_buf_t *buf) | |
2544 | { | |
2545 | arc_state_t *state = buf->b_hdr->b_state; | |
2546 | uint64_t size = buf->b_hdr->b_size; | |
2547 | arc_buf_contents_t type = buf->b_hdr->b_type; | |
2548 | ||
2549 | arc_adapt(size, state); | |
2550 | ||
2551 | /* | |
2552 | * We have not yet reached cache maximum size, | |
2553 | * just allocate a new buffer. | |
2554 | */ | |
2555 | if (!arc_evict_needed(type)) { | |
2556 | if (type == ARC_BUFC_METADATA) { | |
2557 | buf->b_data = zio_buf_alloc(size); | |
d164b209 | 2558 | arc_space_consume(size, ARC_SPACE_DATA); |
34dc7c2f BB |
2559 | } else { |
2560 | ASSERT(type == ARC_BUFC_DATA); | |
2561 | buf->b_data = zio_data_buf_alloc(size); | |
d164b209 | 2562 | ARCSTAT_INCR(arcstat_data_size, size); |
34dc7c2f BB |
2563 | atomic_add_64(&arc_size, size); |
2564 | } | |
2565 | goto out; | |
2566 | } | |
2567 | ||
2568 | /* | |
2569 | * If we are prefetching from the mfu ghost list, this buffer | |
2570 | * will end up on the mru list; so steal space from there. | |
2571 | */ | |
2572 | if (state == arc_mfu_ghost) | |
2573 | state = buf->b_hdr->b_flags & ARC_PREFETCH ? arc_mru : arc_mfu; | |
2574 | else if (state == arc_mru_ghost) | |
2575 | state = arc_mru; | |
2576 | ||
2577 | if (state == arc_mru || state == arc_anon) { | |
2578 | uint64_t mru_used = arc_anon->arcs_size + arc_mru->arcs_size; | |
d164b209 | 2579 | state = (arc_mfu->arcs_lsize[type] >= size && |
34dc7c2f BB |
2580 | arc_p > mru_used) ? arc_mfu : arc_mru; |
2581 | } else { | |
2582 | /* MFU cases */ | |
2583 | uint64_t mfu_space = arc_c - arc_p; | |
d164b209 | 2584 | state = (arc_mru->arcs_lsize[type] >= size && |
34dc7c2f BB |
2585 | mfu_space > arc_mfu->arcs_size) ? arc_mru : arc_mfu; |
2586 | } | |
ab26409d | 2587 | |
b8864a23 | 2588 | if ((buf->b_data = arc_evict(state, 0, size, TRUE, type)) == NULL) { |
34dc7c2f BB |
2589 | if (type == ARC_BUFC_METADATA) { |
2590 | buf->b_data = zio_buf_alloc(size); | |
d164b209 | 2591 | arc_space_consume(size, ARC_SPACE_DATA); |
ab26409d BB |
2592 | |
2593 | /* | |
2594 | * If we are unable to recycle an existing meta buffer | |
2595 | * signal the reclaim thread. It will notify users | |
2596 | * via the prune callback to drop references. The | |
2597 | * prune callback in run in the context of the reclaim | |
2598 | * thread to avoid deadlocking on the hash_lock. | |
2599 | */ | |
2600 | cv_signal(&arc_reclaim_thr_cv); | |
34dc7c2f BB |
2601 | } else { |
2602 | ASSERT(type == ARC_BUFC_DATA); | |
2603 | buf->b_data = zio_data_buf_alloc(size); | |
d164b209 | 2604 | ARCSTAT_INCR(arcstat_data_size, size); |
34dc7c2f BB |
2605 | atomic_add_64(&arc_size, size); |
2606 | } | |
ab26409d | 2607 | |
34dc7c2f BB |
2608 | ARCSTAT_BUMP(arcstat_recycle_miss); |
2609 | } | |
2610 | ASSERT(buf->b_data != NULL); | |
2611 | out: | |
2612 | /* | |
2613 | * Update the state size. Note that ghost states have a | |
2614 | * "ghost size" and so don't need to be updated. | |
2615 | */ | |
2616 | if (!GHOST_STATE(buf->b_hdr->b_state)) { | |
2617 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
2618 | ||
2619 | atomic_add_64(&hdr->b_state->arcs_size, size); | |
2620 | if (list_link_active(&hdr->b_arc_node)) { | |
2621 | ASSERT(refcount_is_zero(&hdr->b_refcnt)); | |
2622 | atomic_add_64(&hdr->b_state->arcs_lsize[type], size); | |
2623 | } | |
2624 | /* | |
2625 | * If we are growing the cache, and we are adding anonymous | |
2626 | * data, and we have outgrown arc_p, update arc_p | |
2627 | */ | |
2628 | if (arc_size < arc_c && hdr->b_state == arc_anon && | |
2629 | arc_anon->arcs_size + arc_mru->arcs_size > arc_p) | |
2630 | arc_p = MIN(arc_c, arc_p + size); | |
2631 | } | |
2632 | } | |
2633 | ||
2634 | /* | |
2635 | * This routine is called whenever a buffer is accessed. | |
2636 | * NOTE: the hash lock is dropped in this function. | |
2637 | */ | |
2638 | static void | |
2639 | arc_access(arc_buf_hdr_t *buf, kmutex_t *hash_lock) | |
2640 | { | |
428870ff BB |
2641 | clock_t now; |
2642 | ||
34dc7c2f BB |
2643 | ASSERT(MUTEX_HELD(hash_lock)); |
2644 | ||
2645 | if (buf->b_state == arc_anon) { | |
2646 | /* | |
2647 | * This buffer is not in the cache, and does not | |
2648 | * appear in our "ghost" list. Add the new buffer | |
2649 | * to the MRU state. | |
2650 | */ | |
2651 | ||
2652 | ASSERT(buf->b_arc_access == 0); | |
428870ff | 2653 | buf->b_arc_access = ddi_get_lbolt(); |
34dc7c2f BB |
2654 | DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, buf); |
2655 | arc_change_state(arc_mru, buf, hash_lock); | |
2656 | ||
2657 | } else if (buf->b_state == arc_mru) { | |
428870ff BB |
2658 | now = ddi_get_lbolt(); |
2659 | ||
34dc7c2f BB |
2660 | /* |
2661 | * If this buffer is here because of a prefetch, then either: | |
2662 | * - clear the flag if this is a "referencing" read | |
2663 | * (any subsequent access will bump this into the MFU state). | |
2664 | * or | |
2665 | * - move the buffer to the head of the list if this is | |
2666 | * another prefetch (to make it less likely to be evicted). | |
2667 | */ | |
2668 | if ((buf->b_flags & ARC_PREFETCH) != 0) { | |
2669 | if (refcount_count(&buf->b_refcnt) == 0) { | |
2670 | ASSERT(list_link_active(&buf->b_arc_node)); | |
2671 | } else { | |
2672 | buf->b_flags &= ~ARC_PREFETCH; | |
2673 | ARCSTAT_BUMP(arcstat_mru_hits); | |
2674 | } | |
428870ff | 2675 | buf->b_arc_access = now; |
34dc7c2f BB |
2676 | return; |
2677 | } | |
2678 | ||
2679 | /* | |
2680 | * This buffer has been "accessed" only once so far, | |
2681 | * but it is still in the cache. Move it to the MFU | |
2682 | * state. | |
2683 | */ | |
428870ff | 2684 | if (now > buf->b_arc_access + ARC_MINTIME) { |
34dc7c2f BB |
2685 | /* |
2686 | * More than 125ms have passed since we | |
2687 | * instantiated this buffer. Move it to the | |
2688 | * most frequently used state. | |
2689 | */ | |
428870ff | 2690 | buf->b_arc_access = now; |
34dc7c2f BB |
2691 | DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); |
2692 | arc_change_state(arc_mfu, buf, hash_lock); | |
2693 | } | |
2694 | ARCSTAT_BUMP(arcstat_mru_hits); | |
2695 | } else if (buf->b_state == arc_mru_ghost) { | |
2696 | arc_state_t *new_state; | |
2697 | /* | |
2698 | * This buffer has been "accessed" recently, but | |
2699 | * was evicted from the cache. Move it to the | |
2700 | * MFU state. | |
2701 | */ | |
2702 | ||
2703 | if (buf->b_flags & ARC_PREFETCH) { | |
2704 | new_state = arc_mru; | |
2705 | if (refcount_count(&buf->b_refcnt) > 0) | |
2706 | buf->b_flags &= ~ARC_PREFETCH; | |
2707 | DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, buf); | |
2708 | } else { | |
2709 | new_state = arc_mfu; | |
2710 | DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); | |
2711 | } | |
2712 | ||
428870ff | 2713 | buf->b_arc_access = ddi_get_lbolt(); |
34dc7c2f BB |
2714 | arc_change_state(new_state, buf, hash_lock); |
2715 | ||
2716 | ARCSTAT_BUMP(arcstat_mru_ghost_hits); | |
2717 | } else if (buf->b_state == arc_mfu) { | |
2718 | /* | |
2719 | * This buffer has been accessed more than once and is | |
2720 | * still in the cache. Keep it in the MFU state. | |
2721 | * | |
2722 | * NOTE: an add_reference() that occurred when we did | |
2723 | * the arc_read() will have kicked this off the list. | |
2724 | * If it was a prefetch, we will explicitly move it to | |
2725 | * the head of the list now. | |
2726 | */ | |
2727 | if ((buf->b_flags & ARC_PREFETCH) != 0) { | |
2728 | ASSERT(refcount_count(&buf->b_refcnt) == 0); | |
2729 | ASSERT(list_link_active(&buf->b_arc_node)); | |
2730 | } | |
2731 | ARCSTAT_BUMP(arcstat_mfu_hits); | |
428870ff | 2732 | buf->b_arc_access = ddi_get_lbolt(); |
34dc7c2f BB |
2733 | } else if (buf->b_state == arc_mfu_ghost) { |
2734 | arc_state_t *new_state = arc_mfu; | |
2735 | /* | |
2736 | * This buffer has been accessed more than once but has | |
2737 | * been evicted from the cache. Move it back to the | |
2738 | * MFU state. | |
2739 | */ | |
2740 | ||
2741 | if (buf->b_flags & ARC_PREFETCH) { | |
2742 | /* | |
2743 | * This is a prefetch access... | |
2744 | * move this block back to the MRU state. | |
2745 | */ | |
c06d4368 | 2746 | ASSERT0(refcount_count(&buf->b_refcnt)); |
34dc7c2f BB |
2747 | new_state = arc_mru; |
2748 | } | |
2749 | ||
428870ff | 2750 | buf->b_arc_access = ddi_get_lbolt(); |
34dc7c2f BB |
2751 | DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); |
2752 | arc_change_state(new_state, buf, hash_lock); | |
2753 | ||
2754 | ARCSTAT_BUMP(arcstat_mfu_ghost_hits); | |
2755 | } else if (buf->b_state == arc_l2c_only) { | |
2756 | /* | |
2757 | * This buffer is on the 2nd Level ARC. | |
2758 | */ | |
2759 | ||
428870ff | 2760 | buf->b_arc_access = ddi_get_lbolt(); |
34dc7c2f BB |
2761 | DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); |
2762 | arc_change_state(arc_mfu, buf, hash_lock); | |
2763 | } else { | |
2764 | ASSERT(!"invalid arc state"); | |
2765 | } | |
2766 | } | |
2767 | ||
2768 | /* a generic arc_done_func_t which you can use */ | |
2769 | /* ARGSUSED */ | |
2770 | void | |
2771 | arc_bcopy_func(zio_t *zio, arc_buf_t *buf, void *arg) | |
2772 | { | |
428870ff BB |
2773 | if (zio == NULL || zio->io_error == 0) |
2774 | bcopy(buf->b_data, arg, buf->b_hdr->b_size); | |
34dc7c2f BB |
2775 | VERIFY(arc_buf_remove_ref(buf, arg) == 1); |
2776 | } | |
2777 | ||
2778 | /* a generic arc_done_func_t */ | |
2779 | void | |
2780 | arc_getbuf_func(zio_t *zio, arc_buf_t *buf, void *arg) | |
2781 | { | |
2782 | arc_buf_t **bufp = arg; | |
2783 | if (zio && zio->io_error) { | |
2784 | VERIFY(arc_buf_remove_ref(buf, arg) == 1); | |
2785 | *bufp = NULL; | |
2786 | } else { | |
2787 | *bufp = buf; | |
428870ff | 2788 | ASSERT(buf->b_data); |
34dc7c2f BB |
2789 | } |
2790 | } | |
2791 | ||
2792 | static void | |
2793 | arc_read_done(zio_t *zio) | |
2794 | { | |
2795 | arc_buf_hdr_t *hdr, *found; | |
2796 | arc_buf_t *buf; | |
2797 | arc_buf_t *abuf; /* buffer we're assigning to callback */ | |
2798 | kmutex_t *hash_lock; | |
2799 | arc_callback_t *callback_list, *acb; | |
2800 | int freeable = FALSE; | |
2801 | ||
2802 | buf = zio->io_private; | |
2803 | hdr = buf->b_hdr; | |
2804 | ||
2805 | /* | |
2806 | * The hdr was inserted into hash-table and removed from lists | |
2807 | * prior to starting I/O. We should find this header, since | |
2808 | * it's in the hash table, and it should be legit since it's | |
2809 | * not possible to evict it during the I/O. The only possible | |
2810 | * reason for it not to be found is if we were freed during the | |
2811 | * read. | |
2812 | */ | |
d164b209 | 2813 | found = buf_hash_find(hdr->b_spa, &hdr->b_dva, hdr->b_birth, |
34dc7c2f BB |
2814 | &hash_lock); |
2815 | ||
2816 | ASSERT((found == NULL && HDR_FREED_IN_READ(hdr) && hash_lock == NULL) || | |
2817 | (found == hdr && DVA_EQUAL(&hdr->b_dva, BP_IDENTITY(zio->io_bp))) || | |
2818 | (found == hdr && HDR_L2_READING(hdr))); | |
2819 | ||
b128c09f | 2820 | hdr->b_flags &= ~ARC_L2_EVICTED; |
34dc7c2f | 2821 | if (l2arc_noprefetch && (hdr->b_flags & ARC_PREFETCH)) |
b128c09f | 2822 | hdr->b_flags &= ~ARC_L2CACHE; |
34dc7c2f BB |
2823 | |
2824 | /* byteswap if necessary */ | |
2825 | callback_list = hdr->b_acb; | |
2826 | ASSERT(callback_list != NULL); | |
428870ff | 2827 | if (BP_SHOULD_BYTESWAP(zio->io_bp) && zio->io_error == 0) { |
9ae529ec CS |
2828 | dmu_object_byteswap_t bswap = |
2829 | DMU_OT_BYTESWAP(BP_GET_TYPE(zio->io_bp)); | |
b01615d5 RY |
2830 | if (BP_GET_LEVEL(zio->io_bp) > 0) |
2831 | byteswap_uint64_array(buf->b_data, hdr->b_size); | |
2832 | else | |
2833 | dmu_ot_byteswap[bswap].ob_func(buf->b_data, hdr->b_size); | |
b128c09f | 2834 | } |
34dc7c2f BB |
2835 | |
2836 | arc_cksum_compute(buf, B_FALSE); | |
2837 | ||
428870ff BB |
2838 | if (hash_lock && zio->io_error == 0 && hdr->b_state == arc_anon) { |
2839 | /* | |
2840 | * Only call arc_access on anonymous buffers. This is because | |
2841 | * if we've issued an I/O for an evicted buffer, we've already | |
2842 | * called arc_access (to prevent any simultaneous readers from | |
2843 | * getting confused). | |
2844 | */ | |
2845 | arc_access(hdr, hash_lock); | |
2846 | } | |
2847 | ||
34dc7c2f BB |
2848 | /* create copies of the data buffer for the callers */ |
2849 | abuf = buf; | |
2850 | for (acb = callback_list; acb; acb = acb->acb_next) { | |
2851 | if (acb->acb_done) { | |
1eb5bfa3 GW |
2852 | if (abuf == NULL) { |
2853 | ARCSTAT_BUMP(arcstat_duplicate_reads); | |
34dc7c2f | 2854 | abuf = arc_buf_clone(buf); |
1eb5bfa3 | 2855 | } |
34dc7c2f BB |
2856 | acb->acb_buf = abuf; |
2857 | abuf = NULL; | |
2858 | } | |
2859 | } | |
2860 | hdr->b_acb = NULL; | |
2861 | hdr->b_flags &= ~ARC_IO_IN_PROGRESS; | |
2862 | ASSERT(!HDR_BUF_AVAILABLE(hdr)); | |
428870ff BB |
2863 | if (abuf == buf) { |
2864 | ASSERT(buf->b_efunc == NULL); | |
2865 | ASSERT(hdr->b_datacnt == 1); | |
34dc7c2f | 2866 | hdr->b_flags |= ARC_BUF_AVAILABLE; |
428870ff | 2867 | } |
34dc7c2f BB |
2868 | |
2869 | ASSERT(refcount_is_zero(&hdr->b_refcnt) || callback_list != NULL); | |
2870 | ||
2871 | if (zio->io_error != 0) { | |
2872 | hdr->b_flags |= ARC_IO_ERROR; | |
2873 | if (hdr->b_state != arc_anon) | |
2874 | arc_change_state(arc_anon, hdr, hash_lock); | |
2875 | if (HDR_IN_HASH_TABLE(hdr)) | |
2876 | buf_hash_remove(hdr); | |
2877 | freeable = refcount_is_zero(&hdr->b_refcnt); | |
34dc7c2f BB |
2878 | } |
2879 | ||
2880 | /* | |
2881 | * Broadcast before we drop the hash_lock to avoid the possibility | |
2882 | * that the hdr (and hence the cv) might be freed before we get to | |
2883 | * the cv_broadcast(). | |
2884 | */ | |
2885 | cv_broadcast(&hdr->b_cv); | |
2886 | ||
2887 | if (hash_lock) { | |
34dc7c2f BB |
2888 | mutex_exit(hash_lock); |
2889 | } else { | |
2890 | /* | |
2891 | * This block was freed while we waited for the read to | |
2892 | * complete. It has been removed from the hash table and | |
2893 | * moved to the anonymous state (so that it won't show up | |
2894 | * in the cache). | |
2895 | */ | |
