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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. |
34dc7c2f BB |
23 | */ |
24 | ||
34dc7c2f BB |
25 | /* |
26 | * DVA-based Adjustable Replacement Cache | |
27 | * | |
28 | * While much of the theory of operation used here is | |
29 | * based on the self-tuning, low overhead replacement cache | |
30 | * presented by Megiddo and Modha at FAST 2003, there are some | |
31 | * significant differences: | |
32 | * | |
33 | * 1. The Megiddo and Modha model assumes any page is evictable. | |
34 | * Pages in its cache cannot be "locked" into memory. This makes | |
35 | * the eviction algorithm simple: evict the last page in the list. | |
36 | * This also make the performance characteristics easy to reason | |
37 | * about. Our cache is not so simple. At any given moment, some | |
38 | * subset of the blocks in the cache are un-evictable because we | |
39 | * have handed out a reference to them. Blocks are only evictable | |
40 | * when there are no external references active. This makes | |
41 | * eviction far more problematic: we choose to evict the evictable | |
42 | * blocks that are the "lowest" in the list. | |
43 | * | |
44 | * There are times when it is not possible to evict the requested | |
45 | * space. In these circumstances we are unable to adjust the cache | |
46 | * size. To prevent the cache growing unbounded at these times we | |
47 | * implement a "cache throttle" that slows the flow of new data | |
48 | * into the cache until we can make space available. | |
49 | * | |
50 | * 2. The Megiddo and Modha model assumes a fixed cache size. | |
51 | * Pages are evicted when the cache is full and there is a cache | |
52 | * miss. Our model has a variable sized cache. It grows with | |
53 | * high use, but also tries to react to memory pressure from the | |
54 | * operating system: decreasing its size when system memory is | |
55 | * tight. | |
56 | * | |
57 | * 3. The Megiddo and Modha model assumes a fixed page size. All | |
58 | * elements of the cache are therefor exactly the same size. So | |
59 | * when adjusting the cache size following a cache miss, its simply | |
60 | * a matter of choosing a single page to evict. In our model, we | |
61 | * have variable sized cache blocks (rangeing from 512 bytes to | |
62 | * 128K bytes). We therefor choose a set of blocks to evict to make | |
63 | * space for a cache miss that approximates as closely as possible | |
64 | * the space used by the new block. | |
65 | * | |
66 | * See also: "ARC: A Self-Tuning, Low Overhead Replacement Cache" | |
67 | * by N. Megiddo & D. Modha, FAST 2003 | |
68 | */ | |
69 | ||
70 | /* | |
71 | * The locking model: | |
72 | * | |
73 | * A new reference to a cache buffer can be obtained in two | |
74 | * ways: 1) via a hash table lookup using the DVA as a key, | |
75 | * or 2) via one of the ARC lists. The arc_read() interface | |
76 | * uses method 1, while the internal arc algorithms for | |
77 | * adjusting the cache use method 2. We therefor provide two | |
78 | * types of locks: 1) the hash table lock array, and 2) the | |
79 | * arc list locks. | |
80 | * | |
81 | * Buffers do not have their own mutexs, rather they rely on the | |
82 | * hash table mutexs for the bulk of their protection (i.e. most | |
83 | * fields in the arc_buf_hdr_t are protected by these mutexs). | |
84 | * | |
85 | * buf_hash_find() returns the appropriate mutex (held) when it | |
86 | * locates the requested buffer in the hash table. It returns | |
87 | * NULL for the mutex if the buffer was not in the table. | |
88 | * | |
89 | * buf_hash_remove() expects the appropriate hash mutex to be | |
90 | * already held before it is invoked. | |
91 | * | |
92 | * Each arc state also has a mutex which is used to protect the | |
93 | * buffer list associated with the state. When attempting to | |
94 | * obtain a hash table lock while holding an arc list lock you | |
