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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. | |
34dc7c2f BB |
25 | */ |
26 | ||
34dc7c2f BB |
27 | /* |
28 | * DVA-based Adjustable Replacement Cache | |
29 | * | |
30 | * While much of the theory of operation used here is | |
31 | * based on the self-tuning, low overhead replacement cache | |
32 | * presented by Megiddo and Modha at FAST 2003, there are some | |
33 | * significant differences: | |
34 | * | |
35 | * 1. The Megiddo and Modha model assumes any page is evictable. | |
36 | * Pages in its cache cannot be "locked" into memory. This makes | |
37 | * the eviction algorithm simple: evict the last page in the list. | |
38 | * This also make the performance characteristics easy to reason | |
39 | * about. Our cache is not so simple. At any given moment, some | |
40 | * subset of the blocks in the cache are un-evictable because we | |
41 | * have handed out a reference to them. Blocks are only evictable | |
42 | * when there are no external references active. This makes | |
43 | * eviction far more problematic: we choose to evict the evictable | |
44 | * blocks that are the "lowest" in the list. | |
45 | * | |
46 | * There are times when it is not possible to evict the requested | |
47 | * space. In these circumstances we are unable to adjust the cache | |
48 | * size. To prevent the cache growing unbounded at these times we | |
49 | * implement a "cache throttle" that slows the flow of new data | |
50 | * into the cache until we can make space available. | |
51 | * | |
52 | * 2. The Megiddo and Modha model assumes a fixed cache size. | |
53 | * Pages are evicted when the cache is full and there is a cache | |
54 | * miss. Our model has a variable sized cache. It grows with | |
55 | * high use, but also tries to react to memory pressure from the | |
56 | * operating system: decreasing its size when system memory is | |
57 | * tight. | |
58 | * | |
59 | * 3. The Megiddo and Modha model assumes a fixed page size. All | |
60 | * elements of the cache are therefor exactly the same size. So | |
61 | * when adjusting the cache size following a cache miss, its simply | |
62 | * a matter of choosing a single page to evict. In our model, we | |
63 | * have variable sized cache blocks (rangeing from 512 bytes to | |
64 | * 128K bytes). We therefor choose a set of blocks to evict to make | |
65 | * space for a cache miss that approximates as closely as possible | |
66 | * the space used by the new block. | |
67 | * | |
68 | * See also: "ARC: A Self-Tuning, Low Overhead Replacement Cache" | |
69 | * by N. Megiddo & D. Modha, FAST 2003 | |
70 | */ | |
71 | ||
72 | /* | |
73 | * The locking model: | |
74 | * | |
75 | * A new reference to a cache buffer can be obtained in two | |
76 | * ways: 1) via a hash table lookup using the DVA as a key, | |
77 | * or 2) via one of the ARC lists. The arc_read() interface | |
78 | * uses method 1, while the internal arc algorithms for | |
79 | * adjusting the cache use method 2. We therefor provide two | |
80 | * types of locks: 1) the hash table lock array, and 2) the | |
81 | * arc list locks. | |
82 | * | |
83 | * Buffers do not have their own mutexs, rather they rely on the | |
84 | * hash table mutexs for the bulk of their protection (i.e. most | |
85 | * fields in the arc_buf_hdr_t are protected by these mutexs). | |
86 | * | |
87 | * buf_hash_find() returns the appropriate mutex (held) when it | |
88 | * locates the requested buffer in the hash table. It returns | |
89 | * NULL for the mutex if the buffer was not in the table. | |
90 | * | |
91 | * buf_hash_remove() expects the appropriate hash mutex to be | |
92 | * already held before it is invoked. | |
93 | * | |
94 | * Each arc state also has a mutex which is used to protect the | |
95 | * buffer list associated with the state. When attempting to | |
96 | * obtain a hash table lock while holding an arc list lock you | |
97 | * must use: mutex_tryenter() to avoid deadlock. Also note that | |
98 | * the active state mutex must be held before the ghost state mutex. | |
99 | * | |
100 | * Arc buffers may have an associated eviction callback function. | |
101 | * This function will be invoked prior to removing the buffer (e.g. | |
102 | * in arc_do_user_evicts()). Note however that the data associated | |
103 | * with the buffer may be evicted prior to the callback. The callback | |
104 | * must be made with *no locks held* (to prevent deadlock). Additionally, | |
105 | * the users of callbacks must ensure that their private data is | |
106 | * protected from simultaneous callbacks from arc_buf_evict() | |
107 | * and arc_do_user_evicts(). | |
108 | * | |
ab26409d BB |
109 | * It as also possible to register a callback which is run when the |
110 | * arc_meta_limit is reached and no buffers can be safely evicted. In | |
111 | * this case the arc user should drop a reference on some arc buffers so | |
112 | * they can be reclaimed and the arc_meta_limit honored. For example, | |
113 | * when using the ZPL each dentry holds a references on a znode. These | |
114 | * dentries must be pruned before the arc buffer holding the znode can | |
115 | * be safely evicted. | |
116 | * | |
34dc7c2f BB |
117 | * Note that the majority of the performance stats are manipulated |
118 | * with atomic operations. | |
119 | * | |
120 | * The L2ARC uses the l2arc_buflist_mtx global mutex for the following: | |
121 | * | |
122 | * - L2ARC buflist creation | |
123 | * - L2ARC buflist eviction | |
124 | * - L2ARC write completion, which walks L2ARC buflists | |
125 | * - ARC header destruction, as it removes from L2ARC buflists | |
126 | * - ARC header release, as it removes from L2ARC buflists | |
127 | */ | |
128 | ||
129 | #include <sys/spa.h> | |
130 | #include <sys/zio.h> | |
34dc7c2f BB |
131 | #include <sys/zfs_context.h> |
132 | #include <sys/arc.h> | |
b128c09f | 133 | #include <sys/vdev.h> |
9babb374 | 134 | #include <sys/vdev_impl.h> |
34dc7c2f BB |
135 | #ifdef _KERNEL |
136 | #include <sys/vmsystm.h> | |
137 | #include <vm/anon.h> | |
138 | #include <sys/fs/swapnode.h> | |
ab26409d | 139 | #include <sys/zpl.h> |
34dc7c2f BB |
140 | #endif |
141 | #include <sys/callb.h> | |
142 | #include <sys/kstat.h> | |
570827e1 | 143 | #include <sys/dmu_tx.h> |
428870ff | 144 | #include <zfs_fletcher.h> |
34dc7c2f BB |
145 | |
146 | static kmutex_t arc_reclaim_thr_lock; | |
147 | static kcondvar_t arc_reclaim_thr_cv; /* used to signal reclaim thr */ | |
148 | static uint8_t arc_thread_exit; | |
149 | ||
150 | extern int zfs_write_limit_shift; | |
151 | extern uint64_t zfs_write_limit_max; | |
b128c09f | 152 | extern kmutex_t zfs_write_limit_lock; |
34dc7c2f | 153 | |
ab26409d BB |
154 | /* number of bytes to prune from caches when at arc_meta_limit is reached */ |
155 | uint_t arc_meta_prune = 1048576; | |
34dc7c2f BB |
156 | |
157 | typedef enum arc_reclaim_strategy { | |
158 | ARC_RECLAIM_AGGR, /* Aggressive reclaim strategy */ | |
159 | ARC_RECLAIM_CONS /* Conservative reclaim strategy */ | |
160 | } arc_reclaim_strategy_t; | |
161 | ||
162 | /* number of seconds before growing cache again */ | |
302f753f BB |
163 | static int arc_grow_retry = 5; |
164 | ||
165 | /* expiration time for arc_no_grow */ | |
166 | static clock_t arc_grow_time = 0; | |
34dc7c2f | 167 | |
d164b209 BB |
168 | /* shift of arc_c for calculating both min and max arc_p */ |
169 | static int arc_p_min_shift = 4; | |
170 | ||
171 | /* log2(fraction of arc to reclaim) */ | |
172 | static int arc_shrink_shift = 5; | |
173 | ||
34dc7c2f BB |
174 | /* |
175 | * minimum lifespan of a prefetch block in clock ticks | |
176 | * (initialized in arc_init()) | |
177 | */ | |
178 | static int arc_min_prefetch_lifespan; | |
179 | ||
180 | static int arc_dead; | |
181 | ||
b128c09f BB |
182 | /* |
183 | * The arc has filled available memory and has now warmed up. | |
184 | */ | |
185 | static boolean_t arc_warm; | |
186 | ||
34dc7c2f BB |
187 | /* |
188 | * These tunables are for performance analysis. | |
189 | */ | |
c28b2279 BB |
190 | unsigned long zfs_arc_max = 0; |
191 | unsigned long zfs_arc_min = 0; | |
192 | unsigned long zfs_arc_meta_limit = 0; | |
d164b209 BB |
193 | int zfs_arc_grow_retry = 0; |
194 | int zfs_arc_shrink_shift = 0; | |
195 | int zfs_arc_p_min_shift = 0; | |
ab26409d | 196 | int zfs_arc_meta_prune = 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; | |
312 | kstat_named_t arcstat_l2_hdr_size; | |
313 | kstat_named_t arcstat_memory_throttle_count; | |
7cb67b45 BB |
314 | kstat_named_t arcstat_memory_direct_count; |
315 | kstat_named_t arcstat_memory_indirect_count; | |
1834f2d8 BB |
316 | kstat_named_t arcstat_no_grow; |
317 | kstat_named_t arcstat_tempreserve; | |
318 | kstat_named_t arcstat_loaned_bytes; | |
ab26409d | 319 | kstat_named_t arcstat_prune; |
1834f2d8 BB |
320 | kstat_named_t arcstat_meta_used; |
321 | kstat_named_t arcstat_meta_limit; | |
322 | kstat_named_t arcstat_meta_max; | |
34dc7c2f BB |
323 | } arc_stats_t; |
324 | ||
325 | static arc_stats_t arc_stats = { | |
326 | { "hits", KSTAT_DATA_UINT64 }, | |
327 | { "misses", KSTAT_DATA_UINT64 }, | |
328 | { "demand_data_hits", KSTAT_DATA_UINT64 }, | |
329 | { "demand_data_misses", KSTAT_DATA_UINT64 }, | |
330 | { "demand_metadata_hits", KSTAT_DATA_UINT64 }, | |
331 | { "demand_metadata_misses", KSTAT_DATA_UINT64 }, | |
332 | { "prefetch_data_hits", KSTAT_DATA_UINT64 }, | |
333 | { "prefetch_data_misses", KSTAT_DATA_UINT64 }, | |
334 | { "prefetch_metadata_hits", KSTAT_DATA_UINT64 }, | |
335 | { "prefetch_metadata_misses", KSTAT_DATA_UINT64 }, | |
336 | { "mru_hits", KSTAT_DATA_UINT64 }, | |
337 | { "mru_ghost_hits", KSTAT_DATA_UINT64 }, | |
338 | { "mfu_hits", KSTAT_DATA_UINT64 }, | |
339 | { "mfu_ghost_hits", KSTAT_DATA_UINT64 }, | |
340 | { "deleted", KSTAT_DATA_UINT64 }, | |
341 | { "recycle_miss", KSTAT_DATA_UINT64 }, | |
342 | { "mutex_miss", KSTAT_DATA_UINT64 }, | |
343 | { "evict_skip", KSTAT_DATA_UINT64 }, | |
428870ff BB |
344 | { "evict_l2_cached", KSTAT_DATA_UINT64 }, |
345 | { "evict_l2_eligible", KSTAT_DATA_UINT64 }, | |
346 | { "evict_l2_ineligible", KSTAT_DATA_UINT64 }, | |
34dc7c2f BB |
347 | { "hash_elements", KSTAT_DATA_UINT64 }, |
348 | { "hash_elements_max", KSTAT_DATA_UINT64 }, | |
349 | { "hash_collisions", KSTAT_DATA_UINT64 }, | |
350 | { "hash_chains", KSTAT_DATA_UINT64 }, | |
351 | { "hash_chain_max", KSTAT_DATA_UINT64 }, | |
352 | { "p", KSTAT_DATA_UINT64 }, | |
353 | { "c", KSTAT_DATA_UINT64 }, | |
354 | { "c_min", KSTAT_DATA_UINT64 }, | |
355 | { "c_max", KSTAT_DATA_UINT64 }, | |
356 | { "size", KSTAT_DATA_UINT64 }, | |
357 | { "hdr_size", KSTAT_DATA_UINT64 }, | |
d164b209 BB |
358 | { "data_size", KSTAT_DATA_UINT64 }, |
359 | { "other_size", KSTAT_DATA_UINT64 }, | |
13be560d BB |
360 | { "anon_size", KSTAT_DATA_UINT64 }, |
361 | { "anon_evict_data", KSTAT_DATA_UINT64 }, | |
362 | { "anon_evict_metadata", KSTAT_DATA_UINT64 }, | |
363 | { "mru_size", KSTAT_DATA_UINT64 }, | |
364 | { "mru_evict_data", KSTAT_DATA_UINT64 }, | |
365 | { "mru_evict_metadata", KSTAT_DATA_UINT64 }, | |
366 | { "mru_ghost_size", KSTAT_DATA_UINT64 }, | |
367 | { "mru_ghost_evict_data", KSTAT_DATA_UINT64 }, | |
368 | { "mru_ghost_evict_metadata", KSTAT_DATA_UINT64 }, | |
369 | { "mfu_size", KSTAT_DATA_UINT64 }, | |
370 | { "mfu_evict_data", KSTAT_DATA_UINT64 }, | |
371 | { "mfu_evict_metadata", KSTAT_DATA_UINT64 }, | |
372 | { "mfu_ghost_size", KSTAT_DATA_UINT64 }, | |
373 | { "mfu_ghost_evict_data", KSTAT_DATA_UINT64 }, | |
374 | { "mfu_ghost_evict_metadata", KSTAT_DATA_UINT64 }, | |
34dc7c2f BB |
375 | { "l2_hits", KSTAT_DATA_UINT64 }, |
376 | { "l2_misses", KSTAT_DATA_UINT64 }, | |
377 | { "l2_feeds", KSTAT_DATA_UINT64 }, | |
378 | { "l2_rw_clash", KSTAT_DATA_UINT64 }, | |
d164b209 BB |
379 | { "l2_read_bytes", KSTAT_DATA_UINT64 }, |
380 | { "l2_write_bytes", KSTAT_DATA_UINT64 }, | |
34dc7c2f BB |
381 | { "l2_writes_sent", KSTAT_DATA_UINT64 }, |
382 | { "l2_writes_done", KSTAT_DATA_UINT64 }, | |
383 | { "l2_writes_error", KSTAT_DATA_UINT64 }, | |
384 | { "l2_writes_hdr_miss", KSTAT_DATA_UINT64 }, | |
385 | { "l2_evict_lock_retry", KSTAT_DATA_UINT64 }, | |
386 | { "l2_evict_reading", KSTAT_DATA_UINT64 }, | |
387 | { "l2_free_on_write", KSTAT_DATA_UINT64 }, | |
388 | { "l2_abort_lowmem", KSTAT_DATA_UINT64 }, | |
389 | { "l2_cksum_bad", KSTAT_DATA_UINT64 }, | |
390 | { "l2_io_error", KSTAT_DATA_UINT64 }, | |
391 | { "l2_size", KSTAT_DATA_UINT64 }, | |
392 | { "l2_hdr_size", KSTAT_DATA_UINT64 }, | |
1834f2d8 | 393 | { "memory_throttle_count", KSTAT_DATA_UINT64 }, |
7cb67b45 BB |
394 | { "memory_direct_count", KSTAT_DATA_UINT64 }, |
395 | { "memory_indirect_count", KSTAT_DATA_UINT64 }, | |
1834f2d8 BB |
396 | { "arc_no_grow", KSTAT_DATA_UINT64 }, |
397 | { "arc_tempreserve", KSTAT_DATA_UINT64 }, | |
398 | { "arc_loaned_bytes", KSTAT_DATA_UINT64 }, | |
ab26409d | 399 | { "arc_prune", KSTAT_DATA_UINT64 }, |
1834f2d8 BB |
400 | { "arc_meta_used", KSTAT_DATA_UINT64 }, |
401 | { "arc_meta_limit", KSTAT_DATA_UINT64 }, | |
402 | { "arc_meta_max", KSTAT_DATA_UINT64 }, | |
34dc7c2f BB |
403 | }; |
404 | ||
405 | #define ARCSTAT(stat) (arc_stats.stat.value.ui64) | |
406 | ||
407 | #define ARCSTAT_INCR(stat, val) \ | |
408 | atomic_add_64(&arc_stats.stat.value.ui64, (val)); | |
409 | ||
428870ff | 410 | #define ARCSTAT_BUMP(stat) ARCSTAT_INCR(stat, 1) |
34dc7c2f BB |
411 | #define ARCSTAT_BUMPDOWN(stat) ARCSTAT_INCR(stat, -1) |
412 | ||
413 | #define ARCSTAT_MAX(stat, val) { \ | |
414 | uint64_t m; \ | |
415 | while ((val) > (m = arc_stats.stat.value.ui64) && \ | |
416 | (m != atomic_cas_64(&arc_stats.stat.value.ui64, m, (val)))) \ | |
417 | continue; \ | |
418 | } | |
419 | ||
420 | #define ARCSTAT_MAXSTAT(stat) \ | |
421 | ARCSTAT_MAX(stat##_max, arc_stats.stat.value.ui64) | |
422 | ||
423 | /* | |
424 | * We define a macro to allow ARC hits/misses to be easily broken down by | |
425 | * two separate conditions, giving a total of four different subtypes for | |
426 | * each of hits and misses (so eight statistics total). | |
427 | */ | |
428 | #define ARCSTAT_CONDSTAT(cond1, stat1, notstat1, cond2, stat2, notstat2, stat) \ | |
429 | if (cond1) { \ | |
430 | if (cond2) { \ | |
431 | ARCSTAT_BUMP(arcstat_##stat1##_##stat2##_##stat); \ | |
432 | } else { \ | |
433 | ARCSTAT_BUMP(arcstat_##stat1##_##notstat2##_##stat); \ | |
434 | } \ | |
435 | } else { \ | |
436 | if (cond2) { \ | |
437 | ARCSTAT_BUMP(arcstat_##notstat1##_##stat2##_##stat); \ | |
438 | } else { \ | |
439 | ARCSTAT_BUMP(arcstat_##notstat1##_##notstat2##_##stat);\ | |
440 | } \ | |
441 | } | |
442 | ||
443 | kstat_t *arc_ksp; | |
428870ff | 444 | static arc_state_t *arc_anon; |
34dc7c2f BB |
445 | static arc_state_t *arc_mru; |
446 | static arc_state_t *arc_mru_ghost; | |
447 | static arc_state_t *arc_mfu; | |
448 | static arc_state_t *arc_mfu_ghost; | |
449 | static arc_state_t *arc_l2c_only; | |
450 | ||
451 | /* | |
452 | * There are several ARC variables that are critical to export as kstats -- | |
453 | * but we don't want to have to grovel around in the kstat whenever we wish to | |
454 | * manipulate them. For these variables, we therefore define them to be in | |
455 | * terms of the statistic variable. This assures that we are not introducing | |
456 | * the possibility of inconsistency by having shadow copies of the variables, | |
457 | * while still allowing the code to be readable. | |
458 | */ | |
459 | #define arc_size ARCSTAT(arcstat_size) /* actual total arc size */ | |
460 | #define arc_p ARCSTAT(arcstat_p) /* target size of MRU */ | |
461 | #define arc_c ARCSTAT(arcstat_c) /* target size of cache */ | |
462 | #define arc_c_min ARCSTAT(arcstat_c_min) /* min target cache size */ | |
463 | #define arc_c_max ARCSTAT(arcstat_c_max) /* max target cache size */ | |
1834f2d8 BB |
464 | #define arc_no_grow ARCSTAT(arcstat_no_grow) |
465 | #define arc_tempreserve ARCSTAT(arcstat_tempreserve) | |
466 | #define arc_loaned_bytes ARCSTAT(arcstat_loaned_bytes) | |
467 | #define arc_meta_used ARCSTAT(arcstat_meta_used) | |
468 | #define arc_meta_limit ARCSTAT(arcstat_meta_limit) | |
469 | #define arc_meta_max ARCSTAT(arcstat_meta_max) | |
34dc7c2f BB |
470 | |
471 | typedef struct l2arc_buf_hdr l2arc_buf_hdr_t; | |
472 | ||
473 | typedef struct arc_callback arc_callback_t; | |
474 | ||
475 | struct arc_callback { | |
476 | void *acb_private; | |
477 | arc_done_func_t *acb_done; | |
34dc7c2f BB |
478 | arc_buf_t *acb_buf; |
479 | zio_t *acb_zio_dummy; | |
480 | arc_callback_t *acb_next; | |
481 | }; | |
482 | ||
483 | typedef struct arc_write_callback arc_write_callback_t; | |
484 | ||
485 | struct arc_write_callback { | |
486 | void *awcb_private; | |
487 | arc_done_func_t *awcb_ready; | |
488 | arc_done_func_t *awcb_done; | |
489 | arc_buf_t *awcb_buf; | |
490 | }; | |
491 | ||
492 | struct arc_buf_hdr { | |
493 | /* protected by hash lock */ | |
494 | dva_t b_dva; | |
495 | uint64_t b_birth; | |
496 | uint64_t b_cksum0; | |
497 | ||
498 | kmutex_t b_freeze_lock; | |
499 | zio_cksum_t *b_freeze_cksum; | |
428870ff | 500 | void *b_thawed; |
34dc7c2f BB |
501 | |
502 | arc_buf_hdr_t *b_hash_next; | |
503 | arc_buf_t *b_buf; | |
504 | uint32_t b_flags; | |
505 | uint32_t b_datacnt; | |
506 | ||
507 | arc_callback_t *b_acb; | |
508 | kcondvar_t b_cv; | |
509 | ||
510 | /* immutable */ | |
511 | arc_buf_contents_t b_type; | |
512 | uint64_t b_size; | |
d164b209 | 513 | uint64_t b_spa; |
34dc7c2f BB |
514 | |
515 | /* protected by arc state mutex */ | |
516 | arc_state_t *b_state; | |
517 | list_node_t b_arc_node; | |
518 | ||
519 | /* updated atomically */ | |
520 | clock_t b_arc_access; | |
521 | ||
522 | /* self protecting */ | |
523 | refcount_t b_refcnt; | |
524 | ||
525 | l2arc_buf_hdr_t *b_l2hdr; | |
526 | list_node_t b_l2node; | |
527 | }; | |
528 | ||
ab26409d BB |
529 | static list_t arc_prune_list; |
530 | static kmutex_t arc_prune_mtx; | |
34dc7c2f BB |
531 | static arc_buf_t *arc_eviction_list; |
532 | static kmutex_t arc_eviction_mtx; | |
533 | static arc_buf_hdr_t arc_eviction_hdr; | |
534 | static void arc_get_data_buf(arc_buf_t *buf); | |
535 | static void arc_access(arc_buf_hdr_t *buf, kmutex_t *hash_lock); | |
536 | static int arc_evict_needed(arc_buf_contents_t type); | |
d164b209 | 537 | static void arc_evict_ghost(arc_state_t *state, uint64_t spa, int64_t bytes); |
34dc7c2f | 538 | |
428870ff BB |
539 | static boolean_t l2arc_write_eligible(uint64_t spa_guid, arc_buf_hdr_t *ab); |
540 | ||
34dc7c2f BB |
541 | #define GHOST_STATE(state) \ |
542 | ((state) == arc_mru_ghost || (state) == arc_mfu_ghost || \ | |
543 | (state) == arc_l2c_only) | |
544 | ||
545 | /* | |
546 | * Private ARC flags. These flags are private ARC only flags that will show up | |
547 | * in b_flags in the arc_hdr_buf_t. Some flags are publicly declared, and can | |
548 | * be passed in as arc_flags in things like arc_read. However, these flags | |
549 | * should never be passed and should only be set by ARC code. When adding new | |
550 | * public flags, make sure not to smash the private ones. | |
551 | */ | |
552 | ||
553 | #define ARC_IN_HASH_TABLE (1 << 9) /* this buffer is hashed */ | |
554 | #define ARC_IO_IN_PROGRESS (1 << 10) /* I/O in progress for buf */ | |
555 | #define ARC_IO_ERROR (1 << 11) /* I/O failed for buf */ | |
556 | #define ARC_FREED_IN_READ (1 << 12) /* buf freed while in read */ | |
557 | #define ARC_BUF_AVAILABLE (1 << 13) /* block not in active use */ | |
558 | #define ARC_INDIRECT (1 << 14) /* this is an indirect block */ | |
559 | #define ARC_FREE_IN_PROGRESS (1 << 15) /* hdr about to be freed */ | |
b128c09f BB |
560 | #define ARC_L2_WRITING (1 << 16) /* L2ARC write in progress */ |
561 | #define ARC_L2_EVICTED (1 << 17) /* evicted during I/O */ | |
562 | #define ARC_L2_WRITE_HEAD (1 << 18) /* head of write list */ | |
34dc7c2f BB |
563 | |
564 | #define HDR_IN_HASH_TABLE(hdr) ((hdr)->b_flags & ARC_IN_HASH_TABLE) | |
565 | #define HDR_IO_IN_PROGRESS(hdr) ((hdr)->b_flags & ARC_IO_IN_PROGRESS) | |
566 | #define HDR_IO_ERROR(hdr) ((hdr)->b_flags & ARC_IO_ERROR) | |
d164b209 | 567 | #define HDR_PREFETCH(hdr) ((hdr)->b_flags & ARC_PREFETCH) |
34dc7c2f BB |
568 | #define HDR_FREED_IN_READ(hdr) ((hdr)->b_flags & ARC_FREED_IN_READ) |
569 | #define HDR_BUF_AVAILABLE(hdr) ((hdr)->b_flags & ARC_BUF_AVAILABLE) | |
570 | #define HDR_FREE_IN_PROGRESS(hdr) ((hdr)->b_flags & ARC_FREE_IN_PROGRESS) | |
b128c09f BB |
571 | #define HDR_L2CACHE(hdr) ((hdr)->b_flags & ARC_L2CACHE) |
572 | #define HDR_L2_READING(hdr) ((hdr)->b_flags & ARC_IO_IN_PROGRESS && \ | |
573 | (hdr)->b_l2hdr != NULL) | |
34dc7c2f BB |
574 | #define HDR_L2_WRITING(hdr) ((hdr)->b_flags & ARC_L2_WRITING) |
575 | #define HDR_L2_EVICTED(hdr) ((hdr)->b_flags & ARC_L2_EVICTED) | |
576 | #define HDR_L2_WRITE_HEAD(hdr) ((hdr)->b_flags & ARC_L2_WRITE_HEAD) | |
577 | ||
578 | /* | |
579 | * Other sizes | |
580 | */ | |
581 | ||
582 | #define HDR_SIZE ((int64_t)sizeof (arc_buf_hdr_t)) | |
583 | #define L2HDR_SIZE ((int64_t)sizeof (l2arc_buf_hdr_t)) | |
584 | ||
585 | /* | |
586 | * Hash table routines | |
587 | */ | |
588 | ||
00b46022 BB |
589 | #define HT_LOCK_ALIGN 64 |
590 | #define HT_LOCK_PAD (P2NPHASE(sizeof (kmutex_t), (HT_LOCK_ALIGN))) | |
34dc7c2f BB |
591 | |
592 | struct ht_lock { | |
593 | kmutex_t ht_lock; | |
594 | #ifdef _KERNEL | |
00b46022 | 595 | unsigned char pad[HT_LOCK_PAD]; |
34dc7c2f BB |
596 | #endif |
597 | }; | |
598 | ||
599 | #define BUF_LOCKS 256 | |
600 | typedef struct buf_hash_table { | |
601 | uint64_t ht_mask; | |
602 | arc_buf_hdr_t **ht_table; | |
603 | struct ht_lock ht_locks[BUF_LOCKS]; | |
604 | } buf_hash_table_t; | |
605 | ||
606 | static buf_hash_table_t buf_hash_table; | |
607 | ||
608 | #define BUF_HASH_INDEX(spa, dva, birth) \ | |
609 | (buf_hash(spa, dva, birth) & buf_hash_table.ht_mask) | |
610 | #define BUF_HASH_LOCK_NTRY(idx) (buf_hash_table.ht_locks[idx & (BUF_LOCKS-1)]) | |
611 | #define BUF_HASH_LOCK(idx) (&(BUF_HASH_LOCK_NTRY(idx).ht_lock)) | |
428870ff BB |
612 | #define HDR_LOCK(hdr) \ |
613 | (BUF_HASH_LOCK(BUF_HASH_INDEX(hdr->b_spa, &hdr->b_dva, hdr->b_birth))) | |
34dc7c2f BB |
614 | |
615 | uint64_t zfs_crc64_table[256]; | |
616 | ||
617 | /* | |
618 | * Level 2 ARC | |
619 | */ | |
620 | ||
621 | #define L2ARC_WRITE_SIZE (8 * 1024 * 1024) /* initial write max */ | |
d164b209 BB |
622 | #define L2ARC_HEADROOM 2 /* num of writes */ |
623 | #define L2ARC_FEED_SECS 1 /* caching interval secs */ | |
624 | #define L2ARC_FEED_MIN_MS 200 /* min caching interval ms */ | |
34dc7c2f BB |
625 | |
626 | #define l2arc_writes_sent ARCSTAT(arcstat_l2_writes_sent) | |
627 | #define l2arc_writes_done ARCSTAT(arcstat_l2_writes_done) | |
628 | ||
629 | /* | |
630 | * L2ARC Performance Tunables | |
631 | */ | |
abd8610c BB |
632 | unsigned long l2arc_write_max = L2ARC_WRITE_SIZE; /* def max write size */ |
633 | unsigned long l2arc_write_boost = L2ARC_WRITE_SIZE; /* extra warmup write */ | |
634 | unsigned long l2arc_headroom = L2ARC_HEADROOM; /* # of dev writes */ | |
635 | unsigned long l2arc_feed_secs = L2ARC_FEED_SECS; /* interval seconds */ | |
636 | unsigned long l2arc_feed_min_ms = L2ARC_FEED_MIN_MS; /* min interval msecs */ | |
637 | int l2arc_noprefetch = B_TRUE; /* don't cache prefetch bufs */ | |
638 | int l2arc_feed_again = B_TRUE; /* turbo warmup */ | |
639 | int l2arc_norw = B_TRUE; /* no reads during writes */ | |
34dc7c2f BB |
640 | |
641 | /* | |
642 | * L2ARC Internals | |
643 | */ | |
644 | typedef struct l2arc_dev { | |
645 | vdev_t *l2ad_vdev; /* vdev */ | |
646 | spa_t *l2ad_spa; /* spa */ | |
647 | uint64_t l2ad_hand; /* next write location */ | |
648 | uint64_t l2ad_write; /* desired write size, bytes */ | |
b128c09f | 649 | uint64_t l2ad_boost; /* warmup write boost, bytes */ |
34dc7c2f BB |