2896 | ASSERT3P(hdr->b_state, ==, arc_anon); | |
2897 | freeable = refcount_is_zero(&hdr->b_refcnt); | |
2898 | } | |
2899 | ||
2900 | /* execute each callback and free its structure */ | |
2901 | while ((acb = callback_list) != NULL) { | |
2902 | if (acb->acb_done) | |
2903 | acb->acb_done(zio, acb->acb_buf, acb->acb_private); | |
2904 | ||
2905 | if (acb->acb_zio_dummy != NULL) { | |
2906 | acb->acb_zio_dummy->io_error = zio->io_error; | |
2907 | zio_nowait(acb->acb_zio_dummy); | |
2908 | } | |
2909 | ||
2910 | callback_list = acb->acb_next; | |
2911 | kmem_free(acb, sizeof (arc_callback_t)); | |
2912 | } | |
2913 | ||
2914 | if (freeable) | |
2915 | arc_hdr_destroy(hdr); | |
2916 | } | |
2917 | ||
2918 | /* | |
5c839890 | 2919 | * "Read" the block at the specified DVA (in bp) via the |
34dc7c2f BB |
2920 | * cache. If the block is found in the cache, invoke the provided |
2921 | * callback immediately and return. Note that the `zio' parameter | |
2922 | * in the callback will be NULL in this case, since no IO was | |
2923 | * required. If the block is not in the cache pass the read request | |
2924 | * on to the spa with a substitute callback function, so that the | |
2925 | * requested block will be added to the cache. | |
2926 | * | |
2927 | * If a read request arrives for a block that has a read in-progress, | |
2928 | * either wait for the in-progress read to complete (and return the | |
2929 | * results); or, if this is a read with a "done" func, add a record | |
2930 | * to the read to invoke the "done" func when the read completes, | |
2931 | * and return; or just return. | |
2932 | * | |
2933 | * arc_read_done() will invoke all the requested "done" functions | |
2934 | * for readers of this block. | |
2935 | */ | |
2936 | int | |
c06d4368 AX |
2937 | arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp, arc_done_func_t *done, |
2938 | void *private, int priority, int zio_flags, uint32_t *arc_flags, | |
2939 | const zbookmark_t *zb) | |
34dc7c2f BB |
2940 | { |
2941 | arc_buf_hdr_t *hdr; | |
d4ed6673 | 2942 | arc_buf_t *buf = NULL; |
34dc7c2f BB |
2943 | kmutex_t *hash_lock; |
2944 | zio_t *rzio; | |
3541dc6d | 2945 | uint64_t guid = spa_load_guid(spa); |
34dc7c2f BB |
2946 | |
2947 | top: | |
428870ff BB |
2948 | hdr = buf_hash_find(guid, BP_IDENTITY(bp), BP_PHYSICAL_BIRTH(bp), |
2949 | &hash_lock); | |
34dc7c2f BB |
2950 | if (hdr && hdr->b_datacnt > 0) { |
2951 | ||
2952 | *arc_flags |= ARC_CACHED; | |
2953 | ||
2954 | if (HDR_IO_IN_PROGRESS(hdr)) { | |
2955 | ||
2956 | if (*arc_flags & ARC_WAIT) { | |
2957 | cv_wait(&hdr->b_cv, hash_lock); | |
2958 | mutex_exit(hash_lock); | |
2959 | goto top; | |
2960 | } | |
2961 | ASSERT(*arc_flags & ARC_NOWAIT); | |
2962 | ||
2963 | if (done) { | |
2964 | arc_callback_t *acb = NULL; | |
2965 | ||
2966 | acb = kmem_zalloc(sizeof (arc_callback_t), | |
691f6ac4 | 2967 | KM_PUSHPAGE); |
34dc7c2f BB |
2968 | acb->acb_done = done; |
2969 | acb->acb_private = private; | |
34dc7c2f BB |
2970 | if (pio != NULL) |
2971 | acb->acb_zio_dummy = zio_null(pio, | |
d164b209 | 2972 | spa, NULL, NULL, NULL, zio_flags); |
34dc7c2f BB |
2973 | |
2974 | ASSERT(acb->acb_done != NULL); | |
2975 | acb->acb_next = hdr->b_acb; | |
2976 | hdr->b_acb = acb; | |
2977 | add_reference(hdr, hash_lock, private); | |
2978 | mutex_exit(hash_lock); | |
2979 | return (0); | |
2980 | } | |
2981 | mutex_exit(hash_lock); | |
2982 | return (0); | |
2983 | } | |
2984 | ||
2985 | ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); | |
2986 | ||
2987 | if (done) { | |
2988 | add_reference(hdr, hash_lock, private); | |
2989 | /* | |
2990 | * If this block is already in use, create a new | |
2991 | * copy of the data so that we will be guaranteed | |
2992 | * that arc_release() will always succeed. | |
2993 | */ | |
2994 | buf = hdr->b_buf; | |
2995 | ASSERT(buf); | |
2996 | ASSERT(buf->b_data); | |
2997 | if (HDR_BUF_AVAILABLE(hdr)) { | |
2998 | ASSERT(buf->b_efunc == NULL); | |
2999 | hdr->b_flags &= ~ARC_BUF_AVAILABLE; | |
3000 | } else { | |
3001 | buf = arc_buf_clone(buf); | |
3002 | } | |
428870ff | 3003 | |
34dc7c2f BB |
3004 | } else if (*arc_flags & ARC_PREFETCH && |
3005 | refcount_count(&hdr->b_refcnt) == 0) { | |
3006 | hdr->b_flags |= ARC_PREFETCH; | |
3007 | } | |
3008 | DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr); | |
3009 | arc_access(hdr, hash_lock); | |
b128c09f BB |
3010 | if (*arc_flags & ARC_L2CACHE) |
3011 | hdr->b_flags |= ARC_L2CACHE; | |
c06d4368 AX |
3012 | if (*arc_flags & ARC_L2COMPRESS) |
3013 | hdr->b_flags |= ARC_L2COMPRESS; | |
34dc7c2f BB |
3014 | mutex_exit(hash_lock); |
3015 | ARCSTAT_BUMP(arcstat_hits); | |
3016 | ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), | |
3017 | demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, | |
3018 | data, metadata, hits); | |
3019 | ||
3020 | if (done) | |
3021 | done(NULL, buf, private); | |
3022 | } else { | |
3023 | uint64_t size = BP_GET_LSIZE(bp); | |
3024 | arc_callback_t *acb; | |
b128c09f | 3025 | vdev_t *vd = NULL; |
e06be586 | 3026 | uint64_t addr = -1; |
d164b209 | 3027 | boolean_t devw = B_FALSE; |
34dc7c2f BB |
3028 | |
3029 | if (hdr == NULL) { | |
3030 | /* this block is not in the cache */ | |
3031 | arc_buf_hdr_t *exists; | |
3032 | arc_buf_contents_t type = BP_GET_BUFC_TYPE(bp); | |
3033 | buf = arc_buf_alloc(spa, size, private, type); | |
3034 | hdr = buf->b_hdr; | |
3035 | hdr->b_dva = *BP_IDENTITY(bp); | |
428870ff | 3036 | hdr->b_birth = BP_PHYSICAL_BIRTH(bp); |
34dc7c2f BB |
3037 | hdr->b_cksum0 = bp->blk_cksum.zc_word[0]; |
3038 | exists = buf_hash_insert(hdr, &hash_lock); | |
3039 | if (exists) { | |
3040 | /* somebody beat us to the hash insert */ | |
3041 | mutex_exit(hash_lock); | |
428870ff | 3042 | buf_discard_identity(hdr); |
34dc7c2f BB |
3043 | (void) arc_buf_remove_ref(buf, private); |
3044 | goto top; /* restart the IO request */ | |
3045 | } | |
3046 | /* if this is a prefetch, we don't have a reference */ | |
3047 | if (*arc_flags & ARC_PREFETCH) { | |
3048 | (void) remove_reference(hdr, hash_lock, | |
3049 | private); | |
3050 | hdr->b_flags |= ARC_PREFETCH; | |
3051 | } | |
b128c09f BB |
3052 | if (*arc_flags & ARC_L2CACHE) |
3053 | hdr->b_flags |= ARC_L2CACHE; | |
c06d4368 AX |
3054 | if (*arc_flags & ARC_L2COMPRESS) |
3055 | hdr->b_flags |= ARC_L2COMPRESS; | |
34dc7c2f BB |
3056 | if (BP_GET_LEVEL(bp) > 0) |
3057 | hdr->b_flags |= ARC_INDIRECT; | |
3058 | } else { | |
3059 | /* this block is in the ghost cache */ | |
3060 | ASSERT(GHOST_STATE(hdr->b_state)); | |
3061 | ASSERT(!HDR_IO_IN_PROGRESS(hdr)); | |
c06d4368 | 3062 | ASSERT0(refcount_count(&hdr->b_refcnt)); |
34dc7c2f BB |
3063 | ASSERT(hdr->b_buf == NULL); |
3064 | ||
3065 | /* if this is a prefetch, we don't have a reference */ | |
3066 | if (*arc_flags & ARC_PREFETCH) | |
3067 | hdr->b_flags |= ARC_PREFETCH; | |
3068 | else | |
3069 | add_reference(hdr, hash_lock, private); | |
b128c09f BB |
3070 | if (*arc_flags & ARC_L2CACHE) |
3071 | hdr->b_flags |= ARC_L2CACHE; | |
c06d4368 AX |
3072 | if (*arc_flags & ARC_L2COMPRESS) |
3073 | hdr->b_flags |= ARC_L2COMPRESS; | |
34dc7c2f BB |
3074 | buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); |
3075 | buf->b_hdr = hdr; | |
3076 | buf->b_data = NULL; | |
3077 | buf->b_efunc = NULL; | |
3078 | buf->b_private = NULL; | |
3079 | buf->b_next = NULL; | |
3080 | hdr->b_buf = buf; | |
34dc7c2f BB |
3081 | ASSERT(hdr->b_datacnt == 0); |
3082 | hdr->b_datacnt = 1; | |
428870ff BB |
3083 | arc_get_data_buf(buf); |
3084 | arc_access(hdr, hash_lock); | |
34dc7c2f BB |
3085 | } |
3086 | ||
428870ff BB |
3087 | ASSERT(!GHOST_STATE(hdr->b_state)); |
3088 | ||
691f6ac4 | 3089 | acb = kmem_zalloc(sizeof (arc_callback_t), KM_PUSHPAGE); |
34dc7c2f BB |
3090 | acb->acb_done = done; |
3091 | acb->acb_private = private; | |
34dc7c2f BB |
3092 | |
3093 | ASSERT(hdr->b_acb == NULL); | |
3094 | hdr->b_acb = acb; | |
3095 | hdr->b_flags |= ARC_IO_IN_PROGRESS; | |
3096 | ||
b128c09f BB |
3097 | if (HDR_L2CACHE(hdr) && hdr->b_l2hdr != NULL && |
3098 | (vd = hdr->b_l2hdr->b_dev->l2ad_vdev) != NULL) { | |
d164b209 | 3099 | devw = hdr->b_l2hdr->b_dev->l2ad_writing; |
b128c09f BB |
3100 | addr = hdr->b_l2hdr->b_daddr; |
3101 | /* | |
3102 | * Lock out device removal. | |
3103 | */ | |
3104 | if (vdev_is_dead(vd) || | |
3105 | !spa_config_tryenter(spa, SCL_L2ARC, vd, RW_READER)) | |
3106 | vd = NULL; | |
3107 | } | |
3108 | ||
3109 | mutex_exit(hash_lock); | |
3110 | ||
34dc7c2f | 3111 | ASSERT3U(hdr->b_size, ==, size); |
428870ff BB |
3112 | DTRACE_PROBE4(arc__miss, arc_buf_hdr_t *, hdr, blkptr_t *, bp, |
3113 | uint64_t, size, zbookmark_t *, zb); | |
34dc7c2f BB |
3114 | ARCSTAT_BUMP(arcstat_misses); |
3115 | ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), | |
3116 | demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, | |
3117 | data, metadata, misses); | |
3118 | ||
d164b209 | 3119 | if (vd != NULL && l2arc_ndev != 0 && !(l2arc_norw && devw)) { |
34dc7c2f BB |
3120 | /* |
3121 | * Read from the L2ARC if the following are true: | |
b128c09f BB |
3122 | * 1. The L2ARC vdev was previously cached. |
3123 | * 2. This buffer still has L2ARC metadata. | |
3124 | * 3. This buffer isn't currently writing to the L2ARC. | |
3125 | * 4. The L2ARC entry wasn't evicted, which may | |
3126 | * also have invalidated the vdev. | |
d164b209 | 3127 | * 5. This isn't prefetch and l2arc_noprefetch is set. |
34dc7c2f | 3128 | */ |
b128c09f | 3129 | if (hdr->b_l2hdr != NULL && |
d164b209 BB |
3130 | !HDR_L2_WRITING(hdr) && !HDR_L2_EVICTED(hdr) && |
3131 | !(l2arc_noprefetch && HDR_PREFETCH(hdr))) { | |
34dc7c2f BB |
3132 | l2arc_read_callback_t *cb; |
3133 | ||
3134 | DTRACE_PROBE1(l2arc__hit, arc_buf_hdr_t *, hdr); | |
3135 | ARCSTAT_BUMP(arcstat_l2_hits); | |
3136 | ||
34dc7c2f | 3137 | cb = kmem_zalloc(sizeof (l2arc_read_callback_t), |
691f6ac4 | 3138 | KM_PUSHPAGE); |
34dc7c2f BB |
3139 | cb->l2rcb_buf = buf; |
3140 | cb->l2rcb_spa = spa; | |
3141 | cb->l2rcb_bp = *bp; | |
3142 | cb->l2rcb_zb = *zb; | |
b128c09f | 3143 | cb->l2rcb_flags = zio_flags; |
c06d4368 | 3144 | cb->l2rcb_compress = hdr->b_l2hdr->b_compress; |
34dc7c2f BB |
3145 | |
3146 | /* | |
b128c09f BB |
3147 | * l2arc read. The SCL_L2ARC lock will be |
3148 | * released by l2arc_read_done(). | |
c06d4368 AX |
3149 | * Issue a null zio if the underlying buffer |
3150 | * was squashed to zero size by compression. | |
34dc7c2f | 3151 | */ |
c06d4368 AX |
3152 | if (hdr->b_l2hdr->b_compress == |
3153 | ZIO_COMPRESS_EMPTY) { | |
3154 | rzio = zio_null(pio, spa, vd, | |
3155 | l2arc_read_done, cb, | |
3156 | zio_flags | ZIO_FLAG_DONT_CACHE | | |
3157 | ZIO_FLAG_CANFAIL | | |
3158 | ZIO_FLAG_DONT_PROPAGATE | | |
3159 | ZIO_FLAG_DONT_RETRY); | |
3160 | } else { | |
3161 | rzio = zio_read_phys(pio, vd, addr, | |
3162 | hdr->b_l2hdr->b_asize, | |
3163 | buf->b_data, ZIO_CHECKSUM_OFF, | |
3164 | l2arc_read_done, cb, priority, | |
3165 | zio_flags | ZIO_FLAG_DONT_CACHE | | |
3166 | ZIO_FLAG_CANFAIL | | |
3167 | ZIO_FLAG_DONT_PROPAGATE | | |
3168 | ZIO_FLAG_DONT_RETRY, B_FALSE); | |
3169 | } | |
34dc7c2f BB |
3170 | DTRACE_PROBE2(l2arc__read, vdev_t *, vd, |
3171 | zio_t *, rzio); | |
c06d4368 AX |
3172 | ARCSTAT_INCR(arcstat_l2_read_bytes, |
3173 | hdr->b_l2hdr->b_asize); | |
34dc7c2f | 3174 | |
b128c09f BB |
3175 | if (*arc_flags & ARC_NOWAIT) { |
3176 | zio_nowait(rzio); | |
3177 | return (0); | |
3178 | } | |
34dc7c2f | 3179 | |
b128c09f BB |
3180 | ASSERT(*arc_flags & ARC_WAIT); |
3181 | if (zio_wait(rzio) == 0) | |
3182 | return (0); | |
3183 | ||
3184 | /* l2arc read error; goto zio_read() */ | |
34dc7c2f BB |
3185 | } else { |
3186 | DTRACE_PROBE1(l2arc__miss, | |
3187 | arc_buf_hdr_t *, hdr); | |
3188 | ARCSTAT_BUMP(arcstat_l2_misses); | |
3189 | if (HDR_L2_WRITING(hdr)) | |
3190 | ARCSTAT_BUMP(arcstat_l2_rw_clash); | |
b128c09f | 3191 | spa_config_exit(spa, SCL_L2ARC, vd); |
34dc7c2f | 3192 | } |
d164b209 BB |
3193 | } else { |
3194 | if (vd != NULL) | |
3195 | spa_config_exit(spa, SCL_L2ARC, vd); | |
3196 | if (l2arc_ndev != 0) { | |
3197 | DTRACE_PROBE1(l2arc__miss, | |
3198 | arc_buf_hdr_t *, hdr); | |
3199 | ARCSTAT_BUMP(arcstat_l2_misses); | |
3200 | } | |
34dc7c2f | 3201 | } |
34dc7c2f BB |
3202 | |
3203 | rzio = zio_read(pio, spa, bp, buf->b_data, size, | |
b128c09f | 3204 | arc_read_done, buf, priority, zio_flags, zb); |
34dc7c2f BB |
3205 | |
3206 | if (*arc_flags & ARC_WAIT) | |
3207 | return (zio_wait(rzio)); | |
3208 | ||
3209 | ASSERT(*arc_flags & ARC_NOWAIT); | |
3210 | zio_nowait(rzio); | |
3211 | } | |
3212 | return (0); | |
3213 | } | |
3214 | ||
ab26409d BB |
3215 | arc_prune_t * |
3216 | arc_add_prune_callback(arc_prune_func_t *func, void *private) | |
3217 | { | |
3218 | arc_prune_t *p; | |
3219 | ||
3220 | p = kmem_alloc(sizeof(*p), KM_SLEEP); | |
3221 | p->p_pfunc = func; | |
3222 | p->p_private = private; | |
3223 | list_link_init(&p->p_node); | |
3224 | refcount_create(&p->p_refcnt); | |
3225 | ||
3226 | mutex_enter(&arc_prune_mtx); | |
3227 | refcount_add(&p->p_refcnt, &arc_prune_list); | |
3228 | list_insert_head(&arc_prune_list, p); | |
3229 | mutex_exit(&arc_prune_mtx); | |
3230 | ||
3231 | return (p); | |
3232 | } | |
3233 | ||
3234 | void | |
3235 | arc_remove_prune_callback(arc_prune_t *p) | |
3236 | { | |
3237 | mutex_enter(&arc_prune_mtx); | |
3238 | list_remove(&arc_prune_list, p); | |
3239 | if (refcount_remove(&p->p_refcnt, &arc_prune_list) == 0) { | |
3240 | refcount_destroy(&p->p_refcnt); | |
3241 | kmem_free(p, sizeof (*p)); | |
3242 | } | |
3243 | mutex_exit(&arc_prune_mtx); | |
3244 | } | |
3245 | ||
34dc7c2f BB |
3246 | void |
3247 | arc_set_callback(arc_buf_t *buf, arc_evict_func_t *func, void *private) | |
3248 | { | |
3249 | ASSERT(buf->b_hdr != NULL); | |
3250 | ASSERT(buf->b_hdr->b_state != arc_anon); | |
3251 | ASSERT(!refcount_is_zero(&buf->b_hdr->b_refcnt) || func == NULL); | |
428870ff BB |
3252 | ASSERT(buf->b_efunc == NULL); |
3253 | ASSERT(!HDR_BUF_AVAILABLE(buf->b_hdr)); | |