95 | * must use: mutex_tryenter() to avoid deadlock. Also note that | |
96 | * the active state mutex must be held before the ghost state mutex. | |
97 | * | |
98 | * Arc buffers may have an associated eviction callback function. | |
99 | * This function will be invoked prior to removing the buffer (e.g. | |
100 | * in arc_do_user_evicts()). Note however that the data associated | |
101 | * with the buffer may be evicted prior to the callback. The callback | |
102 | * must be made with *no locks held* (to prevent deadlock). Additionally, | |
103 | * the users of callbacks must ensure that their private data is | |
104 | * protected from simultaneous callbacks from arc_buf_evict() | |
105 | * and arc_do_user_evicts(). | |
106 | * | |
ab26409d BB |
107 | * It as also possible to register a callback which is run when the |
108 | * arc_meta_limit is reached and no buffers can be safely evicted. In | |
109 | * this case the arc user should drop a reference on some arc buffers so | |
110 | * they can be reclaimed and the arc_meta_limit honored. For example, | |
111 | * when using the ZPL each dentry holds a references on a znode. These | |
112 | * dentries must be pruned before the arc buffer holding the znode can | |
113 | * be safely evicted. | |
114 | * | |
34dc7c2f BB |
115 | * Note that the majority of the performance stats are manipulated |
116 | * with atomic operations. | |
117 | * | |
118 | * The L2ARC uses the l2arc_buflist_mtx global mutex for the following: | |
119 | * | |
120 | * - L2ARC buflist creation | |
121 | * - L2ARC buflist eviction | |
122 | * - L2ARC write completion, which walks L2ARC buflists | |
123 | * - ARC header destruction, as it removes from L2ARC buflists | |
124 | * - ARC header release, as it removes from L2ARC buflists | |
125 | */ | |
126 | ||
127 | #include <sys/spa.h> | |
128 | #include <sys/zio.h> | |
34dc7c2f BB |
129 | #include <sys/zfs_context.h> |
130 | #include <sys/arc.h> | |
b128c09f | 131 | #include <sys/vdev.h> |
9babb374 | 132 | #include <sys/vdev_impl.h> |
34dc7c2f BB |
133 | #ifdef _KERNEL |
134 | #include <sys/vmsystm.h> | |
135 | #include <vm/anon.h> | |
136 | #include <sys/fs/swapnode.h> | |
ab26409d | 137 | #include <sys/zpl.h> |
34dc7c2f BB |
138 | #endif |
139 | #include <sys/callb.h> | |
140 | #include <sys/kstat.h> | |
570827e1 | 141 | #include <sys/dmu_tx.h> |
428870ff | 142 | #include <zfs_fletcher.h> |
34dc7c2f BB |
143 | |
144 | static kmutex_t arc_reclaim_thr_lock; | |
145 | static kcondvar_t arc_reclaim_thr_cv; /* used to signal reclaim thr */ | |
146 | static uint8_t arc_thread_exit; | |
147 | ||
148 | extern int zfs_write_limit_shift; | |
149 | extern uint64_t zfs_write_limit_max; | |
b128c09f | 150 | extern kmutex_t zfs_write_limit_lock; |
34dc7c2f | 151 | |
ab26409d BB |
152 | /* number of bytes to prune from caches when at arc_meta_limit is reached */ |
153 | uint_t arc_meta_prune = 1048576; | |
34dc7c2f BB |
154 | |
155 | typedef enum arc_reclaim_strategy { | |
156 | ARC_RECLAIM_AGGR, /* Aggressive reclaim strategy */ | |
157 | ARC_RECLAIM_CONS /* Conservative reclaim strategy */ | |
158 | } arc_reclaim_strategy_t; | |
159 | ||
160 | /* number of seconds before growing cache again */ | |
161 | static int arc_grow_retry = 60; | |
162 | ||
d164b209 BB |
163 | /* shift of arc_c for calculating both min and max arc_p */ |
164 | static int arc_p_min_shift = 4; | |
165 | ||
166 | /* log2(fraction of arc to reclaim) */ | |
167 | static int arc_shrink_shift = 5; | |
168 | ||
34dc7c2f BB |
169 | /* |
170 | * minimum lifespan of a prefetch block in clock ticks | |
171 | * (initialized in arc_init()) | |
172 | */ | |
173 | static int arc_min_prefetch_lifespan; | |
174 | ||
175 | static int arc_dead; | |
176 | ||
b128c09f BB |
177 | /* |
178 | * The arc has filled available memory and has now warmed up. | |
179 | */ | |
180 | static boolean_t arc_warm; | |
181 | ||
34dc7c2f BB |
182 | /* |
183 | * These tunables are for performance analysis. | |
184 | */ | |
c28b2279 BB |