650 | uint64_t l2ad_start; /* first addr on device */ |
651 | uint64_t l2ad_end; /* last addr on device */ | |
652 | uint64_t l2ad_evict; /* last addr eviction reached */ | |
653 | boolean_t l2ad_first; /* first sweep through */ | |
d164b209 | 654 | boolean_t l2ad_writing; /* currently writing */ |
34dc7c2f BB |
655 | list_t *l2ad_buflist; /* buffer list */ |
656 | list_node_t l2ad_node; /* device list node */ | |
657 | } l2arc_dev_t; | |
658 | ||
659 | static list_t L2ARC_dev_list; /* device list */ | |
660 | static list_t *l2arc_dev_list; /* device list pointer */ | |
661 | static kmutex_t l2arc_dev_mtx; /* device list mutex */ | |
662 | static l2arc_dev_t *l2arc_dev_last; /* last device used */ | |
663 | static kmutex_t l2arc_buflist_mtx; /* mutex for all buflists */ | |
664 | static list_t L2ARC_free_on_write; /* free after write buf list */ | |
665 | static list_t *l2arc_free_on_write; /* free after write list ptr */ | |
666 | static kmutex_t l2arc_free_on_write_mtx; /* mutex for list */ | |
667 | static uint64_t l2arc_ndev; /* number of devices */ | |
668 | ||
669 | typedef struct l2arc_read_callback { | |
670 | arc_buf_t *l2rcb_buf; /* read buffer */ | |
671 | spa_t *l2rcb_spa; /* spa */ | |
672 | blkptr_t l2rcb_bp; /* original blkptr */ | |
673 | zbookmark_t l2rcb_zb; /* original bookmark */ | |
674 | int l2rcb_flags; /* original flags */ | |
675 | } l2arc_read_callback_t; | |
676 | ||
677 | typedef struct l2arc_write_callback { | |
678 | l2arc_dev_t *l2wcb_dev; /* device info */ | |
679 | arc_buf_hdr_t *l2wcb_head; /* head of write buflist */ | |
680 | } l2arc_write_callback_t; | |
681 | ||
682 | struct l2arc_buf_hdr { | |
683 | /* protected by arc_buf_hdr mutex */ | |
684 | l2arc_dev_t *b_dev; /* L2ARC device */ | |
9babb374 | 685 | uint64_t b_daddr; /* disk address, offset byte */ |
34dc7c2f BB |
686 | }; |
687 | ||
688 | typedef struct l2arc_data_free { | |
689 | /* protected by l2arc_free_on_write_mtx */ | |
690 | void *l2df_data; | |
691 | size_t l2df_size; | |
692 | void (*l2df_func)(void *, size_t); | |
693 | list_node_t l2df_list_node; | |
694 | } l2arc_data_free_t; | |
695 | ||
696 | static kmutex_t l2arc_feed_thr_lock; | |
697 | static kcondvar_t l2arc_feed_thr_cv; | |
698 | static uint8_t l2arc_thread_exit; | |
699 | ||
700 | static void l2arc_read_done(zio_t *zio); | |
701 | static void l2arc_hdr_stat_add(void); | |
702 | static void l2arc_hdr_stat_remove(void); | |
703 | ||
704 | static uint64_t | |
d164b209 | 705 | buf_hash(uint64_t spa, const dva_t *dva, uint64_t birth) |
34dc7c2f | 706 | { |
34dc7c2f BB |
707 | uint8_t *vdva = (uint8_t *)dva; |
708 | uint64_t crc = -1ULL; | |
709 | int i; | |
710 | ||
711 | ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY); | |
712 | ||
713 | for (i = 0; i < sizeof (dva_t); i++) | |
714 | crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ vdva[i]) & 0xFF]; | |
715 | ||
d164b209 | 716 | crc ^= (spa>>8) ^ birth; |
34dc7c2f BB |
717 | |
718 | return (crc); | |
719 | } | |
720 | ||
721 | #define BUF_EMPTY(buf) \ | |
722 | ((buf)->b_dva.dva_word[0] == 0 && \ | |
723 | (buf)->b_dva.dva_word[1] == 0 && \ | |
724 | (buf)->b_birth == 0) | |
725 | ||
726 | #define BUF_EQUAL(spa, dva, birth, buf) \ | |
727 | ((buf)->b_dva.dva_word[0] == (dva)->dva_word[0]) && \ | |
728 | ((buf)->b_dva.dva_word[1] == (dva)->dva_word[1]) && \ | |
729 | ((buf)->b_birth == birth) && ((buf)->b_spa == spa) | |
730 | ||
428870ff BB |
731 | static void |
732 | buf_discard_identity(arc_buf_hdr_t *hdr) | |
733 | { | |
734 | hdr->b_dva.dva_word[0] = 0; | |
735 | hdr->b_dva.dva_word[1] = 0; | |
736 | hdr->b_birth = 0; | |
737 | hdr->b_cksum0 = 0; | |
738 | } | |
739 | ||
34dc7c2f | 740 | static arc_buf_hdr_t * |
d164b209 | 741 | buf_hash_find(uint64_t spa, const dva_t *dva, uint64_t birth, kmutex_t **lockp) |
34dc7c2f BB |
742 | { |
743 | uint64_t idx = BUF_HASH_INDEX(spa, dva, birth); | |
744 | kmutex_t *hash_lock = BUF_HASH_LOCK(idx); | |
745 | arc_buf_hdr_t *buf; | |
746 | ||
747 | mutex_enter(hash_lock); | |
748 | for (buf = buf_hash_table.ht_table[idx]; buf != NULL; | |
749 | buf = buf->b_hash_next) { | |
750 | if (BUF_EQUAL(spa, dva, birth, buf)) { | |
751 | *lockp = hash_lock; | |
752 | return (buf); | |
753 | } | |
754 | } | |
755 | mutex_exit(hash_lock); | |
756 | *lockp = NULL; | |
757 | return (NULL); | |
758 | } | |
759 | ||
760 | /* | |
761 | * Insert an entry into the hash table. If there is already an element | |
762 | * equal to elem in the hash table, then the already existing element | |
763 | * will be returned and the new element will not be inserted. | |
764 | * Otherwise returns NULL. | |
765 | */ | |
766 | static arc_buf_hdr_t * | |
767 | buf_hash_insert(arc_buf_hdr_t *buf, kmutex_t **lockp) | |
768 | { | |
769 | uint64_t idx = BUF_HASH_INDEX(buf->b_spa, &buf->b_dva, buf->b_birth); | |
770 | kmutex_t *hash_lock = BUF_HASH_LOCK(idx); | |
771 | arc_buf_hdr_t *fbuf; | |
772 | uint32_t i; | |
773 | ||
774 | ASSERT(!HDR_IN_HASH_TABLE(buf)); | |
775 | *lockp = hash_lock; | |
776 | mutex_enter(hash_lock); | |
777 | for (fbuf = buf_hash_table.ht_table[idx], i = 0; fbuf != NULL; | |
778 | fbuf = fbuf->b_hash_next, i++) { | |
779 | if (BUF_EQUAL(buf->b_spa, &buf->b_dva, buf->b_birth, fbuf)) | |
780 | return (fbuf); | |
781 | } | |
782 | ||
783 | buf->b_hash_next = buf_hash_table.ht_table[idx]; | |
784 | buf_hash_table.ht_table[idx] = buf; | |
785 | buf->b_flags |= ARC_IN_HASH_TABLE; | |
786 | ||
787 | /* collect some hash table performance data */ | |
788 | if (i > 0) { | |
789 | ARCSTAT_BUMP(arcstat_hash_collisions); | |
790 | if (i == 1) | |
791 | ARCSTAT_BUMP(arcstat_hash_chains); | |
792 | ||
793 | ARCSTAT_MAX(arcstat_hash_chain_max, i); | |
794 | } | |
795 | ||
796 | ARCSTAT_BUMP(arcstat_hash_elements); | |
797 | ARCSTAT_MAXSTAT(arcstat_hash_elements); | |
798 | ||
799 | return (NULL); | |
800 | } | |
801 | ||
802 | static void | |
803 | buf_hash_remove(arc_buf_hdr_t *buf) | |
804 | { | |
805 | arc_buf_hdr_t *fbuf, **bufp; | |
806 | uint64_t idx = BUF_HASH_INDEX(buf->b_spa, &buf->b_dva, buf->b_birth); | |
807 | ||
808 | ASSERT(MUTEX_HELD(BUF_HASH_LOCK(idx))); | |
809 | ASSERT(HDR_IN_HASH_TABLE(buf)); | |
810 | ||
811 | bufp = &buf_hash_table.ht_table[idx]; | |
812 | while ((fbuf = *bufp) != buf) { | |
813 | ASSERT(fbuf != NULL); | |
814 | bufp = &fbuf->b_hash_next; | |
815 | } | |
816 | *bufp = buf->b_hash_next; | |
817 | buf->b_hash_next = NULL; | |
818 | buf->b_flags &= ~ARC_IN_HASH_TABLE; | |
819 | ||
820 | /* collect some hash table performance data */ | |
821 | ARCSTAT_BUMPDOWN(arcstat_hash_elements); | |
822 | ||
823 | if (buf_hash_table.ht_table[idx] && | |
824 | buf_hash_table.ht_table[idx]->b_hash_next == NULL) | |
825 | ARCSTAT_BUMPDOWN(arcstat_hash_chains); | |
826 | } | |
827 | ||
828 | /* | |
829 | * Global data structures and functions for the buf kmem cache. | |
830 | */ | |
831 | static kmem_cache_t *hdr_cache; | |
832 | static kmem_cache_t *buf_cache; | |
833 | ||
834 | static void | |
835 | buf_fini(void) | |
836 | { | |
837 | int i; | |
838 | ||
00b46022 BB |
839 | #if defined(_KERNEL) && defined(HAVE_SPL) |
840 | /* Large allocations which do not require contiguous pages | |
841 | * should be using vmem_free() in the linux kernel */ | |
842 | vmem_free(buf_hash_table.ht_table, | |
843 | (buf_hash_table.ht_mask + 1) * sizeof (void *)); | |
844 | #else | |
34dc7c2f BB |
845 | kmem_free(buf_hash_table.ht_table, |
846 | (buf_hash_table.ht_mask + 1) * sizeof (void *)); | |
00b46022 | 847 | #endif |
34dc7c2f BB |
848 | for (i = 0; i < BUF_LOCKS; i++) |
849 | mutex_destroy(&buf_hash_table.ht_locks[i].ht_lock); | |
850 | kmem_cache_destroy(hdr_cache); | |
851 | kmem_cache_destroy(buf_cache); | |
852 | } | |
853 | ||
854 | /* | |
855 | * Constructor callback - called when the cache is empty | |
856 | * and a new buf is requested. | |
857 | */ | |
858 | /* ARGSUSED */ | |
859 | static int | |
860 | hdr_cons(void *vbuf, void *unused, int kmflag) | |
861 | { | |
862 | arc_buf_hdr_t *buf = vbuf; | |
863 | ||
864 | bzero(buf, sizeof (arc_buf_hdr_t)); | |
865 | refcount_create(&buf->b_refcnt); | |
866 | cv_init(&buf->b_cv, NULL, CV_DEFAULT, NULL); | |
867 | mutex_init(&buf->b_freeze_lock, NULL, MUTEX_DEFAULT, NULL); | |
98f72a53 BB |
868 | list_link_init(&buf->b_arc_node); |
869 | list_link_init(&buf->b_l2node); | |
d164b209 | 870 | arc_space_consume(sizeof (arc_buf_hdr_t), ARC_SPACE_HDRS); |
34dc7c2f | 871 | |
34dc7c2f BB |
872 | return (0); |
873 | } | |
874 | ||
b128c09f BB |
875 | /* ARGSUSED */ |
876 | static int | |
877 | buf_cons(void *vbuf, void *unused, int kmflag) | |
878 | { | |
879 | arc_buf_t *buf = vbuf; | |
880 | ||
881 | bzero(buf, sizeof (arc_buf_t)); | |
428870ff BB |
882 | mutex_init(&buf->b_evict_lock, NULL, MUTEX_DEFAULT, NULL); |
883 | rw_init(&buf->b_data_lock, NULL, RW_DEFAULT, NULL); | |
d164b209 BB |
884 | arc_space_consume(sizeof (arc_buf_t), ARC_SPACE_HDRS); |
885 | ||
b128c09f BB |
886 | return (0); |
887 | } | |
888 | ||
34dc7c2f BB |
889 | /* |
890 | * Destructor callback - called when a cached buf is | |
891 | * no longer required. | |
892 | */ | |
893 | /* ARGSUSED */ | |
894 | static void | |
895 | hdr_dest(void *vbuf, void *unused) | |
896 | { | |
897 | arc_buf_hdr_t *buf = vbuf; | |
898 | ||
428870ff | 899 | ASSERT(BUF_EMPTY(buf)); |
34dc7c2f BB |
900 | refcount_destroy(&buf->b_refcnt); |
901 | cv_destroy(&buf->b_cv); | |
902 | mutex_destroy(&buf->b_freeze_lock); | |
d164b209 | 903 | arc_space_return(sizeof (arc_buf_hdr_t), ARC_SPACE_HDRS); |
34dc7c2f BB |
904 | } |
905 | ||
b128c09f BB |
906 | /* ARGSUSED */ |
907 | static void | |
908 | buf_dest(void *vbuf, void *unused) | |
909 | { | |
910 | arc_buf_t *buf = vbuf; | |
911 | ||
428870ff BB |
912 | mutex_destroy(&buf->b_evict_lock); |
913 | rw_destroy(&buf->b_data_lock); | |
d164b209 | 914 | arc_space_return(sizeof (arc_buf_t), ARC_SPACE_HDRS); |
b128c09f BB |
915 | } |
916 | ||
34dc7c2f BB |
917 | static void |
918 | buf_init(void) | |
919 | { | |
920 | uint64_t *ct; | |
921 | uint64_t hsize = 1ULL << 12; | |
922 | int i, j; | |
923 | ||
924 | /* | |
925 | * The hash table is big enough to fill all of physical memory | |
926 | * with an average 64K block size. The table will take up | |
927 | * totalmem*sizeof(void*)/64K (eg. 128KB/GB with 8-byte pointers). | |
928 | */ | |
929 | while (hsize * 65536 < physmem * PAGESIZE) | |
930 | hsize <<= 1; | |
931 | retry: | |
932 | buf_hash_table.ht_mask = hsize - 1; | |
00b46022 BB |
933 | #if defined(_KERNEL) && defined(HAVE_SPL) |
934 | /* Large allocations which do not require contiguous pages | |
935 | * should be using vmem_alloc() in the linux kernel */ | |
936 | buf_hash_table.ht_table = | |
937 | vmem_zalloc(hsize * sizeof (void*), KM_SLEEP); | |
938 | #else | |
34dc7c2f BB |
939 | buf_hash_table.ht_table = |
940 | kmem_zalloc(hsize * sizeof (void*), KM_NOSLEEP); | |
00b46022 | 941 | #endif |
34dc7c2f BB |
942 | if (buf_hash_table.ht_table == NULL) { |
943 | ASSERT(hsize > (1ULL << 8)); | |
944 | hsize >>= 1; | |
945 | goto retry; | |
946 | } | |
947 | ||
948 | hdr_cache = kmem_cache_create("arc_buf_hdr_t", sizeof (arc_buf_hdr_t), | |
302f753f | 949 | 0, hdr_cons, hdr_dest, NULL, NULL, NULL, 0); |
34dc7c2f | 950 | buf_cache = kmem_cache_create("arc_buf_t", sizeof (arc_buf_t), |
b128c09f | 951 | 0, buf_cons, buf_dest, NULL, NULL, NULL, 0); |
34dc7c2f BB |
952 | |
953 | for (i = 0; i < 256; i++) | |
954 | for (ct = zfs_crc64_table + i, *ct = i, j = 8; j > 0; j--) | |
955 | *ct = (*ct >> 1) ^ (-(*ct & 1) & ZFS_CRC64_POLY); | |
956 | ||
957 | for (i = 0; i < BUF_LOCKS; i++) { | |
958 | mutex_init(&buf_hash_table.ht_locks[i].ht_lock, | |
959 | NULL, MUTEX_DEFAULT, NULL); | |
960 | } | |
961 | } | |
962 | ||
963 | #define ARC_MINTIME (hz>>4) /* 62 ms */ | |
964 | ||
965 | static void | |
966 | arc_cksum_verify(arc_buf_t *buf) | |
967 | { | |
968 | zio_cksum_t zc; | |
969 | ||
970 | if (!(zfs_flags & ZFS_DEBUG_MODIFY)) | |
971 | return; | |
972 | ||
973 | mutex_enter(&buf->b_hdr->b_freeze_lock); | |
974 | if (buf->b_hdr->b_freeze_cksum == NULL || | |
975 | (buf->b_hdr->b_flags & ARC_IO_ERROR)) { | |
976 | mutex_exit(&buf->b_hdr->b_freeze_lock); | |
977 | return; | |
978 | } | |
979 | fletcher_2_native(buf->b_data, buf->b_hdr->b_size, &zc); | |
980 | if (!ZIO_CHECKSUM_EQUAL(*buf->b_hdr->b_freeze_cksum, zc)) | |
981 | panic("buffer modified while frozen!"); | |
982 | mutex_exit(&buf->b_hdr->b_freeze_lock); | |
983 | } | |
984 | ||
985 | static int | |
986 | arc_cksum_equal(arc_buf_t *buf) | |
987 | { | |
988 | zio_cksum_t zc; | |
989 | int equal; | |
990 | ||
991 | mutex_enter(&buf->b_hdr->b_freeze_lock); | |
992 | fletcher_2_native(buf->b_data, buf->b_hdr->b_size, &zc); | |
993 | equal = ZIO_CHECKSUM_EQUAL(*buf->b_hdr->b_freeze_cksum, zc); | |
994 | mutex_exit(&buf->b_hdr->b_freeze_lock); | |
995 | ||
996 | return (equal); | |
997 | } | |
998 | ||
999 | static void | |
1000 | arc_cksum_compute(arc_buf_t *buf, boolean_t force) | |
1001 | { | |
1002 | if (!force && !(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 | mutex_exit(&buf->b_hdr->b_freeze_lock); | |
1008 | return; | |
1009 | } | |
409dc1a5 PS |
1010 | buf->b_hdr->b_freeze_cksum = kmem_alloc(sizeof (zio_cksum_t), |
1011 | KM_PUSHPAGE); | |
34dc7c2f BB |
1012 | fletcher_2_native(buf->b_data, buf->b_hdr->b_size, |
1013 | buf->b_hdr->b_freeze_cksum); | |
1014 | mutex_exit(&buf->b_hdr->b_freeze_lock); | |
1015 | } | |
1016 | ||
1017 | void | |
1018 | arc_buf_thaw(arc_buf_t *buf) | |
1019 | { | |
1020 | if (zfs_flags & ZFS_DEBUG_MODIFY) { | |
1021 | if (buf->b_hdr->b_state != arc_anon) | |
1022 | panic("modifying non-anon buffer!"); | |
1023 | if (buf->b_hdr->b_flags & ARC_IO_IN_PROGRESS) | |
1024 | panic("modifying buffer while i/o in progress!"); | |
1025 | arc_cksum_verify(buf); | |
1026 | } | |
1027 | ||
1028 | mutex_enter(&buf->b_hdr->b_freeze_lock); | |
1029 | if (buf->b_hdr->b_freeze_cksum != NULL) { | |
1030 | kmem_free(buf->b_hdr->b_freeze_cksum, sizeof (zio_cksum_t)); | |
1031 | buf->b_hdr->b_freeze_cksum = NULL; | |
1032 | } | |
428870ff BB |
1033 | |
1034 | if (zfs_flags & ZFS_DEBUG_MODIFY) { | |
1035 | if (buf->b_hdr->b_thawed) | |
1036 | kmem_free(buf->b_hdr->b_thawed, 1); | |
1037 | buf->b_hdr->b_thawed = kmem_alloc(1, KM_SLEEP); | |
1038 | } | |
1039 | ||
34dc7c2f BB |
1040 | mutex_exit(&buf->b_hdr->b_freeze_lock); |
1041 | } | |
1042 | ||
1043 | void | |
1044 | arc_buf_freeze(arc_buf_t *buf) | |
1045 | { | |
428870ff BB |
1046 | kmutex_t *hash_lock; |
1047 | ||
34dc7c2f BB |
1048 | if (!(zfs_flags & ZFS_DEBUG_MODIFY)) |
1049 | return; | |
1050 | ||
428870ff BB |
1051 | hash_lock = HDR_LOCK(buf->b_hdr); |
1052 | mutex_enter(hash_lock); | |
1053 | ||
34dc7c2f BB |
1054 | ASSERT(buf->b_hdr->b_freeze_cksum != NULL || |
1055 | buf->b_hdr->b_state == arc_anon); | |
1056 | arc_cksum_compute(buf, B_FALSE); | |
428870ff | 1057 | mutex_exit(hash_lock); |
34dc7c2f BB |
1058 | } |
1059 | ||
1060 | static void | |
1061 | add_reference(arc_buf_hdr_t *ab, kmutex_t *hash_lock, void *tag) | |
1062 | { | |
1063 | ASSERT(MUTEX_HELD(hash_lock)); | |
1064 | ||
1065 | if ((refcount_add(&ab->b_refcnt, tag) == 1) && | |
1066 | (ab->b_state != arc_anon)) { | |
1067 | uint64_t delta = ab->b_size * ab->b_datacnt; | |
1068 | list_t *list = &ab->b_state->arcs_list[ab->b_type]; | |
1069 | uint64_t *size = &ab->b_state->arcs_lsize[ab->b_type]; | |
1070 | ||
1071 | ASSERT(!MUTEX_HELD(&ab->b_state->arcs_mtx)); | |
1072 | mutex_enter(&ab->b_state->arcs_mtx); | |
1073 | ASSERT(list_link_active(&ab->b_arc_node)); | |
1074 | list_remove(list, ab); | |
1075 | if (GHOST_STATE(ab->b_state)) { | |
1076 | ASSERT3U(ab->b_datacnt, ==, 0); | |
1077 | ASSERT3P(ab->b_buf, ==, NULL); | |
1078 | delta = ab->b_size; | |
1079 | } | |
1080 | ASSERT(delta > 0); | |
1081 | ASSERT3U(*size, >=, delta); | |
1082 | atomic_add_64(size, -delta); | |
1083 | mutex_exit(&ab->b_state->arcs_mtx); | |
b128c09f | 1084 | /* remove the prefetch flag if we get a reference */ |
34dc7c2f BB |
1085 | if (ab->b_flags & ARC_PREFETCH) |
1086 | ab->b_flags &= ~ARC_PREFETCH; | |
1087 | } | |
1088 | } | |
1089 | ||
1090 | static int | |
1091 | remove_reference(arc_buf_hdr_t *ab, kmutex_t *hash_lock, void *tag) | |
1092 | { | |
1093 | int cnt; | |
1094 | arc_state_t *state = ab->b_state; | |
1095 | ||
1096 | ASSERT(state == arc_anon || MUTEX_HELD(hash_lock)); | |
1097 | ASSERT(!GHOST_STATE(state)); | |
1098 | ||
1099 | if (((cnt = refcount_remove(&ab->b_refcnt, tag)) == 0) && | |
1100 | (state != arc_anon)) { | |
1101 | uint64_t *size = &state->arcs_lsize[ab->b_type]; | |
1102 | ||
1103 | ASSERT(!MUTEX_HELD(&state->arcs_mtx)); | |
1104 | mutex_enter(&state->arcs_mtx); | |
1105 | ASSERT(!list_link_active(&ab->b_arc_node)); | |
1106 | list_insert_head(&state->arcs_list[ab->b_type], ab); | |
1107 | ASSERT(ab->b_datacnt > 0); | |
1108 | atomic_add_64(size, ab->b_size * ab->b_datacnt); | |
1109 | mutex_exit(&state->arcs_mtx); | |
1110 | } | |
1111 | return (cnt); | |
1112 | } | |
1113 | ||
1114 | /* | |
1115 | * Move the supplied buffer to the indicated state. The mutex | |
1116 | * for the buffer must be held by the caller. | |
1117 | */ | |
1118 | static void | |
1119 | arc_change_state(arc_state_t *new_state, arc_buf_hdr_t *ab, kmutex_t *hash_lock) | |
1120 | { | |
1121 | arc_state_t *old_state = ab->b_state; | |
1122 | int64_t refcnt = refcount_count(&ab->b_refcnt); | |
1123 | uint64_t from_delta, to_delta; | |
1124 | ||
1125 | ASSERT(MUTEX_HELD(hash_lock)); | |
1126 | ASSERT(new_state != old_state); | |
1127 | ASSERT(refcnt == 0 || ab->b_datacnt > 0); | |
1128 | ASSERT(ab->b_datacnt == 0 || !GHOST_STATE(new_state)); | |
428870ff | 1129 | ASSERT(ab->b_datacnt <= 1 || old_state != arc_anon); |
34dc7c2f BB |
1130 | |
1131 | from_delta = to_delta = ab->b_datacnt * ab->b_size; | |
1132 | ||
1133 | /* | |
1134 | * If this buffer is evictable, transfer it from the | |
1135 | * old state list to the new state list. | |
1136 | */ | |
1137 | if (refcnt == 0) { | |
1138 | if (old_state != arc_anon) { | |
1139 | int use_mutex = !MUTEX_HELD(&old_state->arcs_mtx); | |
1140 | uint64_t *size = &old_state->arcs_lsize[ab->b_type]; | |
1141 | ||
1142 | if (use_mutex) | |
1143 | mutex_enter(&old_state->arcs_mtx); | |
1144 | ||
1145 | ASSERT(list_link_active(&ab->b_arc_node)); | |
1146 | list_remove(&old_state->arcs_list[ab->b_type], ab); | |
1147 | ||
1148 | /* | |
1149 | * If prefetching out of the ghost cache, | |
428870ff | 1150 | * we will have a non-zero datacnt. |
34dc7c2f BB |
1151 | */ |
1152 | if (GHOST_STATE(old_state) && ab->b_datacnt == 0) { | |
1153 | /* ghost elements have a ghost size */ | |
1154 | ASSERT(ab->b_buf == NULL); | |
1155 | from_delta = ab->b_size; | |
1156 | } | |
1157 | ASSERT3U(*size, >=, from_delta); | |
1158 | atomic_add_64(size, -from_delta); | |
1159 | ||
1160 | if (use_mutex) | |
1161 | mutex_exit(&old_state->arcs_mtx); | |
1162 | } | |
1163 | if (new_state != arc_anon) { | |
1164 | int use_mutex = !MUTEX_HELD(&new_state->arcs_mtx); | |
1165 | uint64_t *size = &new_state->arcs_lsize[ab->b_type]; | |
1166 | ||
1167 | if (use_mutex) | |
1168 | mutex_enter(&new_state->arcs_mtx); | |
1169 | ||
1170 | list_insert_head(&new_state->arcs_list[ab->b_type], ab); | |
1171 | ||
1172 | /* ghost elements have a ghost size */ | |
1173 | if (GHOST_STATE(new_state)) { | |
1174 | ASSERT(ab->b_datacnt == 0); | |
1175 | ASSERT(ab->b_buf == NULL); | |
1176 | to_delta = ab->b_size; | |
1177 | } | |
1178 | atomic_add_64(size, to_delta); | |
1179 | ||
1180 | if (use_mutex) | |
1181 | mutex_exit(&new_state->arcs_mtx); | |
1182 | } | |
1183 | } | |
1184 | ||
1185 | ASSERT(!BUF_EMPTY(ab)); | |
428870ff | 1186 | if (new_state == arc_anon && HDR_IN_HASH_TABLE(ab)) |
34dc7c2f | 1187 | buf_hash_remove(ab); |
34dc7c2f BB |
1188 | |
1189 | /* adjust state sizes */ | |
1190 | if (to_delta) | |
1191 | atomic_add_64(&new_state->arcs_size, to_delta); | |
1192 | if (from_delta) { | |
1193 | ASSERT3U(old_state->arcs_size, >=, from_delta); | |
1194 | atomic_add_64(&old_state->arcs_size, -from_delta); | |
1195 | } | |
1196 | ab->b_state = new_state; | |
1197 | ||
1198 | /* adjust l2arc hdr stats */ | |
1199 | if (new_state == arc_l2c_only) | |
1200 | l2arc_hdr_stat_add(); | |
1201 | else if (old_state == arc_l2c_only) | |
1202 | l2arc_hdr_stat_remove(); | |
1203 | } | |
1204 | ||
1205 | void | |
d164b209 | 1206 | arc_space_consume(uint64_t space, arc_space_type_t type) |
34dc7c2f | 1207 | { |
d164b209 BB |
1208 | ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES); |
1209 | ||
1210 | switch (type) { | |
e75c13c3 BB |
1211 | default: |
1212 | break; | |
d164b209 BB |
1213 | case ARC_SPACE_DATA: |
1214 | ARCSTAT_INCR(arcstat_data_size, space); | |
1215 | break; | |
1216 | case ARC_SPACE_OTHER: | |
1217 | ARCSTAT_INCR(arcstat_other_size, space); | |
1218 | break; | |
1219 | case ARC_SPACE_HDRS: | |
1220 | ARCSTAT_INCR(arcstat_hdr_size, space); | |
1221 | break; | |
1222 | case ARC_SPACE_L2HDRS: | |
1223 | ARCSTAT_INCR(arcstat_l2_hdr_size, space); | |
1224 | break; | |
1225 | } | |
1226 | ||
34dc7c2f BB |
1227 | atomic_add_64(&arc_meta_used, space); |
1228 | atomic_add_64(&arc_size, space); | |
1229 | } | |
1230 | ||
1231 | void | |
d164b209 | 1232 | arc_space_return(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 | ASSERT(arc_meta_used >= space); |
1254 | if (arc_meta_max < arc_meta_used) | |
1255 | arc_meta_max = arc_meta_used; | |
1256 | atomic_add_64(&arc_meta_used, -space); | |
1257 | ASSERT(arc_size >= space); | |
1258 | atomic_add_64(&arc_size, -space); | |
1259 | } | |
1260 | ||
1261 | void * | |
1262 | arc_data_buf_alloc(uint64_t size) | |
1263 | { | |
1264 | if (arc_evict_needed(ARC_BUFC_DATA)) | |
1265 | cv_signal(&arc_reclaim_thr_cv); | |
1266 | atomic_add_64(&arc_size, size); | |
1267 | return (zio_data_buf_alloc(size)); | |
1268 | } | |
1269 | ||
1270 | void | |
1271 | arc_data_buf_free(void *buf, uint64_t size) | |
1272 | { | |
1273 | zio_data_buf_free(buf, size); | |
1274 | ASSERT(arc_size >= size); | |
1275 | atomic_add_64(&arc_size, -size); | |
1276 | } | |
1277 | ||
1278 | arc_buf_t * | |
1279 | arc_buf_alloc(spa_t *spa, int size, void *tag, arc_buf_contents_t type) | |
1280 | { | |
1281 | arc_buf_hdr_t *hdr; | |
1282 | arc_buf_t *buf; | |
1283 | ||
1284 | ASSERT3U(size, >, 0); | |
1285 | hdr = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); | |
1286 | ASSERT(BUF_EMPTY(hdr)); | |
1287 | hdr->b_size = size; | |
1288 | hdr->b_type = type; | |
3541dc6d | 1289 | hdr->b_spa = spa_load_guid(spa); |
34dc7c2f BB |
1290 | hdr->b_state = arc_anon; |
1291 | hdr->b_arc_access = 0; | |
1292 | buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); | |
1293 | buf->b_hdr = hdr; | |
1294 | buf->b_data = NULL; | |
1295 | buf->b_efunc = NULL; | |
1296 | buf->b_private = NULL; | |
1297 | buf->b_next = NULL; | |
1298 | hdr->b_buf = buf; | |
1299 | arc_get_data_buf(buf); | |
1300 | hdr->b_datacnt = 1; | |
1301 | hdr->b_flags = 0; | |
1302 | ASSERT(refcount_is_zero(&hdr->b_refcnt)); | |
1303 | (void) refcount_add(&hdr->b_refcnt, tag); | |
1304 | ||
1305 | return (buf); | |
1306 | } | |
1307 | ||
9babb374 BB |
1308 | static char *arc_onloan_tag = "onloan"; |
1309 | ||
1310 | /* | |
1311 | * Loan out an anonymous arc buffer. Loaned buffers are not counted as in | |
1312 | * flight data by arc_tempreserve_space() until they are "returned". Loaned | |
1313 | * buffers must be returned to the arc before they can be used by the DMU or | |
1314 | * freed. | |
1315 | */ | |
1316 | arc_buf_t * | |
1317 | arc_loan_buf(spa_t *spa, int size) | |
1318 | { | |
1319 | arc_buf_t *buf; | |
1320 | ||
1321 | buf = arc_buf_alloc(spa, size, arc_onloan_tag, ARC_BUFC_DATA); | |
1322 | ||
1323 | atomic_add_64(&arc_loaned_bytes, size); | |
1324 | return (buf); | |
1325 | } | |
1326 | ||