3254 | ||
34dc7c2f BB |
3255 | buf->b_efunc = func; |
3256 | buf->b_private = private; | |
3257 | } | |
3258 | ||
c06d4368 AX |
3259 | /* |
3260 | * Notify the arc that a block was freed, and thus will never be used again. | |
3261 | */ | |
3262 | void | |
3263 | arc_freed(spa_t *spa, const blkptr_t *bp) | |
3264 | { | |
3265 | arc_buf_hdr_t *hdr; | |
3266 | kmutex_t *hash_lock; | |
3267 | uint64_t guid = spa_load_guid(spa); | |
3268 | ||
3269 | hdr = buf_hash_find(guid, BP_IDENTITY(bp), BP_PHYSICAL_BIRTH(bp), | |
3270 | &hash_lock); | |
3271 | if (hdr == NULL) | |
3272 | return; | |
3273 | if (HDR_BUF_AVAILABLE(hdr)) { | |
3274 | arc_buf_t *buf = hdr->b_buf; | |
3275 | add_reference(hdr, hash_lock, FTAG); | |
3276 | hdr->b_flags &= ~ARC_BUF_AVAILABLE; | |
3277 | mutex_exit(hash_lock); | |
3278 | ||
3279 | arc_release(buf, FTAG); | |
3280 | (void) arc_buf_remove_ref(buf, FTAG); | |
3281 | } else { | |
3282 | mutex_exit(hash_lock); | |
3283 | } | |
3284 | ||
3285 | } | |
3286 | ||
34dc7c2f BB |
3287 | /* |
3288 | * This is used by the DMU to let the ARC know that a buffer is | |
3289 | * being evicted, so the ARC should clean up. If this arc buf | |
3290 | * is not yet in the evicted state, it will be put there. | |
3291 | */ | |
3292 | int | |
3293 | arc_buf_evict(arc_buf_t *buf) | |
3294 | { | |
3295 | arc_buf_hdr_t *hdr; | |
3296 | kmutex_t *hash_lock; | |
3297 | arc_buf_t **bufp; | |
3298 | ||
428870ff | 3299 | mutex_enter(&buf->b_evict_lock); |
34dc7c2f BB |
3300 | hdr = buf->b_hdr; |
3301 | if (hdr == NULL) { | |
3302 | /* | |
3303 | * We are in arc_do_user_evicts(). | |
3304 | */ | |
3305 | ASSERT(buf->b_data == NULL); | |
428870ff | 3306 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f | 3307 | return (0); |
b128c09f BB |
3308 | } else if (buf->b_data == NULL) { |
3309 | arc_buf_t copy = *buf; /* structure assignment */ | |
34dc7c2f | 3310 | /* |
b128c09f BB |
3311 | * We are on the eviction list; process this buffer now |
3312 | * but let arc_do_user_evicts() do the reaping. | |
34dc7c2f | 3313 | */ |
b128c09f | 3314 | buf->b_efunc = NULL; |
428870ff | 3315 | mutex_exit(&buf->b_evict_lock); |
b128c09f BB |
3316 | VERIFY(copy.b_efunc(©) == 0); |
3317 | return (1); | |
34dc7c2f | 3318 | } |
b128c09f BB |
3319 | hash_lock = HDR_LOCK(hdr); |
3320 | mutex_enter(hash_lock); | |
428870ff BB |
3321 | hdr = buf->b_hdr; |
3322 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
34dc7c2f | 3323 | |
34dc7c2f BB |
3324 | ASSERT3U(refcount_count(&hdr->b_refcnt), <, hdr->b_datacnt); |
3325 | ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); | |
3326 | ||
3327 | /* | |
3328 | * Pull this buffer off of the hdr | |
3329 | */ | |
3330 | bufp = &hdr->b_buf; | |
3331 | while (*bufp != buf) | |
3332 | bufp = &(*bufp)->b_next; | |
3333 | *bufp = buf->b_next; | |
3334 | ||
3335 | ASSERT(buf->b_data != NULL); | |
3336 | arc_buf_destroy(buf, FALSE, FALSE); | |
3337 | ||
3338 | if (hdr->b_datacnt == 0) { | |
3339 | arc_state_t *old_state = hdr->b_state; | |
3340 | arc_state_t *evicted_state; | |
3341 | ||
428870ff | 3342 | ASSERT(hdr->b_buf == NULL); |
34dc7c2f BB |
3343 | ASSERT(refcount_is_zero(&hdr->b_refcnt)); |
3344 | ||
3345 | evicted_state = | |
3346 | (old_state == arc_mru) ? arc_mru_ghost : arc_mfu_ghost; | |
3347 | ||
3348 | mutex_enter(&old_state->arcs_mtx); | |
3349 | mutex_enter(&evicted_state->arcs_mtx); | |
3350 | ||
3351 | arc_change_state(evicted_state, hdr, hash_lock); | |
3352 | ASSERT(HDR_IN_HASH_TABLE(hdr)); | |
3353 | hdr->b_flags |= ARC_IN_HASH_TABLE; | |
3354 | hdr->b_flags &= ~ARC_BUF_AVAILABLE; | |
3355 | ||
3356 | mutex_exit(&evicted_state->arcs_mtx); | |
3357 | mutex_exit(&old_state->arcs_mtx); | |
3358 | } | |
3359 | mutex_exit(hash_lock); | |
428870ff | 3360 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
3361 | |
3362 | VERIFY(buf->b_efunc(buf) == 0); | |
3363 | buf->b_efunc = NULL; | |
3364 | buf->b_private = NULL; | |
3365 | buf->b_hdr = NULL; | |
428870ff | 3366 | buf->b_next = NULL; |
34dc7c2f BB |
3367 | kmem_cache_free(buf_cache, buf); |
3368 | return (1); | |
3369 | } | |
3370 | ||
3371 | /* | |
3372 | * Release this buffer from the cache. This must be done | |
3373 | * after a read and prior to modifying the buffer contents. | |
3374 | * If the buffer has more than one reference, we must make | |
b128c09f | 3375 | * a new hdr for the buffer. |
34dc7c2f BB |
3376 | */ |
3377 | void | |
3378 | arc_release(arc_buf_t *buf, void *tag) | |
3379 | { | |
b128c09f | 3380 | arc_buf_hdr_t *hdr; |
428870ff | 3381 | kmutex_t *hash_lock = NULL; |
b128c09f | 3382 | l2arc_buf_hdr_t *l2hdr; |
d4ed6673 | 3383 | uint64_t buf_size = 0; |
34dc7c2f | 3384 | |
428870ff BB |
3385 | /* |
3386 | * It would be nice to assert that if it's DMU metadata (level > | |
3387 | * 0 || it's the dnode file), then it must be syncing context. | |
3388 | * But we don't know that information at this level. | |
3389 | */ | |
3390 | ||
3391 | mutex_enter(&buf->b_evict_lock); | |
b128c09f BB |
3392 | hdr = buf->b_hdr; |
3393 | ||
34dc7c2f BB |
3394 | /* this buffer is not on any list */ |
3395 | ASSERT(refcount_count(&hdr->b_refcnt) > 0); | |
3396 | ||
3397 | if (hdr->b_state == arc_anon) { | |
3398 | /* this buffer is already released */ | |
34dc7c2f | 3399 | ASSERT(buf->b_efunc == NULL); |
9babb374 BB |
3400 | } else { |
3401 | hash_lock = HDR_LOCK(hdr); | |
3402 | mutex_enter(hash_lock); | |
428870ff BB |
3403 | hdr = buf->b_hdr; |
3404 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
34dc7c2f BB |
3405 | } |
3406 | ||
b128c09f BB |
3407 | l2hdr = hdr->b_l2hdr; |
3408 | if (l2hdr) { | |
3409 | mutex_enter(&l2arc_buflist_mtx); | |
3410 | hdr->b_l2hdr = NULL; | |
3411 | buf_size = hdr->b_size; | |
3412 | } | |
3413 | ||
34dc7c2f BB |
3414 | /* |
3415 | * Do we have more than one buf? | |
3416 | */ | |
b128c09f | 3417 | if (hdr->b_datacnt > 1) { |
34dc7c2f BB |
3418 | arc_buf_hdr_t *nhdr; |
3419 | arc_buf_t **bufp; | |
3420 | uint64_t blksz = hdr->b_size; | |
d164b209 | 3421 | uint64_t spa = hdr->b_spa; |
34dc7c2f BB |
3422 | arc_buf_contents_t type = hdr->b_type; |
3423 | uint32_t flags = hdr->b_flags; | |
3424 | ||
b128c09f | 3425 | ASSERT(hdr->b_buf != buf || buf->b_next != NULL); |
34dc7c2f | 3426 | /* |
428870ff BB |
3427 | * Pull the data off of this hdr and attach it to |
3428 | * a new anonymous hdr. | |
34dc7c2f BB |
3429 | */ |
3430 | (void) remove_reference(hdr, hash_lock, tag); | |
3431 | bufp = &hdr->b_buf; | |
3432 | while (*bufp != buf) | |
3433 | bufp = &(*bufp)->b_next; | |
428870ff | 3434 | *bufp = buf->b_next; |
34dc7c2f BB |
3435 | buf->b_next = NULL; |
3436 | ||
3437 | ASSERT3U(hdr->b_state->arcs_size, >=, hdr->b_size); | |
3438 | atomic_add_64(&hdr->b_state->arcs_size, -hdr->b_size); | |
3439 | if (refcount_is_zero(&hdr->b_refcnt)) { | |
3440 | uint64_t *size = &hdr->b_state->arcs_lsize[hdr->b_type]; | |
3441 | ASSERT3U(*size, >=, hdr->b_size); | |
3442 | atomic_add_64(size, -hdr->b_size); | |
3443 | } | |
1eb5bfa3 GW |
3444 | |
3445 | /* | |
3446 | * We're releasing a duplicate user data buffer, update | |
3447 | * our statistics accordingly. | |
3448 | */ | |
3449 | if (hdr->b_type == ARC_BUFC_DATA) { | |
3450 | ARCSTAT_BUMPDOWN(arcstat_duplicate_buffers); | |
3451 | ARCSTAT_INCR(arcstat_duplicate_buffers_size, | |
3452 | -hdr->b_size); | |
3453 | } | |
34dc7c2f | 3454 | hdr->b_datacnt -= 1; |
34dc7c2f BB |
3455 | arc_cksum_verify(buf); |
3456 | ||
3457 | mutex_exit(hash_lock); | |
3458 | ||
3459 | nhdr = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); | |
3460 | nhdr->b_size = blksz; | |
3461 | nhdr->b_spa = spa; | |
3462 | nhdr->b_type = type; | |
3463 | nhdr->b_buf = buf; | |
3464 | nhdr->b_state = arc_anon; | |
3465 | nhdr->b_arc_access = 0; | |
3466 | nhdr->b_flags = flags & ARC_L2_WRITING; | |
3467 | nhdr->b_l2hdr = NULL; | |
3468 | nhdr->b_datacnt = 1; | |
3469 | nhdr->b_freeze_cksum = NULL; | |
3470 | (void) refcount_add(&nhdr->b_refcnt, tag); | |
3471 | buf->b_hdr = nhdr; | |
428870ff | 3472 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
3473 | atomic_add_64(&arc_anon->arcs_size, blksz); |
3474 | } else { | |
428870ff | 3475 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
3476 | ASSERT(refcount_count(&hdr->b_refcnt) == 1); |
3477 | ASSERT(!list_link_active(&hdr->b_arc_node)); | |
3478 | ASSERT(!HDR_IO_IN_PROGRESS(hdr)); | |
428870ff BB |
3479 | if (hdr->b_state != arc_anon) |
3480 | arc_change_state(arc_anon, hdr, hash_lock); | |
34dc7c2f | 3481 | hdr->b_arc_access = 0; |
428870ff BB |
3482 | if (hash_lock) |
3483 | mutex_exit(hash_lock); | |
34dc7c2f | 3484 | |
428870ff | 3485 | buf_discard_identity(hdr); |
34dc7c2f BB |
3486 | arc_buf_thaw(buf); |
3487 | } | |
3488 | buf->b_efunc = NULL; | |
3489 | buf->b_private = NULL; | |
3490 | ||
3491 | if (l2hdr) { | |
c06d4368 | 3492 | ARCSTAT_INCR(arcstat_l2_asize, -l2hdr->b_asize); |
34dc7c2f BB |
3493 | list_remove(l2hdr->b_dev->l2ad_buflist, hdr); |
3494 | kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t)); | |
c06d4368 | 3495 | arc_space_return(L2HDR_SIZE, ARC_SPACE_L2HDRS); |
34dc7c2f | 3496 | ARCSTAT_INCR(arcstat_l2_size, -buf_size); |
34dc7c2f | 3497 | mutex_exit(&l2arc_buflist_mtx); |
b128c09f | 3498 | } |
34dc7c2f BB |
3499 | } |
3500 | ||
3501 | int | |
3502 | arc_released(arc_buf_t *buf) | |
3503 | { | |
b128c09f BB |
3504 | int released; |
3505 | ||
428870ff | 3506 | mutex_enter(&buf->b_evict_lock); |
b128c09f | 3507 | released = (buf->b_data != NULL && buf->b_hdr->b_state == arc_anon); |
428870ff | 3508 | mutex_exit(&buf->b_evict_lock); |
b128c09f | 3509 | return (released); |
34dc7c2f BB |
3510 | } |
3511 | ||
3512 | int | |
3513 | arc_has_callback(arc_buf_t *buf) | |
3514 | { | |
b128c09f BB |
3515 | int callback; |
3516 | ||
428870ff | 3517 | mutex_enter(&buf->b_evict_lock); |
b128c09f | 3518 | callback = (buf->b_efunc != NULL); |
428870ff | 3519 | mutex_exit(&buf->b_evict_lock); |
b128c09f | 3520 | return (callback); |
34dc7c2f BB |
3521 | } |
3522 | ||
3523 | #ifdef ZFS_DEBUG | |
3524 | int | |
3525 | arc_referenced(arc_buf_t *buf) | |
3526 | { | |
b128c09f BB |
3527 | int referenced; |
3528 | ||
428870ff | 3529 | mutex_enter(&buf->b_evict_lock); |
b128c09f | 3530 | referenced = (refcount_count(&buf->b_hdr->b_refcnt)); |
428870ff | 3531 | mutex_exit(&buf->b_evict_lock); |
b128c09f | 3532 | return (referenced); |
34dc7c2f BB |
3533 | } |
3534 | #endif | |
3535 | ||
3536 | static void | |
3537 | arc_write_ready(zio_t *zio) | |
3538 | { | |
3539 | arc_write_callback_t *callback = zio->io_private; | |
3540 | arc_buf_t *buf = callback->awcb_buf; | |
3541 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
3542 | ||
b128c09f BB |
3543 | ASSERT(!refcount_is_zero(&buf->b_hdr->b_refcnt)); |
3544 | callback->awcb_ready(zio, buf, callback->awcb_private); | |
3545 | ||
34dc7c2f BB |
3546 | /* |
3547 | * If the IO is already in progress, then this is a re-write | |
b128c09f BB |
3548 | * attempt, so we need to thaw and re-compute the cksum. |
3549 | * It is the responsibility of the callback to handle the | |
3550 | * accounting for any re-write attempt. | |
34dc7c2f BB |
3551 | */ |
3552 | if (HDR_IO_IN_PROGRESS(hdr)) { | |
34dc7c2f BB |
3553 | mutex_enter(&hdr->b_freeze_lock); |
3554 | if (hdr->b_freeze_cksum != NULL) { | |
3555 | kmem_free(hdr->b_freeze_cksum, sizeof (zio_cksum_t)); | |
3556 | hdr->b_freeze_cksum = NULL; | |
3557 | } | |
3558 | mutex_exit(&hdr->b_freeze_lock); | |
3559 | } | |
3560 | arc_cksum_compute(buf, B_FALSE); | |
3561 | hdr->b_flags |= ARC_IO_IN_PROGRESS; | |
3562 | } | |
3563 | ||
3564 | static void | |
3565 | arc_write_done(zio_t *zio) | |
3566 | { | |
3567 | arc_write_callback_t *callback = zio->io_private; | |
3568 | arc_buf_t *buf = callback->awcb_buf; | |
3569 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
3570 | ||
428870ff BB |
3571 | ASSERT(hdr->b_acb == NULL); |
3572 | ||
3573 | if (zio->io_error == 0) { | |
3574 | hdr->b_dva = *BP_IDENTITY(zio->io_bp); | |
3575 | hdr->b_birth = BP_PHYSICAL_BIRTH(zio->io_bp); | |
3576 | hdr->b_cksum0 = zio->io_bp->blk_cksum.zc_word[0]; | |
3577 | } else { | |
3578 | ASSERT(BUF_EMPTY(hdr)); | |
3579 | } | |
34dc7c2f | 3580 | |
34dc7c2f BB |
3581 | /* |
3582 | * If the block to be written was all-zero, we may have | |
3583 | * compressed it away. In this case no write was performed | |
428870ff BB |
3584 | * so there will be no dva/birth/checksum. The buffer must |
3585 | * therefore remain anonymous (and uncached). | |
34dc7c2f BB |
3586 | */ |
3587 | if (!BUF_EMPTY(hdr)) { | |
3588 | arc_buf_hdr_t *exists; | |
3589 | kmutex_t *hash_lock; | |
3590 | ||
428870ff BB |
3591 | ASSERT(zio->io_error == 0); |
3592 | ||
34dc7c2f BB |
3593 | arc_cksum_verify(buf); |
3594 | ||
3595 | exists = buf_hash_insert(hdr, &hash_lock); | |
3596 | if (exists) { | |
3597 | /* | |
3598 | * This can only happen if we overwrite for | |
3599 | * sync-to-convergence, because we remove | |
3600 | * buffers from the hash table when we arc_free(). | |
3601 | */ | |
428870ff BB |
3602 | if (zio->io_flags & ZIO_FLAG_IO_REWRITE) { |
3603 | if (!BP_EQUAL(&zio->io_bp_orig, zio->io_bp)) | |
3604 | panic("bad overwrite, hdr=%p exists=%p", | |
3605 | (void *)hdr, (void *)exists); | |
3606 | ASSERT(refcount_is_zero(&exists->b_refcnt)); | |
3607 | arc_change_state(arc_anon, exists, hash_lock); | |
3608 | mutex_exit(hash_lock); | |
3609 | arc_hdr_destroy(exists); | |
3610 | exists = buf_hash_insert(hdr, &hash_lock); | |
3611 | ASSERT3P(exists, ==, NULL); | |
3612 | } else { | |
3613 | /* Dedup */ | |
3614 | ASSERT(hdr->b_datacnt == 1); | |
3615 | ASSERT(hdr->b_state == arc_anon); | |
3616 | ASSERT(BP_GET_DEDUP(zio->io_bp)); | |
3617 | ASSERT(BP_GET_LEVEL(zio->io_bp) == 0); | |
3618 | } | |
34dc7c2f BB |
3619 | } |
3620 | hdr->b_flags &= ~ARC_IO_IN_PROGRESS; | |
b128c09f | 3621 | /* if it's not anon, we are doing a scrub */ |
428870ff | 3622 | if (!exists && hdr->b_state == arc_anon) |
b128c09f | 3623 | arc_access(hdr, hash_lock); |
34dc7c2f | 3624 | mutex_exit(hash_lock); |