185 | unsigned long zfs_arc_max = 0; |
186 | unsigned long zfs_arc_min = 0; | |
187 | unsigned long zfs_arc_meta_limit = 0; | |
d164b209 BB |
188 | int zfs_arc_grow_retry = 0; |
189 | int zfs_arc_shrink_shift = 0; | |
190 | int zfs_arc_p_min_shift = 0; | |
ab26409d | 191 | int zfs_arc_meta_prune = 0; |
34dc7c2f BB |
192 | |
193 | /* | |
194 | * Note that buffers can be in one of 6 states: | |
195 | * ARC_anon - anonymous (discussed below) | |
196 | * ARC_mru - recently used, currently cached | |
197 | * ARC_mru_ghost - recentely used, no longer in cache | |
198 | * ARC_mfu - frequently used, currently cached | |
199 | * ARC_mfu_ghost - frequently used, no longer in cache | |
200 | * ARC_l2c_only - exists in L2ARC but not other states | |
201 | * When there are no active references to the buffer, they are | |
202 | * are linked onto a list in one of these arc states. These are | |
203 | * the only buffers that can be evicted or deleted. Within each | |
204 | * state there are multiple lists, one for meta-data and one for | |
205 | * non-meta-data. Meta-data (indirect blocks, blocks of dnodes, | |
206 | * etc.) is tracked separately so that it can be managed more | |
207 | * explicitly: favored over data, limited explicitly. | |
208 | * | |
209 | * Anonymous buffers are buffers that are not associated with | |
210 | * a DVA. These are buffers that hold dirty block copies | |
211 | * before they are written to stable storage. By definition, | |
212 | * they are "ref'd" and are considered part of arc_mru | |
213 | * that cannot be freed. Generally, they will aquire a DVA | |
214 | * as they are written and migrate onto the arc_mru list. | |
215 | * | |
216 | * The ARC_l2c_only state is for buffers that are in the second | |
217 | * level ARC but no longer in any of the ARC_m* lists. The second | |
218 | * level ARC itself may also contain buffers that are in any of | |
219 | * the ARC_m* states - meaning that a buffer can exist in two | |
220 | * places. The reason for the ARC_l2c_only state is to keep the | |
221 | * buffer header in the hash table, so that reads that hit the | |
222 | * second level ARC benefit from these fast lookups. | |
223 | */ | |
224 | ||
225 | typedef struct arc_state { | |
226 | list_t arcs_list[ARC_BUFC_NUMTYPES]; /* list of evictable buffers */ | |
227 | uint64_t arcs_lsize[ARC_BUFC_NUMTYPES]; /* amount of evictable data */ | |
228 | uint64_t arcs_size; /* total amount of data in this state */ | |
229 | kmutex_t arcs_mtx; | |
230 | } arc_state_t; | |
231 | ||
232 | /* The 6 states: */ | |
233 | static arc_state_t ARC_anon; | |
234 | static arc_state_t ARC_mru; | |
235 | static arc_state_t ARC_mru_ghost; | |
236 | static arc_state_t ARC_mfu; | |
237 | static arc_state_t ARC_mfu_ghost; | |
238 | static arc_state_t ARC_l2c_only; | |
239 | ||
240 | typedef struct arc_stats { | |
241 | kstat_named_t arcstat_hits; | |
242 | kstat_named_t arcstat_misses; | |
243 | kstat_named_t arcstat_demand_data_hits; | |
244 | kstat_named_t arcstat_demand_data_misses; | |
245 | kstat_named_t arcstat_demand_metadata_hits; | |
246 | kstat_named_t arcstat_demand_metadata_misses; | |
247 | kstat_named_t arcstat_prefetch_data_hits; | |
248 | kstat_named_t arcstat_prefetch_data_misses; | |
249 | kstat_named_t arcstat_prefetch_metadata_hits; | |
250 | kstat_named_t arcstat_prefetch_metadata_misses; | |
251 | kstat_named_t arcstat_mru_hits; | |
252 | kstat_named_t arcstat_mru_ghost_hits; | |
253 | kstat_named_t arcstat_mfu_hits; | |
254 | kstat_named_t arcstat_mfu_ghost_hits; | |
255 | kstat_named_t arcstat_deleted; | |
256 | kstat_named_t arcstat_recycle_miss; | |
257 | kstat_named_t arcstat_mutex_miss; | |
258 | kstat_named_t arcstat_evict_skip; | |
428870ff BB |
259 | kstat_named_t arcstat_evict_l2_cached; |
260 | kstat_named_t arcstat_evict_l2_eligible; | |
261 | kstat_named_t arcstat_evict_l2_ineligible; | |
34dc7c2f BB |
262 | kstat_named_t arcstat_hash_elements; |
263 | kstat_named_t arcstat_hash_elements_max; | |