1327 | /* | |
1328 | * Return a loaned arc buffer to the arc. | |
1329 | */ | |
1330 | void | |
1331 | arc_return_buf(arc_buf_t *buf, void *tag) | |
1332 | { | |
1333 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
1334 | ||
9babb374 | 1335 | ASSERT(buf->b_data != NULL); |
428870ff BB |
1336 | (void) refcount_add(&hdr->b_refcnt, tag); |
1337 | (void) refcount_remove(&hdr->b_refcnt, arc_onloan_tag); | |
9babb374 BB |
1338 | |
1339 | atomic_add_64(&arc_loaned_bytes, -hdr->b_size); | |
1340 | } | |
1341 | ||
428870ff BB |
1342 | /* Detach an arc_buf from a dbuf (tag) */ |
1343 | void | |
1344 | arc_loan_inuse_buf(arc_buf_t *buf, void *tag) | |
1345 | { | |
1346 | arc_buf_hdr_t *hdr; | |
1347 | ||
1348 | ASSERT(buf->b_data != NULL); | |
1349 | hdr = buf->b_hdr; | |
1350 | (void) refcount_add(&hdr->b_refcnt, arc_onloan_tag); | |
1351 | (void) refcount_remove(&hdr->b_refcnt, tag); | |
1352 | buf->b_efunc = NULL; | |
1353 | buf->b_private = NULL; | |
1354 | ||
1355 | atomic_add_64(&arc_loaned_bytes, hdr->b_size); | |
1356 | } | |
1357 | ||
34dc7c2f BB |
1358 | static arc_buf_t * |
1359 | arc_buf_clone(arc_buf_t *from) | |
1360 | { | |
1361 | arc_buf_t *buf; | |
1362 | arc_buf_hdr_t *hdr = from->b_hdr; | |
1363 | uint64_t size = hdr->b_size; | |
1364 | ||
428870ff BB |
1365 | ASSERT(hdr->b_state != arc_anon); |
1366 | ||
34dc7c2f BB |
1367 | buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); |
1368 | buf->b_hdr = hdr; | |
1369 | buf->b_data = NULL; | |
1370 | buf->b_efunc = NULL; | |
1371 | buf->b_private = NULL; | |
1372 | buf->b_next = hdr->b_buf; | |
1373 | hdr->b_buf = buf; | |
1374 | arc_get_data_buf(buf); | |
1375 | bcopy(from->b_data, buf->b_data, size); | |
1376 | hdr->b_datacnt += 1; | |
1377 | return (buf); | |
1378 | } | |
1379 | ||
1380 | void | |
1381 | arc_buf_add_ref(arc_buf_t *buf, void* tag) | |
1382 | { | |
1383 | arc_buf_hdr_t *hdr; | |
1384 | kmutex_t *hash_lock; | |
1385 | ||
1386 | /* | |
b128c09f BB |
1387 | * Check to see if this buffer is evicted. Callers |
1388 | * must verify b_data != NULL to know if the add_ref | |
1389 | * was successful. | |
34dc7c2f | 1390 | */ |
428870ff | 1391 | mutex_enter(&buf->b_evict_lock); |
b128c09f | 1392 | if (buf->b_data == NULL) { |
428870ff | 1393 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
1394 | return; |
1395 | } | |
428870ff | 1396 | hash_lock = HDR_LOCK(buf->b_hdr); |
34dc7c2f | 1397 | mutex_enter(hash_lock); |
428870ff BB |
1398 | hdr = buf->b_hdr; |
1399 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
1400 | mutex_exit(&buf->b_evict_lock); | |
34dc7c2f | 1401 | |
34dc7c2f BB |
1402 | ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); |
1403 | add_reference(hdr, hash_lock, tag); | |
d164b209 | 1404 | DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr); |
34dc7c2f BB |
1405 | arc_access(hdr, hash_lock); |
1406 | mutex_exit(hash_lock); | |
1407 | ARCSTAT_BUMP(arcstat_hits); | |
1408 | ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), | |
1409 | demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, | |
1410 | data, metadata, hits); | |
1411 | } | |
1412 | ||
1413 | /* | |
1414 | * Free the arc data buffer. If it is an l2arc write in progress, | |
1415 | * the buffer is placed on l2arc_free_on_write to be freed later. | |
1416 | */ | |
1417 | static void | |
1418 | arc_buf_data_free(arc_buf_hdr_t *hdr, void (*free_func)(void *, size_t), | |
1419 | void *data, size_t size) | |
1420 | { | |
1421 | if (HDR_L2_WRITING(hdr)) { | |
1422 | l2arc_data_free_t *df; | |
1423 | df = kmem_alloc(sizeof (l2arc_data_free_t), KM_SLEEP); | |
1424 | df->l2df_data = data; | |
1425 | df->l2df_size = size; | |
1426 | df->l2df_func = free_func; | |
1427 | mutex_enter(&l2arc_free_on_write_mtx); | |
1428 | list_insert_head(l2arc_free_on_write, df); | |
1429 | mutex_exit(&l2arc_free_on_write_mtx); | |
1430 | ARCSTAT_BUMP(arcstat_l2_free_on_write); | |
1431 | } else { | |
1432 | free_func(data, size); | |
1433 | } | |
1434 | } | |
1435 | ||
1436 | static void | |
1437 | arc_buf_destroy(arc_buf_t *buf, boolean_t recycle, boolean_t all) | |
1438 | { | |
1439 | arc_buf_t **bufp; | |
1440 | ||
1441 | /* free up data associated with the buf */ | |
1442 | if (buf->b_data) { | |
1443 | arc_state_t *state = buf->b_hdr->b_state; | |
1444 | uint64_t size = buf->b_hdr->b_size; | |
1445 | arc_buf_contents_t type = buf->b_hdr->b_type; | |
1446 | ||
1447 | arc_cksum_verify(buf); | |
428870ff | 1448 | |
34dc7c2f BB |
1449 | if (!recycle) { |
1450 | if (type == ARC_BUFC_METADATA) { | |
1451 | arc_buf_data_free(buf->b_hdr, zio_buf_free, | |
1452 | buf->b_data, size); | |
d164b209 | 1453 | arc_space_return(size, ARC_SPACE_DATA); |
34dc7c2f BB |
1454 | } else { |
1455 | ASSERT(type == ARC_BUFC_DATA); | |
1456 | arc_buf_data_free(buf->b_hdr, | |
1457 | zio_data_buf_free, buf->b_data, size); | |
d164b209 | 1458 | ARCSTAT_INCR(arcstat_data_size, -size); |
34dc7c2f BB |
1459 | atomic_add_64(&arc_size, -size); |
1460 | } | |
1461 | } | |
1462 | if (list_link_active(&buf->b_hdr->b_arc_node)) { | |
1463 | uint64_t *cnt = &state->arcs_lsize[type]; | |
1464 | ||
1465 | ASSERT(refcount_is_zero(&buf->b_hdr->b_refcnt)); | |
1466 | ASSERT(state != arc_anon); | |
1467 | ||
1468 | ASSERT3U(*cnt, >=, size); | |
1469 | atomic_add_64(cnt, -size); | |
1470 | } | |
1471 | ASSERT3U(state->arcs_size, >=, size); | |
1472 | atomic_add_64(&state->arcs_size, -size); | |
1473 | buf->b_data = NULL; | |
1474 | ASSERT(buf->b_hdr->b_datacnt > 0); | |
1475 | buf->b_hdr->b_datacnt -= 1; | |
1476 | } | |
1477 | ||
1478 | /* only remove the buf if requested */ | |
1479 | if (!all) | |
1480 | return; | |
1481 | ||
1482 | /* remove the buf from the hdr list */ | |
1483 | for (bufp = &buf->b_hdr->b_buf; *bufp != buf; bufp = &(*bufp)->b_next) | |
1484 | continue; | |
1485 | *bufp = buf->b_next; | |
428870ff | 1486 | buf->b_next = NULL; |
34dc7c2f BB |
1487 | |
1488 | ASSERT(buf->b_efunc == NULL); | |
1489 | ||
1490 | /* clean up the buf */ | |
1491 | buf->b_hdr = NULL; | |
1492 | kmem_cache_free(buf_cache, buf); | |
1493 | } | |
1494 | ||
1495 | static void | |
1496 | arc_hdr_destroy(arc_buf_hdr_t *hdr) | |
1497 | { | |
d6320ddb BB |
1498 | l2arc_buf_hdr_t *l2hdr = hdr->b_l2hdr; |
1499 | ||
34dc7c2f BB |
1500 | ASSERT(refcount_is_zero(&hdr->b_refcnt)); |
1501 | ASSERT3P(hdr->b_state, ==, arc_anon); | |
1502 | ASSERT(!HDR_IO_IN_PROGRESS(hdr)); | |
1503 | ||
428870ff BB |
1504 | if (l2hdr != NULL) { |
1505 | boolean_t buflist_held = MUTEX_HELD(&l2arc_buflist_mtx); | |
1506 | /* | |
1507 | * To prevent arc_free() and l2arc_evict() from | |
1508 | * attempting to free the same buffer at the same time, | |
1509 | * a FREE_IN_PROGRESS flag is given to arc_free() to | |
1510 | * give it priority. l2arc_evict() can't destroy this | |
1511 | * header while we are waiting on l2arc_buflist_mtx. | |
1512 | * | |
1513 | * The hdr may be removed from l2ad_buflist before we | |
1514 | * grab l2arc_buflist_mtx, so b_l2hdr is rechecked. | |
1515 | */ | |
1516 | if (!buflist_held) { | |
34dc7c2f | 1517 | mutex_enter(&l2arc_buflist_mtx); |
428870ff | 1518 | l2hdr = hdr->b_l2hdr; |
34dc7c2f | 1519 | } |
428870ff BB |
1520 | |
1521 | if (l2hdr != NULL) { | |
1522 | list_remove(l2hdr->b_dev->l2ad_buflist, hdr); | |
1523 | ARCSTAT_INCR(arcstat_l2_size, -hdr->b_size); | |
1524 | kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t)); | |
1525 | if (hdr->b_state == arc_l2c_only) | |
1526 | l2arc_hdr_stat_remove(); | |
1527 | hdr->b_l2hdr = NULL; | |
1528 | } | |
1529 | ||
1530 | if (!buflist_held) | |
1531 | mutex_exit(&l2arc_buflist_mtx); | |
34dc7c2f BB |
1532 | } |
1533 | ||
1534 | if (!BUF_EMPTY(hdr)) { | |
1535 | ASSERT(!HDR_IN_HASH_TABLE(hdr)); | |
428870ff | 1536 | buf_discard_identity(hdr); |
34dc7c2f BB |
1537 | } |
1538 | while (hdr->b_buf) { | |
1539 | arc_buf_t *buf = hdr->b_buf; | |
1540 | ||
1541 | if (buf->b_efunc) { | |
1542 | mutex_enter(&arc_eviction_mtx); | |
428870ff | 1543 | mutex_enter(&buf->b_evict_lock); |
34dc7c2f BB |
1544 | ASSERT(buf->b_hdr != NULL); |
1545 | arc_buf_destroy(hdr->b_buf, FALSE, FALSE); | |
1546 | hdr->b_buf = buf->b_next; | |
1547 | buf->b_hdr = &arc_eviction_hdr; | |
1548 | buf->b_next = arc_eviction_list; | |
1549 | arc_eviction_list = buf; | |
428870ff | 1550 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
1551 | mutex_exit(&arc_eviction_mtx); |
1552 | } else { | |
1553 | arc_buf_destroy(hdr->b_buf, FALSE, TRUE); | |
1554 | } | |
1555 | } | |
1556 | if (hdr->b_freeze_cksum != NULL) { | |
1557 | kmem_free(hdr->b_freeze_cksum, sizeof (zio_cksum_t)); | |
1558 | hdr->b_freeze_cksum = NULL; | |
1559 | } | |
428870ff BB |
1560 | if (hdr->b_thawed) { |
1561 | kmem_free(hdr->b_thawed, 1); | |
1562 | hdr->b_thawed = NULL; | |
1563 | } | |
34dc7c2f BB |
1564 | |
1565 | ASSERT(!list_link_active(&hdr->b_arc_node)); | |
1566 | ASSERT3P(hdr->b_hash_next, ==, NULL); | |
1567 | ASSERT3P(hdr->b_acb, ==, NULL); | |
1568 | kmem_cache_free(hdr_cache, hdr); | |
1569 | } | |
1570 | ||
1571 | void | |
1572 | arc_buf_free(arc_buf_t *buf, void *tag) | |
1573 | { | |
1574 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
1575 | int hashed = hdr->b_state != arc_anon; | |
1576 | ||
1577 | ASSERT(buf->b_efunc == NULL); | |
1578 | ASSERT(buf->b_data != NULL); | |
1579 | ||
1580 | if (hashed) { | |
1581 | kmutex_t *hash_lock = HDR_LOCK(hdr); | |
1582 | ||
1583 | mutex_enter(hash_lock); | |
428870ff BB |
1584 | hdr = buf->b_hdr; |
1585 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
1586 | ||
34dc7c2f | 1587 | (void) remove_reference(hdr, hash_lock, tag); |
428870ff | 1588 | if (hdr->b_datacnt > 1) { |
34dc7c2f | 1589 | arc_buf_destroy(buf, FALSE, TRUE); |
428870ff BB |
1590 | } else { |
1591 | ASSERT(buf == hdr->b_buf); | |
1592 | ASSERT(buf->b_efunc == NULL); | |
34dc7c2f | 1593 | hdr->b_flags |= ARC_BUF_AVAILABLE; |
428870ff | 1594 | } |
34dc7c2f BB |
1595 | mutex_exit(hash_lock); |
1596 | } else if (HDR_IO_IN_PROGRESS(hdr)) { | |
1597 | int destroy_hdr; | |
1598 | /* | |
1599 | * We are in the middle of an async write. Don't destroy | |
1600 | * this buffer unless the write completes before we finish | |
1601 | * decrementing the reference count. | |
1602 | */ | |
1603 | mutex_enter(&arc_eviction_mtx); | |
1604 | (void) remove_reference(hdr, NULL, tag); | |
1605 | ASSERT(refcount_is_zero(&hdr->b_refcnt)); | |
1606 | destroy_hdr = !HDR_IO_IN_PROGRESS(hdr); | |
1607 | mutex_exit(&arc_eviction_mtx); | |
1608 | if (destroy_hdr) | |
1609 | arc_hdr_destroy(hdr); | |
1610 | } else { | |
428870ff | 1611 | if (remove_reference(hdr, NULL, tag) > 0) |
34dc7c2f | 1612 | arc_buf_destroy(buf, FALSE, TRUE); |
428870ff | 1613 | else |
34dc7c2f | 1614 | arc_hdr_destroy(hdr); |
34dc7c2f BB |
1615 | } |
1616 | } | |
1617 | ||
1618 | int | |
1619 | arc_buf_remove_ref(arc_buf_t *buf, void* tag) | |
1620 | { | |
1621 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
1622 | kmutex_t *hash_lock = HDR_LOCK(hdr); | |
1623 | int no_callback = (buf->b_efunc == NULL); | |
1624 | ||
1625 | if (hdr->b_state == arc_anon) { | |
428870ff | 1626 | ASSERT(hdr->b_datacnt == 1); |
34dc7c2f BB |
1627 | arc_buf_free(buf, tag); |
1628 | return (no_callback); | |
1629 | } | |
1630 | ||
1631 | mutex_enter(hash_lock); | |
428870ff BB |
1632 | hdr = buf->b_hdr; |
1633 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
34dc7c2f BB |
1634 | ASSERT(hdr->b_state != arc_anon); |
1635 | ASSERT(buf->b_data != NULL); | |
1636 | ||
1637 | (void) remove_reference(hdr, hash_lock, tag); | |
1638 | if (hdr->b_datacnt > 1) { | |
1639 | if (no_callback) | |
1640 | arc_buf_destroy(buf, FALSE, TRUE); | |
1641 | } else if (no_callback) { | |
1642 | ASSERT(hdr->b_buf == buf && buf->b_next == NULL); | |
428870ff | 1643 | ASSERT(buf->b_efunc == NULL); |
34dc7c2f BB |
1644 | hdr->b_flags |= ARC_BUF_AVAILABLE; |
1645 | } | |
1646 | ASSERT(no_callback || hdr->b_datacnt > 1 || | |
1647 | refcount_is_zero(&hdr->b_refcnt)); | |
1648 | mutex_exit(hash_lock); | |
1649 | return (no_callback); | |
1650 | } | |
1651 | ||
1652 | int | |
1653 | arc_buf_size(arc_buf_t *buf) | |
1654 | { | |
1655 | return (buf->b_hdr->b_size); | |
1656 | } | |
1657 | ||
1658 | /* | |
1659 | * Evict buffers from list until we've removed the specified number of | |
1660 | * bytes. Move the removed buffers to the appropriate evict state. | |
1661 | * If the recycle flag is set, then attempt to "recycle" a buffer: | |
1662 | * - look for a buffer to evict that is `bytes' long. | |
1663 | * - return the data block from this buffer rather than freeing it. | |
1664 | * This flag is used by callers that are trying to make space for a | |
1665 | * new buffer in a full arc cache. | |
1666 | * | |
1667 | * This function makes a "best effort". It skips over any buffers | |
1668 | * it can't get a hash_lock on, and so may not catch all candidates. | |
1669 | * It may also return without evicting as much space as requested. | |
1670 | */ | |
1671 | static void * | |
d164b209 | 1672 | arc_evict(arc_state_t *state, uint64_t spa, int64_t bytes, boolean_t recycle, |
34dc7c2f BB |
1673 | arc_buf_contents_t type) |
1674 | { | |
1675 | arc_state_t *evicted_state; | |
1676 | uint64_t bytes_evicted = 0, skipped = 0, missed = 0; | |
1677 | arc_buf_hdr_t *ab, *ab_prev = NULL; | |
1678 | list_t *list = &state->arcs_list[type]; | |
1679 | kmutex_t *hash_lock; | |
1680 | boolean_t have_lock; | |
1681 | void *stolen = NULL; | |
1682 | ||
1683 | ASSERT(state == arc_mru || state == arc_mfu); | |
1684 | ||
1685 | evicted_state = (state == arc_mru) ? arc_mru_ghost : arc_mfu_ghost; | |
1686 | ||
1687 | mutex_enter(&state->arcs_mtx); | |
1688 | mutex_enter(&evicted_state->arcs_mtx); | |
1689 | ||
1690 | for (ab = list_tail(list); ab; ab = ab_prev) { | |
1691 | ab_prev = list_prev(list, ab); | |
1692 | /* prefetch buffers have a minimum lifespan */ | |
1693 | if (HDR_IO_IN_PROGRESS(ab) || | |
1694 | (spa && ab->b_spa != spa) || | |
1695 | (ab->b_flags & (ARC_PREFETCH|ARC_INDIRECT) && | |
428870ff BB |
1696 | ddi_get_lbolt() - ab->b_arc_access < |
1697 | arc_min_prefetch_lifespan)) { | |
34dc7c2f BB |
1698 | skipped++; |
1699 | continue; | |
1700 | } | |
1701 | /* "lookahead" for better eviction candidate */ | |
1702 | if (recycle && ab->b_size != bytes && | |
1703 | ab_prev && ab_prev->b_size == bytes) | |
1704 | continue; | |
1705 | hash_lock = HDR_LOCK(ab); | |
1706 | have_lock = MUTEX_HELD(hash_lock); | |
1707 | if (have_lock || mutex_tryenter(hash_lock)) { | |
1708 | ASSERT3U(refcount_count(&ab->b_refcnt), ==, 0); | |
1709 | ASSERT(ab->b_datacnt > 0); | |
1710 | while (ab->b_buf) { | |
1711 | arc_buf_t *buf = ab->b_buf; | |
428870ff | 1712 | if (!mutex_tryenter(&buf->b_evict_lock)) { |
b128c09f BB |
1713 | missed += 1; |
1714 | break; | |
1715 | } | |
34dc7c2f BB |
1716 | if (buf->b_data) { |
1717 | bytes_evicted += ab->b_size; | |
1718 | if (recycle && ab->b_type == type && | |
1719 | ab->b_size == bytes && | |
1720 | !HDR_L2_WRITING(ab)) { | |
1721 | stolen = buf->b_data; | |
1722 | recycle = FALSE; | |
1723 | } | |
1724 | } | |
1725 | if (buf->b_efunc) { | |
1726 | mutex_enter(&arc_eviction_mtx); | |
1727 | arc_buf_destroy(buf, | |
1728 | buf->b_data == stolen, FALSE); | |
1729 | ab->b_buf = buf->b_next; | |
1730 | buf->b_hdr = &arc_eviction_hdr; | |
1731 | buf->b_next = arc_eviction_list; | |
1732 | arc_eviction_list = buf; | |
1733 | mutex_exit(&arc_eviction_mtx); | |
428870ff | 1734 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f | 1735 | } else { |
428870ff | 1736 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
1737 | arc_buf_destroy(buf, |
1738 | buf->b_data == stolen, TRUE); | |
1739 | } | |
1740 | } | |
428870ff BB |
1741 | |
1742 | if (ab->b_l2hdr) { | |
1743 | ARCSTAT_INCR(arcstat_evict_l2_cached, | |
1744 | ab->b_size); | |
1745 | } else { | |
1746 | if (l2arc_write_eligible(ab->b_spa, ab)) { | |
1747 | ARCSTAT_INCR(arcstat_evict_l2_eligible, | |
1748 | ab->b_size); | |
1749 | } else { | |
1750 | ARCSTAT_INCR( | |
1751 | arcstat_evict_l2_ineligible, | |
1752 | ab->b_size); | |
1753 | } | |
1754 | } | |
1755 | ||
b128c09f BB |
1756 | if (ab->b_datacnt == 0) { |
1757 | arc_change_state(evicted_state, ab, hash_lock); | |
1758 | ASSERT(HDR_IN_HASH_TABLE(ab)); | |
1759 | ab->b_flags |= ARC_IN_HASH_TABLE; | |
1760 | ab->b_flags &= ~ARC_BUF_AVAILABLE; | |
1761 | DTRACE_PROBE1(arc__evict, arc_buf_hdr_t *, ab); | |
1762 | } | |
34dc7c2f BB |
1763 | if (!have_lock) |
1764 | mutex_exit(hash_lock); | |
1765 | if (bytes >= 0 && bytes_evicted >= bytes) | |
1766 | break; | |
1767 | } else { | |
1768 | missed += 1; | |
1769 | } | |
1770 | } | |
1771 | ||
1772 | mutex_exit(&evicted_state->arcs_mtx); | |
1773 | mutex_exit(&state->arcs_mtx); | |
1774 | ||
1775 | if (bytes_evicted < bytes) | |
3f504482 | 1776 | dprintf("only evicted %lld bytes from %x\n", |
34dc7c2f BB |
1777 | (longlong_t)bytes_evicted, state); |
1778 | ||
1779 | if (skipped) | |
1780 | ARCSTAT_INCR(arcstat_evict_skip, skipped); | |
1781 | ||
1782 | if (missed) | |
1783 | ARCSTAT_INCR(arcstat_mutex_miss, missed); | |
1784 | ||
1785 | /* | |
1786 | * We have just evicted some date into the ghost state, make | |
1787 | * sure we also adjust the ghost state size if necessary. | |
1788 | */ | |
1789 | if (arc_no_grow && | |
1790 | arc_mru_ghost->arcs_size + arc_mfu_ghost->arcs_size > arc_c) { | |
1791 | int64_t mru_over = arc_anon->arcs_size + arc_mru->arcs_size + | |
1792 | arc_mru_ghost->arcs_size - arc_c; | |
1793 | ||
1794 | if (mru_over > 0 && arc_mru_ghost->arcs_lsize[type] > 0) { | |
1795 | int64_t todelete = | |
1796 | MIN(arc_mru_ghost->arcs_lsize[type], mru_over); | |
b8864a23 | 1797 | arc_evict_ghost(arc_mru_ghost, 0, todelete); |
34dc7c2f BB |
1798 | } else if (arc_mfu_ghost->arcs_lsize[type] > 0) { |
1799 | int64_t todelete = MIN(arc_mfu_ghost->arcs_lsize[type], | |
1800 | arc_mru_ghost->arcs_size + | |
1801 | arc_mfu_ghost->arcs_size - arc_c); | |
b8864a23 | 1802 | arc_evict_ghost(arc_mfu_ghost, 0, todelete); |
34dc7c2f BB |
1803 | } |
1804 | } | |
1805 | ||
1806 | return (stolen); | |
1807 | } | |
1808 | ||
1809 | /* | |
1810 | * Remove buffers from list until we've removed the specified number of | |
1811 | * bytes. Destroy the buffers that are removed. | |
1812 | */ | |
1813 | static void | |
d164b209 | 1814 | arc_evict_ghost(arc_state_t *state, uint64_t spa, int64_t bytes) |
34dc7c2f BB |
1815 | { |
1816 | arc_buf_hdr_t *ab, *ab_prev; | |
2598c001 | 1817 | arc_buf_hdr_t marker; |
34dc7c2f BB |
1818 | list_t *list = &state->arcs_list[ARC_BUFC_DATA]; |
1819 | kmutex_t *hash_lock; | |
1820 | uint64_t bytes_deleted = 0; | |
1821 | uint64_t bufs_skipped = 0; | |
1822 | ||
1823 | ASSERT(GHOST_STATE(state)); | |
2598c001 | 1824 | bzero(&marker, sizeof(marker)); |
34dc7c2f BB |
1825 | top: |
1826 | mutex_enter(&state->arcs_mtx); | |
1827 | for (ab = list_tail(list); ab; ab = ab_prev) { | |
1828 | ab_prev = list_prev(list, ab); | |
1829 | if (spa && ab->b_spa != spa) | |
1830 | continue; | |
572e2857 BB |
1831 | |
1832 | /* ignore markers */ | |
1833 | if (ab->b_spa == 0) | |
1834 | continue; | |
1835 | ||
34dc7c2f | 1836 | hash_lock = HDR_LOCK(ab); |
428870ff BB |
1837 | /* caller may be trying to modify this buffer, skip it */ |
1838 | if (MUTEX_HELD(hash_lock)) | |
1839 | continue; | |
34dc7c2f BB |
1840 | if (mutex_tryenter(hash_lock)) { |
1841 | ASSERT(!HDR_IO_IN_PROGRESS(ab)); | |
1842 | ASSERT(ab->b_buf == NULL); | |
1843 | ARCSTAT_BUMP(arcstat_deleted); | |
1844 | bytes_deleted += ab->b_size; | |
1845 | ||
1846 | if (ab->b_l2hdr != NULL) { | |
1847 | /* | |
1848 | * This buffer is cached on the 2nd Level ARC; | |
1849 | * don't destroy the header. | |
1850 | */ | |
1851 | arc_change_state(arc_l2c_only, ab, hash_lock); | |
1852 | mutex_exit(hash_lock); | |
1853 | } else { | |
1854 | arc_change_state(arc_anon, ab, hash_lock); | |
1855 | mutex_exit(hash_lock); | |
1856 | arc_hdr_destroy(ab); | |
1857 | } | |
1858 | ||
1859 | DTRACE_PROBE1(arc__delete, arc_buf_hdr_t *, ab); | |
1860 | if (bytes >= 0 && bytes_deleted >= bytes) | |
1861 | break; | |
572e2857 BB |
1862 | } else if (bytes < 0) { |
1863 | /* | |
1864 | * Insert a list marker and then wait for the | |
1865 | * hash lock to become available. Once its | |
1866 | * available, restart from where we left off. | |
1867 | */ | |
1868 | list_insert_after(list, ab, &marker); | |
1869 | mutex_exit(&state->arcs_mtx); | |
1870 | mutex_enter(hash_lock); | |
1871 | mutex_exit(hash_lock); | |
1872 | mutex_enter(&state->arcs_mtx); | |
1873 | ab_prev = list_prev(list, &marker); | |
1874 | list_remove(list, &marker); | |
1875 | } else | |
34dc7c2f | 1876 | bufs_skipped += 1; |
34dc7c2f BB |
1877 | } |
1878 | mutex_exit(&state->arcs_mtx); | |
1879 | ||
1880 | if (list == &state->arcs_list[ARC_BUFC_DATA] && | |
1881 | (bytes < 0 || bytes_deleted < bytes)) { | |
1882 | list = &state->arcs_list[ARC_BUFC_METADATA]; | |
1883 | goto top; | |
1884 | } | |
1885 | ||
1886 | if (bufs_skipped) { | |
1887 | ARCSTAT_INCR(arcstat_mutex_miss, bufs_skipped); | |
1888 | ASSERT(bytes >= 0); | |
1889 | } | |
1890 | ||
1891 | if (bytes_deleted < bytes) | |
3f504482 | 1892 | dprintf("only deleted %lld bytes from %p\n", |
34dc7c2f BB |
1893 | (longlong_t)bytes_deleted, state); |
1894 | } | |
1895 | ||
1896 | static void | |
1897 | arc_adjust(void) | |
1898 | { | |
d164b209 BB |
1899 | int64_t adjustment, delta; |
1900 | ||
1901 | /* | |
1902 | * Adjust MRU size | |
1903 | */ | |
34dc7c2f | 1904 | |
572e2857 BB |
1905 | adjustment = MIN((int64_t)(arc_size - arc_c), |
1906 | (int64_t)(arc_anon->arcs_size + arc_mru->arcs_size + arc_meta_used - | |
1907 | arc_p)); | |
34dc7c2f | 1908 | |
d164b209 BB |
1909 | if (adjustment > 0 && arc_mru->arcs_lsize[ARC_BUFC_DATA] > 0) { |
1910 | delta = MIN(arc_mru->arcs_lsize[ARC_BUFC_DATA], adjustment); | |
b8864a23 | 1911 | (void) arc_evict(arc_mru, 0, delta, FALSE, ARC_BUFC_DATA); |
d164b209 | 1912 | adjustment -= delta; |
34dc7c2f BB |
1913 | } |
1914 | ||
d164b209 BB |
1915 | if (adjustment > 0 && arc_mru->arcs_lsize[ARC_BUFC_METADATA] > 0) { |
1916 | delta = MIN(arc_mru->arcs_lsize[ARC_BUFC_METADATA], adjustment); | |
b8864a23 | 1917 | (void) arc_evict(arc_mru, 0, delta, FALSE, |
34dc7c2f | 1918 | ARC_BUFC_METADATA); |
34dc7c2f BB |
1919 | } |
1920 | ||
d164b209 BB |
1921 | /* |
1922 | * Adjust MFU size | |
1923 | */ | |
34dc7c2f | 1924 | |
d164b209 BB |
1925 | adjustment = arc_size - arc_c; |
1926 | ||
1927 | if (adjustment > 0 && arc_mfu->arcs_lsize[ARC_BUFC_DATA] > 0) { | |
1928 | delta = MIN(adjustment, arc_mfu->arcs_lsize[ARC_BUFC_DATA]); | |
b8864a23 | 1929 | (void) arc_evict(arc_mfu, 0, delta, FALSE, ARC_BUFC_DATA); |
d164b209 | 1930 | adjustment -= delta; |
34dc7c2f BB |
1931 | } |
1932 | ||
d164b209 BB |
1933 | if (adjustment > 0 && arc_mfu->arcs_lsize[ARC_BUFC_METADATA] > 0) { |
1934 | int64_t delta = MIN(adjustment, | |
1935 | arc_mfu->arcs_lsize[ARC_BUFC_METADATA]); | |
b8864a23 | 1936 | (void) arc_evict(arc_mfu, 0, delta, FALSE, |
d164b209 BB |
1937 | ARC_BUFC_METADATA); |
1938 | } | |
34dc7c2f | 1939 | |
d164b209 BB |
1940 | /* |
1941 | * Adjust ghost lists | |
1942 | */ | |
34dc7c2f | 1943 | |
d164b209 BB |
1944 | adjustment = arc_mru->arcs_size + arc_mru_ghost->arcs_size - arc_c; |
1945 | ||
1946 | if (adjustment > 0 && arc_mru_ghost->arcs_size > 0) { | |
1947 | delta = MIN(arc_mru_ghost->arcs_size, adjustment); | |
b8864a23 | 1948 | arc_evict_ghost(arc_mru_ghost, 0, delta); |
d164b209 | 1949 | } |
34dc7c2f | 1950 | |
d164b209 BB |
1951 | adjustment = |
1952 | arc_mru_ghost->arcs_size + arc_mfu_ghost->arcs_size - arc_c; | |
34dc7c2f | 1953 | |
d164b209 BB |
1954 | if (adjustment > 0 && arc_mfu_ghost->arcs_size > 0) { |
1955 | delta = MIN(arc_mfu_ghost->arcs_size, adjustment); | |
b8864a23 | 1956 | arc_evict_ghost(arc_mfu_ghost, 0, delta); |
34dc7c2f BB |
1957 | } |
1958 | } | |