34dc7c2f BB |
3625 | } else { |
3626 | hdr->b_flags &= ~ARC_IO_IN_PROGRESS; | |
3627 | } | |
3628 | ||
428870ff BB |
3629 | ASSERT(!refcount_is_zero(&hdr->b_refcnt)); |
3630 | callback->awcb_done(zio, buf, callback->awcb_private); | |
34dc7c2f BB |
3631 | |
3632 | kmem_free(callback, sizeof (arc_write_callback_t)); | |
3633 | } | |
3634 | ||
3635 | zio_t * | |
428870ff | 3636 | arc_write(zio_t *pio, spa_t *spa, uint64_t txg, |
c06d4368 AX |
3637 | blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, boolean_t l2arc_compress, |
3638 | const zio_prop_t *zp, arc_done_func_t *ready, arc_done_func_t *done, | |
3639 | void *private, int priority, int zio_flags, const zbookmark_t *zb) | |
34dc7c2f BB |
3640 | { |
3641 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
3642 | arc_write_callback_t *callback; | |
b128c09f | 3643 | zio_t *zio; |
34dc7c2f | 3644 | |
b128c09f | 3645 | ASSERT(ready != NULL); |
428870ff | 3646 | ASSERT(done != NULL); |
34dc7c2f BB |
3647 | ASSERT(!HDR_IO_ERROR(hdr)); |
3648 | ASSERT((hdr->b_flags & ARC_IO_IN_PROGRESS) == 0); | |
428870ff | 3649 | ASSERT(hdr->b_acb == NULL); |
b128c09f BB |
3650 | if (l2arc) |
3651 | hdr->b_flags |= ARC_L2CACHE; | |
c06d4368 AX |
3652 | if (l2arc_compress) |
3653 | hdr->b_flags |= ARC_L2COMPRESS; | |
b8d06fca | 3654 | callback = kmem_zalloc(sizeof (arc_write_callback_t), KM_PUSHPAGE); |
34dc7c2f BB |
3655 | callback->awcb_ready = ready; |
3656 | callback->awcb_done = done; | |
3657 | callback->awcb_private = private; | |
3658 | callback->awcb_buf = buf; | |
b128c09f | 3659 | |
428870ff | 3660 | zio = zio_write(pio, spa, txg, bp, buf->b_data, hdr->b_size, zp, |
b128c09f | 3661 | arc_write_ready, arc_write_done, callback, priority, zio_flags, zb); |
34dc7c2f BB |
3662 | |
3663 | return (zio); | |
3664 | } | |
3665 | ||
34dc7c2f | 3666 | static int |
9babb374 | 3667 | arc_memory_throttle(uint64_t reserve, uint64_t inflight_data, uint64_t txg) |
34dc7c2f BB |
3668 | { |
3669 | #ifdef _KERNEL | |
302f753f | 3670 | uint64_t available_memory; |
34dc7c2f | 3671 | |
0c5493d4 BB |
3672 | if (zfs_arc_memory_throttle_disable) |
3673 | return (0); | |
3674 | ||
302f753f BB |
3675 | /* Easily reclaimable memory (free + inactive + arc-evictable) */ |
3676 | available_memory = ptob(spl_kmem_availrmem()) + arc_evictable_memory(); | |
34dc7c2f | 3677 | |
302f753f | 3678 | if (available_memory <= zfs_write_limit_max) { |
34dc7c2f | 3679 | ARCSTAT_INCR(arcstat_memory_throttle_count, 1); |
570827e1 | 3680 | DMU_TX_STAT_BUMP(dmu_tx_memory_reclaim); |
34dc7c2f BB |
3681 | return (EAGAIN); |
3682 | } | |
34dc7c2f BB |
3683 | |
3684 | if (inflight_data > available_memory / 4) { | |
3685 | ARCSTAT_INCR(arcstat_memory_throttle_count, 1); | |
570827e1 | 3686 | DMU_TX_STAT_BUMP(dmu_tx_memory_inflight); |
34dc7c2f BB |
3687 | return (ERESTART); |
3688 | } | |
3689 | #endif | |
3690 | return (0); | |
3691 | } | |
3692 | ||
3693 | void | |
3694 | arc_tempreserve_clear(uint64_t reserve) | |
3695 | { | |
3696 | atomic_add_64(&arc_tempreserve, -reserve); | |
3697 | ASSERT((int64_t)arc_tempreserve >= 0); | |
3698 | } | |
3699 | ||
3700 | int | |
3701 | arc_tempreserve_space(uint64_t reserve, uint64_t txg) | |
3702 | { | |
3703 | int error; | |
9babb374 | 3704 | uint64_t anon_size; |
34dc7c2f BB |
3705 | |
3706 | #ifdef ZFS_DEBUG | |
3707 | /* | |
3708 | * Once in a while, fail for no reason. Everything should cope. | |
3709 | */ | |
3710 | if (spa_get_random(10000) == 0) { | |
3711 | dprintf("forcing random failure\n"); | |
3712 | return (ERESTART); | |
3713 | } | |
3714 | #endif | |
3715 | if (reserve > arc_c/4 && !arc_no_grow) | |
3716 | arc_c = MIN(arc_c_max, reserve * 4); | |
570827e1 BB |
3717 | if (reserve > arc_c) { |
3718 | DMU_TX_STAT_BUMP(dmu_tx_memory_reserve); | |
34dc7c2f | 3719 | return (ENOMEM); |
570827e1 | 3720 | } |
34dc7c2f | 3721 | |
9babb374 BB |
3722 | /* |
3723 | * Don't count loaned bufs as in flight dirty data to prevent long | |
3724 | * network delays from blocking transactions that are ready to be | |
3725 | * assigned to a txg. | |
3726 | */ | |
3727 | anon_size = MAX((int64_t)(arc_anon->arcs_size - arc_loaned_bytes), 0); | |
3728 | ||
34dc7c2f BB |
3729 | /* |
3730 | * Writes will, almost always, require additional memory allocations | |
3731 | * in order to compress/encrypt/etc the data. We therefor need to | |
3732 | * make sure that there is sufficient available memory for this. | |
3733 | */ | |
c65aa5b2 | 3734 | if ((error = arc_memory_throttle(reserve, anon_size, txg))) |
34dc7c2f BB |
3735 | return (error); |
3736 | ||
3737 | /* | |
3738 | * Throttle writes when the amount of dirty data in the cache | |
3739 | * gets too large. We try to keep the cache less than half full | |
3740 | * of dirty blocks so that our sync times don't grow too large. | |
3741 | * Note: if two requests come in concurrently, we might let them | |
3742 | * both succeed, when one of them should fail. Not a huge deal. | |
3743 | */ | |
9babb374 BB |
3744 | |
3745 | if (reserve + arc_tempreserve + anon_size > arc_c / 2 && | |
3746 | anon_size > arc_c / 4) { | |
34dc7c2f BB |
3747 | dprintf("failing, arc_tempreserve=%lluK anon_meta=%lluK " |
3748 | "anon_data=%lluK tempreserve=%lluK arc_c=%lluK\n", | |
3749 | arc_tempreserve>>10, | |
3750 | arc_anon->arcs_lsize[ARC_BUFC_METADATA]>>10, | |
3751 | arc_anon->arcs_lsize[ARC_BUFC_DATA]>>10, | |
3752 | reserve>>10, arc_c>>10); | |
570827e1 | 3753 | DMU_TX_STAT_BUMP(dmu_tx_dirty_throttle); |
34dc7c2f BB |
3754 | return (ERESTART); |
3755 | } | |
3756 | atomic_add_64(&arc_tempreserve, reserve); | |
3757 | return (0); | |
3758 | } | |
3759 | ||
13be560d BB |
3760 | static void |
3761 | arc_kstat_update_state(arc_state_t *state, kstat_named_t *size, | |
3762 | kstat_named_t *evict_data, kstat_named_t *evict_metadata) | |
3763 | { | |
3764 | size->value.ui64 = state->arcs_size; | |
3765 | evict_data->value.ui64 = state->arcs_lsize[ARC_BUFC_DATA]; | |
3766 | evict_metadata->value.ui64 = state->arcs_lsize[ARC_BUFC_METADATA]; | |
3767 | } | |
3768 | ||
3769 | static int | |
3770 | arc_kstat_update(kstat_t *ksp, int rw) | |
3771 | { | |
3772 | arc_stats_t *as = ksp->ks_data; | |
3773 | ||
3774 | if (rw == KSTAT_WRITE) { | |
3775 | return (EACCES); | |
3776 | } else { | |
3777 | arc_kstat_update_state(arc_anon, | |
3778 | &as->arcstat_anon_size, | |
3779 | &as->arcstat_anon_evict_data, | |
3780 | &as->arcstat_anon_evict_metadata); | |
3781 | arc_kstat_update_state(arc_mru, | |
3782 | &as->arcstat_mru_size, | |
3783 | &as->arcstat_mru_evict_data, | |
3784 | &as->arcstat_mru_evict_metadata); | |
3785 | arc_kstat_update_state(arc_mru_ghost, | |
3786 | &as->arcstat_mru_ghost_size, | |
3787 | &as->arcstat_mru_ghost_evict_data, | |
3788 | &as->arcstat_mru_ghost_evict_metadata); | |
3789 | arc_kstat_update_state(arc_mfu, | |
3790 | &as->arcstat_mfu_size, | |
3791 | &as->arcstat_mfu_evict_data, | |
3792 | &as->arcstat_mfu_evict_metadata); | |
fc41c640 | 3793 | arc_kstat_update_state(arc_mfu_ghost, |
13be560d BB |
3794 | &as->arcstat_mfu_ghost_size, |
3795 | &as->arcstat_mfu_ghost_evict_data, | |
3796 | &as->arcstat_mfu_ghost_evict_metadata); | |
3797 | } | |
3798 | ||
3799 | return (0); | |
3800 | } | |
3801 | ||
34dc7c2f BB |
3802 | void |
3803 | arc_init(void) | |
3804 | { | |
3805 | mutex_init(&arc_reclaim_thr_lock, NULL, MUTEX_DEFAULT, NULL); | |
3806 | cv_init(&arc_reclaim_thr_cv, NULL, CV_DEFAULT, NULL); | |
3807 | ||
3808 | /* Convert seconds to clock ticks */ | |
c06d4368 | 3809 | zfs_arc_min_prefetch_lifespan = 1 * hz; |
34dc7c2f BB |
3810 | |
3811 | /* Start out with 1/8 of all memory */ | |
3812 | arc_c = physmem * PAGESIZE / 8; | |
3813 | ||
3814 | #ifdef _KERNEL | |
3815 | /* | |
3816 | * On architectures where the physical memory can be larger | |
3817 | * than the addressable space (intel in 32-bit mode), we may | |
3818 | * need to limit the cache to 1/8 of VM size. | |
3819 | */ | |
3820 | arc_c = MIN(arc_c, vmem_size(heap_arena, VMEM_ALLOC | VMEM_FREE) / 8); | |
7cb67b45 BB |
3821 | /* |
3822 | * Register a shrinker to support synchronous (direct) memory | |
3823 | * reclaim from the arc. This is done to prevent kswapd from | |
3824 | * swapping out pages when it is preferable to shrink the arc. | |
3825 | */ | |
3826 | spl_register_shrinker(&arc_shrinker); | |
34dc7c2f BB |
3827 | #endif |
3828 | ||
3829 | /* set min cache to 1/32 of all memory, or 64MB, whichever is more */ | |
3830 | arc_c_min = MAX(arc_c / 4, 64<<20); | |
518b4876 | 3831 | /* set max to 1/2 of all memory */ |
23bdb07d | 3832 | arc_c_max = MAX(arc_c * 4, arc_c_max); |
34dc7c2f BB |
3833 | |
3834 | /* | |
3835 | * Allow the tunables to override our calculations if they are | |
3836 | * reasonable (ie. over 64MB) | |
3837 | */ | |
3838 | if (zfs_arc_max > 64<<20 && zfs_arc_max < physmem * PAGESIZE) | |
3839 | arc_c_max = zfs_arc_max; | |
3840 | if (zfs_arc_min > 64<<20 && zfs_arc_min <= arc_c_max) | |
3841 | arc_c_min = zfs_arc_min; | |
3842 | ||
3843 | arc_c = arc_c_max; | |
3844 | arc_p = (arc_c >> 1); | |
3845 | ||
3846 | /* limit meta-data to 1/4 of the arc capacity */ | |
3847 | arc_meta_limit = arc_c_max / 4; | |
1834f2d8 | 3848 | arc_meta_max = 0; |
34dc7c2f BB |
3849 | |
3850 | /* Allow the tunable to override if it is reasonable */ | |
3851 | if (zfs_arc_meta_limit > 0 && zfs_arc_meta_limit <= arc_c_max) | |
3852 | arc_meta_limit = zfs_arc_meta_limit; | |
3853 | ||
3854 | if (arc_c_min < arc_meta_limit / 2 && zfs_arc_min == 0) | |
3855 | arc_c_min = arc_meta_limit / 2; | |
3856 | ||
3857 | /* if kmem_flags are set, lets try to use less memory */ | |
3858 | if (kmem_debugging()) | |
3859 | arc_c = arc_c / 2; | |
3860 | if (arc_c < arc_c_min) | |
3861 | arc_c = arc_c_min; | |
3862 | ||
3863 | arc_anon = &ARC_anon; | |
3864 | arc_mru = &ARC_mru; | |
3865 | arc_mru_ghost = &ARC_mru_ghost; | |
3866 | arc_mfu = &ARC_mfu; | |
3867 | arc_mfu_ghost = &ARC_mfu_ghost; | |
3868 | arc_l2c_only = &ARC_l2c_only; | |
3869 | arc_size = 0; | |
3870 | ||
3871 | mutex_init(&arc_anon->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3872 | mutex_init(&arc_mru->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3873 | mutex_init(&arc_mru_ghost->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3874 | mutex_init(&arc_mfu->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3875 | mutex_init(&arc_mfu_ghost->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3876 | mutex_init(&arc_l2c_only->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3877 | ||
3878 | list_create(&arc_mru->arcs_list[ARC_BUFC_METADATA], | |
3879 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3880 | list_create(&arc_mru->arcs_list[ARC_BUFC_DATA], | |
3881 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3882 | list_create(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA], | |
3883 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3884 | list_create(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA], | |
3885 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3886 | list_create(&arc_mfu->arcs_list[ARC_BUFC_METADATA], | |
3887 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3888 | list_create(&arc_mfu->arcs_list[ARC_BUFC_DATA], | |
3889 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3890 | list_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA], | |
3891 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3892 | list_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA], | |
3893 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3894 | list_create(&arc_l2c_only->arcs_list[ARC_BUFC_METADATA], | |
3895 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3896 | list_create(&arc_l2c_only->arcs_list[ARC_BUFC_DATA], | |
3897 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3898 | ||
3899 | buf_init(); | |
3900 | ||
3901 | arc_thread_exit = 0; | |
ab26409d BB |
3902 | list_create(&arc_prune_list, sizeof (arc_prune_t), |
3903 | offsetof(arc_prune_t, p_node)); | |
34dc7c2f | 3904 | arc_eviction_list = NULL; |
ab26409d | 3905 | mutex_init(&arc_prune_mtx, NULL, MUTEX_DEFAULT, NULL); |
34dc7c2f BB |
3906 | mutex_init(&arc_eviction_mtx, NULL, MUTEX_DEFAULT, NULL); |
3907 | bzero(&arc_eviction_hdr, sizeof (arc_buf_hdr_t)); | |
3908 | ||
3909 | arc_ksp = kstat_create("zfs", 0, "arcstats", "misc", KSTAT_TYPE_NAMED, | |
3910 | sizeof (arc_stats) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL); | |
3911 | ||
3912 | if (arc_ksp != NULL) { | |
3913 | arc_ksp->ks_data = &arc_stats; | |
13be560d | 3914 | arc_ksp->ks_update = arc_kstat_update; |
34dc7c2f BB |
3915 | kstat_install(arc_ksp); |
3916 | } | |
3917 | ||
302f753f | 3918 | (void) thread_create(NULL, 0, arc_adapt_thread, NULL, 0, &p0, |
34dc7c2f BB |
3919 | TS_RUN, minclsyspri); |
3920 | ||
3921 | arc_dead = FALSE; | |
b128c09f | 3922 | arc_warm = B_FALSE; |
34dc7c2f BB |
3923 | |
3924 | if (zfs_write_limit_max == 0) | |
b128c09f | 3925 | zfs_write_limit_max = ptob(physmem) >> zfs_write_limit_shift; |
34dc7c2f BB |
3926 | else |
3927 | zfs_write_limit_shift = 0; | |
b128c09f | 3928 | mutex_init(&zfs_write_limit_lock, NULL, MUTEX_DEFAULT, NULL); |
34dc7c2f BB |
3929 | } |
3930 | ||
3931 | void | |
3932 | arc_fini(void) | |
3933 | { | |
ab26409d BB |
3934 | arc_prune_t *p; |
3935 | ||
34dc7c2f | 3936 | mutex_enter(&arc_reclaim_thr_lock); |
7cb67b45 BB |
3937 | #ifdef _KERNEL |
3938 | spl_unregister_shrinker(&arc_shrinker); | |
3939 | #endif /* _KERNEL */ | |
3940 | ||
34dc7c2f BB |
3941 | arc_thread_exit = 1; |
3942 | while (arc_thread_exit != 0) | |
3943 | cv_wait(&arc_reclaim_thr_cv, &arc_reclaim_thr_lock); | |
3944 | mutex_exit(&arc_reclaim_thr_lock); | |
3945 | ||
3946 | arc_flush(NULL); | |
3947 | ||
3948 | arc_dead = TRUE; | |
3949 | ||
3950 | if (arc_ksp != NULL) { | |
3951 | kstat_delete(arc_ksp); | |
3952 | arc_ksp = NULL; | |
3953 | } | |
3954 | ||
ab26409d BB |
3955 | mutex_enter(&arc_prune_mtx); |
3956 | while ((p = list_head(&arc_prune_list)) != NULL) { | |