1959 | ||
ab26409d BB |
1960 | /* |
1961 | * Request that arc user drop references so that N bytes can be released | |
1962 | * from the cache. This provides a mechanism to ensure the arc can honor | |
1963 | * the arc_meta_limit and reclaim buffers which are pinned in the cache | |
1964 | * by higher layers. (i.e. the zpl) | |
1965 | */ | |
1966 | static void | |
1967 | arc_do_user_prune(int64_t adjustment) | |
1968 | { | |
1969 | arc_prune_func_t *func; | |
1970 | void *private; | |
1971 | arc_prune_t *cp, *np; | |
1972 | ||
1973 | mutex_enter(&arc_prune_mtx); | |
1974 | ||
1975 | cp = list_head(&arc_prune_list); | |
1976 | while (cp != NULL) { | |
1977 | func = cp->p_pfunc; | |
1978 | private = cp->p_private; | |
1979 | np = list_next(&arc_prune_list, cp); | |
1980 | refcount_add(&cp->p_refcnt, func); | |
1981 | mutex_exit(&arc_prune_mtx); | |
1982 | ||
1983 | if (func != NULL) | |
1984 | func(adjustment, private); | |
1985 | ||
1986 | mutex_enter(&arc_prune_mtx); | |
1987 | ||
1988 | /* User removed prune callback concurrently with execution */ | |
1989 | if (refcount_remove(&cp->p_refcnt, func) == 0) { | |
1990 | ASSERT(!list_link_active(&cp->p_node)); | |
1991 | refcount_destroy(&cp->p_refcnt); | |
1992 | kmem_free(cp, sizeof (*cp)); | |
1993 | } | |
1994 | ||
1995 | cp = np; | |
1996 | } | |
1997 | ||
1998 | ARCSTAT_BUMP(arcstat_prune); | |
1999 | mutex_exit(&arc_prune_mtx); | |
2000 | } | |
2001 | ||
34dc7c2f BB |
2002 | static void |
2003 | arc_do_user_evicts(void) | |
2004 | { | |
2005 | mutex_enter(&arc_eviction_mtx); | |
2006 | while (arc_eviction_list != NULL) { | |
2007 | arc_buf_t *buf = arc_eviction_list; | |
2008 | arc_eviction_list = buf->b_next; | |
428870ff | 2009 | mutex_enter(&buf->b_evict_lock); |
34dc7c2f | 2010 | buf->b_hdr = NULL; |
428870ff | 2011 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
2012 | mutex_exit(&arc_eviction_mtx); |
2013 | ||
2014 | if (buf->b_efunc != NULL) | |
2015 | VERIFY(buf->b_efunc(buf) == 0); | |
2016 | ||
2017 | buf->b_efunc = NULL; | |
2018 | buf->b_private = NULL; | |
2019 | kmem_cache_free(buf_cache, buf); | |
2020 | mutex_enter(&arc_eviction_mtx); | |
2021 | } | |
2022 | mutex_exit(&arc_eviction_mtx); | |
2023 | } | |
2024 | ||
ab26409d BB |
2025 | /* |
2026 | * Evict only meta data objects from the cache leaving the data objects. | |
2027 | * This is only used to enforce the tunable arc_meta_limit, if we are | |
2028 | * unable to evict enough buffers notify the user via the prune callback. | |
2029 | */ | |
2030 | void | |
2031 | arc_adjust_meta(int64_t adjustment, boolean_t may_prune) | |
2032 | { | |
2033 | int64_t delta; | |
2034 | ||
2035 | if (adjustment > 0 && arc_mru->arcs_lsize[ARC_BUFC_METADATA] > 0) { | |
2036 | delta = MIN(arc_mru->arcs_lsize[ARC_BUFC_METADATA], adjustment); | |
2037 | arc_evict(arc_mru, 0, delta, FALSE, ARC_BUFC_METADATA); | |
2038 | adjustment -= delta; | |
2039 | } | |
2040 | ||
2041 | if (adjustment > 0 && arc_mfu->arcs_lsize[ARC_BUFC_METADATA] > 0) { | |
2042 | delta = MIN(arc_mfu->arcs_lsize[ARC_BUFC_METADATA], adjustment); | |
2043 | arc_evict(arc_mfu, 0, delta, FALSE, ARC_BUFC_METADATA); | |
2044 | adjustment -= delta; | |
2045 | } | |
2046 | ||
2047 | if (may_prune && (adjustment > 0) && (arc_meta_used > arc_meta_limit)) | |
2048 | arc_do_user_prune(arc_meta_prune); | |
2049 | } | |
2050 | ||
34dc7c2f BB |
2051 | /* |
2052 | * Flush all *evictable* data from the cache for the given spa. | |
2053 | * NOTE: this will not touch "active" (i.e. referenced) data. | |
2054 | */ | |
2055 | void | |
2056 | arc_flush(spa_t *spa) | |
2057 | { | |
d164b209 BB |
2058 | uint64_t guid = 0; |
2059 | ||
2060 | if (spa) | |
3541dc6d | 2061 | guid = spa_load_guid(spa); |
d164b209 | 2062 | |
34dc7c2f | 2063 | while (list_head(&arc_mru->arcs_list[ARC_BUFC_DATA])) { |
d164b209 | 2064 | (void) arc_evict(arc_mru, guid, -1, FALSE, ARC_BUFC_DATA); |
34dc7c2f BB |
2065 | if (spa) |
2066 | break; | |
2067 | } | |
2068 | while (list_head(&arc_mru->arcs_list[ARC_BUFC_METADATA])) { | |
d164b209 | 2069 | (void) arc_evict(arc_mru, guid, -1, FALSE, ARC_BUFC_METADATA); |
34dc7c2f BB |
2070 | if (spa) |
2071 | break; | |
2072 | } | |
2073 | while (list_head(&arc_mfu->arcs_list[ARC_BUFC_DATA])) { | |
d164b209 | 2074 | (void) arc_evict(arc_mfu, guid, -1, FALSE, ARC_BUFC_DATA); |
34dc7c2f BB |
2075 | if (spa) |
2076 | break; | |
2077 | } | |
2078 | while (list_head(&arc_mfu->arcs_list[ARC_BUFC_METADATA])) { | |
d164b209 | 2079 | (void) arc_evict(arc_mfu, guid, -1, FALSE, ARC_BUFC_METADATA); |
34dc7c2f BB |
2080 | if (spa) |
2081 | break; | |
2082 | } | |
2083 | ||
d164b209 BB |
2084 | arc_evict_ghost(arc_mru_ghost, guid, -1); |
2085 | arc_evict_ghost(arc_mfu_ghost, guid, -1); | |
34dc7c2f BB |
2086 | |
2087 | mutex_enter(&arc_reclaim_thr_lock); | |
2088 | arc_do_user_evicts(); | |
2089 | mutex_exit(&arc_reclaim_thr_lock); | |
2090 | ASSERT(spa || arc_eviction_list == NULL); | |
2091 | } | |
2092 | ||
34dc7c2f | 2093 | void |
302f753f | 2094 | arc_shrink(uint64_t bytes) |
34dc7c2f BB |
2095 | { |
2096 | if (arc_c > arc_c_min) { | |
2097 | uint64_t to_free; | |
2098 | ||
302f753f BB |
2099 | to_free = bytes ? bytes : arc_c >> arc_shrink_shift; |
2100 | ||
34dc7c2f BB |
2101 | if (arc_c > arc_c_min + to_free) |
2102 | atomic_add_64(&arc_c, -to_free); | |
2103 | else | |
2104 | arc_c = arc_c_min; | |
2105 | ||
2106 | atomic_add_64(&arc_p, -(arc_p >> arc_shrink_shift)); | |
2107 | if (arc_c > arc_size) | |
2108 | arc_c = MAX(arc_size, arc_c_min); | |
2109 | if (arc_p > arc_c) | |
2110 | arc_p = (arc_c >> 1); | |
2111 | ASSERT(arc_c >= arc_c_min); | |
2112 | ASSERT((int64_t)arc_p >= 0); | |
2113 | } | |
2114 | ||
2115 | if (arc_size > arc_c) | |
2116 | arc_adjust(); | |
2117 | } | |
2118 | ||
34dc7c2f | 2119 | static void |
302f753f | 2120 | arc_kmem_reap_now(arc_reclaim_strategy_t strat, uint64_t bytes) |
34dc7c2f BB |
2121 | { |
2122 | size_t i; | |
2123 | kmem_cache_t *prev_cache = NULL; | |
2124 | kmem_cache_t *prev_data_cache = NULL; | |
2125 | extern kmem_cache_t *zio_buf_cache[]; | |
2126 | extern kmem_cache_t *zio_data_buf_cache[]; | |
34dc7c2f BB |
2127 | |
2128 | /* | |
2129 | * An aggressive reclamation will shrink the cache size as well as | |
2130 | * reap free buffers from the arc kmem caches. | |
2131 | */ | |
2132 | if (strat == ARC_RECLAIM_AGGR) | |
302f753f | 2133 | arc_shrink(bytes); |
34dc7c2f BB |
2134 | |
2135 | for (i = 0; i < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; i++) { | |
2136 | if (zio_buf_cache[i] != prev_cache) { | |
2137 | prev_cache = zio_buf_cache[i]; | |
2138 | kmem_cache_reap_now(zio_buf_cache[i]); | |
2139 | } | |
2140 | if (zio_data_buf_cache[i] != prev_data_cache) { | |
2141 | prev_data_cache = zio_data_buf_cache[i]; | |
2142 | kmem_cache_reap_now(zio_data_buf_cache[i]); | |
2143 | } | |
2144 | } | |
ab26409d | 2145 | |
34dc7c2f BB |
2146 | kmem_cache_reap_now(buf_cache); |
2147 | kmem_cache_reap_now(hdr_cache); | |
2148 | } | |
2149 | ||
302f753f BB |
2150 | /* |
2151 | * Unlike other ZFS implementations this thread is only responsible for | |
2152 | * adapting the target ARC size on Linux. The responsibility for memory | |
2153 | * reclamation has been entirely delegated to the arc_shrinker_func() | |
2154 | * which is registered with the VM. To reflect this change in behavior | |
2155 | * the arc_reclaim thread has been renamed to arc_adapt. | |
2156 | */ | |
34dc7c2f | 2157 | static void |
302f753f | 2158 | arc_adapt_thread(void) |
34dc7c2f | 2159 | { |
34dc7c2f | 2160 | callb_cpr_t cpr; |
ab26409d | 2161 | int64_t prune; |
34dc7c2f BB |
2162 | |
2163 | CALLB_CPR_INIT(&cpr, &arc_reclaim_thr_lock, callb_generic_cpr, FTAG); | |
2164 | ||
2165 | mutex_enter(&arc_reclaim_thr_lock); | |
2166 | while (arc_thread_exit == 0) { | |
302f753f BB |
2167 | #ifndef _KERNEL |
2168 | arc_reclaim_strategy_t last_reclaim = ARC_RECLAIM_CONS; | |
2169 | ||
2170 | if (spa_get_random(100) == 0) { | |
34dc7c2f BB |
2171 | |
2172 | if (arc_no_grow) { | |
2173 | if (last_reclaim == ARC_RECLAIM_CONS) { | |
2174 | last_reclaim = ARC_RECLAIM_AGGR; | |
2175 | } else { | |
2176 | last_reclaim = ARC_RECLAIM_CONS; | |
2177 | } | |
2178 | } else { | |
2179 | arc_no_grow = TRUE; | |
2180 | last_reclaim = ARC_RECLAIM_AGGR; | |
2181 | membar_producer(); | |
2182 | } | |
2183 | ||
2184 | /* reset the growth delay for every reclaim */ | |
302f753f | 2185 | arc_grow_time = ddi_get_lbolt()+(arc_grow_retry * hz); |
34dc7c2f | 2186 | |
302f753f | 2187 | arc_kmem_reap_now(last_reclaim, 0); |
b128c09f | 2188 | arc_warm = B_TRUE; |
302f753f BB |
2189 | } |
2190 | #endif /* !_KERNEL */ | |
34dc7c2f | 2191 | |
302f753f BB |
2192 | /* No recent memory pressure allow the ARC to grow. */ |
2193 | if (arc_no_grow && ddi_get_lbolt() >= arc_grow_time) | |
34dc7c2f | 2194 | arc_no_grow = FALSE; |
34dc7c2f | 2195 | |
ab26409d BB |
2196 | /* |
2197 | * Keep meta data usage within limits, arc_shrink() is not | |
2198 | * used to avoid collapsing the arc_c value when only the | |
2199 | * arc_meta_limit is being exceeded. | |
2200 | */ | |
2201 | prune = (int64_t)arc_meta_used - (int64_t)arc_meta_limit; | |
2202 | if (prune > 0) | |
2203 | arc_adjust_meta(prune, B_TRUE); | |
6a8f9b6b | 2204 | |
572e2857 | 2205 | arc_adjust(); |
34dc7c2f BB |
2206 | |
2207 | if (arc_eviction_list != NULL) | |
2208 | arc_do_user_evicts(); | |
2209 | ||
2210 | /* block until needed, or one second, whichever is shorter */ | |
2211 | CALLB_CPR_SAFE_BEGIN(&cpr); | |
5b63b3eb | 2212 | (void) cv_timedwait_interruptible(&arc_reclaim_thr_cv, |
428870ff | 2213 | &arc_reclaim_thr_lock, (ddi_get_lbolt() + hz)); |
34dc7c2f BB |
2214 | CALLB_CPR_SAFE_END(&cpr, &arc_reclaim_thr_lock); |
2215 | } | |
2216 | ||
2217 | arc_thread_exit = 0; | |
2218 | cv_broadcast(&arc_reclaim_thr_cv); | |
2219 | CALLB_CPR_EXIT(&cpr); /* drops arc_reclaim_thr_lock */ | |
2220 | thread_exit(); | |
2221 | } | |
2222 | ||
7cb67b45 BB |
2223 | #ifdef _KERNEL |
2224 | /* | |
302f753f BB |
2225 | * Determine the amount of memory eligible for eviction contained in the |
2226 | * ARC. All clean data reported by the ghost lists can always be safely | |
2227 | * evicted. Due to arc_c_min, the same does not hold for all clean data | |
2228 | * contained by the regular mru and mfu lists. | |
2229 | * | |
2230 | * In the case of the regular mru and mfu lists, we need to report as | |
2231 | * much clean data as possible, such that evicting that same reported | |
2232 | * data will not bring arc_size below arc_c_min. Thus, in certain | |
2233 | * circumstances, the total amount of clean data in the mru and mfu | |
2234 | * lists might not actually be evictable. | |
2235 | * | |
2236 | * The following two distinct cases are accounted for: | |
2237 | * | |
2238 | * 1. The sum of the amount of dirty data contained by both the mru and | |
2239 | * mfu lists, plus the ARC's other accounting (e.g. the anon list), | |
2240 | * is greater than or equal to arc_c_min. | |
2241 | * (i.e. amount of dirty data >= arc_c_min) | |
2242 | * | |
2243 | * This is the easy case; all clean data contained by the mru and mfu | |
2244 | * lists is evictable. Evicting all clean data can only drop arc_size | |
2245 | * to the amount of dirty data, which is greater than arc_c_min. | |
2246 | * | |
2247 | * 2. The sum of the amount of dirty data contained by both the mru and | |
2248 | * mfu lists, plus the ARC's other accounting (e.g. the anon list), | |
2249 | * is less than arc_c_min. | |
2250 | * (i.e. arc_c_min > amount of dirty data) | |
2251 | * | |
2252 | * 2.1. arc_size is greater than or equal arc_c_min. | |
2253 | * (i.e. arc_size >= arc_c_min > amount of dirty data) | |
2254 | * | |
2255 | * In this case, not all clean data from the regular mru and mfu | |
2256 | * lists is actually evictable; we must leave enough clean data | |
2257 | * to keep arc_size above arc_c_min. Thus, the maximum amount of | |
2258 | * evictable data from the two lists combined, is exactly the | |
2259 | * difference between arc_size and arc_c_min. | |
2260 | * | |
2261 | * 2.2. arc_size is less than arc_c_min | |
2262 | * (i.e. arc_c_min > arc_size > amount of dirty data) | |
2263 | * | |
2264 | * In this case, none of the data contained in the mru and mfu | |
2265 | * lists is evictable, even if it's clean. Since arc_size is | |
2266 | * already below arc_c_min, evicting any more would only | |
2267 | * increase this negative difference. | |
7cb67b45 | 2268 | */ |
302f753f BB |
2269 | static uint64_t |
2270 | arc_evictable_memory(void) { | |
2271 | uint64_t arc_clean = | |
2272 | arc_mru->arcs_lsize[ARC_BUFC_DATA] + | |
2273 | arc_mru->arcs_lsize[ARC_BUFC_METADATA] + | |
2274 | arc_mfu->arcs_lsize[ARC_BUFC_DATA] + | |
2275 | arc_mfu->arcs_lsize[ARC_BUFC_METADATA]; | |
2276 | uint64_t ghost_clean = | |
2277 | arc_mru_ghost->arcs_lsize[ARC_BUFC_DATA] + | |
2278 | arc_mru_ghost->arcs_lsize[ARC_BUFC_METADATA] + | |
2279 | arc_mfu_ghost->arcs_lsize[ARC_BUFC_DATA] + | |
2280 | arc_mfu_ghost->arcs_lsize[ARC_BUFC_METADATA]; | |
2281 | uint64_t arc_dirty = MAX((int64_t)arc_size - (int64_t)arc_clean, 0); | |
2282 | ||
2283 | if (arc_dirty >= arc_c_min) | |
2284 | return (ghost_clean + arc_clean); | |
2285 | ||
2286 | return (ghost_clean + MAX((int64_t)arc_size - (int64_t)arc_c_min, 0)); | |
2287 | } | |
2288 | ||
7e7baeca BB |
2289 | static int |
2290 | __arc_shrinker_func(struct shrinker *shrink, struct shrink_control *sc) | |
7cb67b45 | 2291 | { |
302f753f | 2292 | uint64_t pages; |
7cb67b45 | 2293 | |
302f753f BB |
2294 | /* The arc is considered warm once reclaim has occurred */ |
2295 | if (unlikely(arc_warm == B_FALSE)) | |
2296 | arc_warm = B_TRUE; | |
7cb67b45 | 2297 | |
302f753f BB |
2298 | /* Return the potential number of reclaimable pages */ |
2299 | pages = btop(arc_evictable_memory()); | |
2300 | if (sc->nr_to_scan == 0) | |
2301 | return (pages); | |
3fd70ee6 BB |
2302 | |
2303 | /* Not allowed to perform filesystem reclaim */ | |
7e7baeca | 2304 | if (!(sc->gfp_mask & __GFP_FS)) |
3fd70ee6 BB |
2305 | return (-1); |
2306 | ||
7cb67b45 BB |
2307 | /* Reclaim in progress */ |
2308 | if (mutex_tryenter(&arc_reclaim_thr_lock) == 0) | |
2309 | return (-1); | |
2310 | ||
302f753f BB |
2311 | /* |
2312 | * Evict the requested number of pages by shrinking arc_c the | |
2313 | * requested amount. If there is nothing left to evict just | |
2314 | * reap whatever we can from the various arc slabs. | |
2315 | */ | |
2316 | if (pages > 0) { | |
2317 | arc_kmem_reap_now(ARC_RECLAIM_AGGR, ptob(sc->nr_to_scan)); | |
2318 | pages = btop(arc_evictable_memory()); | |
2319 | } else { | |
2320 | arc_kmem_reap_now(ARC_RECLAIM_CONS, ptob(sc->nr_to_scan)); | |
2321 | pages = -1; | |
2322 | } | |
2323 | ||
2324 | /* | |
2325 | * When direct reclaim is observed it usually indicates a rapid | |
2326 | * increase in memory pressure. This occurs because the kswapd | |
2327 | * threads were unable to asynchronously keep enough free memory | |
2328 | * available. In this case set arc_no_grow to briefly pause arc | |
2329 | * growth to avoid compounding the memory pressure. | |
2330 | */ | |
7cb67b45 | 2331 | if (current_is_kswapd()) { |
302f753f | 2332 | ARCSTAT_BUMP(arcstat_memory_indirect_count); |
7cb67b45 | 2333 | } else { |
302f753f BB |
2334 | arc_no_grow = B_TRUE; |
2335 | arc_grow_time = ddi_get_lbolt() + (arc_grow_retry * hz); | |
2336 | ARCSTAT_BUMP(arcstat_memory_direct_count); | |
7cb67b45 BB |
2337 | } |
2338 | ||
7cb67b45 BB |
2339 | mutex_exit(&arc_reclaim_thr_lock); |
2340 | ||
302f753f | 2341 | return (pages); |
7cb67b45 | 2342 | } |
7e7baeca | 2343 | SPL_SHRINKER_CALLBACK_WRAPPER(arc_shrinker_func); |
7cb67b45 BB |
2344 | |
2345 | SPL_SHRINKER_DECLARE(arc_shrinker, arc_shrinker_func, DEFAULT_SEEKS); | |
2346 | #endif /* _KERNEL */ | |
2347 | ||
34dc7c2f BB |
2348 | /* |
2349 | * Adapt arc info given the number of bytes we are trying to add and | |
2350 | * the state that we are comming from. This function is only called | |
2351 | * when we are adding new content to the cache. | |
2352 | */ | |
2353 | static void | |
2354 | arc_adapt(int bytes, arc_state_t *state) | |
2355 | { | |
2356 | int mult; | |
d164b209 | 2357 | uint64_t arc_p_min = (arc_c >> arc_p_min_shift); |
34dc7c2f BB |
2358 | |
2359 | if (state == arc_l2c_only) | |
2360 | return; | |
2361 | ||
2362 | ASSERT(bytes > 0); | |
2363 | /* | |
2364 | * Adapt the target size of the MRU list: | |
2365 | * - if we just hit in the MRU ghost list, then increase | |
2366 | * the target size of the MRU list. | |
2367 | * - if we just hit in the MFU ghost list, then increase | |
2368 | * the target size of the MFU list by decreasing the | |
2369 | * target size of the MRU list. | |
2370 | */ | |
2371 | if (state == arc_mru_ghost) { | |
2372 | mult = ((arc_mru_ghost->arcs_size >= arc_mfu_ghost->arcs_size) ? | |
2373 | 1 : (arc_mfu_ghost->arcs_size/arc_mru_ghost->arcs_size)); | |
572e2857 | 2374 | mult = MIN(mult, 10); /* avoid wild arc_p adjustment */ |
34dc7c2f | 2375 | |
d164b209 | 2376 | arc_p = MIN(arc_c - arc_p_min, arc_p + bytes * mult); |
34dc7c2f | 2377 | } else if (state == arc_mfu_ghost) { |
d164b209 BB |
2378 | uint64_t delta; |
2379 | ||
34dc7c2f BB |
2380 | mult = ((arc_mfu_ghost->arcs_size >= arc_mru_ghost->arcs_size) ? |
2381 | 1 : (arc_mru_ghost->arcs_size/arc_mfu_ghost->arcs_size)); | |
572e2857 | 2382 | mult = MIN(mult, 10); |
34dc7c2f | 2383 | |
d164b209 BB |
2384 | delta = MIN(bytes * mult, arc_p); |
2385 | arc_p = MAX(arc_p_min, arc_p - delta); | |
34dc7c2f BB |
2386 | } |
2387 | ASSERT((int64_t)arc_p >= 0); | |
2388 | ||
34dc7c2f BB |
2389 | if (arc_no_grow) |
2390 | return; | |
2391 | ||
2392 | if (arc_c >= arc_c_max) | |
2393 | return; | |
2394 | ||
2395 | /* | |
2396 | * If we're within (2 * maxblocksize) bytes of the target | |
2397 | * cache size, increment the target cache size | |
2398 | */ | |
2399 | if (arc_size > arc_c - (2ULL << SPA_MAXBLOCKSHIFT)) { | |
2400 | atomic_add_64(&arc_c, (int64_t)bytes); | |
2401 | if (arc_c > arc_c_max) | |
2402 | arc_c = arc_c_max; | |
2403 | else if (state == arc_anon) | |
2404 | atomic_add_64(&arc_p, (int64_t)bytes); | |
2405 | if (arc_p > arc_c) | |
2406 | arc_p = arc_c; | |
2407 | } | |
2408 | ASSERT((int64_t)arc_p >= 0); | |
2409 | } | |
2410 | ||
2411 | /* | |
2412 | * Check if the cache has reached its limits and eviction is required | |
2413 | * prior to insert. | |
2414 | */ | |
2415 | static int | |
2416 | arc_evict_needed(arc_buf_contents_t type) | |
2417 | { | |
2418 | if (type == ARC_BUFC_METADATA && arc_meta_used >= arc_meta_limit) | |
2419 | return (1); | |
2420 | ||
2421 | #ifdef _KERNEL | |
2422 | /* | |
2423 | * If zio data pages are being allocated out of a separate heap segment, | |
2424 | * then enforce that the size of available vmem for this area remains | |
2425 | * above about 1/32nd free. | |
2426 | */ | |
2427 | if (type == ARC_BUFC_DATA && zio_arena != NULL && | |
2428 | vmem_size(zio_arena, VMEM_FREE) < | |
2429 | (vmem_size(zio_arena, VMEM_ALLOC) >> 5)) | |
2430 | return (1); | |
2431 | #endif | |
2432 | ||
302f753f | 2433 | if (arc_no_grow) |
34dc7c2f BB |
2434 | return (1); |
2435 | ||
2436 | return (arc_size > arc_c); | |
2437 | } | |
2438 | ||
2439 | /* | |
2440 | * The buffer, supplied as the first argument, needs a data block. | |
2441 | * So, if we are at cache max, determine which cache should be victimized. | |
2442 | * We have the following cases: | |
2443 | * | |
2444 | * 1. Insert for MRU, p > sizeof(arc_anon + arc_mru) -> | |
2445 | * In this situation if we're out of space, but the resident size of the MFU is | |
2446 | * under the limit, victimize the MFU cache to satisfy this insertion request. | |
2447 | * | |
2448 | * 2. Insert for MRU, p <= sizeof(arc_anon + arc_mru) -> | |
2449 | * Here, we've used up all of the available space for the MRU, so we need to | |
2450 | * evict from our own cache instead. Evict from the set of resident MRU | |
2451 | * entries. | |
2452 | * | |
2453 | * 3. Insert for MFU (c - p) > sizeof(arc_mfu) -> | |
2454 | * c minus p represents the MFU space in the cache, since p is the size of the | |
2455 | * cache that is dedicated to the MRU. In this situation there's still space on | |
2456 | * the MFU side, so the MRU side needs to be victimized. | |
2457 | * | |
2458 | * 4. Insert for MFU (c - p) < sizeof(arc_mfu) -> | |
2459 | * MFU's resident set is consuming more space than it has been allotted. In | |
2460 | * this situation, we must victimize our own cache, the MFU, for this insertion. | |
2461 | */ | |
2462 | static void | |
2463 | arc_get_data_buf(arc_buf_t *buf) | |
2464 | { | |
2465 | arc_state_t *state = buf->b_hdr->b_state; | |
2466 | uint64_t size = buf->b_hdr->b_size; | |
2467 | arc_buf_contents_t type = buf->b_hdr->b_type; | |
2468 | ||
2469 | arc_adapt(size, state); | |
2470 | ||
2471 | /* | |
2472 | * We have not yet reached cache maximum size, | |
2473 | * just allocate a new buffer. | |
2474 | */ | |
2475 | if (!arc_evict_needed(type)) { | |
2476 | if (type == ARC_BUFC_METADATA) { | |
2477 | buf->b_data = zio_buf_alloc(size); | |
d164b209 | 2478 | arc_space_consume(size, ARC_SPACE_DATA); |
34dc7c2f BB |
2479 | } else { |
2480 | ASSERT(type == ARC_BUFC_DATA); | |
2481 | buf->b_data = zio_data_buf_alloc(size); | |
d164b209 | 2482 | ARCSTAT_INCR(arcstat_data_size, size); |
34dc7c2f BB |
2483 | atomic_add_64(&arc_size, size); |
2484 | } | |
2485 | goto out; | |
2486 | } | |
2487 | ||
2488 | /* | |
2489 | * If we are prefetching from the mfu ghost list, this buffer | |
2490 | * will end up on the mru list; so steal space from there. | |
2491 | */ | |
2492 | if (state == arc_mfu_ghost) | |
2493 | state = buf->b_hdr->b_flags & ARC_PREFETCH ? arc_mru : arc_mfu; | |
2494 | else if (state == arc_mru_ghost) | |
2495 | state = arc_mru; | |
2496 | ||
2497 | if (state == arc_mru || state == arc_anon) { | |
2498 | uint64_t mru_used = arc_anon->arcs_size + arc_mru->arcs_size; | |
d164b209 | 2499 | state = (arc_mfu->arcs_lsize[type] >= size && |
34dc7c2f BB |
2500 | arc_p > mru_used) ? arc_mfu : arc_mru; |
2501 | } else { | |
2502 | /* MFU cases */ | |
2503 | uint64_t mfu_space = arc_c - arc_p; | |
d164b209 | 2504 | state = (arc_mru->arcs_lsize[type] >= size && |
34dc7c2f BB |
2505 | mfu_space > arc_mfu->arcs_size) ? arc_mru : arc_mfu; |
2506 | } | |
ab26409d | 2507 | |
b8864a23 | 2508 | if ((buf->b_data = arc_evict(state, 0, size, TRUE, type)) == NULL) { |
34dc7c2f BB |
2509 | if (type == ARC_BUFC_METADATA) { |
2510 | buf->b_data = zio_buf_alloc(size); | |
d164b209 | 2511 | arc_space_consume(size, ARC_SPACE_DATA); |
ab26409d BB |
2512 | |
2513 | /* | |
2514 | * If we are unable to recycle an existing meta buffer | |
2515 | * signal the reclaim thread. It will notify users | |
2516 | * via the prune callback to drop references. The | |
2517 | * prune callback in run in the context of the reclaim | |
2518 | * thread to avoid deadlocking on the hash_lock. | |
2519 | */ | |
2520 | cv_signal(&arc_reclaim_thr_cv); | |
34dc7c2f BB |
2521 | } else { |
2522 | ASSERT(type == ARC_BUFC_DATA); | |
2523 | buf->b_data = zio_data_buf_alloc(size); | |
d164b209 | 2524 | ARCSTAT_INCR(arcstat_data_size, size); |
34dc7c2f BB |
2525 | atomic_add_64(&arc_size, size); |
2526 | } | |
ab26409d | 2527 | |
34dc7c2f BB |
2528 | ARCSTAT_BUMP(arcstat_recycle_miss); |
2529 | } | |
2530 | ASSERT(buf->b_data != NULL); | |
2531 | out: | |
2532 | /* | |
2533 | * Update the state size. Note that ghost states have a | |
2534 | * "ghost size" and so don't need to be updated. | |
2535 | */ | |
2536 | if (!GHOST_STATE(buf->b_hdr->b_state)) { | |
2537 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
2538 | ||
2539 | atomic_add_64(&hdr->b_state->arcs_size, size); | |
2540 | if (list_link_active(&hdr->b_arc_node)) { | |
2541 | ASSERT(refcount_is_zero(&hdr->b_refcnt)); | |
2542 | atomic_add_64(&hdr->b_state->arcs_lsize[type], size); | |
2543 | } | |
2544 | /* | |
2545 | * If we are growing the cache, and we are adding anonymous | |
2546 | * data, and we have outgrown arc_p, update arc_p | |
2547 | */ | |
2548 | if (arc_size < arc_c && hdr->b_state == arc_anon && | |
2549 | arc_anon->arcs_size + arc_mru->arcs_size > arc_p) | |
2550 | arc_p = MIN(arc_c, arc_p + size); | |
2551 | } | |
2552 | } | |
2553 | ||
2554 | /* | |
2555 | * This routine is called whenever a buffer is accessed. | |
2556 | * NOTE: the hash lock is dropped in this function. | |
2557 | */ | |
2558 | static void | |
2559 | arc_access(arc_buf_hdr_t *buf, kmutex_t *hash_lock) | |
2560 | { | |
428870ff BB |
2561 | clock_t now; |
2562 | ||
34dc7c2f BB |
2563 | ASSERT(MUTEX_HELD(hash_lock)); |
2564 | ||
2565 | if (buf->b_state == arc_anon) { | |
2566 | /* | |
2567 | * This buffer is not in the cache, and does not | |
2568 | * appear in our "ghost" list. Add the new buffer | |
2569 | * to the MRU state. | |
2570 | */ | |
2571 | ||
2572 | ASSERT(buf->b_arc_access == 0); | |
428870ff | 2573 | buf->b_arc_access = ddi_get_lbolt(); |
34dc7c2f BB |
2574 | DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, buf); |
2575 | arc_change_state(arc_mru, buf, hash_lock); | |
2576 | ||
2577 | } else if (buf->b_state == arc_mru) { | |
428870ff BB |
2578 | now = ddi_get_lbolt(); |
2579 | ||
34dc7c2f BB |
2580 | /* |
2581 | * If this buffer is here because of a prefetch, then either: | |
2582 | * - clear the flag if this is a "referencing" read | |
2583 | * (any subsequent access will bump this into the MFU state). | |
2584 | * or | |
2585 | * - move the buffer to the head of the list if this is | |
2586 | * another prefetch (to make it less likely to be evicted). | |
2587 | */ | |
2588 | if ((buf->b_flags & ARC_PREFETCH) != 0) { | |
2589 | if (refcount_count(&buf->b_refcnt) == 0) { | |
2590 | ASSERT(list_link_active(&buf->b_arc_node)); | |
2591 | } else { | |
2592 | buf->b_flags &= ~ARC_PREFETCH; | |
2593 | ARCSTAT_BUMP(arcstat_mru_hits); | |
2594 | } | |
428870ff | 2595 | buf->b_arc_access = now; |
34dc7c2f BB |
2596 | return; |
2597 | } | |
2598 | ||
2599 | /* | |
2600 | * This buffer has been "accessed" only once so far, | |
2601 | * but it is still in the cache. Move it to the MFU | |
2602 | * state. | |
2603 | */ | |
428870ff | 2604 | if (now > buf->b_arc_access + ARC_MINTIME) { |
34dc7c2f BB |
2605 | /* |
2606 | * More than 125ms have passed since we | |
2607 | * instantiated this buffer. Move it to the | |
2608 | * most frequently used state. | |
2609 | */ | |
428870ff | 2610 | buf->b_arc_access = now; |
34dc7c2f BB |
2611 | DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); |
2612 | arc_change_state(arc_mfu, buf, hash_lock); | |
2613 | } | |
2614 | ARCSTAT_BUMP(arcstat_mru_hits); | |
2615 | } else if (buf->b_state == arc_mru_ghost) { | |
2616 | arc_state_t *new_state; | |
2617 | /* | |
2618 | * This buffer has been "accessed" recently, but | |
2619 | * was evicted from the cache. Move it to the | |
2620 | * MFU state. | |
2621 | */ | |
2622 | ||
2623 | if (buf->b_flags & ARC_PREFETCH) { | |
2624 | new_state = arc_mru; | |
2625 | if (refcount_count(&buf->b_refcnt) > 0) | |
2626 | buf->b_flags &= ~ARC_PREFETCH; | |
2627 | DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, buf); | |
2628 | } else { | |
2629 | new_state = arc_mfu; | |
2630 | DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); | |
2631 | } | |
2632 | ||
428870ff | 2633 | buf->b_arc_access = ddi_get_lbolt(); |
34dc7c2f BB |
2634 | arc_change_state(new_state, buf, hash_lock); |
2635 | ||
2636 | ARCSTAT_BUMP(arcstat_mru_ghost_hits); | |
2637 | } else if (buf->b_state == arc_mfu) { | |
2638 | /* | |
2639 | * This buffer has been accessed more than once and is | |
2640 | * still in the cache. Keep it in the MFU state. | |
2641 | * | |
2642 | * NOTE: an add_reference() that occurred when we did | |
2643 | * the arc_read() will have kicked this off the list. | |
2644 | * If it was a prefetch, we will explicitly move it to | |
2645 | * the head of the list now. | |
2646 | */ | |
2647 | if ((buf->b_flags & ARC_PREFETCH) != 0) { | |
2648 | ASSERT(refcount_count(&buf->b_refcnt) == 0); | |
2649 | ASSERT(list_link_active(&buf->b_arc_node)); | |
2650 | } | |
2651 | ARCSTAT_BUMP(arcstat_mfu_hits); | |
428870ff | 2652 | buf->b_arc_access = ddi_get_lbolt(); |
34dc7c2f BB |
2653 | } else if (buf->b_state == arc_mfu_ghost) { |
2654 | arc_state_t *new_state = arc_mfu; | |
2655 | /* | |
2656 | * This buffer has been accessed more than once but has | |
2657 | * been evicted from the cache. Move it back to the | |
2658 | * MFU state. | |
2659 | */ | |
2660 | ||
2661 | if (buf->b_flags & ARC_PREFETCH) { | |
2662 | /* | |
2663 | * This is a prefetch access... | |
2664 | * move this block back to the MRU state. | |
2665 | */ | |
2666 | ASSERT3U(refcount_count(&buf->b_refcnt), ==, 0); | |
2667 | new_state = arc_mru; | |
2668 | } | |
2669 | ||
428870ff | 2670 | buf->b_arc_access = ddi_get_lbolt(); |
34dc7c2f BB |
2671 | DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); |
2672 | arc_change_state(new_state, buf, hash_lock); | |
2673 | ||
2674 | ARCSTAT_BUMP(arcstat_mfu_ghost_hits); | |
2675 | } else if (buf->b_state == arc_l2c_only) { | |
2676 | /* | |
2677 | * This buffer is on the 2nd Level ARC. | |
2678 | */ | |
2679 | ||
428870ff | 2680 | buf->b_arc_access = ddi_get_lbolt(); |
34dc7c2f BB |
2681 | DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); |
2682 | arc_change_state(arc_mfu, buf, hash_lock); | |
2683 | } else { | |
2684 | ASSERT(!"invalid arc state"); | |
2685 | } | |
2686 | } | |
2687 | ||
2688 | /* a generic arc_done_func_t which you can use */ | |
2689 | /* ARGSUSED */ | |
2690 | void | |
2691 | arc_bcopy_func(zio_t *zio, arc_buf_t *buf, void *arg) | |
2692 | { | |
428870ff BB |
2693 | if (zio == NULL || zio->io_error == 0) |
2694 | bcopy(buf->b_data, arg, buf->b_hdr->b_size); | |
34dc7c2f BB |
2695 | VERIFY(arc_buf_remove_ref(buf, arg) == 1); |
2696 | } | |
2697 | ||
2698 | /* a generic arc_done_func_t */ | |
2699 | void | |
2700 | arc_getbuf_func(zio_t *zio, arc_buf_t *buf, void *arg) | |
2701 | { | |
2702 | arc_buf_t **bufp = arg; | |
2703 | if (zio && zio->io_error) { | |
2704 | VERIFY(arc_buf_remove_ref(buf, arg) == 1); | |
2705 | *bufp = NULL; | |
2706 | } else { | |
2707 | *bufp = buf; | |
428870ff | 2708 | ASSERT(buf->b_data); |
34dc7c2f BB |
2709 | } |
2710 | } | |
2711 | ||
2712 | static void | |
2713 | arc_read_done(zio_t *zio) | |
2714 | { | |
2715 | arc_buf_hdr_t *hdr, *found; | |
2716 | arc_buf_t *buf; | |
2717 | arc_buf_t *abuf; /* buffer we're assigning to callback */ | |
2718 | kmutex_t *hash_lock; | |
2719 | arc_callback_t *callback_list, *acb; | |
2720 | int freeable = FALSE; | |
2721 | ||
2722 | buf = zio->io_private; | |
2723 | hdr = buf->b_hdr; | |
2724 | ||
2725 | /* | |
2726 | * The hdr was inserted into hash-table and removed from lists | |
2727 | * prior to starting I/O. We should find this header, since | |
2728 | * it's in the hash table, and it should be legit since it's | |
2729 | * not possible to evict it during the I/O. The only possible | |
2730 | * reason for it not to be found is if we were freed during the | |
2731 | * read. | |
2732 | */ | |
d164b209 | 2733 | found = buf_hash_find(hdr->b_spa, &hdr->b_dva, hdr->b_birth, |
34dc7c2f BB |
2734 | &hash_lock); |
2735 | ||
2736 | ASSERT((found == NULL && HDR_FREED_IN_READ(hdr) && hash_lock == NULL) || | |
2737 | (found == hdr && DVA_EQUAL(&hdr->b_dva, BP_IDENTITY(zio->io_bp))) || | |
2738 | (found == hdr && HDR_L2_READING(hdr))); | |
2739 | ||
b128c09f | 2740 | hdr->b_flags &= ~ARC_L2_EVICTED; |
34dc7c2f | 2741 | if (l2arc_noprefetch && (hdr->b_flags & ARC_PREFETCH)) |
b128c09f | 2742 | hdr->b_flags &= ~ARC_L2CACHE; |
34dc7c2f BB |
2743 | |
2744 | /* byteswap if necessary */ | |
2745 | callback_list = hdr->b_acb; | |
2746 | ASSERT(callback_list != NULL); | |
428870ff | 2747 | if (BP_SHOULD_BYTESWAP(zio->io_bp) && zio->io_error == 0) { |
b128c09f BB |
2748 | arc_byteswap_func_t *func = BP_GET_LEVEL(zio->io_bp) > 0 ? |
2749 | byteswap_uint64_array : | |
2750 | dmu_ot[BP_GET_TYPE(zio->io_bp)].ot_byteswap; | |
2751 | func(buf->b_data, hdr->b_size); | |
2752 | } | |
34dc7c2f BB |
2753 | |
2754 | arc_cksum_compute(buf, B_FALSE); | |
2755 | ||
428870ff BB |
2756 | if (hash_lock && zio->io_error == 0 && hdr->b_state == arc_anon) { |
2757 | /* | |
2758 | * Only call arc_access on anonymous buffers. This is because | |
2759 | * if we've issued an I/O for an evicted buffer, we've already | |
2760 | * called arc_access (to prevent any simultaneous readers from | |
2761 | * getting confused). | |
2762 | */ | |
2763 | arc_access(hdr, hash_lock); | |
2764 | } | |
2765 | ||
34dc7c2f BB |
2766 | /* create copies of the data buffer for the callers */ |
2767 | abuf = buf; | |
2768 | for (acb = callback_list; acb; acb = acb->acb_next) { | |
2769 | if (acb->acb_done) { | |
2770 | if (abuf == NULL) | |
2771 | abuf = arc_buf_clone(buf); | |
2772 | acb->acb_buf = abuf; | |
2773 | abuf = NULL; | |
2774 | } | |
2775 | } | |
2776 | hdr->b_acb = NULL; | |
2777 | hdr->b_flags &= ~ARC_IO_IN_PROGRESS; | |
2778 | ASSERT(!HDR_BUF_AVAILABLE(hdr)); | |
428870ff BB |
2779 | if (abuf == buf) { |
2780 | ASSERT(buf->b_efunc == NULL); | |
2781 | ASSERT(hdr->b_datacnt == 1); | |
34dc7c2f | 2782 | hdr->b_flags |= ARC_BUF_AVAILABLE; |
428870ff | 2783 | } |
34dc7c2f BB |
2784 | |
2785 | ASSERT(refcount_is_zero(&hdr->b_refcnt) || callback_list != NULL); | |
2786 | ||
2787 | if (zio->io_error != 0) { | |
2788 | hdr->b_flags |= ARC_IO_ERROR; | |
2789 | if (hdr->b_state != arc_anon) | |
2790 | arc_change_state(arc_anon, hdr, hash_lock); | |
2791 | if (HDR_IN_HASH_TABLE(hdr)) | |
2792 | buf_hash_remove(hdr); | |
2793 | freeable = refcount_is_zero(&hdr->b_refcnt); | |
34dc7c2f BB |
2794 | } |
2795 | ||
2796 | /* | |
2797 | * Broadcast before we drop the hash_lock to avoid the possibility | |
2798 | * that the hdr (and hence the cv) might be freed before we get to | |
2799 | * the cv_broadcast(). | |
2800 | */ | |
2801 | cv_broadcast(&hdr->b_cv); | |
2802 | ||
2803 | if (hash_lock) { | |
34dc7c2f BB |
2804 | mutex_exit(hash_lock); |
2805 | } else { | |
2806 | /* | |
2807 | * This block was freed while we waited for the read to | |
2808 | * complete. It has been removed from the hash table and | |
2809 | * moved to the anonymous state (so that it won't show up | |
2810 | * in the cache). | |
2811 | */ | |
2812 | ASSERT3P(hdr->b_state, ==, arc_anon); | |
2813 | freeable = refcount_is_zero(&hdr->b_refcnt); | |
2814 | } | |
2815 | ||
2816 | /* execute each callback and free its structure */ | |
2817 | while ((acb = callback_list) != NULL) { | |
2818 | if (acb->acb_done) | |
2819 | acb->acb_done(zio, acb->acb_buf, acb->acb_private); | |
2820 | ||
2821 | if (acb->acb_zio_dummy != NULL) { | |
2822 | acb->acb_zio_dummy->io_error = zio->io_error; | |
2823 | zio_nowait(acb->acb_zio_dummy); | |
2824 | } | |
2825 | ||
2826 | callback_list = acb->acb_next; | |
2827 | kmem_free(acb, sizeof (arc_callback_t)); | |
2828 | } | |
2829 | ||
2830 | if (freeable) | |
2831 | arc_hdr_destroy(hdr); | |
2832 | } | |
2833 | ||
2834 | /* | |
2835 | * "Read" the block block at the specified DVA (in bp) via the | |
2836 | * cache. If the block is found in the cache, invoke the provided | |
2837 | * callback immediately and return. Note that the `zio' parameter | |
2838 | * in the callback will be NULL in this case, since no IO was | |
2839 | * required. If the block is not in the cache pass the read request | |
2840 | * on to the spa with a substitute callback function, so that the | |
2841 | * requested block will be added to the cache. | |
2842 | * | |
2843 | * If a read request arrives for a block that has a read in-progress, | |
2844 | * either wait for the in-progress read to complete (and return the | |
2845 | * results); or, if this is a read with a "done" func, add a record | |
2846 | * to the read to invoke the "done" func when the read completes, | |
2847 | * and return; or just return. | |
2848 | * | |
2849 | * arc_read_done() will invoke all the requested "done" functions | |
2850 | * for readers of this block. | |
b128c09f BB |
2851 | * |
2852 | * Normal callers should use arc_read and pass the arc buffer and offset | |
2853 | * for the bp. But if you know you don't need locking, you can use | |
2854 | * arc_read_bp. | |
34dc7c2f BB |
2855 | */ |
2856 | int | |
428870ff | 2857 | arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp, arc_buf_t *pbuf, |
b128c09f BB |
2858 | arc_done_func_t *done, void *private, int priority, int zio_flags, |
2859 | uint32_t *arc_flags, const zbookmark_t *zb) | |
2860 | { | |
2861 | int err; | |
b128c09f | 2862 | |
428870ff BB |
2863 | if (pbuf == NULL) { |
2864 | /* | |
2865 | * XXX This happens from traverse callback funcs, for | |
2866 | * the objset_phys_t block. | |
2867 | */ | |
2868 | return (arc_read_nolock(pio, spa, bp, done, private, priority, | |
2869 | zio_flags, arc_flags, zb)); | |
2870 | } | |
2871 | ||
b128c09f BB |
2872 | ASSERT(!refcount_is_zero(&pbuf->b_hdr->b_refcnt)); |
2873 | ASSERT3U((char *)bp - (char *)pbuf->b_data, <, pbuf->b_hdr->b_size); | |
428870ff | 2874 | rw_enter(&pbuf->b_data_lock, RW_READER); |
b128c09f BB |
2875 | |
2876 | err = arc_read_nolock(pio, spa, bp, done, private, priority, | |
2877 | zio_flags, arc_flags, zb); | |
428870ff | 2878 | rw_exit(&pbuf->b_data_lock); |
9babb374 | 2879 | |
b128c09f BB |
2880 | return (err); |
2881 | } | |
2882 | ||
2883 | int | |
428870ff | 2884 | arc_read_nolock(zio_t *pio, spa_t *spa, const blkptr_t *bp, |
b128c09f BB |
2885 | arc_done_func_t *done, void *private, int priority, int zio_flags, |
2886 | uint32_t *arc_flags, const zbookmark_t *zb) | |
34dc7c2f BB |
2887 | { |
2888 | arc_buf_hdr_t *hdr; | |
d4ed6673 | 2889 | arc_buf_t *buf = NULL; |
34dc7c2f BB |
2890 | kmutex_t *hash_lock; |
2891 | zio_t *rzio; | |
3541dc6d | 2892 | uint64_t guid = spa_load_guid(spa); |
34dc7c2f BB |
2893 | |
2894 | top: | |
428870ff BB |
2895 | hdr = buf_hash_find(guid, BP_IDENTITY(bp), BP_PHYSICAL_BIRTH(bp), |
2896 | &hash_lock); | |
34dc7c2f BB |
2897 | if (hdr && hdr->b_datacnt > 0) { |
2898 | ||
2899 | *arc_flags |= ARC_CACHED; | |
2900 | ||
2901 | if (HDR_IO_IN_PROGRESS(hdr)) { | |
2902 | ||
2903 | if (*arc_flags & ARC_WAIT) { | |
2904 | cv_wait(&hdr->b_cv, hash_lock); | |
2905 | mutex_exit(hash_lock); | |
2906 | goto top; | |
2907 | } | |
2908 | ASSERT(*arc_flags & ARC_NOWAIT); | |
2909 | ||
2910 | if (done) { | |
2911 | arc_callback_t *acb = NULL; | |
2912 | ||
2913 | acb = kmem_zalloc(sizeof (arc_callback_t), | |
691f6ac4 | 2914 | KM_PUSHPAGE); |
34dc7c2f BB |
2915 | acb->acb_done = done; |
2916 | acb->acb_private = private; | |
34dc7c2f BB |
2917 | if (pio != NULL) |
2918 | acb->acb_zio_dummy = zio_null(pio, | |
d164b209 | 2919 | spa, NULL, NULL, NULL, zio_flags); |
34dc7c2f BB |
2920 | |
2921 | ASSERT(acb->acb_done != NULL); | |
2922 | acb->acb_next = hdr->b_acb; | |
2923 | hdr->b_acb = acb; | |
2924 | add_reference(hdr, hash_lock, private); | |
2925 | mutex_exit(hash_lock); | |
2926 | return (0); | |
2927 | } | |
2928 | mutex_exit(hash_lock); | |
2929 | return (0); | |
2930 | } | |
2931 | ||
2932 | ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); | |
2933 | ||
2934 | if (done) { | |
2935 | add_reference(hdr, hash_lock, private); | |
2936 | /* | |
2937 | * If this block is already in use, create a new | |
2938 | * copy of the data so that we will be guaranteed | |
2939 | * that arc_release() will always succeed. | |
2940 | */ | |
2941 | buf = hdr->b_buf; | |
2942 | ASSERT(buf); | |
2943 | ASSERT(buf->b_data); | |
2944 | if (HDR_BUF_AVAILABLE(hdr)) { | |
2945 | ASSERT(buf->b_efunc == NULL); | |
2946 | hdr->b_flags &= ~ARC_BUF_AVAILABLE; | |
2947 | } else { | |
2948 | buf = arc_buf_clone(buf); | |
2949 | } | |
428870ff | 2950 | |
34dc7c2f BB |
2951 | } else if (*arc_flags & ARC_PREFETCH && |
2952 | refcount_count(&hdr->b_refcnt) == 0) { | |
2953 | hdr->b_flags |= ARC_PREFETCH; | |
2954 | } | |
2955 | DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr); | |
2956 | arc_access(hdr, hash_lock); | |
b128c09f BB |
2957 | if (*arc_flags & ARC_L2CACHE) |
2958 | hdr->b_flags |= ARC_L2CACHE; | |
34dc7c2f BB |
2959 | mutex_exit(hash_lock); |
2960 | ARCSTAT_BUMP(arcstat_hits); | |
2961 | ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), | |
2962 | demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, | |
2963 | data, metadata, hits); | |
2964 | ||
2965 | if (done) | |
2966 | done(NULL, buf, private); | |
2967 | } else { | |
2968 | uint64_t size = BP_GET_LSIZE(bp); | |
2969 | arc_callback_t *acb; | |
b128c09f | 2970 | vdev_t *vd = NULL; |
e06be586 | 2971 | uint64_t addr = -1; |
d164b209 | 2972 | boolean_t devw = B_FALSE; |
34dc7c2f BB |
2973 | |
2974 | if (hdr == NULL) { | |
2975 | /* this block is not in the cache */ | |
2976 | arc_buf_hdr_t *exists; | |
2977 | arc_buf_contents_t type = BP_GET_BUFC_TYPE(bp); | |
2978 | buf = arc_buf_alloc(spa, size, private, type); | |
2979 | hdr = buf->b_hdr; | |
2980 | hdr->b_dva = *BP_IDENTITY(bp); | |
428870ff | 2981 | hdr->b_birth = BP_PHYSICAL_BIRTH(bp); |
34dc7c2f BB |
2982 | hdr->b_cksum0 = bp->blk_cksum.zc_word[0]; |
2983 | exists = buf_hash_insert(hdr, &hash_lock); | |
2984 | if (exists) { | |
2985 | /* somebody beat us to the hash insert */ | |
2986 | mutex_exit(hash_lock); | |
428870ff | 2987 | buf_discard_identity(hdr); |
34dc7c2f BB |
2988 | (void) arc_buf_remove_ref(buf, private); |
2989 | goto top; /* restart the IO request */ | |
2990 | } | |
2991 | /* if this is a prefetch, we don't have a reference */ | |
2992 | if (*arc_flags & ARC_PREFETCH) { | |
2993 | (void) remove_reference(hdr, hash_lock, | |
2994 | private); | |
2995 | hdr->b_flags |= ARC_PREFETCH; | |
2996 | } | |
b128c09f BB |
2997 | if (*arc_flags & ARC_L2CACHE) |
2998 | hdr->b_flags |= ARC_L2CACHE; | |
34dc7c2f BB |
2999 | if (BP_GET_LEVEL(bp) > 0) |
3000 | hdr->b_flags |= ARC_INDIRECT; | |
3001 | } else { | |
3002 | /* this block is in the ghost cache */ | |
3003 | ASSERT(GHOST_STATE(hdr->b_state)); | |
3004 | ASSERT(!HDR_IO_IN_PROGRESS(hdr)); | |
3005 | ASSERT3U(refcount_count(&hdr->b_refcnt), ==, 0); | |
3006 | ASSERT(hdr->b_buf == NULL); | |
3007 | ||
3008 | /* if this is a prefetch, we don't have a reference */ | |
3009 | if (*arc_flags & ARC_PREFETCH) | |
3010 | hdr->b_flags |= ARC_PREFETCH; | |
3011 | else | |
3012 | add_reference(hdr, hash_lock, private); | |
b128c09f BB |
3013 | if (*arc_flags & ARC_L2CACHE) |
3014 | hdr->b_flags |= ARC_L2CACHE; | |
34dc7c2f BB |
3015 | buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); |
3016 | buf->b_hdr = hdr; | |
3017 | buf->b_data = NULL; | |
3018 | buf->b_efunc = NULL; | |
3019 | buf->b_private = NULL; | |
3020 | buf->b_next = NULL; | |
3021 | hdr->b_buf = buf; | |
34dc7c2f BB |
3022 | ASSERT(hdr->b_datacnt == 0); |
3023 | hdr->b_datacnt = 1; | |
428870ff BB |
3024 | arc_get_data_buf(buf); |
3025 | arc_access(hdr, hash_lock); | |
34dc7c2f BB |
3026 | } |
3027 | ||
428870ff BB |
3028 | ASSERT(!GHOST_STATE(hdr->b_state)); |
3029 | ||
691f6ac4 | 3030 | acb = kmem_zalloc(sizeof (arc_callback_t), KM_PUSHPAGE); |
34dc7c2f BB |
3031 | acb->acb_done = done; |
3032 | acb->acb_private = private; | |
34dc7c2f BB |
3033 | |
3034 | ASSERT(hdr->b_acb == NULL); | |
3035 | hdr->b_acb = acb; | |
3036 | hdr->b_flags |= ARC_IO_IN_PROGRESS; | |
3037 | ||
b128c09f BB |
3038 | if (HDR_L2CACHE(hdr) && hdr->b_l2hdr != NULL && |
3039 | (vd = hdr->b_l2hdr->b_dev->l2ad_vdev) != NULL) { | |
d164b209 | 3040 | devw = hdr->b_l2hdr->b_dev->l2ad_writing; |
b128c09f BB |
3041 | addr = hdr->b_l2hdr->b_daddr; |
3042 | /* | |
3043 | * Lock out device removal. | |
3044 | */ | |
3045 | if (vdev_is_dead(vd) || | |
3046 | !spa_config_tryenter(spa, SCL_L2ARC, vd, RW_READER)) | |
3047 | vd = NULL; | |
3048 | } | |
3049 | ||
3050 | mutex_exit(hash_lock); | |
3051 | ||
34dc7c2f | 3052 | ASSERT3U(hdr->b_size, ==, size); |
428870ff BB |
3053 | DTRACE_PROBE4(arc__miss, arc_buf_hdr_t *, hdr, blkptr_t *, bp, |
3054 | uint64_t, size, zbookmark_t *, zb); | |
34dc7c2f BB |
3055 | ARCSTAT_BUMP(arcstat_misses); |
3056 | ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), | |
3057 | demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, | |
3058 | data, metadata, misses); | |
3059 | ||
d164b209 | 3060 | if (vd != NULL && l2arc_ndev != 0 && !(l2arc_norw && devw)) { |
34dc7c2f BB |
3061 | /* |
3062 | * Read from the L2ARC if the following are true: | |
b128c09f BB |
3063 | * 1. The L2ARC vdev was previously cached. |
3064 | * 2. This buffer still has L2ARC metadata. | |
3065 | * 3. This buffer isn't currently writing to the L2ARC. | |
3066 | * 4. The L2ARC entry wasn't evicted, which may | |
3067 | * also have invalidated the vdev. | |
d164b209 | 3068 | * 5. This isn't prefetch and l2arc_noprefetch is set. |
34dc7c2f | 3069 | */ |
b128c09f | 3070 | if (hdr->b_l2hdr != NULL && |
d164b209 BB |
3071 | !HDR_L2_WRITING(hdr) && !HDR_L2_EVICTED(hdr) && |
3072 | !(l2arc_noprefetch && HDR_PREFETCH(hdr))) { | |
34dc7c2f BB |
3073 | l2arc_read_callback_t *cb; |
3074 | ||
3075 | DTRACE_PROBE1(l2arc__hit, arc_buf_hdr_t *, hdr); | |
3076 | ARCSTAT_BUMP(arcstat_l2_hits); | |
3077 | ||
34dc7c2f | 3078 | cb = kmem_zalloc(sizeof (l2arc_read_callback_t), |
691f6ac4 | 3079 | KM_PUSHPAGE); |
34dc7c2f BB |
3080 | cb->l2rcb_buf = buf; |
3081 | cb->l2rcb_spa = spa; | |
3082 | cb->l2rcb_bp = *bp; | |
3083 | cb->l2rcb_zb = *zb; | |
b128c09f | 3084 | cb->l2rcb_flags = zio_flags; |
34dc7c2f BB |
3085 | |
3086 | /* | |
b128c09f BB |
3087 | * l2arc read. The SCL_L2ARC lock will be |
3088 | * released by l2arc_read_done(). | |
34dc7c2f BB |
3089 | */ |
3090 | rzio = zio_read_phys(pio, vd, addr, size, | |
3091 | buf->b_data, ZIO_CHECKSUM_OFF, | |
b128c09f BB |
3092 | l2arc_read_done, cb, priority, zio_flags | |
3093 | ZIO_FLAG_DONT_CACHE | ZIO_FLAG_CANFAIL | | |
3094 | ZIO_FLAG_DONT_PROPAGATE | | |
3095 | ZIO_FLAG_DONT_RETRY, B_FALSE); | |
34dc7c2f BB |
3096 | DTRACE_PROBE2(l2arc__read, vdev_t *, vd, |
3097 | zio_t *, rzio); | |
d164b209 | 3098 | ARCSTAT_INCR(arcstat_l2_read_bytes, size); |
34dc7c2f | 3099 | |
b128c09f BB |
3100 | if (*arc_flags & ARC_NOWAIT) { |
3101 | zio_nowait(rzio); | |
3102 | return (0); | |
3103 | } | |
34dc7c2f | 3104 | |
b128c09f BB |
3105 | ASSERT(*arc_flags & ARC_WAIT); |
3106 | if (zio_wait(rzio) == 0) | |
3107 | return (0); | |
3108 | ||
3109 | /* l2arc read error; goto zio_read() */ | |
34dc7c2f BB |
3110 | } else { |
3111 | DTRACE_PROBE1(l2arc__miss, | |
3112 | arc_buf_hdr_t *, hdr); | |
3113 | ARCSTAT_BUMP(arcstat_l2_misses); | |
3114 | if (HDR_L2_WRITING(hdr)) | |
3115 | ARCSTAT_BUMP(arcstat_l2_rw_clash); | |
b128c09f | 3116 | spa_config_exit(spa, SCL_L2ARC, vd); |
34dc7c2f | 3117 | } |
d164b209 BB |
3118 | } else { |
3119 | if (vd != NULL) | |
3120 | spa_config_exit(spa, SCL_L2ARC, vd); | |
3121 | if (l2arc_ndev != 0) { | |
3122 | DTRACE_PROBE1(l2arc__miss, | |
3123 | arc_buf_hdr_t *, hdr); | |
3124 | ARCSTAT_BUMP(arcstat_l2_misses); | |
3125 | } | |
34dc7c2f | 3126 | } |
34dc7c2f BB |
3127 | |
3128 | rzio = zio_read(pio, spa, bp, buf->b_data, size, | |
b128c09f | 3129 | arc_read_done, buf, priority, zio_flags, zb); |
34dc7c2f BB |
3130 | |
3131 | if (*arc_flags & ARC_WAIT) | |
3132 | return (zio_wait(rzio)); | |
3133 | ||
3134 | ASSERT(*arc_flags & ARC_NOWAIT); | |
3135 | zio_nowait(rzio); | |
3136 | } | |
3137 | return (0); | |
3138 | } | |
3139 | ||
ab26409d BB |
3140 | arc_prune_t * |
3141 | arc_add_prune_callback(arc_prune_func_t *func, void *private) | |
3142 | { | |
3143 | arc_prune_t *p; | |
3144 | ||
3145 | p = kmem_alloc(sizeof(*p), KM_SLEEP); | |
3146 | p->p_pfunc = func; | |