3957 | list_remove(&arc_prune_list, p); | |
3958 | refcount_remove(&p->p_refcnt, &arc_prune_list); | |
3959 | refcount_destroy(&p->p_refcnt); | |
3960 | kmem_free(p, sizeof (*p)); | |
3961 | } | |
3962 | mutex_exit(&arc_prune_mtx); | |
3963 | ||
3964 | list_destroy(&arc_prune_list); | |
3965 | mutex_destroy(&arc_prune_mtx); | |
34dc7c2f BB |
3966 | mutex_destroy(&arc_eviction_mtx); |
3967 | mutex_destroy(&arc_reclaim_thr_lock); | |
3968 | cv_destroy(&arc_reclaim_thr_cv); | |
3969 | ||
3970 | list_destroy(&arc_mru->arcs_list[ARC_BUFC_METADATA]); | |
3971 | list_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA]); | |
3972 | list_destroy(&arc_mfu->arcs_list[ARC_BUFC_METADATA]); | |
3973 | list_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA]); | |
3974 | list_destroy(&arc_mru->arcs_list[ARC_BUFC_DATA]); | |
3975 | list_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA]); | |
3976 | list_destroy(&arc_mfu->arcs_list[ARC_BUFC_DATA]); | |
3977 | list_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA]); | |
3978 | ||
3979 | mutex_destroy(&arc_anon->arcs_mtx); | |
3980 | mutex_destroy(&arc_mru->arcs_mtx); | |
3981 | mutex_destroy(&arc_mru_ghost->arcs_mtx); | |
3982 | mutex_destroy(&arc_mfu->arcs_mtx); | |
3983 | mutex_destroy(&arc_mfu_ghost->arcs_mtx); | |
fb5f0bc8 | 3984 | mutex_destroy(&arc_l2c_only->arcs_mtx); |
34dc7c2f | 3985 | |
b128c09f BB |
3986 | mutex_destroy(&zfs_write_limit_lock); |
3987 | ||
34dc7c2f | 3988 | buf_fini(); |
9babb374 BB |
3989 | |
3990 | ASSERT(arc_loaned_bytes == 0); | |
34dc7c2f BB |
3991 | } |
3992 | ||
3993 | /* | |
3994 | * Level 2 ARC | |
3995 | * | |
3996 | * The level 2 ARC (L2ARC) is a cache layer in-between main memory and disk. | |
3997 | * It uses dedicated storage devices to hold cached data, which are populated | |
3998 | * using large infrequent writes. The main role of this cache is to boost | |
3999 | * the performance of random read workloads. The intended L2ARC devices | |
4000 | * include short-stroked disks, solid state disks, and other media with | |
4001 | * substantially faster read latency than disk. | |
4002 | * | |
4003 | * +-----------------------+ | |
4004 | * | ARC | | |
4005 | * +-----------------------+ | |
4006 | * | ^ ^ | |
4007 | * | | | | |
4008 | * l2arc_feed_thread() arc_read() | |
4009 | * | | | | |
4010 | * | l2arc read | | |
4011 | * V | | | |
4012 | * +---------------+ | | |
4013 | * | L2ARC | | | |
4014 | * +---------------+ | | |
4015 | * | ^ | | |
4016 | * l2arc_write() | | | |
4017 | * | | | | |
4018 | * V | | | |
4019 | * +-------+ +-------+ | |
4020 | * | vdev | | vdev | | |
4021 | * | cache | | cache | | |
4022 | * +-------+ +-------+ | |
4023 | * +=========+ .-----. | |
4024 | * : L2ARC : |-_____-| | |
4025 | * : devices : | Disks | | |
4026 | * +=========+ `-_____-' | |
4027 | * | |
4028 | * Read requests are satisfied from the following sources, in order: | |
4029 | * | |
4030 | * 1) ARC | |
4031 | * 2) vdev cache of L2ARC devices | |
4032 | * 3) L2ARC devices | |
4033 | * 4) vdev cache of disks | |
4034 | * 5) disks | |
4035 | * | |
4036 | * Some L2ARC device types exhibit extremely slow write performance. | |
4037 | * To accommodate for this there are some significant differences between | |
4038 | * the L2ARC and traditional cache design: | |
4039 | * | |
4040 | * 1. There is no eviction path from the ARC to the L2ARC. Evictions from | |
4041 | * the ARC behave as usual, freeing buffers and placing headers on ghost | |
4042 | * lists. The ARC does not send buffers to the L2ARC during eviction as | |
4043 | * this would add inflated write latencies for all ARC memory pressure. | |
4044 | * | |
4045 | * 2. The L2ARC attempts to cache data from the ARC before it is evicted. | |
4046 | * It does this by periodically scanning buffers from the eviction-end of | |
4047 | * the MFU and MRU ARC lists, copying them to the L2ARC devices if they are | |
c06d4368 AX |
4048 | * not already there. It scans until a headroom of buffers is satisfied, |
4049 | * which itself is a buffer for ARC eviction. If a compressible buffer is | |
4050 | * found during scanning and selected for writing to an L2ARC device, we | |
4051 | * temporarily boost scanning headroom during the next scan cycle to make | |
4052 | * sure we adapt to compression effects (which might significantly reduce | |
4053 | * the data volume we write to L2ARC). The thread that does this is | |
34dc7c2f BB |
4054 | * l2arc_feed_thread(), illustrated below; example sizes are included to |
4055 | * provide a better sense of ratio than this diagram: | |
4056 | * | |
4057 | * head --> tail | |
4058 | * +---------------------+----------+ | |
4059 | * ARC_mfu |:::::#:::::::::::::::|o#o###o###|-->. # already on L2ARC | |
4060 | * +---------------------+----------+ | o L2ARC eligible | |
4061 | * ARC_mru |:#:::::::::::::::::::|#o#ooo####|-->| : ARC buffer | |
4062 | * +---------------------+----------+ | | |
4063 | * 15.9 Gbytes ^ 32 Mbytes | | |
4064 | * headroom | | |
4065 | * l2arc_feed_thread() | |
4066 | * | | |
4067 | * l2arc write hand <--[oooo]--' | |
4068 | * | 8 Mbyte | |
4069 | * | write max | |
4070 | * V | |
4071 | * +==============================+ | |
4072 | * L2ARC dev |####|#|###|###| |####| ... | | |
4073 | * +==============================+ | |
4074 | * 32 Gbytes | |
4075 | * | |
4076 | * 3. If an ARC buffer is copied to the L2ARC but then hit instead of | |
4077 | * evicted, then the L2ARC has cached a buffer much sooner than it probably | |
4078 | * needed to, potentially wasting L2ARC device bandwidth and storage. It is | |
4079 | * safe to say that this is an uncommon case, since buffers at the end of | |
4080 | * the ARC lists have moved there due to inactivity. | |
4081 | * | |
4082 | * 4. If the ARC evicts faster than the L2ARC can maintain a headroom, | |
4083 | * then the L2ARC simply misses copying some buffers. This serves as a | |
4084 | * pressure valve to prevent heavy read workloads from both stalling the ARC | |
4085 | * with waits and clogging the L2ARC with writes. This also helps prevent | |
4086 | * the potential for the L2ARC to churn if it attempts to cache content too | |
4087 | * quickly, such as during backups of the entire pool. | |
4088 | * | |
b128c09f BB |
4089 | * 5. After system boot and before the ARC has filled main memory, there are |
4090 | * no evictions from the ARC and so the tails of the ARC_mfu and ARC_mru | |
4091 | * lists can remain mostly static. Instead of searching from tail of these | |
4092 | * lists as pictured, the l2arc_feed_thread() will search from the list heads | |
4093 | * for eligible buffers, greatly increasing its chance of finding them. | |
4094 | * | |
4095 | * The L2ARC device write speed is also boosted during this time so that | |
4096 | * the L2ARC warms up faster. Since there have been no ARC evictions yet, | |
4097 | * there are no L2ARC reads, and no fear of degrading read performance | |
4098 | * through increased writes. | |
4099 | * | |
4100 | * 6. Writes to the L2ARC devices are grouped and sent in-sequence, so that | |
34dc7c2f BB |
4101 | * the vdev queue can aggregate them into larger and fewer writes. Each |
4102 | * device is written to in a rotor fashion, sweeping writes through | |
4103 | * available space then repeating. | |
4104 | * | |
b128c09f | 4105 | * 7. The L2ARC does not store dirty content. It never needs to flush |
34dc7c2f BB |
4106 | * write buffers back to disk based storage. |
4107 | * | |
b128c09f | 4108 | * 8. If an ARC buffer is written (and dirtied) which also exists in the |
34dc7c2f BB |
4109 | * L2ARC, the now stale L2ARC buffer is immediately dropped. |
4110 | * | |
4111 | * The performance of the L2ARC can be tweaked by a number of tunables, which | |
4112 | * may be necessary for different workloads: | |
4113 | * | |
4114 | * l2arc_write_max max write bytes per interval | |
b128c09f | 4115 | * l2arc_write_boost extra write bytes during device warmup |
34dc7c2f | 4116 | * l2arc_noprefetch skip caching prefetched buffers |
c06d4368 | 4117 | * l2arc_nocompress skip compressing buffers |
34dc7c2f | 4118 | * l2arc_headroom number of max device writes to precache |
c06d4368 AX |
4119 | * l2arc_headroom_boost when we find compressed buffers during ARC |
4120 | * scanning, we multiply headroom by this | |
4121 | * percentage factor for the next scan cycle, | |
4122 | * since more compressed buffers are likely to | |
4123 | * be present | |
34dc7c2f BB |
4124 | * l2arc_feed_secs seconds between L2ARC writing |
4125 | * | |
4126 | * Tunables may be removed or added as future performance improvements are | |
4127 | * integrated, and also may become zpool properties. | |
d164b209 BB |
4128 | * |
4129 | * There are three key functions that control how the L2ARC warms up: | |
4130 | * | |
4131 | * l2arc_write_eligible() check if a buffer is eligible to cache | |
4132 | * l2arc_write_size() calculate how much to write | |
4133 | * l2arc_write_interval() calculate sleep delay between writes | |
4134 | * | |
4135 | * These three functions determine what to write, how much, and how quickly | |
4136 | * to send writes. | |
34dc7c2f BB |
4137 | */ |
4138 | ||
d164b209 BB |
4139 | static boolean_t |
4140 | l2arc_write_eligible(uint64_t spa_guid, arc_buf_hdr_t *ab) | |
4141 | { | |
4142 | /* | |
4143 | * A buffer is *not* eligible for the L2ARC if it: | |
4144 | * 1. belongs to a different spa. | |
428870ff BB |
4145 | * 2. is already cached on the L2ARC. |
4146 | * 3. has an I/O in progress (it may be an incomplete read). | |
4147 | * 4. is flagged not eligible (zfs property). | |
d164b209 | 4148 | */ |
428870ff | 4149 | if (ab->b_spa != spa_guid || ab->b_l2hdr != NULL || |
d164b209 BB |
4150 | HDR_IO_IN_PROGRESS(ab) || !HDR_L2CACHE(ab)) |
4151 | return (B_FALSE); | |
4152 | ||
4153 | return (B_TRUE); | |
4154 | } | |
4155 | ||
4156 | static uint64_t | |
c06d4368 | 4157 | l2arc_write_size(void) |
d164b209 BB |
4158 | { |
4159 | uint64_t size; | |
4160 | ||
c06d4368 AX |
4161 | /* |
4162 | * Make sure our globals have meaningful values in case the user | |
4163 | * altered them. | |
4164 | */ | |
4165 | size = l2arc_write_max; | |
4166 | if (size == 0) { | |
4167 | cmn_err(CE_NOTE, "Bad value for l2arc_write_max, value must " | |
4168 | "be greater than zero, resetting it to the default (%d)", | |
4169 | L2ARC_WRITE_SIZE); | |
4170 | size = l2arc_write_max = L2ARC_WRITE_SIZE; | |
4171 | } | |
d164b209 BB |
4172 | |
4173 | if (arc_warm == B_FALSE) | |
c06d4368 | 4174 | size += l2arc_write_boost; |
d164b209 BB |
4175 | |
4176 | return (size); | |
4177 | ||
4178 | } | |
4179 | ||
4180 | static clock_t | |
4181 | l2arc_write_interval(clock_t began, uint64_t wanted, uint64_t wrote) | |
4182 | { | |
428870ff | 4183 | clock_t interval, next, now; |
d164b209 BB |
4184 | |
4185 | /* | |
4186 | * If the ARC lists are busy, increase our write rate; if the | |
4187 | * lists are stale, idle back. This is achieved by checking | |
4188 | * how much we previously wrote - if it was more than half of | |
4189 | * what we wanted, schedule the next write much sooner. | |
4190 | */ | |
4191 | if (l2arc_feed_again && wrote > (wanted / 2)) | |
4192 | interval = (hz * l2arc_feed_min_ms) / 1000; | |
4193 | else | |
4194 | interval = hz * l2arc_feed_secs; | |
4195 | ||
428870ff BB |
4196 | now = ddi_get_lbolt(); |
4197 | next = MAX(now, MIN(now + interval, began + interval)); | |
d164b209 BB |
4198 | |
4199 | return (next); | |
4200 | } | |
4201 | ||
34dc7c2f BB |
4202 | static void |
4203 | l2arc_hdr_stat_add(void) | |
4204 | { | |
c06d4368 | 4205 | ARCSTAT_INCR(arcstat_l2_hdr_size, HDR_SIZE); |
34dc7c2f BB |
4206 | ARCSTAT_INCR(arcstat_hdr_size, -HDR_SIZE); |
4207 | } | |
4208 | ||
4209 | static void | |
4210 | l2arc_hdr_stat_remove(void) | |
4211 | { | |
c06d4368 | 4212 | ARCSTAT_INCR(arcstat_l2_hdr_size, -HDR_SIZE); |
34dc7c2f BB |
4213 | ARCSTAT_INCR(arcstat_hdr_size, HDR_SIZE); |
4214 | } | |
4215 | ||
4216 | /* | |
4217 | * Cycle through L2ARC devices. This is how L2ARC load balances. | |
b128c09f | 4218 | * If a device is returned, this also returns holding the spa config lock. |
34dc7c2f BB |
4219 | */ |
4220 | static l2arc_dev_t * | |
4221 | l2arc_dev_get_next(void) | |
4222 | { | |
b128c09f | 4223 | l2arc_dev_t *first, *next = NULL; |
34dc7c2f | 4224 | |
b128c09f BB |
4225 | /* |
4226 | * Lock out the removal of spas (spa_namespace_lock), then removal | |
4227 | * of cache devices (l2arc_dev_mtx). Once a device has been selected, | |
4228 | * both locks will be dropped and a spa config lock held instead. | |
4229 | */ | |
4230 | mutex_enter(&spa_namespace_lock); | |
4231 | mutex_enter(&l2arc_dev_mtx); | |
4232 | ||
4233 | /* if there are no vdevs, there is nothing to do */ | |
4234 | if (l2arc_ndev == 0) | |
4235 | goto out; | |
4236 | ||
4237 | first = NULL; | |
4238 | next = l2arc_dev_last; | |
4239 | do { | |
4240 | /* loop around the list looking for a non-faulted vdev */ | |
4241 | if (next == NULL) { | |
34dc7c2f | 4242 | next = list_head(l2arc_dev_list); |
b128c09f BB |
4243 | } else { |
4244 | next = list_next(l2arc_dev_list, next); | |
4245 | if (next == NULL) | |
4246 | next = list_head(l2arc_dev_list); | |
4247 | } | |
4248 | ||
4249 | /* if we have come back to the start, bail out */ | |
4250 | if (first == NULL) | |
4251 | first = next; | |
4252 | else if (next == first) | |
4253 | break; | |
4254 | ||
4255 | } while (vdev_is_dead(next->l2ad_vdev)); | |
4256 | ||
4257 | /* if we were unable to find any usable vdevs, return NULL */ | |
4258 | if (vdev_is_dead(next->l2ad_vdev)) | |
4259 | next = NULL; | |
34dc7c2f BB |
4260 | |
4261 | l2arc_dev_last = next; | |
4262 | ||
b128c09f BB |
4263 | out: |
4264 | mutex_exit(&l2arc_dev_mtx); | |
4265 | ||
4266 | /* | |
4267 | * Grab the config lock to prevent the 'next' device from being | |
4268 | * removed while we are writing to it. | |
4269 | */ | |
4270 | if (next != NULL) | |
4271 | spa_config_enter(next->l2ad_spa, SCL_L2ARC, next, RW_READER); | |