3147 | p->p_private = private; | |
3148 | list_link_init(&p->p_node); | |
3149 | refcount_create(&p->p_refcnt); | |
3150 | ||
3151 | mutex_enter(&arc_prune_mtx); | |
3152 | refcount_add(&p->p_refcnt, &arc_prune_list); | |
3153 | list_insert_head(&arc_prune_list, p); | |
3154 | mutex_exit(&arc_prune_mtx); | |
3155 | ||
3156 | return (p); | |
3157 | } | |
3158 | ||
3159 | void | |
3160 | arc_remove_prune_callback(arc_prune_t *p) | |
3161 | { | |
3162 | mutex_enter(&arc_prune_mtx); | |
3163 | list_remove(&arc_prune_list, p); | |
3164 | if (refcount_remove(&p->p_refcnt, &arc_prune_list) == 0) { | |
3165 | refcount_destroy(&p->p_refcnt); | |
3166 | kmem_free(p, sizeof (*p)); | |
3167 | } | |
3168 | mutex_exit(&arc_prune_mtx); | |
3169 | } | |
3170 | ||
34dc7c2f BB |
3171 | void |
3172 | arc_set_callback(arc_buf_t *buf, arc_evict_func_t *func, void *private) | |
3173 | { | |
3174 | ASSERT(buf->b_hdr != NULL); | |
3175 | ASSERT(buf->b_hdr->b_state != arc_anon); | |
3176 | ASSERT(!refcount_is_zero(&buf->b_hdr->b_refcnt) || func == NULL); | |
428870ff BB |
3177 | ASSERT(buf->b_efunc == NULL); |
3178 | ASSERT(!HDR_BUF_AVAILABLE(buf->b_hdr)); | |
3179 | ||
34dc7c2f BB |
3180 | buf->b_efunc = func; |
3181 | buf->b_private = private; | |
3182 | } | |
3183 | ||
3184 | /* | |
3185 | * This is used by the DMU to let the ARC know that a buffer is | |
3186 | * being evicted, so the ARC should clean up. If this arc buf | |
3187 | * is not yet in the evicted state, it will be put there. | |
3188 | */ | |
3189 | int | |
3190 | arc_buf_evict(arc_buf_t *buf) | |
3191 | { | |
3192 | arc_buf_hdr_t *hdr; | |
3193 | kmutex_t *hash_lock; | |
3194 | arc_buf_t **bufp; | |
3195 | ||
428870ff | 3196 | mutex_enter(&buf->b_evict_lock); |
34dc7c2f BB |
3197 | hdr = buf->b_hdr; |
3198 | if (hdr == NULL) { | |
3199 | /* | |
3200 | * We are in arc_do_user_evicts(). | |
3201 | */ | |
3202 | ASSERT(buf->b_data == NULL); | |
428870ff | 3203 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f | 3204 | return (0); |
b128c09f BB |
3205 | } else if (buf->b_data == NULL) { |
3206 | arc_buf_t copy = *buf; /* structure assignment */ | |
34dc7c2f | 3207 | /* |
b128c09f BB |
3208 | * We are on the eviction list; process this buffer now |
3209 | * but let arc_do_user_evicts() do the reaping. | |
34dc7c2f | 3210 | */ |
b128c09f | 3211 | buf->b_efunc = NULL; |
428870ff | 3212 | mutex_exit(&buf->b_evict_lock); |
b128c09f BB |
3213 | VERIFY(copy.b_efunc(©) == 0); |
3214 | return (1); | |
34dc7c2f | 3215 | } |
b128c09f BB |
3216 | hash_lock = HDR_LOCK(hdr); |
3217 | mutex_enter(hash_lock); | |
428870ff BB |
3218 | hdr = buf->b_hdr; |
3219 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
34dc7c2f | 3220 | |
34dc7c2f BB |
3221 | ASSERT3U(refcount_count(&hdr->b_refcnt), <, hdr->b_datacnt); |
3222 | ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); | |
3223 | ||
3224 | /* | |
3225 | * Pull this buffer off of the hdr | |
3226 | */ | |
3227 | bufp = &hdr->b_buf; | |
3228 | while (*bufp != buf) | |
3229 | bufp = &(*bufp)->b_next; | |
3230 | *bufp = buf->b_next; | |
3231 | ||
3232 | ASSERT(buf->b_data != NULL); | |
3233 | arc_buf_destroy(buf, FALSE, FALSE); | |
3234 | ||
3235 | if (hdr->b_datacnt == 0) { | |
3236 | arc_state_t *old_state = hdr->b_state; | |
3237 | arc_state_t *evicted_state; | |
3238 | ||
428870ff | 3239 | ASSERT(hdr->b_buf == NULL); |
34dc7c2f BB |
3240 | ASSERT(refcount_is_zero(&hdr->b_refcnt)); |
3241 | ||
3242 | evicted_state = | |
3243 | (old_state == arc_mru) ? arc_mru_ghost : arc_mfu_ghost; | |
3244 | ||
3245 | mutex_enter(&old_state->arcs_mtx); | |
3246 | mutex_enter(&evicted_state->arcs_mtx); | |
3247 | ||
3248 | arc_change_state(evicted_state, hdr, hash_lock); | |
3249 | ASSERT(HDR_IN_HASH_TABLE(hdr)); | |
3250 | hdr->b_flags |= ARC_IN_HASH_TABLE; | |
3251 | hdr->b_flags &= ~ARC_BUF_AVAILABLE; | |
3252 | ||
3253 | mutex_exit(&evicted_state->arcs_mtx); | |
3254 | mutex_exit(&old_state->arcs_mtx); | |
3255 | } | |
3256 | mutex_exit(hash_lock); | |
428870ff | 3257 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
3258 | |
3259 | VERIFY(buf->b_efunc(buf) == 0); | |
3260 | buf->b_efunc = NULL; | |
3261 | buf->b_private = NULL; | |
3262 | buf->b_hdr = NULL; | |
428870ff | 3263 | buf->b_next = NULL; |
34dc7c2f BB |
3264 | kmem_cache_free(buf_cache, buf); |
3265 | return (1); | |
3266 | } | |
3267 | ||
3268 | /* | |
3269 | * Release this buffer from the cache. This must be done | |
3270 | * after a read and prior to modifying the buffer contents. | |
3271 | * If the buffer has more than one reference, we must make | |
b128c09f | 3272 | * a new hdr for the buffer. |
34dc7c2f BB |
3273 | */ |
3274 | void | |
3275 | arc_release(arc_buf_t *buf, void *tag) | |
3276 | { | |
b128c09f | 3277 | arc_buf_hdr_t *hdr; |
428870ff | 3278 | kmutex_t *hash_lock = NULL; |
b128c09f | 3279 | l2arc_buf_hdr_t *l2hdr; |
d4ed6673 | 3280 | uint64_t buf_size = 0; |
34dc7c2f | 3281 | |
428870ff BB |
3282 | /* |
3283 | * It would be nice to assert that if it's DMU metadata (level > | |
3284 | * 0 || it's the dnode file), then it must be syncing context. | |
3285 | * But we don't know that information at this level. | |
3286 | */ | |
3287 | ||
3288 | mutex_enter(&buf->b_evict_lock); | |
b128c09f BB |
3289 | hdr = buf->b_hdr; |
3290 | ||
34dc7c2f BB |
3291 | /* this buffer is not on any list */ |
3292 | ASSERT(refcount_count(&hdr->b_refcnt) > 0); | |
3293 | ||
3294 | if (hdr->b_state == arc_anon) { | |
3295 | /* this buffer is already released */ | |
34dc7c2f | 3296 | ASSERT(buf->b_efunc == NULL); |
9babb374 BB |
3297 | } else { |
3298 | hash_lock = HDR_LOCK(hdr); | |
3299 | mutex_enter(hash_lock); | |
428870ff BB |
3300 | hdr = buf->b_hdr; |
3301 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
34dc7c2f BB |
3302 | } |
3303 | ||
b128c09f BB |
3304 | l2hdr = hdr->b_l2hdr; |
3305 | if (l2hdr) { | |
3306 | mutex_enter(&l2arc_buflist_mtx); | |
3307 | hdr->b_l2hdr = NULL; | |
3308 | buf_size = hdr->b_size; | |
3309 | } | |
3310 | ||
34dc7c2f BB |
3311 | /* |
3312 | * Do we have more than one buf? | |
3313 | */ | |
b128c09f | 3314 | if (hdr->b_datacnt > 1) { |
34dc7c2f BB |
3315 | arc_buf_hdr_t *nhdr; |
3316 | arc_buf_t **bufp; | |
3317 | uint64_t blksz = hdr->b_size; | |
d164b209 | 3318 | uint64_t spa = hdr->b_spa; |
34dc7c2f BB |
3319 | arc_buf_contents_t type = hdr->b_type; |
3320 | uint32_t flags = hdr->b_flags; | |
3321 | ||
b128c09f | 3322 | ASSERT(hdr->b_buf != buf || buf->b_next != NULL); |
34dc7c2f | 3323 | /* |
428870ff BB |
3324 | * Pull the data off of this hdr and attach it to |
3325 | * a new anonymous hdr. | |
34dc7c2f BB |
3326 | */ |
3327 | (void) remove_reference(hdr, hash_lock, tag); | |
3328 | bufp = &hdr->b_buf; | |
3329 | while (*bufp != buf) | |
3330 | bufp = &(*bufp)->b_next; | |
428870ff | 3331 | *bufp = buf->b_next; |
34dc7c2f BB |
3332 | buf->b_next = NULL; |
3333 | ||
3334 | ASSERT3U(hdr->b_state->arcs_size, >=, hdr->b_size); | |
3335 | atomic_add_64(&hdr->b_state->arcs_size, -hdr->b_size); | |
3336 | if (refcount_is_zero(&hdr->b_refcnt)) { | |
3337 | uint64_t *size = &hdr->b_state->arcs_lsize[hdr->b_type]; | |
3338 | ASSERT3U(*size, >=, hdr->b_size); | |
3339 | atomic_add_64(size, -hdr->b_size); | |
3340 | } | |
3341 | hdr->b_datacnt -= 1; | |
34dc7c2f BB |
3342 | arc_cksum_verify(buf); |
3343 | ||
3344 | mutex_exit(hash_lock); | |
3345 | ||
3346 | nhdr = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); | |
3347 | nhdr->b_size = blksz; | |
3348 | nhdr->b_spa = spa; | |
3349 | nhdr->b_type = type; | |
3350 | nhdr->b_buf = buf; | |
3351 | nhdr->b_state = arc_anon; | |
3352 | nhdr->b_arc_access = 0; | |
3353 | nhdr->b_flags = flags & ARC_L2_WRITING; | |
3354 | nhdr->b_l2hdr = NULL; | |
3355 | nhdr->b_datacnt = 1; | |
3356 | nhdr->b_freeze_cksum = NULL; | |
3357 | (void) refcount_add(&nhdr->b_refcnt, tag); | |
3358 | buf->b_hdr = nhdr; | |
428870ff | 3359 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
3360 | atomic_add_64(&arc_anon->arcs_size, blksz); |
3361 | } else { | |
428870ff | 3362 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
3363 | ASSERT(refcount_count(&hdr->b_refcnt) == 1); |
3364 | ASSERT(!list_link_active(&hdr->b_arc_node)); | |
3365 | ASSERT(!HDR_IO_IN_PROGRESS(hdr)); | |
428870ff BB |
3366 | if (hdr->b_state != arc_anon) |
3367 | arc_change_state(arc_anon, hdr, hash_lock); | |
34dc7c2f | 3368 | hdr->b_arc_access = 0; |
428870ff BB |
3369 | if (hash_lock) |
3370 | mutex_exit(hash_lock); | |
34dc7c2f | 3371 | |
428870ff | 3372 | buf_discard_identity(hdr); |
34dc7c2f BB |
3373 | arc_buf_thaw(buf); |
3374 | } | |
3375 | buf->b_efunc = NULL; | |
3376 | buf->b_private = NULL; | |
3377 | ||
3378 | if (l2hdr) { | |
3379 | list_remove(l2hdr->b_dev->l2ad_buflist, hdr); | |
3380 | kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t)); | |
3381 | ARCSTAT_INCR(arcstat_l2_size, -buf_size); | |
34dc7c2f | 3382 | mutex_exit(&l2arc_buflist_mtx); |
b128c09f | 3383 | } |
34dc7c2f BB |
3384 | } |
3385 | ||
428870ff BB |
3386 | /* |
3387 | * Release this buffer. If it does not match the provided BP, fill it | |
3388 | * with that block's contents. | |
3389 | */ | |
3390 | /* ARGSUSED */ | |
3391 | int | |
3392 | arc_release_bp(arc_buf_t *buf, void *tag, blkptr_t *bp, spa_t *spa, | |
3393 | zbookmark_t *zb) | |
3394 | { | |
3395 | arc_release(buf, tag); | |
3396 | return (0); | |
3397 | } | |
3398 | ||
34dc7c2f BB |
3399 | int |
3400 | arc_released(arc_buf_t *buf) | |
3401 | { | |
b128c09f BB |
3402 | int released; |
3403 | ||
428870ff | 3404 | mutex_enter(&buf->b_evict_lock); |
b128c09f | 3405 | released = (buf->b_data != NULL && buf->b_hdr->b_state == arc_anon); |
428870ff | 3406 | mutex_exit(&buf->b_evict_lock); |
b128c09f | 3407 | return (released); |
34dc7c2f BB |
3408 | } |
3409 | ||
3410 | int | |
3411 | arc_has_callback(arc_buf_t *buf) | |
3412 | { | |
b128c09f BB |
3413 | int callback; |
3414 | ||
428870ff | 3415 | mutex_enter(&buf->b_evict_lock); |
b128c09f | 3416 | callback = (buf->b_efunc != NULL); |
428870ff | 3417 | mutex_exit(&buf->b_evict_lock); |
b128c09f | 3418 | return (callback); |
34dc7c2f BB |
3419 | } |
3420 | ||
3421 | #ifdef ZFS_DEBUG | |
3422 | int | |
3423 | arc_referenced(arc_buf_t *buf) | |
3424 | { | |
b128c09f BB |
3425 | int referenced; |
3426 | ||
428870ff | 3427 | mutex_enter(&buf->b_evict_lock); |
b128c09f | 3428 | referenced = (refcount_count(&buf->b_hdr->b_refcnt)); |
428870ff | 3429 | mutex_exit(&buf->b_evict_lock); |
b128c09f | 3430 | return (referenced); |
34dc7c2f BB |
3431 | } |
3432 | #endif | |
3433 | ||
3434 | static void | |
3435 | arc_write_ready(zio_t *zio) | |
3436 | { | |
3437 | arc_write_callback_t *callback = zio->io_private; | |
3438 | arc_buf_t *buf = callback->awcb_buf; | |
3439 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
3440 | ||
b128c09f BB |
3441 | ASSERT(!refcount_is_zero(&buf->b_hdr->b_refcnt)); |
3442 | callback->awcb_ready(zio, buf, callback->awcb_private); | |
3443 | ||
34dc7c2f BB |
3444 | /* |
3445 | * If the IO is already in progress, then this is a re-write | |
b128c09f BB |
3446 | * attempt, so we need to thaw and re-compute the cksum. |
3447 | * It is the responsibility of the callback to handle the | |
3448 | * accounting for any re-write attempt. | |
34dc7c2f BB |
3449 | */ |
3450 | if (HDR_IO_IN_PROGRESS(hdr)) { | |
34dc7c2f BB |
3451 | mutex_enter(&hdr->b_freeze_lock); |
3452 | if (hdr->b_freeze_cksum != NULL) { | |
3453 | kmem_free(hdr->b_freeze_cksum, sizeof (zio_cksum_t)); | |
3454 | hdr->b_freeze_cksum = NULL; | |
3455 | } | |
3456 | mutex_exit(&hdr->b_freeze_lock); | |
3457 | } | |
3458 | arc_cksum_compute(buf, B_FALSE); | |
3459 | hdr->b_flags |= ARC_IO_IN_PROGRESS; | |
3460 | } | |
3461 | ||
3462 | static void | |
3463 | arc_write_done(zio_t *zio) | |
3464 | { | |
3465 | arc_write_callback_t *callback = zio->io_private; | |
3466 | arc_buf_t *buf = callback->awcb_buf; | |
3467 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
3468 | ||
428870ff BB |
3469 | ASSERT(hdr->b_acb == NULL); |
3470 | ||
3471 | if (zio->io_error == 0) { | |
3472 | hdr->b_dva = *BP_IDENTITY(zio->io_bp); | |
3473 | hdr->b_birth = BP_PHYSICAL_BIRTH(zio->io_bp); | |
3474 | hdr->b_cksum0 = zio->io_bp->blk_cksum.zc_word[0]; | |
3475 | } else { | |
3476 | ASSERT(BUF_EMPTY(hdr)); | |
3477 | } | |
34dc7c2f | 3478 | |
34dc7c2f BB |
3479 | /* |
3480 | * If the block to be written was all-zero, we may have | |
3481 | * compressed it away. In this case no write was performed | |
428870ff BB |
3482 | * so there will be no dva/birth/checksum. The buffer must |
3483 | * therefore remain anonymous (and uncached). | |
34dc7c2f BB |
3484 | */ |
3485 | if (!BUF_EMPTY(hdr)) { | |
3486 | arc_buf_hdr_t *exists; | |
3487 | kmutex_t *hash_lock; | |
3488 | ||
428870ff BB |
3489 | ASSERT(zio->io_error == 0); |
3490 | ||
34dc7c2f BB |
3491 | arc_cksum_verify(buf); |
3492 | ||
3493 | exists = buf_hash_insert(hdr, &hash_lock); | |
3494 | if (exists) { | |
3495 | /* | |
3496 | * This can only happen if we overwrite for | |
3497 | * sync-to-convergence, because we remove | |
3498 | * buffers from the hash table when we arc_free(). | |
3499 | */ | |
428870ff BB |
3500 | if (zio->io_flags & ZIO_FLAG_IO_REWRITE) { |
3501 | if (!BP_EQUAL(&zio->io_bp_orig, zio->io_bp)) | |
3502 | panic("bad overwrite, hdr=%p exists=%p", | |
3503 | (void *)hdr, (void *)exists); | |
3504 | ASSERT(refcount_is_zero(&exists->b_refcnt)); | |
3505 | arc_change_state(arc_anon, exists, hash_lock); | |
3506 | mutex_exit(hash_lock); | |
3507 | arc_hdr_destroy(exists); | |
3508 | exists = buf_hash_insert(hdr, &hash_lock); | |
3509 | ASSERT3P(exists, ==, NULL); | |
3510 | } else { | |
3511 | /* Dedup */ | |
3512 | ASSERT(hdr->b_datacnt == 1); | |
3513 | ASSERT(hdr->b_state == arc_anon); | |
3514 | ASSERT(BP_GET_DEDUP(zio->io_bp)); | |
3515 | ASSERT(BP_GET_LEVEL(zio->io_bp) == 0); | |
3516 | } | |
34dc7c2f BB |
3517 | } |
3518 | hdr->b_flags &= ~ARC_IO_IN_PROGRESS; | |
b128c09f | 3519 | /* if it's not anon, we are doing a scrub */ |
428870ff | 3520 | if (!exists && hdr->b_state == arc_anon) |
b128c09f | 3521 | arc_access(hdr, hash_lock); |
34dc7c2f | 3522 | mutex_exit(hash_lock); |
34dc7c2f BB |
3523 | } else { |
3524 | hdr->b_flags &= ~ARC_IO_IN_PROGRESS; | |
3525 | } | |
3526 | ||
428870ff BB |
3527 | ASSERT(!refcount_is_zero(&hdr->b_refcnt)); |
3528 | callback->awcb_done(zio, buf, callback->awcb_private); | |
34dc7c2f BB |
3529 | |
3530 | kmem_free(callback, sizeof (arc_write_callback_t)); | |
3531 | } | |
3532 | ||
3533 | zio_t * | |
428870ff BB |
3534 | arc_write(zio_t *pio, spa_t *spa, uint64_t txg, |
3535 | blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, const zio_prop_t *zp, | |
3536 | arc_done_func_t *ready, arc_done_func_t *done, void *private, | |
3537 | int priority, int zio_flags, const zbookmark_t *zb) | |
34dc7c2f BB |
3538 | { |
3539 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
3540 | arc_write_callback_t *callback; | |
b128c09f | 3541 | zio_t *zio; |
34dc7c2f | 3542 | |
b128c09f | 3543 | ASSERT(ready != NULL); |
428870ff | 3544 | ASSERT(done != NULL); |
34dc7c2f BB |
3545 | ASSERT(!HDR_IO_ERROR(hdr)); |
3546 | ASSERT((hdr->b_flags & ARC_IO_IN_PROGRESS) == 0); | |
428870ff | 3547 | ASSERT(hdr->b_acb == NULL); |
b128c09f BB |
3548 | if (l2arc) |
3549 | hdr->b_flags |= ARC_L2CACHE; | |
34dc7c2f BB |
3550 | callback = kmem_zalloc(sizeof (arc_write_callback_t), KM_SLEEP); |
3551 | callback->awcb_ready = ready; | |
3552 | callback->awcb_done = done; | |
3553 | callback->awcb_private = private; | |
3554 | callback->awcb_buf = buf; | |
b128c09f | 3555 | |
428870ff | 3556 | zio = zio_write(pio, spa, txg, bp, buf->b_data, hdr->b_size, zp, |
b128c09f | 3557 | arc_write_ready, arc_write_done, callback, priority, zio_flags, zb); |
34dc7c2f BB |
3558 | |
3559 | return (zio); | |
3560 | } | |
3561 | ||
34dc7c2f | 3562 | static int |
9babb374 | 3563 | arc_memory_throttle(uint64_t reserve, uint64_t inflight_data, uint64_t txg) |
34dc7c2f BB |
3564 | { |
3565 | #ifdef _KERNEL | |
302f753f | 3566 | uint64_t available_memory; |
34dc7c2f | 3567 | |
302f753f BB |
3568 | /* Easily reclaimable memory (free + inactive + arc-evictable) */ |
3569 | available_memory = ptob(spl_kmem_availrmem()) + arc_evictable_memory(); | |
34dc7c2f BB |
3570 | #if defined(__i386) |
3571 | available_memory = | |
3572 | MIN(available_memory, vmem_size(heap_arena, VMEM_FREE)); | |
3573 | #endif | |
34dc7c2f | 3574 | |
302f753f | 3575 | if (available_memory <= zfs_write_limit_max) { |
34dc7c2f | 3576 | ARCSTAT_INCR(arcstat_memory_throttle_count, 1); |
570827e1 | 3577 | DMU_TX_STAT_BUMP(dmu_tx_memory_reclaim); |
34dc7c2f BB |
3578 | return (EAGAIN); |
3579 | } | |
34dc7c2f BB |
3580 | |
3581 | if (inflight_data > available_memory / 4) { | |
3582 | ARCSTAT_INCR(arcstat_memory_throttle_count, 1); | |
570827e1 | 3583 | DMU_TX_STAT_BUMP(dmu_tx_memory_inflight); |
34dc7c2f BB |
3584 | return (ERESTART); |
3585 | } | |
3586 | #endif | |
3587 | return (0); | |
3588 | } | |
3589 | ||
3590 | void | |
3591 | arc_tempreserve_clear(uint64_t reserve) | |
3592 | { | |
3593 | atomic_add_64(&arc_tempreserve, -reserve); | |
3594 | ASSERT((int64_t)arc_tempreserve >= 0); | |
3595 | } | |
3596 | ||
3597 | int | |
3598 | arc_tempreserve_space(uint64_t reserve, uint64_t txg) | |
3599 | { | |
3600 | int error; | |
9babb374 | 3601 | uint64_t anon_size; |
34dc7c2f BB |
3602 | |
3603 | #ifdef ZFS_DEBUG | |
3604 | /* | |
3605 | * Once in a while, fail for no reason. Everything should cope. | |
3606 | */ | |
3607 | if (spa_get_random(10000) == 0) { | |
3608 | dprintf("forcing random failure\n"); | |
3609 | return (ERESTART); | |
3610 | } | |
3611 | #endif | |
3612 | if (reserve > arc_c/4 && !arc_no_grow) | |
3613 | arc_c = MIN(arc_c_max, reserve * 4); | |
570827e1 BB |
3614 | if (reserve > arc_c) { |
3615 | DMU_TX_STAT_BUMP(dmu_tx_memory_reserve); | |
34dc7c2f | 3616 | return (ENOMEM); |
570827e1 | 3617 | } |
34dc7c2f | 3618 | |
9babb374 BB |
3619 | /* |
3620 | * Don't count loaned bufs as in flight dirty data to prevent long | |
3621 | * network delays from blocking transactions that are ready to be | |
3622 | * assigned to a txg. | |
3623 | */ | |
3624 | anon_size = MAX((int64_t)(arc_anon->arcs_size - arc_loaned_bytes), 0); | |
3625 | ||
34dc7c2f BB |
3626 | /* |
3627 | * Writes will, almost always, require additional memory allocations | |
3628 | * in order to compress/encrypt/etc the data. We therefor need to | |
3629 | * make sure that there is sufficient available memory for this. | |
3630 | */ | |
c65aa5b2 | 3631 | if ((error = arc_memory_throttle(reserve, anon_size, txg))) |
34dc7c2f BB |
3632 | return (error); |
3633 | ||
3634 | /* | |
3635 | * Throttle writes when the amount of dirty data in the cache | |
3636 | * gets too large. We try to keep the cache less than half full | |
3637 | * of dirty blocks so that our sync times don't grow too large. | |
3638 | * Note: if two requests come in concurrently, we might let them | |
3639 | * both succeed, when one of them should fail. Not a huge deal. | |
3640 | */ | |
9babb374 BB |
3641 | |
3642 | if (reserve + arc_tempreserve + anon_size > arc_c / 2 && | |
3643 | anon_size > arc_c / 4) { | |
34dc7c2f BB |
3644 | dprintf("failing, arc_tempreserve=%lluK anon_meta=%lluK " |
3645 | "anon_data=%lluK tempreserve=%lluK arc_c=%lluK\n", | |
3646 | arc_tempreserve>>10, | |
3647 | arc_anon->arcs_lsize[ARC_BUFC_METADATA]>>10, | |
3648 | arc_anon->arcs_lsize[ARC_BUFC_DATA]>>10, | |
3649 | reserve>>10, arc_c>>10); | |
570827e1 | 3650 | DMU_TX_STAT_BUMP(dmu_tx_dirty_throttle); |
34dc7c2f BB |
3651 | return (ERESTART); |
3652 | } | |
3653 | atomic_add_64(&arc_tempreserve, reserve); | |
3654 | return (0); | |
3655 | } | |
3656 | ||
13be560d BB |
3657 | static void |
3658 | arc_kstat_update_state(arc_state_t *state, kstat_named_t *size, | |
3659 | kstat_named_t *evict_data, kstat_named_t *evict_metadata) | |
3660 | { | |
3661 | size->value.ui64 = state->arcs_size; | |
3662 | evict_data->value.ui64 = state->arcs_lsize[ARC_BUFC_DATA]; | |
3663 | evict_metadata->value.ui64 = state->arcs_lsize[ARC_BUFC_METADATA]; | |
3664 | } | |
3665 | ||
3666 | static int | |
3667 | arc_kstat_update(kstat_t *ksp, int rw) | |
3668 | { | |
3669 | arc_stats_t *as = ksp->ks_data; | |
3670 | ||
3671 | if (rw == KSTAT_WRITE) { | |
3672 | return (EACCES); | |
3673 | } else { | |
3674 | arc_kstat_update_state(arc_anon, | |
3675 | &as->arcstat_anon_size, | |
3676 | &as->arcstat_anon_evict_data, | |
3677 | &as->arcstat_anon_evict_metadata); | |
3678 | arc_kstat_update_state(arc_mru, | |
3679 | &as->arcstat_mru_size, | |
3680 | &as->arcstat_mru_evict_data, | |
3681 | &as->arcstat_mru_evict_metadata); | |
3682 | arc_kstat_update_state(arc_mru_ghost, | |
3683 | &as->arcstat_mru_ghost_size, | |
3684 | &as->arcstat_mru_ghost_evict_data, | |
3685 | &as->arcstat_mru_ghost_evict_metadata); | |
3686 | arc_kstat_update_state(arc_mfu, | |
3687 | &as->arcstat_mfu_size, | |
3688 | &as->arcstat_mfu_evict_data, | |
3689 | &as->arcstat_mfu_evict_metadata); | |
fc41c640 | 3690 | arc_kstat_update_state(arc_mfu_ghost, |
13be560d BB |
3691 | &as->arcstat_mfu_ghost_size, |
3692 | &as->arcstat_mfu_ghost_evict_data, | |
3693 | &as->arcstat_mfu_ghost_evict_metadata); | |
3694 | } | |
3695 | ||
3696 | return (0); | |
3697 | } | |
3698 | ||
34dc7c2f BB |
3699 | void |
3700 | arc_init(void) | |
3701 | { | |
3702 | mutex_init(&arc_reclaim_thr_lock, NULL, MUTEX_DEFAULT, NULL); | |
3703 | cv_init(&arc_reclaim_thr_cv, NULL, CV_DEFAULT, NULL); | |
3704 | ||
3705 | /* Convert seconds to clock ticks */ | |
3706 | arc_min_prefetch_lifespan = 1 * hz; | |
3707 | ||
3708 | /* Start out with 1/8 of all memory */ | |
3709 | arc_c = physmem * PAGESIZE / 8; | |
3710 | ||
3711 | #ifdef _KERNEL | |
3712 | /* | |
3713 | * On architectures where the physical memory can be larger | |
3714 | * than the addressable space (intel in 32-bit mode), we may | |
3715 | * need to limit the cache to 1/8 of VM size. | |
3716 | */ | |
3717 | arc_c = MIN(arc_c, vmem_size(heap_arena, VMEM_ALLOC | VMEM_FREE) / 8); | |
7cb67b45 BB |
3718 | /* |
3719 | * Register a shrinker to support synchronous (direct) memory | |
3720 | * reclaim from the arc. This is done to prevent kswapd from | |
3721 | * swapping out pages when it is preferable to shrink the arc. | |
3722 | */ | |
3723 | spl_register_shrinker(&arc_shrinker); | |
34dc7c2f BB |
3724 | #endif |
3725 | ||
3726 | /* set min cache to 1/32 of all memory, or 64MB, whichever is more */ | |
3727 | arc_c_min = MAX(arc_c / 4, 64<<20); | |
518b4876 | 3728 | /* set max to 1/2 of all memory */ |
23bdb07d | 3729 | arc_c_max = MAX(arc_c * 4, arc_c_max); |
34dc7c2f BB |
3730 | |
3731 | /* | |
3732 | * Allow the tunables to override our calculations if they are | |
3733 | * reasonable (ie. over 64MB) | |
3734 | */ | |
3735 | if (zfs_arc_max > 64<<20 && zfs_arc_max < physmem * PAGESIZE) | |
3736 | arc_c_max = zfs_arc_max; | |
3737 | if (zfs_arc_min > 64<<20 && zfs_arc_min <= arc_c_max) | |
3738 | arc_c_min = zfs_arc_min; | |
3739 | ||
3740 | arc_c = arc_c_max; | |
3741 | arc_p = (arc_c >> 1); | |
3742 | ||
3743 | /* limit meta-data to 1/4 of the arc capacity */ | |
3744 | arc_meta_limit = arc_c_max / 4; | |
1834f2d8 | 3745 | arc_meta_max = 0; |
34dc7c2f BB |
3746 | |
3747 | /* Allow the tunable to override if it is reasonable */ | |
3748 | if (zfs_arc_meta_limit > 0 && zfs_arc_meta_limit <= arc_c_max) | |
3749 | arc_meta_limit = zfs_arc_meta_limit; | |
3750 | ||
3751 | if (arc_c_min < arc_meta_limit / 2 && zfs_arc_min == 0) | |
3752 | arc_c_min = arc_meta_limit / 2; | |
3753 | ||
d164b209 BB |
3754 | if (zfs_arc_grow_retry > 0) |
3755 | arc_grow_retry = zfs_arc_grow_retry; | |
3756 | ||
3757 | if (zfs_arc_shrink_shift > 0) | |
3758 | arc_shrink_shift = zfs_arc_shrink_shift; | |
3759 | ||
3760 | if (zfs_arc_p_min_shift > 0) | |