4272 | mutex_exit(&spa_namespace_lock); | |
4273 | ||
34dc7c2f BB |
4274 | return (next); |
4275 | } | |
4276 | ||
b128c09f BB |
4277 | /* |
4278 | * Free buffers that were tagged for destruction. | |
4279 | */ | |
4280 | static void | |
0bc8fd78 | 4281 | l2arc_do_free_on_write(void) |
b128c09f BB |
4282 | { |
4283 | list_t *buflist; | |
4284 | l2arc_data_free_t *df, *df_prev; | |
4285 | ||
4286 | mutex_enter(&l2arc_free_on_write_mtx); | |
4287 | buflist = l2arc_free_on_write; | |
4288 | ||
4289 | for (df = list_tail(buflist); df; df = df_prev) { | |
4290 | df_prev = list_prev(buflist, df); | |
4291 | ASSERT(df->l2df_data != NULL); | |
4292 | ASSERT(df->l2df_func != NULL); | |
4293 | df->l2df_func(df->l2df_data, df->l2df_size); | |
4294 | list_remove(buflist, df); | |
4295 | kmem_free(df, sizeof (l2arc_data_free_t)); | |
4296 | } | |
4297 | ||
4298 | mutex_exit(&l2arc_free_on_write_mtx); | |
4299 | } | |
4300 | ||
34dc7c2f BB |
4301 | /* |
4302 | * A write to a cache device has completed. Update all headers to allow | |
4303 | * reads from these buffers to begin. | |
4304 | */ | |
4305 | static void | |
4306 | l2arc_write_done(zio_t *zio) | |
4307 | { | |
4308 | l2arc_write_callback_t *cb; | |
4309 | l2arc_dev_t *dev; | |
4310 | list_t *buflist; | |
34dc7c2f | 4311 | arc_buf_hdr_t *head, *ab, *ab_prev; |
b128c09f | 4312 | l2arc_buf_hdr_t *abl2; |
34dc7c2f BB |
4313 | kmutex_t *hash_lock; |
4314 | ||
4315 | cb = zio->io_private; | |
4316 | ASSERT(cb != NULL); | |
4317 | dev = cb->l2wcb_dev; | |
4318 | ASSERT(dev != NULL); | |
4319 | head = cb->l2wcb_head; | |
4320 | ASSERT(head != NULL); | |
4321 | buflist = dev->l2ad_buflist; | |
4322 | ASSERT(buflist != NULL); | |
4323 | DTRACE_PROBE2(l2arc__iodone, zio_t *, zio, | |
4324 | l2arc_write_callback_t *, cb); | |
4325 | ||
4326 | if (zio->io_error != 0) | |
4327 | ARCSTAT_BUMP(arcstat_l2_writes_error); | |
4328 | ||
4329 | mutex_enter(&l2arc_buflist_mtx); | |
4330 | ||
4331 | /* | |
4332 | * All writes completed, or an error was hit. | |
4333 | */ | |
4334 | for (ab = list_prev(buflist, head); ab; ab = ab_prev) { | |
4335 | ab_prev = list_prev(buflist, ab); | |
4336 | ||
4337 | hash_lock = HDR_LOCK(ab); | |
4338 | if (!mutex_tryenter(hash_lock)) { | |
4339 | /* | |
4340 | * This buffer misses out. It may be in a stage | |
4341 | * of eviction. Its ARC_L2_WRITING flag will be | |
4342 | * left set, denying reads to this buffer. | |
4343 | */ | |
4344 | ARCSTAT_BUMP(arcstat_l2_writes_hdr_miss); | |
4345 | continue; | |
4346 | } | |
4347 | ||
c06d4368 AX |
4348 | abl2 = ab->b_l2hdr; |
4349 | ||
4350 | /* | |
4351 | * Release the temporary compressed buffer as soon as possible. | |
4352 | */ | |
4353 | if (abl2->b_compress != ZIO_COMPRESS_OFF) | |
4354 | l2arc_release_cdata_buf(ab); | |
4355 | ||
34dc7c2f BB |
4356 | if (zio->io_error != 0) { |
4357 | /* | |
b128c09f | 4358 | * Error - drop L2ARC entry. |
34dc7c2f | 4359 | */ |
b128c09f | 4360 | list_remove(buflist, ab); |
c06d4368 | 4361 | ARCSTAT_INCR(arcstat_l2_asize, -abl2->b_asize); |
34dc7c2f | 4362 | ab->b_l2hdr = NULL; |
b128c09f | 4363 | kmem_free(abl2, sizeof (l2arc_buf_hdr_t)); |
c06d4368 | 4364 | arc_space_return(L2HDR_SIZE, ARC_SPACE_L2HDRS); |
b128c09f | 4365 | ARCSTAT_INCR(arcstat_l2_size, -ab->b_size); |
34dc7c2f BB |
4366 | } |
4367 | ||
4368 | /* | |
4369 | * Allow ARC to begin reads to this L2ARC entry. | |
4370 | */ | |
4371 | ab->b_flags &= ~ARC_L2_WRITING; | |
4372 | ||
4373 | mutex_exit(hash_lock); | |
4374 | } | |
4375 | ||
4376 | atomic_inc_64(&l2arc_writes_done); | |
4377 | list_remove(buflist, head); | |
4378 | kmem_cache_free(hdr_cache, head); | |
4379 | mutex_exit(&l2arc_buflist_mtx); | |
4380 | ||
b128c09f | 4381 | l2arc_do_free_on_write(); |
34dc7c2f BB |
4382 | |
4383 | kmem_free(cb, sizeof (l2arc_write_callback_t)); | |
4384 | } | |
4385 | ||
4386 | /* | |
4387 | * A read to a cache device completed. Validate buffer contents before | |
4388 | * handing over to the regular ARC routines. | |
4389 | */ | |
4390 | static void | |
4391 | l2arc_read_done(zio_t *zio) | |
4392 | { | |
4393 | l2arc_read_callback_t *cb; | |
4394 | arc_buf_hdr_t *hdr; | |
4395 | arc_buf_t *buf; | |
34dc7c2f | 4396 | kmutex_t *hash_lock; |
b128c09f BB |
4397 | int equal; |
4398 | ||
4399 | ASSERT(zio->io_vd != NULL); | |
4400 | ASSERT(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE); | |
4401 | ||
4402 | spa_config_exit(zio->io_spa, SCL_L2ARC, zio->io_vd); | |
34dc7c2f BB |
4403 | |
4404 | cb = zio->io_private; | |
4405 | ASSERT(cb != NULL); | |
4406 | buf = cb->l2rcb_buf; | |
4407 | ASSERT(buf != NULL); | |
34dc7c2f | 4408 | |
428870ff | 4409 | hash_lock = HDR_LOCK(buf->b_hdr); |
34dc7c2f | 4410 | mutex_enter(hash_lock); |
428870ff BB |
4411 | hdr = buf->b_hdr; |
4412 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
34dc7c2f | 4413 | |
c06d4368 AX |
4414 | /* |
4415 | * If the buffer was compressed, decompress it first. | |
4416 | */ | |
4417 | if (cb->l2rcb_compress != ZIO_COMPRESS_OFF) | |
4418 | l2arc_decompress_zio(zio, hdr, cb->l2rcb_compress); | |
4419 | ASSERT(zio->io_data != NULL); | |
4420 | ||
34dc7c2f BB |
4421 | /* |
4422 | * Check this survived the L2ARC journey. | |
4423 | */ | |
4424 | equal = arc_cksum_equal(buf); | |
4425 | if (equal && zio->io_error == 0 && !HDR_L2_EVICTED(hdr)) { | |
4426 | mutex_exit(hash_lock); | |
4427 | zio->io_private = buf; | |
b128c09f BB |
4428 | zio->io_bp_copy = cb->l2rcb_bp; /* XXX fix in L2ARC 2.0 */ |
4429 | zio->io_bp = &zio->io_bp_copy; /* XXX fix in L2ARC 2.0 */ | |
34dc7c2f BB |
4430 | arc_read_done(zio); |
4431 | } else { | |
4432 | mutex_exit(hash_lock); | |
4433 | /* | |
4434 | * Buffer didn't survive caching. Increment stats and | |
4435 | * reissue to the original storage device. | |
4436 | */ | |
b128c09f | 4437 | if (zio->io_error != 0) { |
34dc7c2f | 4438 | ARCSTAT_BUMP(arcstat_l2_io_error); |
b128c09f BB |
4439 | } else { |
4440 | zio->io_error = EIO; | |
4441 | } | |
34dc7c2f BB |
4442 | if (!equal) |
4443 | ARCSTAT_BUMP(arcstat_l2_cksum_bad); | |
4444 | ||
34dc7c2f | 4445 | /* |
b128c09f BB |
4446 | * If there's no waiter, issue an async i/o to the primary |
4447 | * storage now. If there *is* a waiter, the caller must | |
4448 | * issue the i/o in a context where it's OK to block. | |
34dc7c2f | 4449 | */ |
d164b209 BB |
4450 | if (zio->io_waiter == NULL) { |
4451 | zio_t *pio = zio_unique_parent(zio); | |
4452 | ||
4453 | ASSERT(!pio || pio->io_child_type == ZIO_CHILD_LOGICAL); | |
4454 | ||
4455 | zio_nowait(zio_read(pio, cb->l2rcb_spa, &cb->l2rcb_bp, | |
b128c09f BB |
4456 | buf->b_data, zio->io_size, arc_read_done, buf, |
4457 | zio->io_priority, cb->l2rcb_flags, &cb->l2rcb_zb)); | |
d164b209 | 4458 | } |
34dc7c2f BB |
4459 | } |
4460 | ||
4461 | kmem_free(cb, sizeof (l2arc_read_callback_t)); | |
4462 | } | |
4463 | ||
4464 | /* | |
4465 | * This is the list priority from which the L2ARC will search for pages to | |
4466 | * cache. This is used within loops (0..3) to cycle through lists in the | |
4467 | * desired order. This order can have a significant effect on cache | |
4468 | * performance. | |
4469 | * | |
4470 | * Currently the metadata lists are hit first, MFU then MRU, followed by | |
4471 | * the data lists. This function returns a locked list, and also returns | |
4472 | * the lock pointer. | |
4473 | */ | |
4474 | static list_t * | |
4475 | l2arc_list_locked(int list_num, kmutex_t **lock) | |
4476 | { | |
d4ed6673 | 4477 | list_t *list = NULL; |
34dc7c2f BB |
4478 | |
4479 | ASSERT(list_num >= 0 && list_num <= 3); | |
4480 | ||
4481 | switch (list_num) { | |
4482 | case 0: | |
4483 | list = &arc_mfu->arcs_list[ARC_BUFC_METADATA]; | |
4484 | *lock = &arc_mfu->arcs_mtx; | |
4485 | break; | |
4486 | case 1: | |
4487 | list = &arc_mru->arcs_list[ARC_BUFC_METADATA]; | |
4488 | *lock = &arc_mru->arcs_mtx; | |
4489 | break; | |
4490 | case 2: | |
4491 | list = &arc_mfu->arcs_list[ARC_BUFC_DATA]; | |
4492 | *lock = &arc_mfu->arcs_mtx; | |
4493 | break; | |
4494 | case 3: | |
4495 | list = &arc_mru->arcs_list[ARC_BUFC_DATA]; | |
4496 | *lock = &arc_mru->arcs_mtx; | |
4497 | break; | |
4498 | } | |
4499 | ||
4500 | ASSERT(!(MUTEX_HELD(*lock))); | |
4501 | mutex_enter(*lock); | |
4502 | return (list); | |
4503 | } | |
4504 | ||
4505 | /* | |
4506 | * Evict buffers from the device write hand to the distance specified in | |
4507 | * bytes. This distance may span populated buffers, it may span nothing. | |
4508 | * This is clearing a region on the L2ARC device ready for writing. | |
4509 | * If the 'all' boolean is set, every buffer is evicted. | |
4510 | */ | |
4511 | static void | |
4512 | l2arc_evict(l2arc_dev_t *dev, uint64_t distance, boolean_t all) | |
4513 | { | |
4514 | list_t *buflist; | |
4515 | l2arc_buf_hdr_t *abl2; | |
4516 | arc_buf_hdr_t *ab, *ab_prev; | |
4517 | kmutex_t *hash_lock; | |
4518 | uint64_t taddr; | |
4519 | ||
34dc7c2f BB |
4520 | buflist = dev->l2ad_buflist; |
4521 | ||
4522 | if (buflist == NULL) | |
4523 | return; | |
4524 | ||
4525 | if (!all && dev->l2ad_first) { | |
4526 | /* | |
4527 | * This is the first sweep through the device. There is | |
4528 | * nothing to evict. | |
4529 | */ | |
4530 | return; | |
4531 | } | |
4532 | ||
b128c09f | 4533 | if (dev->l2ad_hand >= (dev->l2ad_end - (2 * distance))) { |
34dc7c2f BB |
4534 | /* |
4535 | * When nearing the end of the device, evict to the end | |
4536 | * before the device write hand jumps to the start. | |
4537 | */ | |
4538 | taddr = dev->l2ad_end; | |
4539 | } else { | |
4540 | taddr = dev->l2ad_hand + distance; | |
4541 | } | |
4542 | DTRACE_PROBE4(l2arc__evict, l2arc_dev_t *, dev, list_t *, buflist, | |
4543 | uint64_t, taddr, boolean_t, all); | |
4544 | ||
4545 | top: | |
4546 | mutex_enter(&l2arc_buflist_mtx); | |
4547 | for (ab = list_tail(buflist); ab; ab = ab_prev) { | |
4548 | ab_prev = list_prev(buflist, ab); | |
4549 | ||
4550 | hash_lock = HDR_LOCK(ab); | |
4551 | if (!mutex_tryenter(hash_lock)) { | |
4552 | /* | |
4553 | * Missed the hash lock. Retry. | |
4554 | */ | |
4555 | ARCSTAT_BUMP(arcstat_l2_evict_lock_retry); | |
4556 | mutex_exit(&l2arc_buflist_mtx); | |
4557 | mutex_enter(hash_lock); | |
4558 | mutex_exit(hash_lock); | |
4559 | goto top; | |
4560 | } | |
4561 | ||
4562 | if (HDR_L2_WRITE_HEAD(ab)) { | |
4563 | /* | |
4564 | * We hit a write head node. Leave it for | |
4565 | * l2arc_write_done(). | |
4566 | */ | |
4567 | list_remove(buflist, ab); | |
4568 | mutex_exit(hash_lock); | |
4569 | continue; | |
4570 | } | |
4571 | ||
4572 | if (!all && ab->b_l2hdr != NULL && | |
4573 | (ab->b_l2hdr->b_daddr > taddr || | |
4574 | ab->b_l2hdr->b_daddr < dev->l2ad_hand)) { | |
4575 | /* | |
4576 | * We've evicted to the target address, | |
4577 | * or the end of the device. | |
4578 | */ | |
4579 | mutex_exit(hash_lock); | |
4580 | break; | |
4581 | } | |
4582 | ||
4583 | if (HDR_FREE_IN_PROGRESS(ab)) { | |
4584 | /* | |
4585 | * Already on the path to destruction. | |
4586 | */ | |
4587 | mutex_exit(hash_lock); | |
4588 | continue; | |
4589 | } | |
4590 | ||
4591 | if (ab->b_state == arc_l2c_only) { | |
4592 | ASSERT(!HDR_L2_READING(ab)); | |
4593 | /* | |
4594 | * This doesn't exist in the ARC. Destroy. | |
4595 | * arc_hdr_destroy() will call list_remove() | |
4596 | * and decrement arcstat_l2_size. | |
4597 | */ | |
4598 | arc_change_state(arc_anon, ab, hash_lock); | |
4599 | arc_hdr_destroy(ab); | |
4600 | } else { | |
b128c09f BB |
4601 | /* |
4602 | * Invalidate issued or about to be issued | |
4603 | * reads, since we may be about to write | |
4604 | * over this location. | |
4605 | */ | |
4606 | if (HDR_L2_READING(ab)) { | |
4607 | ARCSTAT_BUMP(arcstat_l2_evict_reading); | |
4608 | ab->b_flags |= ARC_L2_EVICTED; | |
4609 | } | |
4610 | ||
34dc7c2f BB |
4611 | /* |
4612 | * Tell ARC this no longer exists in L2ARC. | |
4613 | */ | |
4614 | if (ab->b_l2hdr != NULL) { | |
4615 | abl2 = ab->b_l2hdr; | |
c06d4368 | 4616 | ARCSTAT_INCR(arcstat_l2_asize, -abl2->b_asize); |
34dc7c2f BB |
4617 | ab->b_l2hdr = NULL; |
4618 | kmem_free(abl2, sizeof (l2arc_buf_hdr_t)); | |
c06d4368 | 4619 | arc_space_return(L2HDR_SIZE, ARC_SPACE_L2HDRS); |
34dc7c2f BB |
4620 | ARCSTAT_INCR(arcstat_l2_size, -ab->b_size); |
4621 | } | |
4622 | list_remove(buflist, ab); | |
4623 | ||
4624 | /* | |
4625 | * This may have been leftover after a | |
4626 | * failed write. | |
4627 | */ | |
4628 | ab->b_flags &= ~ARC_L2_WRITING; | |
34dc7c2f BB |
4629 | } |
4630 | mutex_exit(hash_lock); | |
4631 | } | |
4632 | mutex_exit(&l2arc_buflist_mtx); | |
4633 | ||
428870ff | 4634 | vdev_space_update(dev->l2ad_vdev, -(taddr - dev->l2ad_evict), 0, 0); |
34dc7c2f BB |
4635 | dev->l2ad_evict = taddr; |
4636 | } | |
4637 | ||
4638 | /* | |
4639 | * Find and write ARC buffers to the L2ARC device. | |
4640 | * | |
4641 | * An ARC_L2_WRITING flag is set so that the L2ARC buffers are not valid | |
4642 | * for reading until they have completed writing. | |
c06d4368 AX |
4643 | * The headroom_boost is an in-out parameter used to maintain headroom boost |
4644 | * state between calls to this function. | |
4645 | * | |
4646 | * Returns the number of bytes actually written (which may be smaller than | |
4647 | * the delta by which the device hand has changed due to alignment). | |
34dc7c2f | 4648 | */ |
d164b209 | 4649 | static uint64_t |
c06d4368 AX |
4650 | l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz, |
4651 | boolean_t *headroom_boost) | |
34dc7c2f BB |
4652 | { |
4653 | arc_buf_hdr_t *ab, *ab_prev, *head; | |
34dc7c2f | 4654 | list_t *list; |
c06d4368 AX |
4655 | uint64_t write_asize, write_psize, write_sz, headroom, |
4656 | buf_compress_minsz; | |
34dc7c2f | 4657 | void *buf_data; |
c06d4368 AX |
4658 | kmutex_t *list_lock = NULL; |
4659 | boolean_t full; | |
34dc7c2f BB |
4660 | l2arc_write_callback_t *cb; |
4661 | zio_t *pio, *wzio; | |
3541dc6d | 4662 | uint64_t guid = spa_load_guid(spa); |
d6320ddb | 4663 | int try; |