3761 | arc_p_min_shift = zfs_arc_p_min_shift; | |
3762 | ||
ab26409d BB |
3763 | if (zfs_arc_meta_prune > 0) |
3764 | arc_meta_prune = zfs_arc_meta_prune; | |
6a8f9b6b | 3765 | |
34dc7c2f BB |
3766 | /* if kmem_flags are set, lets try to use less memory */ |
3767 | if (kmem_debugging()) | |
3768 | arc_c = arc_c / 2; | |
3769 | if (arc_c < arc_c_min) | |
3770 | arc_c = arc_c_min; | |
3771 | ||
3772 | arc_anon = &ARC_anon; | |
3773 | arc_mru = &ARC_mru; | |
3774 | arc_mru_ghost = &ARC_mru_ghost; | |
3775 | arc_mfu = &ARC_mfu; | |
3776 | arc_mfu_ghost = &ARC_mfu_ghost; | |
3777 | arc_l2c_only = &ARC_l2c_only; | |
3778 | arc_size = 0; | |
3779 | ||
3780 | mutex_init(&arc_anon->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3781 | mutex_init(&arc_mru->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3782 | mutex_init(&arc_mru_ghost->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3783 | mutex_init(&arc_mfu->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3784 | mutex_init(&arc_mfu_ghost->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3785 | mutex_init(&arc_l2c_only->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3786 | ||
3787 | list_create(&arc_mru->arcs_list[ARC_BUFC_METADATA], | |
3788 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3789 | list_create(&arc_mru->arcs_list[ARC_BUFC_DATA], | |
3790 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3791 | list_create(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA], | |
3792 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3793 | list_create(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA], | |
3794 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3795 | list_create(&arc_mfu->arcs_list[ARC_BUFC_METADATA], | |
3796 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3797 | list_create(&arc_mfu->arcs_list[ARC_BUFC_DATA], | |
3798 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3799 | list_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA], | |
3800 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3801 | list_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA], | |
3802 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3803 | list_create(&arc_l2c_only->arcs_list[ARC_BUFC_METADATA], | |
3804 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3805 | list_create(&arc_l2c_only->arcs_list[ARC_BUFC_DATA], | |
3806 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3807 | ||
3808 | buf_init(); | |
3809 | ||
3810 | arc_thread_exit = 0; | |
ab26409d BB |
3811 | list_create(&arc_prune_list, sizeof (arc_prune_t), |
3812 | offsetof(arc_prune_t, p_node)); | |
34dc7c2f | 3813 | arc_eviction_list = NULL; |
ab26409d | 3814 | mutex_init(&arc_prune_mtx, NULL, MUTEX_DEFAULT, NULL); |
34dc7c2f BB |
3815 | mutex_init(&arc_eviction_mtx, NULL, MUTEX_DEFAULT, NULL); |
3816 | bzero(&arc_eviction_hdr, sizeof (arc_buf_hdr_t)); | |
3817 | ||
3818 | arc_ksp = kstat_create("zfs", 0, "arcstats", "misc", KSTAT_TYPE_NAMED, | |
3819 | sizeof (arc_stats) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL); | |
3820 | ||
3821 | if (arc_ksp != NULL) { | |
3822 | arc_ksp->ks_data = &arc_stats; | |
13be560d | 3823 | arc_ksp->ks_update = arc_kstat_update; |
34dc7c2f BB |
3824 | kstat_install(arc_ksp); |
3825 | } | |
3826 | ||
302f753f | 3827 | (void) thread_create(NULL, 0, arc_adapt_thread, NULL, 0, &p0, |
34dc7c2f BB |
3828 | TS_RUN, minclsyspri); |
3829 | ||
3830 | arc_dead = FALSE; | |
b128c09f | 3831 | arc_warm = B_FALSE; |
34dc7c2f BB |
3832 | |
3833 | if (zfs_write_limit_max == 0) | |
b128c09f | 3834 | zfs_write_limit_max = ptob(physmem) >> zfs_write_limit_shift; |
34dc7c2f BB |
3835 | else |
3836 | zfs_write_limit_shift = 0; | |
b128c09f | 3837 | mutex_init(&zfs_write_limit_lock, NULL, MUTEX_DEFAULT, NULL); |
34dc7c2f BB |
3838 | } |
3839 | ||
3840 | void | |
3841 | arc_fini(void) | |
3842 | { | |
ab26409d BB |
3843 | arc_prune_t *p; |
3844 | ||
34dc7c2f | 3845 | mutex_enter(&arc_reclaim_thr_lock); |
7cb67b45 BB |
3846 | #ifdef _KERNEL |
3847 | spl_unregister_shrinker(&arc_shrinker); | |
3848 | #endif /* _KERNEL */ | |
3849 | ||
34dc7c2f BB |
3850 | arc_thread_exit = 1; |
3851 | while (arc_thread_exit != 0) | |
3852 | cv_wait(&arc_reclaim_thr_cv, &arc_reclaim_thr_lock); | |
3853 | mutex_exit(&arc_reclaim_thr_lock); | |
3854 | ||
3855 | arc_flush(NULL); | |
3856 | ||
3857 | arc_dead = TRUE; | |
3858 | ||
3859 | if (arc_ksp != NULL) { | |
3860 | kstat_delete(arc_ksp); | |
3861 | arc_ksp = NULL; | |
3862 | } | |
3863 | ||
ab26409d BB |
3864 | mutex_enter(&arc_prune_mtx); |
3865 | while ((p = list_head(&arc_prune_list)) != NULL) { | |
3866 | list_remove(&arc_prune_list, p); | |
3867 | refcount_remove(&p->p_refcnt, &arc_prune_list); | |
3868 | refcount_destroy(&p->p_refcnt); | |
3869 | kmem_free(p, sizeof (*p)); | |
3870 | } | |
3871 | mutex_exit(&arc_prune_mtx); | |
3872 | ||
3873 | list_destroy(&arc_prune_list); | |
3874 | mutex_destroy(&arc_prune_mtx); | |
34dc7c2f BB |
3875 | mutex_destroy(&arc_eviction_mtx); |
3876 | mutex_destroy(&arc_reclaim_thr_lock); | |
3877 | cv_destroy(&arc_reclaim_thr_cv); | |
3878 | ||
3879 | list_destroy(&arc_mru->arcs_list[ARC_BUFC_METADATA]); | |
3880 | list_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA]); | |
3881 | list_destroy(&arc_mfu->arcs_list[ARC_BUFC_METADATA]); | |
3882 | list_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA]); | |
3883 | list_destroy(&arc_mru->arcs_list[ARC_BUFC_DATA]); | |
3884 | list_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA]); | |
3885 | list_destroy(&arc_mfu->arcs_list[ARC_BUFC_DATA]); | |
3886 | list_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA]); | |
3887 | ||
3888 | mutex_destroy(&arc_anon->arcs_mtx); | |
3889 | mutex_destroy(&arc_mru->arcs_mtx); | |
3890 | mutex_destroy(&arc_mru_ghost->arcs_mtx); | |
3891 | mutex_destroy(&arc_mfu->arcs_mtx); | |
3892 | mutex_destroy(&arc_mfu_ghost->arcs_mtx); | |
fb5f0bc8 | 3893 | mutex_destroy(&arc_l2c_only->arcs_mtx); |
34dc7c2f | 3894 | |
b128c09f BB |
3895 | mutex_destroy(&zfs_write_limit_lock); |
3896 | ||
34dc7c2f | 3897 | buf_fini(); |
9babb374 BB |
3898 | |
3899 | ASSERT(arc_loaned_bytes == 0); | |
34dc7c2f BB |
3900 | } |
3901 | ||
3902 | /* | |
3903 | * Level 2 ARC | |
3904 | * | |
3905 | * The level 2 ARC (L2ARC) is a cache layer in-between main memory and disk. | |
3906 | * It uses dedicated storage devices to hold cached data, which are populated | |
3907 | * using large infrequent writes. The main role of this cache is to boost | |
3908 | * the performance of random read workloads. The intended L2ARC devices | |
3909 | * include short-stroked disks, solid state disks, and other media with | |
3910 | * substantially faster read latency than disk. | |
3911 | * | |
3912 | * +-----------------------+ | |
3913 | * | ARC | | |
3914 | * +-----------------------+ | |
3915 | * | ^ ^ | |
3916 | * | | | | |
3917 | * l2arc_feed_thread() arc_read() | |
3918 | * | | | | |
3919 | * | l2arc read | | |
3920 | * V | | | |
3921 | * +---------------+ | | |
3922 | * | L2ARC | | | |
3923 | * +---------------+ | | |
3924 | * | ^ | | |
3925 | * l2arc_write() | | | |
3926 | * | | | | |
3927 | * V | | | |
3928 | * +-------+ +-------+ | |
3929 | * | vdev | | vdev | | |
3930 | * | cache | | cache | | |
3931 | * +-------+ +-------+ | |
3932 | * +=========+ .-----. | |
3933 | * : L2ARC : |-_____-| | |
3934 | * : devices : | Disks | | |
3935 | * +=========+ `-_____-' | |
3936 | * | |
3937 | * Read requests are satisfied from the following sources, in order: | |
3938 | * | |
3939 | * 1) ARC | |
3940 | * 2) vdev cache of L2ARC devices | |
3941 | * 3) L2ARC devices | |
3942 | * 4) vdev cache of disks | |
3943 | * 5) disks | |
3944 | * | |
3945 | * Some L2ARC device types exhibit extremely slow write performance. | |
3946 | * To accommodate for this there are some significant differences between | |
3947 | * the L2ARC and traditional cache design: | |
3948 | * | |
3949 | * 1. There is no eviction path from the ARC to the L2ARC. Evictions from | |
3950 | * the ARC behave as usual, freeing buffers and placing headers on ghost | |
3951 | * lists. The ARC does not send buffers to the L2ARC during eviction as | |
3952 | * this would add inflated write latencies for all ARC memory pressure. | |
3953 | * | |
3954 | * 2. The L2ARC attempts to cache data from the ARC before it is evicted. | |
3955 | * It does this by periodically scanning buffers from the eviction-end of | |
3956 | * the MFU and MRU ARC lists, copying them to the L2ARC devices if they are | |
3957 | * not already there. It scans until a headroom of buffers is satisfied, | |
3958 | * which itself is a buffer for ARC eviction. The thread that does this is | |
3959 | * l2arc_feed_thread(), illustrated below; example sizes are included to | |
3960 | * provide a better sense of ratio than this diagram: | |
3961 | * | |
3962 | * head --> tail | |
3963 | * +---------------------+----------+ | |
3964 | * ARC_mfu |:::::#:::::::::::::::|o#o###o###|-->. # already on L2ARC | |
3965 | * +---------------------+----------+ | o L2ARC eligible | |
3966 | * ARC_mru |:#:::::::::::::::::::|#o#ooo####|-->| : ARC buffer | |
3967 | * +---------------------+----------+ | | |
3968 | * 15.9 Gbytes ^ 32 Mbytes | | |
3969 | * headroom | | |
3970 | * l2arc_feed_thread() | |
3971 | * | | |
3972 | * l2arc write hand <--[oooo]--' | |
3973 | * | 8 Mbyte | |
3974 | * | write max | |
3975 | * V | |
3976 | * +==============================+ | |
3977 | * L2ARC dev |####|#|###|###| |####| ... | | |
3978 | * +==============================+ | |
3979 | * 32 Gbytes | |
3980 | * | |
3981 | * 3. If an ARC buffer is copied to the L2ARC but then hit instead of | |
3982 | * evicted, then the L2ARC has cached a buffer much sooner than it probably | |
3983 | * needed to, potentially wasting L2ARC device bandwidth and storage. It is | |
3984 | * safe to say that this is an uncommon case, since buffers at the end of | |
3985 | * the ARC lists have moved there due to inactivity. | |
3986 | * | |
3987 | * 4. If the ARC evicts faster than the L2ARC can maintain a headroom, | |
3988 | * then the L2ARC simply misses copying some buffers. This serves as a | |
3989 | * pressure valve to prevent heavy read workloads from both stalling the ARC | |
3990 | * with waits and clogging the L2ARC with writes. This also helps prevent | |
3991 | * the potential for the L2ARC to churn if it attempts to cache content too | |
3992 | * quickly, such as during backups of the entire pool. | |
3993 | * | |
b128c09f BB |
3994 | * 5. After system boot and before the ARC has filled main memory, there are |
3995 | * no evictions from the ARC and so the tails of the ARC_mfu and ARC_mru | |
3996 | * lists can remain mostly static. Instead of searching from tail of these | |
3997 | * lists as pictured, the l2arc_feed_thread() will search from the list heads | |
3998 | * for eligible buffers, greatly increasing its chance of finding them. | |
3999 | * | |
4000 | * The L2ARC device write speed is also boosted during this time so that | |
4001 | * the L2ARC warms up faster. Since there have been no ARC evictions yet, | |
4002 | * there are no L2ARC reads, and no fear of degrading read performance | |
4003 | * through increased writes. | |
4004 | * | |
4005 | * 6. Writes to the L2ARC devices are grouped and sent in-sequence, so that | |
34dc7c2f BB |
4006 | * the vdev queue can aggregate them into larger and fewer writes. Each |
4007 | * device is written to in a rotor fashion, sweeping writes through | |
4008 | * available space then repeating. | |
4009 | * | |
b128c09f | 4010 | * 7. The L2ARC does not store dirty content. It never needs to flush |
34dc7c2f BB |
4011 | * write buffers back to disk based storage. |
4012 | * | |
b128c09f | 4013 | * 8. If an ARC buffer is written (and dirtied) which also exists in the |
34dc7c2f BB |
4014 | * L2ARC, the now stale L2ARC buffer is immediately dropped. |
4015 | * | |
4016 | * The performance of the L2ARC can be tweaked by a number of tunables, which | |
4017 | * may be necessary for different workloads: | |
4018 | * | |
4019 | * l2arc_write_max max write bytes per interval | |
b128c09f | 4020 | * l2arc_write_boost extra write bytes during device warmup |
34dc7c2f BB |
4021 | * l2arc_noprefetch skip caching prefetched buffers |
4022 | * l2arc_headroom number of max device writes to precache | |
4023 | * l2arc_feed_secs seconds between L2ARC writing | |
4024 | * | |
4025 | * Tunables may be removed or added as future performance improvements are | |
4026 | * integrated, and also may become zpool properties. | |
d164b209 BB |
4027 | * |
4028 | * There are three key functions that control how the L2ARC warms up: | |
4029 | * | |
4030 | * l2arc_write_eligible() check if a buffer is eligible to cache | |
4031 | * l2arc_write_size() calculate how much to write | |
4032 | * l2arc_write_interval() calculate sleep delay between writes | |
4033 | * | |
4034 | * These three functions determine what to write, how much, and how quickly | |
4035 | * to send writes. | |
34dc7c2f BB |
4036 | */ |
4037 | ||
d164b209 BB |
4038 | static boolean_t |
4039 | l2arc_write_eligible(uint64_t spa_guid, arc_buf_hdr_t *ab) | |
4040 | { | |
4041 | /* | |
4042 | * A buffer is *not* eligible for the L2ARC if it: | |
4043 | * 1. belongs to a different spa. | |
428870ff BB |
4044 | * 2. is already cached on the L2ARC. |
4045 | * 3. has an I/O in progress (it may be an incomplete read). | |
4046 | * 4. is flagged not eligible (zfs property). | |
d164b209 | 4047 | */ |
428870ff | 4048 | if (ab->b_spa != spa_guid || ab->b_l2hdr != NULL || |
d164b209 BB |
4049 | HDR_IO_IN_PROGRESS(ab) || !HDR_L2CACHE(ab)) |
4050 | return (B_FALSE); | |
4051 | ||
4052 | return (B_TRUE); | |
4053 | } | |
4054 | ||
4055 | static uint64_t | |
4056 | l2arc_write_size(l2arc_dev_t *dev) | |
4057 | { | |
4058 | uint64_t size; | |
4059 | ||
4060 | size = dev->l2ad_write; | |
4061 | ||
4062 | if (arc_warm == B_FALSE) | |
4063 | size += dev->l2ad_boost; | |
4064 | ||
4065 | return (size); | |
4066 | ||
4067 | } | |
4068 | ||
4069 | static clock_t | |
4070 | l2arc_write_interval(clock_t began, uint64_t wanted, uint64_t wrote) | |
4071 | { | |
428870ff | 4072 | clock_t interval, next, now; |
d164b209 BB |
4073 | |
4074 | /* | |
4075 | * If the ARC lists are busy, increase our write rate; if the | |
4076 | * lists are stale, idle back. This is achieved by checking | |
4077 | * how much we previously wrote - if it was more than half of | |
4078 | * what we wanted, schedule the next write much sooner. | |
4079 | */ | |
4080 | if (l2arc_feed_again && wrote > (wanted / 2)) | |
4081 | interval = (hz * l2arc_feed_min_ms) / 1000; | |
4082 | else | |
4083 | interval = hz * l2arc_feed_secs; | |
4084 | ||
428870ff BB |
4085 | now = ddi_get_lbolt(); |
4086 | next = MAX(now, MIN(now + interval, began + interval)); | |
d164b209 BB |
4087 | |
4088 | return (next); | |
4089 | } | |
4090 | ||
34dc7c2f BB |
4091 | static void |
4092 | l2arc_hdr_stat_add(void) | |
4093 | { | |
4094 | ARCSTAT_INCR(arcstat_l2_hdr_size, HDR_SIZE + L2HDR_SIZE); | |
4095 | ARCSTAT_INCR(arcstat_hdr_size, -HDR_SIZE); | |
4096 | } | |
4097 | ||
4098 | static void | |
4099 | l2arc_hdr_stat_remove(void) | |
4100 | { | |
4101 | ARCSTAT_INCR(arcstat_l2_hdr_size, -(HDR_SIZE + L2HDR_SIZE)); | |
4102 | ARCSTAT_INCR(arcstat_hdr_size, HDR_SIZE); | |
4103 | } | |
4104 | ||
4105 | /* | |
4106 | * Cycle through L2ARC devices. This is how L2ARC load balances. | |
b128c09f | 4107 | * If a device is returned, this also returns holding the spa config lock. |
34dc7c2f BB |
4108 | */ |
4109 | static l2arc_dev_t * | |
4110 | l2arc_dev_get_next(void) | |
4111 | { | |
b128c09f | 4112 | l2arc_dev_t *first, *next = NULL; |
34dc7c2f | 4113 | |
b128c09f BB |
4114 | /* |
4115 | * Lock out the removal of spas (spa_namespace_lock), then removal | |
4116 | * of cache devices (l2arc_dev_mtx). Once a device has been selected, | |
4117 | * both locks will be dropped and a spa config lock held instead. | |
4118 | */ | |
4119 | mutex_enter(&spa_namespace_lock); | |
4120 | mutex_enter(&l2arc_dev_mtx); | |
4121 | ||
4122 | /* if there are no vdevs, there is nothing to do */ | |
4123 | if (l2arc_ndev == 0) | |
4124 | goto out; | |
4125 | ||
4126 | first = NULL; | |
4127 | next = l2arc_dev_last; | |
4128 | do { | |
4129 | /* loop around the list looking for a non-faulted vdev */ | |
4130 | if (next == NULL) { | |
34dc7c2f | 4131 | next = list_head(l2arc_dev_list); |
b128c09f BB |
4132 | } else { |
4133 | next = list_next(l2arc_dev_list, next); | |
4134 | if (next == NULL) | |
4135 | next = list_head(l2arc_dev_list); | |
4136 | } | |
4137 | ||
4138 | /* if we have come back to the start, bail out */ | |
4139 | if (first == NULL) | |
4140 | first = next; | |
4141 | else if (next == first) | |
4142 | break; | |
4143 | ||
4144 | } while (vdev_is_dead(next->l2ad_vdev)); | |
4145 | ||
4146 | /* if we were unable to find any usable vdevs, return NULL */ | |
4147 | if (vdev_is_dead(next->l2ad_vdev)) | |
4148 | next = NULL; | |
34dc7c2f BB |
4149 | |
4150 | l2arc_dev_last = next; | |
4151 | ||
b128c09f BB |
4152 | out: |
4153 | mutex_exit(&l2arc_dev_mtx); | |
4154 | ||
4155 | /* | |
4156 | * Grab the config lock to prevent the 'next' device from being | |
4157 | * removed while we are writing to it. | |
4158 | */ | |
4159 | if (next != NULL) | |
4160 | spa_config_enter(next->l2ad_spa, SCL_L2ARC, next, RW_READER); | |
4161 | mutex_exit(&spa_namespace_lock); | |
4162 | ||
34dc7c2f BB |
4163 | return (next); |
4164 | } | |
4165 | ||
b128c09f BB |
4166 | /* |
4167 | * Free buffers that were tagged for destruction. | |
4168 | */ | |
4169 | static void | |
0bc8fd78 | 4170 | l2arc_do_free_on_write(void) |
b128c09f BB |
4171 | { |
4172 | list_t *buflist; | |
4173 | l2arc_data_free_t *df, *df_prev; | |
4174 | ||
4175 | mutex_enter(&l2arc_free_on_write_mtx); | |
4176 | buflist = l2arc_free_on_write; | |
4177 | ||
4178 | for (df = list_tail(buflist); df; df = df_prev) { | |
4179 | df_prev = list_prev(buflist, df); | |
4180 | ASSERT(df->l2df_data != NULL); | |
4181 | ASSERT(df->l2df_func != NULL); | |
4182 | df->l2df_func(df->l2df_data, df->l2df_size); | |
4183 | list_remove(buflist, df); | |
4184 | kmem_free(df, sizeof (l2arc_data_free_t)); | |
4185 | } | |
4186 | ||
4187 | mutex_exit(&l2arc_free_on_write_mtx); | |
4188 | } | |
4189 | ||
34dc7c2f BB |
4190 | /* |
4191 | * A write to a cache device has completed. Update all headers to allow | |
4192 | * reads from these buffers to begin. | |
4193 | */ | |
4194 | static void | |
4195 | l2arc_write_done(zio_t *zio) | |
4196 | { | |
4197 | l2arc_write_callback_t *cb; | |
4198 | l2arc_dev_t *dev; | |
4199 | list_t *buflist; | |
34dc7c2f | 4200 | arc_buf_hdr_t *head, *ab, *ab_prev; |
b128c09f | 4201 | l2arc_buf_hdr_t *abl2; |
34dc7c2f BB |
4202 | kmutex_t *hash_lock; |
4203 | ||
4204 | cb = zio->io_private; | |
4205 | ASSERT(cb != NULL); | |
4206 | dev = cb->l2wcb_dev; | |
4207 | ASSERT(dev != NULL); | |
4208 | head = cb->l2wcb_head; | |
4209 | ASSERT(head != NULL); | |
4210 | buflist = dev->l2ad_buflist; | |
4211 | ASSERT(buflist != NULL); | |
4212 | DTRACE_PROBE2(l2arc__iodone, zio_t *, zio, | |
4213 | l2arc_write_callback_t *, cb); | |
4214 | ||
4215 | if (zio->io_error != 0) | |
4216 | ARCSTAT_BUMP(arcstat_l2_writes_error); | |
4217 | ||
4218 | mutex_enter(&l2arc_buflist_mtx); | |
4219 | ||
4220 | /* | |
4221 | * All writes completed, or an error was hit. | |
4222 | */ | |
4223 | for (ab = list_prev(buflist, head); ab; ab = ab_prev) { | |
4224 | ab_prev = list_prev(buflist, ab); | |
4225 | ||
4226 | hash_lock = HDR_LOCK(ab); | |
4227 | if (!mutex_tryenter(hash_lock)) { | |
4228 | /* | |
4229 | * This buffer misses out. It may be in a stage | |
4230 | * of eviction. Its ARC_L2_WRITING flag will be | |
4231 | * left set, denying reads to this buffer. | |
4232 | */ | |
4233 | ARCSTAT_BUMP(arcstat_l2_writes_hdr_miss); | |
4234 | continue; | |
4235 | } | |
4236 | ||
4237 | if (zio->io_error != 0) { | |
4238 | /* | |
b128c09f | 4239 | * Error - drop L2ARC entry. |
34dc7c2f | 4240 | */ |
b128c09f BB |
4241 | list_remove(buflist, ab); |
4242 | abl2 = ab->b_l2hdr; | |
34dc7c2f | 4243 | ab->b_l2hdr = NULL; |
b128c09f BB |
4244 | kmem_free(abl2, sizeof (l2arc_buf_hdr_t)); |
4245 | ARCSTAT_INCR(arcstat_l2_size, -ab->b_size); | |
34dc7c2f BB |
4246 | } |
4247 | ||
4248 | /* | |
4249 | * Allow ARC to begin reads to this L2ARC entry. | |
4250 | */ | |
4251 | ab->b_flags &= ~ARC_L2_WRITING; | |
4252 | ||
4253 | mutex_exit(hash_lock); | |
4254 | } | |
4255 | ||
4256 | atomic_inc_64(&l2arc_writes_done); | |
4257 | list_remove(buflist, head); | |
4258 | kmem_cache_free(hdr_cache, head); | |
4259 | mutex_exit(&l2arc_buflist_mtx); | |
4260 | ||
b128c09f | 4261 | l2arc_do_free_on_write(); |
34dc7c2f BB |
4262 | |
4263 | kmem_free(cb, sizeof (l2arc_write_callback_t)); | |
4264 | } | |
4265 | ||
4266 | /* | |
4267 | * A read to a cache device completed. Validate buffer contents before | |
4268 | * handing over to the regular ARC routines. | |
4269 | */ | |
4270 | static void | |
4271 | l2arc_read_done(zio_t *zio) | |
4272 | { | |
4273 | l2arc_read_callback_t *cb; | |
4274 | arc_buf_hdr_t *hdr; | |
4275 | arc_buf_t *buf; | |
34dc7c2f | 4276 | kmutex_t *hash_lock; |
b128c09f BB |
4277 | int equal; |
4278 | ||
4279 | ASSERT(zio->io_vd != NULL); | |
4280 | ASSERT(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE); | |
4281 | ||
4282 | spa_config_exit(zio->io_spa, SCL_L2ARC, zio->io_vd); | |
34dc7c2f BB |
4283 | |
4284 | cb = zio->io_private; | |
4285 | ASSERT(cb != NULL); | |
4286 | buf = cb->l2rcb_buf; | |
4287 | ASSERT(buf != NULL); | |
34dc7c2f | 4288 | |
428870ff | 4289 | hash_lock = HDR_LOCK(buf->b_hdr); |
34dc7c2f | 4290 | mutex_enter(hash_lock); |
428870ff BB |
4291 | hdr = buf->b_hdr; |
4292 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
34dc7c2f BB |
4293 | |
4294 | /* | |
4295 | * Check this survived the L2ARC journey. | |
4296 | */ | |
4297 | equal = arc_cksum_equal(buf); | |
4298 | if (equal && zio->io_error == 0 && !HDR_L2_EVICTED(hdr)) { | |
4299 | mutex_exit(hash_lock); | |
4300 | zio->io_private = buf; | |
b128c09f BB |
4301 | zio->io_bp_copy = cb->l2rcb_bp; /* XXX fix in L2ARC 2.0 */ |
4302 | zio->io_bp = &zio->io_bp_copy; /* XXX fix in L2ARC 2.0 */ | |
34dc7c2f BB |
4303 | arc_read_done(zio); |
4304 | } else { | |
4305 | mutex_exit(hash_lock); | |
4306 | /* | |
4307 | * Buffer didn't survive caching. Increment stats and | |
4308 | * reissue to the original storage device. | |
4309 | */ | |
b128c09f | 4310 | if (zio->io_error != 0) { |
34dc7c2f | 4311 | ARCSTAT_BUMP(arcstat_l2_io_error); |
b128c09f BB |
4312 | } else { |
4313 | zio->io_error = EIO; | |
4314 | } | |
34dc7c2f BB |
4315 | if (!equal) |
4316 | ARCSTAT_BUMP(arcstat_l2_cksum_bad); | |
4317 | ||
34dc7c2f | 4318 | /* |
b128c09f BB |
4319 | * If there's no waiter, issue an async i/o to the primary |
4320 | * storage now. If there *is* a waiter, the caller must | |
4321 | * issue the i/o in a context where it's OK to block. | |
34dc7c2f | 4322 | */ |
d164b209 BB |
4323 | if (zio->io_waiter == NULL) { |
4324 | zio_t *pio = zio_unique_parent(zio); | |
4325 | ||
4326 | ASSERT(!pio || pio->io_child_type == ZIO_CHILD_LOGICAL); | |
4327 | ||
4328 | zio_nowait(zio_read(pio, cb->l2rcb_spa, &cb->l2rcb_bp, | |
b128c09f BB |
4329 | buf->b_data, zio->io_size, arc_read_done, buf, |
4330 | zio->io_priority, cb->l2rcb_flags, &cb->l2rcb_zb)); | |
d164b209 | 4331 | } |
34dc7c2f BB |
4332 | } |
4333 | ||
4334 | kmem_free(cb, sizeof (l2arc_read_callback_t)); | |
4335 | } | |
4336 | ||
4337 | /* | |
4338 | * This is the list priority from which the L2ARC will search for pages to | |
4339 | * cache. This is used within loops (0..3) to cycle through lists in the | |
4340 | * desired order. This order can have a significant effect on cache | |
4341 | * performance. | |
4342 | * | |
4343 | * Currently the metadata lists are hit first, MFU then MRU, followed by | |
4344 | * the data lists. This function returns a locked list, and also returns | |
4345 | * the lock pointer. | |
4346 | */ | |
4347 | static list_t * | |
4348 | l2arc_list_locked(int list_num, kmutex_t **lock) | |
4349 | { | |
d4ed6673 | 4350 | list_t *list = NULL; |
34dc7c2f BB |
4351 | |
4352 | ASSERT(list_num >= 0 && list_num <= 3); | |
4353 | ||
4354 | switch (list_num) { | |
4355 | case 0: | |
4356 | list = &arc_mfu->arcs_list[ARC_BUFC_METADATA]; | |
4357 | *lock = &arc_mfu->arcs_mtx; | |
4358 | break; | |
4359 | case 1: | |
4360 | list = &arc_mru->arcs_list[ARC_BUFC_METADATA]; | |
4361 | *lock = &arc_mru->arcs_mtx; | |
4362 | break; | |
4363 | case 2: | |
4364 | list = &arc_mfu->arcs_list[ARC_BUFC_DATA]; | |
4365 | *lock = &arc_mfu->arcs_mtx; | |
4366 | break; | |
4367 | case 3: | |
4368 | list = &arc_mru->arcs_list[ARC_BUFC_DATA]; | |
4369 | *lock = &arc_mru->arcs_mtx; | |
4370 | break; | |
4371 | } | |
4372 | ||
4373 | ASSERT(!(MUTEX_HELD(*lock))); | |
4374 | mutex_enter(*lock); | |
4375 | return (list); | |
4376 | } | |
4377 | ||
4378 | /* | |
4379 | * Evict buffers from the device write hand to the distance specified in | |
4380 | * bytes. This distance may span populated buffers, it may span nothing. | |
4381 | * This is clearing a region on the L2ARC device ready for writing. | |
4382 | * If the 'all' boolean is set, every buffer is evicted. | |
4383 | */ | |
4384 | static void | |
4385 | l2arc_evict(l2arc_dev_t *dev, uint64_t distance, boolean_t all) | |
4386 | { | |
4387 | list_t *buflist; | |
4388 | l2arc_buf_hdr_t *abl2; | |
4389 | arc_buf_hdr_t *ab, *ab_prev; | |
4390 | kmutex_t *hash_lock; | |
4391 | uint64_t taddr; | |
4392 | ||
34dc7c2f BB |
4393 | buflist = dev->l2ad_buflist; |
4394 | ||
4395 | if (buflist == NULL) | |
4396 | return; | |
4397 | ||
4398 | if (!all && dev->l2ad_first) { | |
4399 | /* | |
4400 | * This is the first sweep through the device. There is | |
4401 | * nothing to evict. | |
4402 | */ | |
4403 | return; | |
4404 | } | |
4405 | ||
b128c09f | 4406 | if (dev->l2ad_hand >= (dev->l2ad_end - (2 * distance))) { |
34dc7c2f BB |
4407 | /* |
4408 | * When nearing the end of the device, evict to the end | |
4409 | * before the device write hand jumps to the start. | |
4410 | */ | |
4411 | taddr = dev->l2ad_end; | |
4412 | } else { | |
4413 | taddr = dev->l2ad_hand + distance; | |
4414 | } | |
4415 | DTRACE_PROBE4(l2arc__evict, l2arc_dev_t *, dev, list_t *, buflist, | |
4416 | uint64_t, taddr, boolean_t, all); | |
4417 | ||
4418 | top: | |
4419 | mutex_enter(&l2arc_buflist_mtx); | |
4420 | for (ab = list_tail(buflist); ab; ab = ab_prev) { | |
4421 | ab_prev = list_prev(buflist, ab); | |
4422 | ||
4423 | hash_lock = HDR_LOCK(ab); | |
4424 | if (!mutex_tryenter(hash_lock)) { | |
4425 | /* | |
4426 | * Missed the hash lock. Retry. | |
4427 | */ | |
4428 | ARCSTAT_BUMP(arcstat_l2_evict_lock_retry); | |
4429 | mutex_exit(&l2arc_buflist_mtx); | |
4430 | mutex_enter(hash_lock); | |
4431 | mutex_exit(hash_lock); | |
4432 | goto top; | |
4433 | } | |
4434 | ||
4435 | if (HDR_L2_WRITE_HEAD(ab)) { | |
4436 | /* | |
4437 | * We hit a write head node. Leave it for | |
4438 | * l2arc_write_done(). | |
4439 | */ | |
4440 | list_remove(buflist, ab); | |
4441 | mutex_exit(hash_lock); | |
4442 | continue; | |
4443 | } | |
4444 | ||
4445 | if (!all && ab->b_l2hdr != NULL && | |
4446 | (ab->b_l2hdr->b_daddr > taddr || | |
4447 | ab->b_l2hdr->b_daddr < dev->l2ad_hand)) { | |
4448 | /* | |
4449 | * We've evicted to the target address, | |
4450 | * or the end of the device. | |
4451 | */ | |
4452 | mutex_exit(hash_lock); | |
4453 | break; | |
4454 | } | |
4455 | ||
4456 | if (HDR_FREE_IN_PROGRESS(ab)) { | |
4457 | /* | |
4458 | * Already on the path to destruction. | |
4459 | */ | |
4460 | mutex_exit(hash_lock); | |
4461 | continue; | |
4462 | } | |
4463 | ||
4464 | if (ab->b_state == arc_l2c_only) { | |
4465 | ASSERT(!HDR_L2_READING(ab)); | |
4466 | /* | |
4467 | * This doesn't exist in the ARC. Destroy. | |
4468 | * arc_hdr_destroy() will call list_remove() | |
4469 | * and decrement arcstat_l2_size. | |
4470 | */ | |
4471 | arc_change_state(arc_anon, ab, hash_lock); | |
4472 | arc_hdr_destroy(ab); | |
4473 | } else { | |
b128c09f BB |
4474 | /* |
4475 | * Invalidate issued or about to be issued | |
4476 | * reads, since we may be about to write | |
4477 | * over this location. | |
4478 | */ | |
4479 | if (HDR_L2_READING(ab)) { | |
4480 | ARCSTAT_BUMP(arcstat_l2_evict_reading); | |
4481 | ab->b_flags |= ARC_L2_EVICTED; | |
4482 | } | |
4483 | ||
34dc7c2f BB |
4484 | /* |
4485 | * Tell ARC this no longer exists in L2ARC. | |
4486 | */ | |
4487 | if (ab->b_l2hdr != NULL) { | |
4488 | abl2 = ab->b_l2hdr; | |
4489 | ab->b_l2hdr = NULL; | |
4490 | kmem_free(abl2, sizeof (l2arc_buf_hdr_t)); | |
4491 | ARCSTAT_INCR(arcstat_l2_size, -ab->b_size); | |
4492 | } | |
4493 | list_remove(buflist, ab); | |
4494 | ||
4495 | /* | |
4496 | * This may have been leftover after a | |
4497 | * failed write. | |
4498 | */ | |
4499 | ab->b_flags &= ~ARC_L2_WRITING; | |
34dc7c2f BB |
4500 | } |
4501 | mutex_exit(hash_lock); | |
4502 | } | |
4503 | mutex_exit(&l2arc_buflist_mtx); | |
4504 | ||
428870ff | 4505 | vdev_space_update(dev->l2ad_vdev, -(taddr - dev->l2ad_evict), 0, 0); |
34dc7c2f BB |
4506 | dev->l2ad_evict = taddr; |
4507 | } | |
4508 | ||
4509 | /* | |
4510 | * Find and write ARC buffers to the L2ARC device. | |
4511 | * | |
4512 | * An ARC_L2_WRITING flag is set so that the L2ARC buffers are not valid | |
4513 | * for reading until they have completed writing. | |
4514 | */ | |
d164b209 | 4515 | static uint64_t |
b128c09f | 4516 | l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz) |
34dc7c2f BB |
4517 | { |
4518 | arc_buf_hdr_t *ab, *ab_prev, *head; | |
4519 | l2arc_buf_hdr_t *hdrl2; | |
4520 | list_t *list; | |
b128c09f | 4521 | uint64_t passed_sz, write_sz, buf_sz, headroom; |
34dc7c2f | 4522 | void *buf_data; |
d4ed6673 | 4523 | kmutex_t *hash_lock, *list_lock = NULL; |
34dc7c2f BB |
4524 | boolean_t have_lock, full; |
4525 | l2arc_write_callback_t *cb; | |
4526 | zio_t *pio, *wzio; | |
3541dc6d | 4527 | uint64_t guid = spa_load_guid(spa); |
d6320ddb | 4528 | int try; |
34dc7c2f | 4529 | |
34dc7c2f BB |
4530 | ASSERT(dev->l2ad_vdev != NULL); |
4531 | ||
4532 | pio = NULL; | |
4533 | write_sz = 0; | |
4534 | full = B_FALSE; | |
4535 | head = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); | |
4536 | head->b_flags |= ARC_L2_WRITE_HEAD; | |
4537 | ||
4538 | /* | |
4539 | * Copy buffers for L2ARC writing. | |
4540 | */ | |
4541 | mutex_enter(&l2arc_buflist_mtx); | |
d6320ddb | 4542 | for (try = 0; try <= 3; try++) { |
34dc7c2f BB |
4543 | list = l2arc_list_locked(try, &list_lock); |
4544 | passed_sz = 0; | |
4545 | ||
b128c09f BB |
4546 | /* |
4547 | * L2ARC fast warmup. | |
4548 | * | |
4549 | * Until the ARC is warm and starts to evict, read from the | |
4550 | * head of the ARC lists rather than the tail. | |
4551 | */ | |
4552 | headroom = target_sz * l2arc_headroom; | |
4553 | if (arc_warm == B_FALSE) | |
4554 | ab = list_head(list); | |
4555 | else | |
4556 | ab = list_tail(list); | |
4557 | ||
4558 | for (; ab; ab = ab_prev) { | |
4559 | if (arc_warm == B_FALSE) | |
4560 | ab_prev = list_next(list, ab); | |
4561 | else | |
4562 | ab_prev = list_prev(list, ab); | |
34dc7c2f BB |
4563 | |
4564 | hash_lock = HDR_LOCK(ab); | |
4565 | have_lock = MUTEX_HELD(hash_lock); | |
4566 | if (!have_lock && !mutex_tryenter(hash_lock)) { | |
4567 | /* | |
4568 | * Skip this buffer rather than waiting. | |
4569 | */ | |
4570 | continue; | |
4571 | } | |
4572 | ||
4573 | passed_sz += ab->b_size; | |
4574 | if (passed_sz > headroom) { | |
4575 | /* | |
4576 | * Searched too far. | |
4577 | */ | |
4578 | mutex_exit(hash_lock); | |
4579 | break; | |
4580 | } | |
4581 | ||
d164b209 | 4582 | if (!l2arc_write_eligible(guid, ab)) { |
34dc7c2f BB |
4583 | mutex_exit(hash_lock); |
4584 | continue; | |
4585 | } | |
4586 | ||
4587 | if ((write_sz + ab->b_size) > target_sz) { | |
4588 | full = B_TRUE; | |
4589 | mutex_exit(hash_lock); | |
4590 | break; | |
4591 | } | |
4592 | ||
34dc7c2f BB |
4593 | if (pio == NULL) { |
4594 | /* | |
4595 | * Insert a dummy header on the buflist so | |
4596 | * l2arc_write_done() can find where the | |
4597 | * write buffers begin without searching. | |
4598 | */ | |
4599 | list_insert_head(dev->l2ad_buflist, head); | |
4600 | ||
409dc1a5 PS |
4601 | cb = kmem_alloc(sizeof (l2arc_write_callback_t), |
4602 | KM_PUSHPAGE); | |
34dc7c2f BB |
4603 | cb->l2wcb_dev = dev; |
4604 | cb->l2wcb_head = head; | |
4605 | pio = zio_root(spa, l2arc_write_done, cb, | |
4606 | ZIO_FLAG_CANFAIL); | |
4607 | } | |
4608 | ||
4609 | /* | |
4610 | * Create and add a new L2ARC header. | |
4611 | */ | |
409dc1a5 PS |
4612 | hdrl2 = kmem_zalloc(sizeof (l2arc_buf_hdr_t), |
4613 | KM_PUSHPAGE); | |
34dc7c2f BB |
4614 | hdrl2->b_dev = dev; |
4615 | hdrl2->b_daddr = dev->l2ad_hand; | |
4616 | ||
4617 | ab->b_flags |= ARC_L2_WRITING; | |
4618 | ab->b_l2hdr = hdrl2; | |
4619 | list_insert_head(dev->l2ad_buflist, ab); | |
4620 | buf_data = ab->b_buf->b_data; | |
4621 | buf_sz = ab->b_size; | |
4622 | ||
4623 | /* | |
4624 | * Compute and store the buffer cksum before | |
4625 | * writing. On debug the cksum is verified first. | |
4626 | */ | |
4627 | arc_cksum_verify(ab->b_buf); | |
4628 | arc_cksum_compute(ab->b_buf, B_TRUE); | |
4629 | ||
4630 | mutex_exit(hash_lock); | |
4631 | ||
4632 | wzio = zio_write_phys(pio, dev->l2ad_vdev, | |
4633 | dev->l2ad_hand, buf_sz, buf_data, ZIO_CHECKSUM_OFF, | |
4634 | NULL, NULL, ZIO_PRIORITY_ASYNC_WRITE, | |
4635 | ZIO_FLAG_CANFAIL, B_FALSE); | |
4636 | ||
4637 | DTRACE_PROBE2(l2arc__write, vdev_t *, dev->l2ad_vdev, | |
4638 | zio_t *, wzio); | |
4639 | (void) zio_nowait(wzio); | |
4640 | ||
b128c09f BB |
4641 | /* |
4642 | * Keep the clock hand suitably device-aligned. | |
4643 | */ | |
4644 | buf_sz = vdev_psize_to_asize(dev->l2ad_vdev, buf_sz); | |
4645 | ||
34dc7c2f BB |
4646 | write_sz += buf_sz; |
4647 | dev->l2ad_hand += buf_sz; | |
4648 | } | |
4649 | ||
4650 | mutex_exit(list_lock); | |
4651 | ||
4652 | if (full == B_TRUE) | |
4653 | break; | |
4654 | } | |
4655 | mutex_exit(&l2arc_buflist_mtx); | |
4656 | ||
4657 | if (pio == NULL) { | |
4658 | ASSERT3U(write_sz, ==, 0); | |
4659 | kmem_cache_free(hdr_cache, head); | |
d164b209 | 4660 | return (0); |
34dc7c2f BB |
4661 | } |
4662 | ||
4663 | ASSERT3U(write_sz, <=, target_sz); | |
4664 | ARCSTAT_BUMP(arcstat_l2_writes_sent); | |
d164b209 | 4665 | ARCSTAT_INCR(arcstat_l2_write_bytes, write_sz); |
34dc7c2f | 4666 | ARCSTAT_INCR(arcstat_l2_size, write_sz); |
428870ff | 4667 | vdev_space_update(dev->l2ad_vdev, write_sz, 0, 0); |
34dc7c2f BB |
4668 | |
4669 | /* | |
4670 | * Bump device hand to the device start if it is approaching the end. | |
4671 | * l2arc_evict() will already have evicted ahead for this case. | |
4672 | */ | |
b128c09f | 4673 | if (dev->l2ad_hand >= (dev->l2ad_end - target_sz)) { |
428870ff BB |
4674 | vdev_space_update(dev->l2ad_vdev, |
4675 | dev->l2ad_end - dev->l2ad_hand, 0, 0); | |
34dc7c2f BB |
4676 | dev->l2ad_hand = dev->l2ad_start; |
4677 | dev->l2ad_evict = dev->l2ad_start; | |
4678 | dev->l2ad_first = B_FALSE; | |
4679 | } | |
4680 | ||
d164b209 | 4681 | dev->l2ad_writing = B_TRUE; |
34dc7c2f | 4682 | (void) zio_wait(pio); |
d164b209 BB |
4683 | dev->l2ad_writing = B_FALSE; |
4684 | ||
4685 | return (write_sz); | |
34dc7c2f BB |
4686 | } |
4687 | ||
4688 | /* | |
4689 | * This thread feeds the L2ARC at regular intervals. This is the beating | |
4690 | * heart of the L2ARC. | |
4691 | */ | |
4692 | static void | |
4693 | l2arc_feed_thread(void) | |
4694 | { | |
4695 | callb_cpr_t cpr; | |
4696 | l2arc_dev_t *dev; | |
4697 | spa_t *spa; | |
d164b209 | 4698 | uint64_t size, wrote; |
428870ff | 4699 | clock_t begin, next = ddi_get_lbolt(); |
34dc7c2f BB |
4700 | |
4701 | CALLB_CPR_INIT(&cpr, &l2arc_feed_thr_lock, callb_generic_cpr, FTAG); | |
4702 | ||
4703 | mutex_enter(&l2arc_feed_thr_lock); | |
4704 | ||
4705 | while (l2arc_thread_exit == 0) { | |
34dc7c2f | 4706 | CALLB_CPR_SAFE_BEGIN(&cpr); |
5b63b3eb BB |
4707 | (void) cv_timedwait_interruptible(&l2arc_feed_thr_cv, |
4708 | &l2arc_feed_thr_lock, next); | |
34dc7c2f | 4709 | CALLB_CPR_SAFE_END(&cpr, &l2arc_feed_thr_lock); |
428870ff | 4710 | next = ddi_get_lbolt() + hz; |
34dc7c2f BB |
4711 | |
4712 | /* | |
b128c09f | 4713 | * Quick check for L2ARC devices. |
34dc7c2f BB |
4714 | */ |
4715 | mutex_enter(&l2arc_dev_mtx); | |
4716 | if (l2arc_ndev == 0) { | |
4717 | mutex_exit(&l2arc_dev_mtx); | |
4718 | continue; | |
4719 | } | |
b128c09f | 4720 | mutex_exit(&l2arc_dev_mtx); |
428870ff | 4721 | begin = ddi_get_lbolt(); |
34dc7c2f BB |
4722 | |
4723 | /* | |
b128c09f BB |
4724 | * This selects the next l2arc device to write to, and in |
4725 | * doing so the next spa to feed from: dev->l2ad_spa. This | |
4726 | * will return NULL if there are now no l2arc devices or if | |
4727 | * they are all faulted. | |
4728 | * | |
4729 | * If a device is returned, its spa's config lock is also | |
4730 | * held to prevent device removal. l2arc_dev_get_next() | |
4731 | * will grab and release l2arc_dev_mtx. | |
34dc7c2f | 4732 | */ |
b128c09f | 4733 | if ((dev = l2arc_dev_get_next()) == NULL) |
34dc7c2f | 4734 | continue; |
b128c09f BB |
4735 | |
4736 | spa = dev->l2ad_spa; | |
4737 | ASSERT(spa != NULL); | |
34dc7c2f | 4738 | |
572e2857 BB |
4739 | /* |
4740 | * If the pool is read-only then force the feed thread to | |
4741 | * sleep a little longer. | |
4742 | */ | |
4743 | if (!spa_writeable(spa)) { | |
4744 | next = ddi_get_lbolt() + 5 * l2arc_feed_secs * hz; | |
4745 | spa_config_exit(spa, SCL_L2ARC, dev); | |
4746 | continue; | |
4747 | } | |
4748 | ||
34dc7c2f | 4749 | /* |
b128c09f | 4750 | * Avoid contributing to memory pressure. |
34dc7c2f | 4751 | */ |
302f753f | 4752 | if (arc_no_grow) { |
b128c09f BB |
4753 | ARCSTAT_BUMP(arcstat_l2_abort_lowmem); |
4754 | spa_config_exit(spa, SCL_L2ARC, dev); | |
34dc7c2f BB |
4755 | continue; |
4756 | } | |
b128c09f | 4757 | |
34dc7c2f BB |
4758 | ARCSTAT_BUMP(arcstat_l2_feeds); |
4759 | ||
d164b209 | 4760 | size = l2arc_write_size(dev); |
b128c09f | 4761 | |
34dc7c2f BB |
4762 | /* |
4763 | * Evict L2ARC buffers that will be overwritten. | |
4764 | */ | |
b128c09f | 4765 | l2arc_evict(dev, size, B_FALSE); |
34dc7c2f BB |
4766 | |
4767 | /* | |
4768 | * Write ARC buffers. | |
4769 | */ | |
d164b209 BB |
4770 | wrote = l2arc_write_buffers(spa, dev, size); |
4771 | ||
4772 | /* | |
4773 | * Calculate interval between writes. | |
4774 | */ | |
4775 | next = l2arc_write_interval(begin, size, wrote); | |
b128c09f | 4776 | spa_config_exit(spa, SCL_L2ARC, dev); |
34dc7c2f BB |
4777 | } |
4778 | ||
4779 | l2arc_thread_exit = 0; | |
4780 | cv_broadcast(&l2arc_feed_thr_cv); | |
4781 | CALLB_CPR_EXIT(&cpr); /* drops l2arc_feed_thr_lock */ | |
4782 | thread_exit(); | |
4783 | } | |
4784 | ||
b128c09f BB |
4785 | boolean_t |
4786 | l2arc_vdev_present(vdev_t *vd) | |
4787 | { | |
4788 | l2arc_dev_t *dev; | |
4789 | ||
4790 | mutex_enter(&l2arc_dev_mtx); | |
4791 | for (dev = list_head(l2arc_dev_list); dev != NULL; | |
4792 | dev = list_next(l2arc_dev_list, dev)) { | |
4793 | if (dev->l2ad_vdev == vd) | |
4794 | break; | |
4795 | } | |
4796 | mutex_exit(&l2arc_dev_mtx); | |
4797 | ||
4798 | return (dev != NULL); | |
4799 | } | |
4800 | ||
34dc7c2f BB |
4801 | /* |
4802 | * Add a vdev for use by the L2ARC. By this point the spa has already | |
4803 | * validated the vdev and opened it. | |
4804 | */ | |
4805 | void | |
9babb374 | 4806 | l2arc_add_vdev(spa_t *spa, vdev_t *vd) |
34dc7c2f BB |
4807 | { |
4808 | l2arc_dev_t *adddev; | |
4809 | ||
b128c09f BB |
4810 | ASSERT(!l2arc_vdev_present(vd)); |
4811 | ||
34dc7c2f BB |
4812 | /* |
4813 | * Create a new l2arc device entry. | |
4814 | */ | |
4815 | adddev = kmem_zalloc(sizeof (l2arc_dev_t), KM_SLEEP); | |
4816 | adddev->l2ad_spa = spa; | |
4817 | adddev->l2ad_vdev = vd; | |
4818 | adddev->l2ad_write = l2arc_write_max; | |
b128c09f | 4819 | adddev->l2ad_boost = l2arc_write_boost; |
9babb374 BB |
4820 | adddev->l2ad_start = VDEV_LABEL_START_SIZE; |
4821 | adddev->l2ad_end = VDEV_LABEL_START_SIZE + vdev_get_min_asize(vd); | |
34dc7c2f BB |
4822 | adddev->l2ad_hand = adddev->l2ad_start; |
4823 | adddev->l2ad_evict = adddev->l2ad_start; | |
4824 | adddev->l2ad_first = B_TRUE; | |
d164b209 | 4825 | adddev->l2ad_writing = B_FALSE; |
98f72a53 | 4826 | list_link_init(&adddev->l2ad_node); |
34dc7c2f BB |
4827 | ASSERT3U(adddev->l2ad_write, >, 0); |
4828 | ||
4829 | /* | |
4830 | * This is a list of all ARC buffers that are still valid on the | |
4831 | * device. | |
4832 | */ | |
4833 | adddev->l2ad_buflist = kmem_zalloc(sizeof (list_t), KM_SLEEP); | |
4834 | list_create(adddev->l2ad_buflist, sizeof (arc_buf_hdr_t), | |
4835 | offsetof(arc_buf_hdr_t, b_l2node)); | |
4836 | ||
428870ff | 4837 | vdev_space_update(vd, 0, 0, adddev->l2ad_end - adddev->l2ad_hand); |
34dc7c2f BB |
4838 | |
4839 | /* | |
4840 | * Add device to global list | |
4841 | */ | |
4842 | mutex_enter(&l2arc_dev_mtx); | |
4843 | list_insert_head(l2arc_dev_list, adddev); | |
4844 | atomic_inc_64(&l2arc_ndev); | |
4845 | mutex_exit(&l2arc_dev_mtx); | |
4846 | } | |
4847 | ||
4848 | /* | |
4849 | * Remove a vdev from the L2ARC. | |
4850 | */ | |
4851 | void | |
4852 | l2arc_remove_vdev(vdev_t *vd) | |
4853 | { | |
4854 | l2arc_dev_t *dev, *nextdev, *remdev = NULL; | |
4855 | ||
34dc7c2f BB |
4856 | /* |
4857 | * Find the device by vdev | |
4858 | */ | |
4859 | mutex_enter(&l2arc_dev_mtx); | |
4860 | for (dev = list_head(l2arc_dev_list); dev; dev = nextdev) { | |
4861 | nextdev = list_next(l2arc_dev_list, dev); | |
4862 | if (vd == dev->l2ad_vdev) { | |
4863 | remdev = dev; | |
4864 | break; | |
4865 | } | |
4866 | } | |
4867 | ASSERT(remdev != NULL); | |
4868 | ||
4869 | /* | |
4870 | * Remove device from global list | |
4871 | */ | |
4872 | list_remove(l2arc_dev_list, remdev); | |
4873 | l2arc_dev_last = NULL; /* may have been invalidated */ | |
b128c09f BB |
4874 | atomic_dec_64(&l2arc_ndev); |
4875 | mutex_exit(&l2arc_dev_mtx); | |
34dc7c2f BB |
4876 | |
4877 | /* | |
4878 | * Clear all buflists and ARC references. L2ARC device flush. | |
4879 | */ | |
4880 | l2arc_evict(remdev, 0, B_TRUE); | |
4881 | list_destroy(remdev->l2ad_buflist); | |
4882 | kmem_free(remdev->l2ad_buflist, sizeof (list_t)); | |
4883 | kmem_free(remdev, sizeof (l2arc_dev_t)); | |
34dc7c2f BB |
4884 | } |
4885 | ||
4886 | void | |
b128c09f | 4887 | l2arc_init(void) |
34dc7c2f BB |
4888 | { |
4889 | l2arc_thread_exit = 0; | |
4890 | l2arc_ndev = 0; | |
4891 | l2arc_writes_sent = 0; | |
4892 | l2arc_writes_done = 0; | |
4893 | ||
4894 | mutex_init(&l2arc_feed_thr_lock, NULL, MUTEX_DEFAULT, NULL); | |
4895 | cv_init(&l2arc_feed_thr_cv, NULL, CV_DEFAULT, NULL); | |
4896 | mutex_init(&l2arc_dev_mtx, NULL, MUTEX_DEFAULT, NULL); | |
4897 | mutex_init(&l2arc_buflist_mtx, NULL, MUTEX_DEFAULT, NULL); | |
4898 | mutex_init(&l2arc_free_on_write_mtx, NULL, MUTEX_DEFAULT, NULL); | |
4899 | ||
4900 | l2arc_dev_list = &L2ARC_dev_list; | |
4901 | l2arc_free_on_write = &L2ARC_free_on_write; | |
4902 | list_create(l2arc_dev_list, sizeof (l2arc_dev_t), | |
4903 | offsetof(l2arc_dev_t, l2ad_node)); | |
4904 | list_create(l2arc_free_on_write, sizeof (l2arc_data_free_t), | |
4905 | offsetof(l2arc_data_free_t, l2df_list_node)); | |
34dc7c2f BB |
4906 | } |
4907 | ||
4908 | void | |
b128c09f | 4909 | l2arc_fini(void) |
34dc7c2f | 4910 | { |
b128c09f BB |
4911 | /* |
4912 | * This is called from dmu_fini(), which is called from spa_fini(); | |
4913 | * Because of this, we can assume that all l2arc devices have | |
4914 | * already been removed when the pools themselves were removed. | |
4915 | */ | |
4916 | ||
4917 | l2arc_do_free_on_write(); | |
34dc7c2f BB |
4918 | |
4919 | mutex_destroy(&l2arc_feed_thr_lock); | |
4920 | cv_destroy(&l2arc_feed_thr_cv); | |
4921 | mutex_destroy(&l2arc_dev_mtx); | |
4922 | mutex_destroy(&l2arc_buflist_mtx); | |
4923 | mutex_destroy(&l2arc_free_on_write_mtx); | |
4924 | ||
4925 | list_destroy(l2arc_dev_list); | |
4926 | list_destroy(l2arc_free_on_write); | |
4927 | } | |
b128c09f BB |
4928 | |
4929 | void | |
4930 | l2arc_start(void) | |
4931 | { | |
fb5f0bc8 | 4932 | if (!(spa_mode_global & FWRITE)) |
b128c09f BB |
4933 | return; |
4934 | ||
4935 | (void) thread_create(NULL, 0, l2arc_feed_thread, NULL, 0, &p0, | |
4936 | TS_RUN, minclsyspri); | |
4937 | } | |
4938 | ||
4939 | void | |
4940 | l2arc_stop(void) | |
4941 | { | |
fb5f0bc8 | 4942 | if (!(spa_mode_global & FWRITE)) |
b128c09f BB |
4943 | return; |
4944 | ||
4945 | mutex_enter(&l2arc_feed_thr_lock); | |
4946 | cv_signal(&l2arc_feed_thr_cv); /* kick thread out of startup */ | |
4947 | l2arc_thread_exit = 1; | |
4948 | while (l2arc_thread_exit != 0) | |
4949 | cv_wait(&l2arc_feed_thr_cv, &l2arc_feed_thr_lock); | |
4950 | mutex_exit(&l2arc_feed_thr_lock); | |
4951 | } | |
c28b2279 BB |
4952 | |
4953 | #if defined(_KERNEL) && defined(HAVE_SPL) | |
4954 | EXPORT_SYMBOL(arc_read); | |
4955 | EXPORT_SYMBOL(arc_buf_remove_ref); | |
4956 | EXPORT_SYMBOL(arc_getbuf_func); | |
ab26409d BB |
4957 | EXPORT_SYMBOL(arc_add_prune_callback); |
4958 | EXPORT_SYMBOL(arc_remove_prune_callback); | |
c28b2279 | 4959 | |
c409e464 BB |
4960 | module_param(zfs_arc_min, ulong, 0444); |
4961 | MODULE_PARM_DESC(zfs_arc_min, "Min arc size"); | |
c28b2279 | 4962 | |
c409e464 BB |
4963 | module_param(zfs_arc_max, ulong, 0444); |
4964 | MODULE_PARM_DESC(zfs_arc_max, "Max arc size"); | |
c28b2279 | 4965 | |
c409e464 | 4966 | module_param(zfs_arc_meta_limit, ulong, 0444); |
c28b2279 | 4967 | MODULE_PARM_DESC(zfs_arc_meta_limit, "Meta limit for arc size"); |
6a8f9b6b | 4968 | |
ab26409d BB |
4969 | module_param(zfs_arc_meta_prune, int, 0444); |
4970 | MODULE_PARM_DESC(zfs_arc_meta_prune, "Bytes of meta data to prune"); | |
c409e464 BB |
4971 | |
4972 | module_param(zfs_arc_grow_retry, int, 0444); | |
4973 | MODULE_PARM_DESC(zfs_arc_grow_retry, "Seconds before growing arc size"); | |
4974 | ||
4975 | module_param(zfs_arc_shrink_shift, int, 0444); | |
4976 | MODULE_PARM_DESC(zfs_arc_shrink_shift, "log2(fraction of arc to reclaim)"); | |
4977 | ||
4978 | module_param(zfs_arc_p_min_shift, int, 0444); | |
4979 | MODULE_PARM_DESC(zfs_arc_p_min_shift, "arc_c shift to calc min/max arc_p"); | |
4980 | ||
abd8610c BB |
4981 | module_param(l2arc_write_max, ulong, 0444); |
4982 | MODULE_PARM_DESC(l2arc_write_max, "Max write bytes per interval"); | |
4983 | ||
4984 | module_param(l2arc_write_boost, ulong, 0444); | |
4985 | MODULE_PARM_DESC(l2arc_write_boost, "Extra write bytes during device warmup"); | |
4986 | ||
4987 | module_param(l2arc_headroom, ulong, 0444); | |
4988 | MODULE_PARM_DESC(l2arc_headroom, "Number of max device writes to precache"); | |
4989 | ||
4990 | module_param(l2arc_feed_secs, ulong, 0444); | |
4991 | MODULE_PARM_DESC(l2arc_feed_secs, "Seconds between L2ARC writing"); | |
4992 | ||
4993 | module_param(l2arc_feed_min_ms, ulong, 0444); | |
4994 | MODULE_PARM_DESC(l2arc_feed_min_ms, "Min feed interval in milliseconds"); | |
4995 | ||
4996 | module_param(l2arc_noprefetch, int, 0444); | |
4997 | MODULE_PARM_DESC(l2arc_noprefetch, "Skip caching prefetched buffers"); | |
4998 | ||
4999 | module_param(l2arc_feed_again, int, 0444); | |
5000 | MODULE_PARM_DESC(l2arc_feed_again, "Turbo L2ARC warmup"); | |
5001 | ||
5002 | module_param(l2arc_norw, int, 0444); | |
5003 | MODULE_PARM_DESC(l2arc_norw, "No reads during writes"); | |
5004 | ||
c28b2279 | 5005 | #endif |