c06d4368 | 4664 | const boolean_t do_headroom_boost = *headroom_boost; |
34dc7c2f | 4665 | |
34dc7c2f BB |
4666 | ASSERT(dev->l2ad_vdev != NULL); |
4667 | ||
c06d4368 AX |
4668 | /* Lower the flag now, we might want to raise it again later. */ |
4669 | *headroom_boost = B_FALSE; | |
4670 | ||
34dc7c2f | 4671 | pio = NULL; |
c06d4368 | 4672 | write_sz = write_asize = write_psize = 0; |
34dc7c2f BB |
4673 | full = B_FALSE; |
4674 | head = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); | |
4675 | head->b_flags |= ARC_L2_WRITE_HEAD; | |
4676 | ||
c06d4368 AX |
4677 | /* |
4678 | * We will want to try to compress buffers that are at least 2x the | |
4679 | * device sector size. | |
4680 | */ | |
4681 | buf_compress_minsz = 2 << dev->l2ad_vdev->vdev_ashift; | |
4682 | ||
34dc7c2f BB |
4683 | /* |
4684 | * Copy buffers for L2ARC writing. | |
4685 | */ | |
4686 | mutex_enter(&l2arc_buflist_mtx); | |
d6320ddb | 4687 | for (try = 0; try <= 3; try++) { |
c06d4368 AX |
4688 | uint64_t passed_sz = 0; |
4689 | ||
34dc7c2f | 4690 | list = l2arc_list_locked(try, &list_lock); |
34dc7c2f | 4691 | |
b128c09f BB |
4692 | /* |
4693 | * L2ARC fast warmup. | |
4694 | * | |
4695 | * Until the ARC is warm and starts to evict, read from the | |
4696 | * head of the ARC lists rather than the tail. | |
4697 | */ | |
b128c09f BB |
4698 | if (arc_warm == B_FALSE) |
4699 | ab = list_head(list); | |
4700 | else | |
4701 | ab = list_tail(list); | |
4702 | ||
c06d4368 AX |
4703 | headroom = target_sz * l2arc_headroom; |
4704 | if (do_headroom_boost) | |
4705 | headroom = (headroom * l2arc_headroom_boost) / 100; | |
4706 | ||
b128c09f | 4707 | for (; ab; ab = ab_prev) { |
c06d4368 AX |
4708 | l2arc_buf_hdr_t *l2hdr; |
4709 | kmutex_t *hash_lock; | |
4710 | uint64_t buf_sz; | |
4711 | ||
b128c09f BB |
4712 | if (arc_warm == B_FALSE) |
4713 | ab_prev = list_next(list, ab); | |
4714 | else | |
4715 | ab_prev = list_prev(list, ab); | |
34dc7c2f BB |
4716 | |
4717 | hash_lock = HDR_LOCK(ab); | |
c06d4368 | 4718 | if (!mutex_tryenter(hash_lock)) { |
34dc7c2f BB |
4719 | /* |
4720 | * Skip this buffer rather than waiting. | |
4721 | */ | |
4722 | continue; | |
4723 | } | |
4724 | ||
4725 | passed_sz += ab->b_size; | |
4726 | if (passed_sz > headroom) { | |
4727 | /* | |
4728 | * Searched too far. | |
4729 | */ | |
4730 | mutex_exit(hash_lock); | |
4731 | break; | |
4732 | } | |
4733 | ||
d164b209 | 4734 | if (!l2arc_write_eligible(guid, ab)) { |
34dc7c2f BB |
4735 | mutex_exit(hash_lock); |
4736 | continue; | |
4737 | } | |
4738 | ||
4739 | if ((write_sz + ab->b_size) > target_sz) { | |
4740 | full = B_TRUE; | |
4741 | mutex_exit(hash_lock); | |
4742 | break; | |
4743 | } | |
4744 | ||
34dc7c2f BB |
4745 | if (pio == NULL) { |
4746 | /* | |
4747 | * Insert a dummy header on the buflist so | |
4748 | * l2arc_write_done() can find where the | |
4749 | * write buffers begin without searching. | |
4750 | */ | |
4751 | list_insert_head(dev->l2ad_buflist, head); | |
4752 | ||
409dc1a5 PS |
4753 | cb = kmem_alloc(sizeof (l2arc_write_callback_t), |
4754 | KM_PUSHPAGE); | |
34dc7c2f BB |
4755 | cb->l2wcb_dev = dev; |
4756 | cb->l2wcb_head = head; | |
4757 | pio = zio_root(spa, l2arc_write_done, cb, | |
4758 | ZIO_FLAG_CANFAIL); | |
4759 | } | |
4760 | ||
4761 | /* | |
4762 | * Create and add a new L2ARC header. | |
4763 | */ | |
c06d4368 AX |
4764 | l2hdr = kmem_zalloc(sizeof (l2arc_buf_hdr_t), |
4765 | KM_PUSHPAGE); | |
4766 | l2hdr->b_dev = dev; | |
4767 | arc_space_consume(L2HDR_SIZE, ARC_SPACE_L2HDRS); | |
34dc7c2f BB |
4768 | |
4769 | ab->b_flags |= ARC_L2_WRITING; | |
c06d4368 AX |
4770 | |
4771 | /* | |
4772 | * Temporarily stash the data buffer in b_tmp_cdata. | |
4773 | * The subsequent write step will pick it up from | |
4774 | * there. This is because can't access ab->b_buf | |
4775 | * without holding the hash_lock, which we in turn | |
4776 | * can't access without holding the ARC list locks | |
4777 | * (which we want to avoid during compression/writing) | |
4778 | */ | |
4779 | l2hdr->b_compress = ZIO_COMPRESS_OFF; | |
4780 | l2hdr->b_asize = ab->b_size; | |
4781 | l2hdr->b_tmp_cdata = ab->b_buf->b_data; | |
4782 | ||
34dc7c2f | 4783 | buf_sz = ab->b_size; |
c06d4368 AX |
4784 | ab->b_l2hdr = l2hdr; |
4785 | ||
4786 | list_insert_head(dev->l2ad_buflist, ab); | |
34dc7c2f BB |
4787 | |
4788 | /* | |
4789 | * Compute and store the buffer cksum before | |
4790 | * writing. On debug the cksum is verified first. | |
4791 | */ | |
4792 | arc_cksum_verify(ab->b_buf); | |
4793 | arc_cksum_compute(ab->b_buf, B_TRUE); | |
4794 | ||
4795 | mutex_exit(hash_lock); | |
4796 | ||
c06d4368 AX |
4797 | write_sz += buf_sz; |
4798 | } | |
4799 | ||
4800 | mutex_exit(list_lock); | |
4801 | ||
4802 | if (full == B_TRUE) | |
4803 | break; | |
4804 | } | |
4805 | ||
4806 | /* No buffers selected for writing? */ | |
4807 | if (pio == NULL) { | |
4808 | ASSERT0(write_sz); | |
4809 | mutex_exit(&l2arc_buflist_mtx); | |
4810 | kmem_cache_free(hdr_cache, head); | |
4811 | return (0); | |
4812 | } | |
4813 | ||
4814 | /* | |
4815 | * Now start writing the buffers. We're starting at the write head | |
4816 | * and work backwards, retracing the course of the buffer selector | |
4817 | * loop above. | |
4818 | */ | |
4819 | for (ab = list_prev(dev->l2ad_buflist, head); ab; | |
4820 | ab = list_prev(dev->l2ad_buflist, ab)) { | |
4821 | l2arc_buf_hdr_t *l2hdr; | |
4822 | uint64_t buf_sz; | |
4823 | ||
4824 | /* | |
4825 | * We shouldn't need to lock the buffer here, since we flagged | |
4826 | * it as ARC_L2_WRITING in the previous step, but we must take | |
4827 | * care to only access its L2 cache parameters. In particular, | |
4828 | * ab->b_buf may be invalid by now due to ARC eviction. | |
4829 | */ | |
4830 | l2hdr = ab->b_l2hdr; | |
4831 | l2hdr->b_daddr = dev->l2ad_hand; | |
4832 | ||
4833 | if (!l2arc_nocompress && (ab->b_flags & ARC_L2COMPRESS) && | |
4834 | l2hdr->b_asize >= buf_compress_minsz) { | |
4835 | if (l2arc_compress_buf(l2hdr)) { | |
4836 | /* | |
4837 | * If compression succeeded, enable headroom | |
4838 | * boost on the next scan cycle. | |
4839 | */ | |
4840 | *headroom_boost = B_TRUE; | |
4841 | } | |
4842 | } | |
4843 | ||
4844 | /* | |
4845 | * Pick up the buffer data we had previously stashed away | |
4846 | * (and now potentially also compressed). | |
4847 | */ | |
4848 | buf_data = l2hdr->b_tmp_cdata; | |
4849 | buf_sz = l2hdr->b_asize; | |
4850 | ||
4851 | /* Compression may have squashed the buffer to zero length. */ | |
4852 | if (buf_sz != 0) { | |
4853 | uint64_t buf_p_sz; | |
4854 | ||
34dc7c2f BB |
4855 | wzio = zio_write_phys(pio, dev->l2ad_vdev, |
4856 | dev->l2ad_hand, buf_sz, buf_data, ZIO_CHECKSUM_OFF, | |
4857 | NULL, NULL, ZIO_PRIORITY_ASYNC_WRITE, | |
4858 | ZIO_FLAG_CANFAIL, B_FALSE); | |
4859 | ||
4860 | DTRACE_PROBE2(l2arc__write, vdev_t *, dev->l2ad_vdev, | |
4861 | zio_t *, wzio); | |
4862 | (void) zio_nowait(wzio); | |
4863 | ||
c06d4368 | 4864 | write_asize += buf_sz; |
b128c09f BB |
4865 | /* |
4866 | * Keep the clock hand suitably device-aligned. | |
4867 | */ | |
c06d4368 AX |
4868 | buf_p_sz = vdev_psize_to_asize(dev->l2ad_vdev, buf_sz); |
4869 | write_psize += buf_p_sz; | |
4870 | dev->l2ad_hand += buf_p_sz; | |
34dc7c2f | 4871 | } |
34dc7c2f | 4872 | } |
34dc7c2f | 4873 | |
c06d4368 | 4874 | mutex_exit(&l2arc_buflist_mtx); |
34dc7c2f | 4875 | |
c06d4368 | 4876 | ASSERT3U(write_asize, <=, target_sz); |
34dc7c2f | 4877 | ARCSTAT_BUMP(arcstat_l2_writes_sent); |
c06d4368 | 4878 | ARCSTAT_INCR(arcstat_l2_write_bytes, write_asize); |
34dc7c2f | 4879 | ARCSTAT_INCR(arcstat_l2_size, write_sz); |
c06d4368 AX |
4880 | ARCSTAT_INCR(arcstat_l2_asize, write_asize); |
4881 | vdev_space_update(dev->l2ad_vdev, write_psize, 0, 0); | |
34dc7c2f BB |
4882 | |
4883 | /* | |
4884 | * Bump device hand to the device start if it is approaching the end. | |
4885 | * l2arc_evict() will already have evicted ahead for this case. | |
4886 | */ | |
b128c09f | 4887 | if (dev->l2ad_hand >= (dev->l2ad_end - target_sz)) { |
428870ff BB |
4888 | vdev_space_update(dev->l2ad_vdev, |
4889 | dev->l2ad_end - dev->l2ad_hand, 0, 0); | |
34dc7c2f BB |
4890 | dev->l2ad_hand = dev->l2ad_start; |
4891 | dev->l2ad_evict = dev->l2ad_start; | |
4892 | dev->l2ad_first = B_FALSE; | |
4893 | } | |
4894 | ||
d164b209 | 4895 | dev->l2ad_writing = B_TRUE; |
34dc7c2f | 4896 | (void) zio_wait(pio); |
d164b209 BB |
4897 | dev->l2ad_writing = B_FALSE; |
4898 | ||
c06d4368 AX |
4899 | return (write_asize); |
4900 | } | |
4901 | ||
4902 | /* | |
4903 | * Compresses an L2ARC buffer. | |
4904 | * The data to be compressed must be prefilled in l2hdr->b_tmp_cdata and its | |
4905 | * size in l2hdr->b_asize. This routine tries to compress the data and | |
4906 | * depending on the compression result there are three possible outcomes: | |
4907 | * *) The buffer was incompressible. The original l2hdr contents were left | |
4908 | * untouched and are ready for writing to an L2 device. | |
4909 | * *) The buffer was all-zeros, so there is no need to write it to an L2 | |
4910 | * device. To indicate this situation b_tmp_cdata is NULL'ed, b_asize is | |
4911 | * set to zero and b_compress is set to ZIO_COMPRESS_EMPTY. | |
4912 | * *) Compression succeeded and b_tmp_cdata was replaced with a temporary | |
4913 | * data buffer which holds the compressed data to be written, and b_asize | |
4914 | * tells us how much data there is. b_compress is set to the appropriate | |
4915 | * compression algorithm. Once writing is done, invoke | |
4916 | * l2arc_release_cdata_buf on this l2hdr to free this temporary buffer. | |
4917 | * | |
4918 | * Returns B_TRUE if compression succeeded, or B_FALSE if it didn't (the | |
4919 | * buffer was incompressible). | |
4920 | */ | |
4921 | static boolean_t | |
4922 | l2arc_compress_buf(l2arc_buf_hdr_t *l2hdr) | |
4923 | { | |
4924 | void *cdata; | |
4925 | size_t csize, len; | |
4926 | ||
4927 | ASSERT(l2hdr->b_compress == ZIO_COMPRESS_OFF); | |
4928 | ASSERT(l2hdr->b_tmp_cdata != NULL); | |
4929 | ||
4930 | len = l2hdr->b_asize; | |
4931 | cdata = zio_data_buf_alloc(len); | |
4932 | csize = zio_compress_data(ZIO_COMPRESS_LZ4, l2hdr->b_tmp_cdata, | |
4933 | cdata, l2hdr->b_asize); | |
4934 | ||
4935 | if (csize == 0) { | |
4936 | /* zero block, indicate that there's nothing to write */ | |
4937 | zio_data_buf_free(cdata, len); | |
4938 | l2hdr->b_compress = ZIO_COMPRESS_EMPTY; | |
4939 | l2hdr->b_asize = 0; | |
4940 | l2hdr->b_tmp_cdata = NULL; | |
4941 | ARCSTAT_BUMP(arcstat_l2_compress_zeros); | |
4942 | return (B_TRUE); | |
4943 | } else if (csize > 0 && csize < len) { | |
4944 | /* | |
4945 | * Compression succeeded, we'll keep the cdata around for | |
4946 | * writing and release it afterwards. | |
4947 | */ | |
4948 | l2hdr->b_compress = ZIO_COMPRESS_LZ4; | |
4949 | l2hdr->b_asize = csize; | |
4950 | l2hdr->b_tmp_cdata = cdata; | |
4951 | ARCSTAT_BUMP(arcstat_l2_compress_successes); | |
4952 | return (B_TRUE); | |
4953 | } else { | |
4954 | /* | |
4955 | * Compression failed, release the compressed buffer. | |
4956 | * l2hdr will be left unmodified. | |
4957 | */ | |
4958 | zio_data_buf_free(cdata, len); | |
4959 | ARCSTAT_BUMP(arcstat_l2_compress_failures); | |
4960 | return (B_FALSE); | |
4961 | } | |
4962 | } | |
4963 | ||
4964 | /* | |
4965 | * Decompresses a zio read back from an l2arc device. On success, the | |
4966 | * underlying zio's io_data buffer is overwritten by the uncompressed | |
4967 | * version. On decompression error (corrupt compressed stream), the | |
4968 | * zio->io_error value is set to signal an I/O error. | |
4969 | * | |
4970 | * Please note that the compressed data stream is not checksummed, so | |
4971 | * if the underlying device is experiencing data corruption, we may feed | |
4972 | * corrupt data to the decompressor, so the decompressor needs to be | |
4973 | * able to handle this situation (LZ4 does). | |
4974 | */ | |
4975 | static void | |
4976 | l2arc_decompress_zio(zio_t *zio, arc_buf_hdr_t *hdr, enum zio_compress c) | |
4977 | { | |
4978 | uint64_t csize; | |
4979 | void *cdata; | |
4980 | ||
4981 | ASSERT(L2ARC_IS_VALID_COMPRESS(c)); | |
4982 | ||
4983 | if (zio->io_error != 0) { | |
4984 | /* | |
4985 | * An io error has occured, just restore the original io | |
4986 | * size in preparation for a main pool read. | |
4987 | */ | |
4988 | zio->io_orig_size = zio->io_size = hdr->b_size; | |
4989 | return; | |
4990 | } | |
4991 | ||
4992 | if (c == ZIO_COMPRESS_EMPTY) { | |
4993 | /* | |
4994 | * An empty buffer results in a null zio, which means we | |
4995 | * need to fill its io_data after we're done restoring the | |
4996 | * buffer's contents. | |
4997 | */ | |
4998 | ASSERT(hdr->b_buf != NULL); | |
4999 | bzero(hdr->b_buf->b_data, hdr->b_size); | |
5000 | zio->io_data = zio->io_orig_data = hdr->b_buf->b_data; | |
5001 | } else { | |
5002 | ASSERT(zio->io_data != NULL); | |
5003 | /* | |
5004 | * We copy the compressed data from the start of the arc buffer | |
5005 | * (the zio_read will have pulled in only what we need, the | |
5006 | * rest is garbage which we will overwrite at decompression) | |
5007 | * and then decompress back to the ARC data buffer. This way we | |
5008 | * can minimize copying by simply decompressing back over the | |
5009 | * original compressed data (rather than decompressing to an | |
5010 | * aux buffer and then copying back the uncompressed buffer, | |
5011 | * which is likely to be much larger). | |
5012 | */ | |
5013 | csize = zio->io_size; | |
5014 | cdata = zio_data_buf_alloc(csize); | |
5015 | bcopy(zio->io_data, cdata, csize); | |
5016 | if (zio_decompress_data(c, cdata, zio->io_data, csize, | |
5017 | hdr->b_size) != 0) | |
5018 | zio->io_error = EIO; | |
5019 | zio_data_buf_free(cdata, csize); | |
5020 | } | |
5021 | ||
5022 | /* Restore the expected uncompressed IO size. */ | |
5023 | zio->io_orig_size = zio->io_size = hdr->b_size; | |
5024 | } | |
5025 | ||
5026 | /* | |
5027 | * Releases the temporary b_tmp_cdata buffer in an l2arc header structure. | |
5028 | * This buffer serves as a temporary holder of compressed data while | |
5029 | * the buffer entry is being written to an l2arc device. Once that is | |
5030 | * done, we can dispose of it. | |
5031 | */ | |
5032 | static void | |
5033 | l2arc_release_cdata_buf(arc_buf_hdr_t *ab) | |
5034 | { | |
5035 | l2arc_buf_hdr_t *l2hdr = ab->b_l2hdr; | |
5036 | ||
5037 | if (l2hdr->b_compress == ZIO_COMPRESS_LZ4) { | |
5038 | /* | |
5039 | * If the data was compressed, then we've allocated a | |
5040 | * temporary buffer for it, so now we need to release it. | |
5041 | */ | |
5042 | ASSERT(l2hdr->b_tmp_cdata != NULL); | |
5043 | zio_data_buf_free(l2hdr->b_tmp_cdata, ab->b_size); | |
5044 | } | |
5045 | l2hdr->b_tmp_cdata = NULL; | |
34dc7c2f BB |
5046 | } |
5047 | ||
5048 | /* | |
5049 | * This thread feeds the L2ARC at regular intervals. This is the beating | |
5050 | * heart of the L2ARC. | |
5051 | */ | |
5052 | static void | |
5053 | l2arc_feed_thread(void) | |
5054 | { | |
5055 | callb_cpr_t cpr; | |
5056 | l2arc_dev_t *dev; | |
5057 | spa_t *spa; | |
d164b209 | 5058 | uint64_t size, wrote; |
428870ff | 5059 | clock_t begin, next = ddi_get_lbolt(); |
c06d4368 | 5060 | boolean_t headroom_boost = B_FALSE; |
34dc7c2f BB |
5061 | |
5062 | CALLB_CPR_INIT(&cpr, &l2arc_feed_thr_lock, callb_generic_cpr, FTAG); | |
5063 | ||
5064 | mutex_enter(&l2arc_feed_thr_lock); | |
5065 | ||
5066 | while (l2arc_thread_exit == 0) { | |
34dc7c2f | 5067 | CALLB_CPR_SAFE_BEGIN(&cpr); |
5b63b3eb BB |
5068 | (void) cv_timedwait_interruptible(&l2arc_feed_thr_cv, |
5069 | &l2arc_feed_thr_lock, next); | |
34dc7c2f | 5070 | CALLB_CPR_SAFE_END(&cpr, &l2arc_feed_thr_lock); |
428870ff | 5071 | next = ddi_get_lbolt() + hz; |
34dc7c2f BB |
5072 | |
5073 | /* | |
b128c09f | 5074 | * Quick check for L2ARC devices. |
34dc7c2f BB |
5075 | */ |
5076 | mutex_enter(&l2arc_dev_mtx); | |
5077 | if (l2arc_ndev == 0) { | |
5078 | mutex_exit(&l2arc_dev_mtx); | |
5079 | continue; | |
5080 | } | |
b128c09f | 5081 | mutex_exit(&l2arc_dev_mtx); |
428870ff | 5082 | begin = ddi_get_lbolt(); |
34dc7c2f BB |
5083 | |
5084 | /* | |
b128c09f BB |
5085 | * This selects the next l2arc device to write to, and in |
5086 | * doing so the next spa to feed from: dev->l2ad_spa. This | |
5087 | * will return NULL if there are now no l2arc devices or if | |
5088 | * they are all faulted. | |
5089 | * | |
5090 | * If a device is returned, its spa's config lock is also | |
5091 | * held to prevent device removal. l2arc_dev_get_next() | |
5092 | * will grab and release l2arc_dev_mtx. | |
34dc7c2f | 5093 | */ |
b128c09f | 5094 | if ((dev = l2arc_dev_get_next()) == NULL) |
34dc7c2f | 5095 | continue; |
b128c09f BB |
5096 | |
5097 | spa = dev->l2ad_spa; | |
5098 | ASSERT(spa != NULL); | |
34dc7c2f | 5099 | |
572e2857 BB |
5100 | /* |
5101 | * If the pool is read-only then force the feed thread to | |
5102 | * sleep a little longer. | |
5103 | */ | |
5104 | if (!spa_writeable(spa)) { | |
5105 | next = ddi_get_lbolt() + 5 * l2arc_feed_secs * hz; | |
5106 | spa_config_exit(spa, SCL_L2ARC, dev); | |
5107 | continue; | |
5108 | } | |
5109 | ||
34dc7c2f | 5110 | /* |
b128c09f | 5111 | * Avoid contributing to memory pressure. |
34dc7c2f | 5112 | */ |
302f753f | 5113 | if (arc_no_grow) { |
b128c09f BB |
5114 | ARCSTAT_BUMP(arcstat_l2_abort_lowmem); |
5115 | spa_config_exit(spa, SCL_L2ARC, dev); | |
34dc7c2f BB |
5116 | continue; |
5117 | } | |
b128c09f | 5118 | |
34dc7c2f BB |
5119 | ARCSTAT_BUMP(arcstat_l2_feeds); |
5120 | ||
c06d4368 | 5121 | size = l2arc_write_size(); |
b128c09f | 5122 | |
34dc7c2f BB |
5123 | /* |
5124 | * Evict L2ARC buffers that will be overwritten. | |
5125 | */ | |
b128c09f | 5126 | l2arc_evict(dev, size, B_FALSE); |
34dc7c2f BB |
5127 | |
5128 | /* | |
5129 | * Write ARC buffers. | |
5130 | */ | |
c06d4368 | 5131 | wrote = l2arc_write_buffers(spa, dev, size, &headroom_boost); |
d164b209 BB |
5132 | |
5133 | /* | |
5134 | * Calculate interval between writes. | |
5135 | */ | |
5136 | next = l2arc_write_interval(begin, size, wrote); | |
b128c09f | 5137 | spa_config_exit(spa, SCL_L2ARC, dev); |
34dc7c2f BB |
5138 | } |
5139 | ||
5140 | l2arc_thread_exit = 0; | |
5141 | cv_broadcast(&l2arc_feed_thr_cv); | |
5142 | CALLB_CPR_EXIT(&cpr); /* drops l2arc_feed_thr_lock */ | |
5143 | thread_exit(); | |
5144 | } | |
5145 | ||
b128c09f BB |
5146 | boolean_t |
5147 | l2arc_vdev_present(vdev_t *vd) | |
5148 | { | |
5149 | l2arc_dev_t *dev; | |
5150 | ||
5151 | mutex_enter(&l2arc_dev_mtx); | |
5152 | for (dev = list_head(l2arc_dev_list); dev != NULL; | |
5153 | dev = list_next(l2arc_dev_list, dev)) { | |
5154 | if (dev->l2ad_vdev == vd) | |
5155 | break; | |
5156 | } | |
5157 | mutex_exit(&l2arc_dev_mtx); | |
5158 | ||
5159 | return (dev != NULL); | |
5160 | } | |
5161 | ||
34dc7c2f BB |
5162 | /* |
5163 | * Add a vdev for use by the L2ARC. By this point the spa has already | |
5164 | * validated the vdev and opened it. | |
5165 | */ | |
5166 | void | |
9babb374 | 5167 | l2arc_add_vdev(spa_t *spa, vdev_t *vd) |
34dc7c2f BB |
5168 | { |
5169 | l2arc_dev_t *adddev; | |
5170 | ||
b128c09f BB |
5171 | ASSERT(!l2arc_vdev_present(vd)); |
5172 | ||
34dc7c2f BB |
5173 | /* |
5174 | * Create a new l2arc device entry. | |
5175 | */ | |
5176 | adddev = kmem_zalloc(sizeof (l2arc_dev_t), KM_SLEEP); | |
5177 | adddev->l2ad_spa = spa; | |
5178 | adddev->l2ad_vdev = vd; | |
9babb374 BB |
5179 | adddev->l2ad_start = VDEV_LABEL_START_SIZE; |
5180 | adddev->l2ad_end = VDEV_LABEL_START_SIZE + vdev_get_min_asize(vd); | |
34dc7c2f BB |
5181 | adddev->l2ad_hand = adddev->l2ad_start; |
5182 | adddev->l2ad_evict = adddev->l2ad_start; | |
5183 | adddev->l2ad_first = B_TRUE; | |
d164b209 | 5184 | adddev->l2ad_writing = B_FALSE; |
98f72a53 | 5185 | list_link_init(&adddev->l2ad_node); |
34dc7c2f BB |
5186 | |
5187 | /* | |
5188 | * This is a list of all ARC buffers that are still valid on the | |
5189 | * device. | |
5190 | */ | |
5191 | adddev->l2ad_buflist = kmem_zalloc(sizeof (list_t), KM_SLEEP); | |
5192 | list_create(adddev->l2ad_buflist, sizeof (arc_buf_hdr_t), | |
5193 | offsetof(arc_buf_hdr_t, b_l2node)); | |
5194 | ||
428870ff | 5195 | vdev_space_update(vd, 0, 0, adddev->l2ad_end - adddev->l2ad_hand); |
34dc7c2f BB |
5196 | |
5197 | /* | |
5198 | * Add device to global list | |
5199 | */ | |
5200 | mutex_enter(&l2arc_dev_mtx); | |
5201 | list_insert_head(l2arc_dev_list, adddev); | |
5202 | atomic_inc_64(&l2arc_ndev); | |
5203 | mutex_exit(&l2arc_dev_mtx); | |
5204 | } | |
5205 | ||
5206 | /* | |
5207 | * Remove a vdev from the L2ARC. | |
5208 | */ | |
5209 | void | |
5210 | l2arc_remove_vdev(vdev_t *vd) | |
5211 | { | |
5212 | l2arc_dev_t *dev, *nextdev, *remdev = NULL; | |
5213 | ||
34dc7c2f BB |
5214 | /* |
5215 | * Find the device by vdev | |
5216 | */ | |
5217 | mutex_enter(&l2arc_dev_mtx); | |
5218 | for (dev = list_head(l2arc_dev_list); dev; dev = nextdev) { | |
5219 | nextdev = list_next(l2arc_dev_list, dev); | |
5220 | if (vd == dev->l2ad_vdev) { | |
5221 | remdev = dev; | |
5222 | break; | |
5223 | } | |
5224 | } | |
5225 | ASSERT(remdev != NULL); | |
5226 | ||
5227 | /* | |
5228 | * Remove device from global list | |
5229 | */ | |
5230 | list_remove(l2arc_dev_list, remdev); | |
5231 | l2arc_dev_last = NULL; /* may have been invalidated */ | |
b128c09f BB |
5232 | atomic_dec_64(&l2arc_ndev); |
5233 | mutex_exit(&l2arc_dev_mtx); | |
34dc7c2f BB |
5234 | |
5235 | /* | |
5236 | * Clear all buflists and ARC references. L2ARC device flush. | |
5237 | */ | |
5238 | l2arc_evict(remdev, 0, B_TRUE); | |
5239 | list_destroy(remdev->l2ad_buflist); | |
5240 | kmem_free(remdev->l2ad_buflist, sizeof (list_t)); | |
5241 | kmem_free(remdev, sizeof (l2arc_dev_t)); | |
34dc7c2f BB |
5242 | } |
5243 | ||
5244 | void | |
b128c09f | 5245 | l2arc_init(void) |
34dc7c2f BB |
5246 | { |
5247 | l2arc_thread_exit = 0; | |
5248 | l2arc_ndev = 0; | |
5249 | l2arc_writes_sent = 0; | |
5250 | l2arc_writes_done = 0; | |
5251 | ||
5252 | mutex_init(&l2arc_feed_thr_lock, NULL, MUTEX_DEFAULT, NULL); | |
5253 | cv_init(&l2arc_feed_thr_cv, NULL, CV_DEFAULT, NULL); | |
5254 | mutex_init(&l2arc_dev_mtx, NULL, MUTEX_DEFAULT, NULL); | |
5255 | mutex_init(&l2arc_buflist_mtx, NULL, MUTEX_DEFAULT, NULL); | |
5256 | mutex_init(&l2arc_free_on_write_mtx, NULL, MUTEX_DEFAULT, NULL); | |
5257 | ||
5258 | l2arc_dev_list = &L2ARC_dev_list; | |
5259 | l2arc_free_on_write = &L2ARC_free_on_write; | |
5260 | list_create(l2arc_dev_list, sizeof (l2arc_dev_t), | |
5261 | offsetof(l2arc_dev_t, l2ad_node)); | |
5262 | list_create(l2arc_free_on_write, sizeof (l2arc_data_free_t), | |
5263 | offsetof(l2arc_data_free_t, l2df_list_node)); | |
34dc7c2f BB |
5264 | } |
5265 | ||
5266 | void | |
b128c09f | 5267 | l2arc_fini(void) |
34dc7c2f | 5268 | { |
b128c09f BB |
5269 | /* |
5270 | * This is called from dmu_fini(), which is called from spa_fini(); | |
5271 | * Because of this, we can assume that all l2arc devices have | |
5272 | * already been removed when the pools themselves were removed. | |
5273 | */ | |
5274 | ||
5275 | l2arc_do_free_on_write(); | |
34dc7c2f BB |
5276 | |
5277 | mutex_destroy(&l2arc_feed_thr_lock); | |
5278 | cv_destroy(&l2arc_feed_thr_cv); | |
5279 | mutex_destroy(&l2arc_dev_mtx); | |
5280 | mutex_destroy(&l2arc_buflist_mtx); | |
5281 | mutex_destroy(&l2arc_free_on_write_mtx); | |
5282 | ||
5283 | list_destroy(l2arc_dev_list); | |
5284 | list_destroy(l2arc_free_on_write); | |
5285 | } | |
b128c09f BB |
5286 | |
5287 | void | |
5288 | l2arc_start(void) | |
5289 | { | |
fb5f0bc8 | 5290 | if (!(spa_mode_global & FWRITE)) |
b128c09f BB |
5291 | return; |
5292 | ||
5293 | (void) thread_create(NULL, 0, l2arc_feed_thread, NULL, 0, &p0, | |
5294 | TS_RUN, minclsyspri); | |
5295 | } | |
5296 | ||
5297 | void | |
5298 | l2arc_stop(void) | |
5299 | { | |
fb5f0bc8 | 5300 | if (!(spa_mode_global & FWRITE)) |
b128c09f BB |
5301 | return; |
5302 | ||
5303 | mutex_enter(&l2arc_feed_thr_lock); | |
5304 | cv_signal(&l2arc_feed_thr_cv); /* kick thread out of startup */ | |
5305 | l2arc_thread_exit = 1; | |
5306 | while (l2arc_thread_exit != 0) | |
5307 | cv_wait(&l2arc_feed_thr_cv, &l2arc_feed_thr_lock); | |
5308 | mutex_exit(&l2arc_feed_thr_lock); | |
5309 | } | |
c28b2279 BB |
5310 | |
5311 | #if defined(_KERNEL) && defined(HAVE_SPL) | |
5312 | EXPORT_SYMBOL(arc_read); | |
5313 | EXPORT_SYMBOL(arc_buf_remove_ref); | |
5314 | EXPORT_SYMBOL(arc_getbuf_func); | |
ab26409d BB |
5315 | EXPORT_SYMBOL(arc_add_prune_callback); |
5316 | EXPORT_SYMBOL(arc_remove_prune_callback); | |
c28b2279 | 5317 | |
c06d4368 | 5318 | module_param(zfs_arc_min, ulong, 0644); |
c409e464 | 5319 | MODULE_PARM_DESC(zfs_arc_min, "Min arc size"); |
c28b2279 | 5320 | |
c06d4368 | 5321 | module_param(zfs_arc_max, ulong, 0644); |
c409e464 | 5322 | MODULE_PARM_DESC(zfs_arc_max, "Max arc size"); |
c28b2279 | 5323 | |
c06d4368 | 5324 | module_param(zfs_arc_meta_limit, ulong, 0644); |
c28b2279 | 5325 | MODULE_PARM_DESC(zfs_arc_meta_limit, "Meta limit for arc size"); |
6a8f9b6b | 5326 | |
c06d4368 | 5327 | module_param(zfs_arc_meta_prune, int, 0644); |
ab26409d | 5328 | MODULE_PARM_DESC(zfs_arc_meta_prune, "Bytes of meta data to prune"); |
c409e464 | 5329 | |
c06d4368 | 5330 | module_param(zfs_arc_grow_retry, int, 0644); |
c409e464 BB |
5331 | MODULE_PARM_DESC(zfs_arc_grow_retry, "Seconds before growing arc size"); |
5332 | ||
c06d4368 | 5333 | module_param(zfs_arc_shrink_shift, int, 0644); |
c409e464 BB |
5334 | MODULE_PARM_DESC(zfs_arc_shrink_shift, "log2(fraction of arc to reclaim)"); |
5335 | ||
c06d4368 | 5336 | module_param(zfs_arc_p_min_shift, int, 0644); |
c409e464 BB |
5337 | MODULE_PARM_DESC(zfs_arc_p_min_shift, "arc_c shift to calc min/max arc_p"); |
5338 | ||
1f7c30df BB |
5339 | module_param(zfs_disable_dup_eviction, int, 0644); |
5340 | MODULE_PARM_DESC(zfs_disable_dup_eviction, "disable duplicate buffer eviction"); | |
5341 | ||
0c5493d4 BB |
5342 | module_param(zfs_arc_memory_throttle_disable, int, 0644); |
5343 | MODULE_PARM_DESC(zfs_arc_memory_throttle_disable, "disable memory throttle"); | |
5344 | ||
c06d4368 AX |
5345 | module_param(zfs_arc_min_prefetch_lifespan, int, 0644); |
5346 | MODULE_PARM_DESC(zfs_arc_min_prefetch_lifespan, "Min life of prefetch block"); | |
5347 | ||
5348 | module_param(l2arc_write_max, ulong, 0644); | |
abd8610c BB |
5349 | MODULE_PARM_DESC(l2arc_write_max, "Max write bytes per interval"); |
5350 | ||
c06d4368 | 5351 | module_param(l2arc_write_boost, ulong, 0644); |
abd8610c BB |
5352 | MODULE_PARM_DESC(l2arc_write_boost, "Extra write bytes during device warmup"); |
5353 | ||
c06d4368 | 5354 | module_param(l2arc_headroom, ulong, 0644); |
abd8610c BB |
5355 | MODULE_PARM_DESC(l2arc_headroom, "Number of max device writes to precache"); |
5356 | ||
c06d4368 AX |
5357 | module_param(l2arc_headroom_boost, ulong, 0644); |
5358 | MODULE_PARM_DESC(l2arc_headroom_boost, "Compressed l2arc_headroom multiplier"); | |
5359 | ||
5360 | module_param(l2arc_feed_secs, ulong, 0644); | |
abd8610c BB |
5361 | MODULE_PARM_DESC(l2arc_feed_secs, "Seconds between L2ARC writing"); |
5362 | ||
c06d4368 | 5363 | module_param(l2arc_feed_min_ms, ulong, 0644); |
abd8610c BB |
5364 | MODULE_PARM_DESC(l2arc_feed_min_ms, "Min feed interval in milliseconds"); |
5365 | ||
c06d4368 | 5366 | module_param(l2arc_noprefetch, int, 0644); |
abd8610c BB |
5367 | MODULE_PARM_DESC(l2arc_noprefetch, "Skip caching prefetched buffers"); |
5368 | ||
c06d4368 AX |
5369 | module_param(l2arc_nocompress, int, 0644); |
5370 | MODULE_PARM_DESC(l2arc_nocompress, "Skip compressing L2ARC buffers"); | |
5371 | ||
5372 | module_param(l2arc_feed_again, int, 0644); | |
abd8610c BB |
5373 | MODULE_PARM_DESC(l2arc_feed_again, "Turbo L2ARC warmup"); |
5374 | ||
c06d4368 | 5375 | module_param(l2arc_norw, int, 0644); |
abd8610c BB |
5376 | MODULE_PARM_DESC(l2arc_norw, "No reads during writes"); |
5377 | ||
c28b2279 | 5378 | #endif |