264 | kstat_named_t arcstat_hash_collisions; | |
265 | kstat_named_t arcstat_hash_chains; | |
266 | kstat_named_t arcstat_hash_chain_max; | |
267 | kstat_named_t arcstat_p; | |
268 | kstat_named_t arcstat_c; | |
269 | kstat_named_t arcstat_c_min; | |
270 | kstat_named_t arcstat_c_max; | |
271 | kstat_named_t arcstat_size; | |
272 | kstat_named_t arcstat_hdr_size; | |
d164b209 BB |
273 | kstat_named_t arcstat_data_size; |
274 | kstat_named_t arcstat_other_size; | |
13be560d BB |
275 | kstat_named_t arcstat_anon_size; |
276 | kstat_named_t arcstat_anon_evict_data; | |
277 | kstat_named_t arcstat_anon_evict_metadata; | |
278 | kstat_named_t arcstat_mru_size; | |
279 | kstat_named_t arcstat_mru_evict_data; | |
280 | kstat_named_t arcstat_mru_evict_metadata; | |
281 | kstat_named_t arcstat_mru_ghost_size; | |
282 | kstat_named_t arcstat_mru_ghost_evict_data; | |
283 | kstat_named_t arcstat_mru_ghost_evict_metadata; | |
284 | kstat_named_t arcstat_mfu_size; | |
285 | kstat_named_t arcstat_mfu_evict_data; | |
286 | kstat_named_t arcstat_mfu_evict_metadata; | |
287 | kstat_named_t arcstat_mfu_ghost_size; | |
288 | kstat_named_t arcstat_mfu_ghost_evict_data; | |
289 | kstat_named_t arcstat_mfu_ghost_evict_metadata; | |
34dc7c2f BB |
290 | kstat_named_t arcstat_l2_hits; |
291 | kstat_named_t arcstat_l2_misses; | |
292 | kstat_named_t arcstat_l2_feeds; | |
293 | kstat_named_t arcstat_l2_rw_clash; | |
d164b209 BB |
294 | kstat_named_t arcstat_l2_read_bytes; |
295 | kstat_named_t arcstat_l2_write_bytes; | |
34dc7c2f BB |
296 | kstat_named_t arcstat_l2_writes_sent; |
297 | kstat_named_t arcstat_l2_writes_done; | |
298 | kstat_named_t arcstat_l2_writes_error; | |
299 | kstat_named_t arcstat_l2_writes_hdr_miss; | |
300 | kstat_named_t arcstat_l2_evict_lock_retry; | |
301 | kstat_named_t arcstat_l2_evict_reading; | |
302 | kstat_named_t arcstat_l2_free_on_write; | |
303 | kstat_named_t arcstat_l2_abort_lowmem; | |
304 | kstat_named_t arcstat_l2_cksum_bad; | |
305 | kstat_named_t arcstat_l2_io_error; | |
306 | kstat_named_t arcstat_l2_size; | |
307 | kstat_named_t arcstat_l2_hdr_size; | |
308 | kstat_named_t arcstat_memory_throttle_count; | |
7cb67b45 BB |
309 | kstat_named_t arcstat_memory_direct_count; |
310 | kstat_named_t arcstat_memory_indirect_count; | |
1834f2d8 BB |
311 | kstat_named_t arcstat_no_grow; |
312 | kstat_named_t arcstat_tempreserve; | |
313 | kstat_named_t arcstat_loaned_bytes; | |
ab26409d | 314 | kstat_named_t arcstat_prune; |
1834f2d8 BB |
315 | kstat_named_t arcstat_meta_used; |
316 | kstat_named_t arcstat_meta_limit; | |
317 | kstat_named_t arcstat_meta_max; | |
34dc7c2f BB |
318 | } arc_stats_t; |
319 | ||
320 | static arc_stats_t arc_stats = { | |
321 | { "hits", KSTAT_DATA_UINT64 }, | |
322 | { "misses", KSTAT_DATA_UINT64 }, | |
323 | { "demand_data_hits", KSTAT_DATA_UINT64 }, | |
324 | { "demand_data_misses", KSTAT_DATA_UINT64 }, | |
325 | { "demand_metadata_hits", KSTAT_DATA_UINT64 }, | |
326 | { "demand_metadata_misses", KSTAT_DATA_UINT64 }, | |
327 | { "prefetch_data_hits", KSTAT_DATA_UINT64 }, | |
328 | { "prefetch_data_misses", KSTAT_DATA_UINT64 }, | |
329 | { "prefetch_metadata_hits", KSTAT_DATA_UINT64 }, | |
330 | { "prefetch_metadata_misses", KSTAT_DATA_UINT64 }, | |
331 | { "mru_hits", KSTAT_DATA_UINT64 }, | |
332 | { "mru_ghost_hits", KSTAT_DATA_UINT64 }, | |
333 | { "mfu_hits", KSTAT_DATA_UINT64 }, | |
334 | { "mfu_ghost_hits", KSTAT_DATA_UINT64 }, | |
335 | { "deleted", KSTAT_DATA_UINT64 }, | |
336 | { "recycle_miss", KSTAT_DATA_UINT64 }, | |
337 | { "mutex_miss", KSTAT_DATA_UINT64 }, | |
338 | { "evict_skip", KSTAT_DATA_UINT64 }, | |
428870ff BB |
339 | { "evict_l2_cached", KSTAT_DATA_UINT64 }, |
340 | { "evict_l2_eligible", KSTAT_DATA_UINT64 }, | |
341 | { "evict_l2_ineligible", KSTAT_DATA_UINT64 }, | |
34dc7c2f BB |
342 | { "hash_elements", KSTAT_DATA_UINT64 }, |
343 | { "hash_elements_max", KSTAT_DATA_UINT64 }, | |
344 | { "hash_collisions", KSTAT_DATA_UINT64 }, | |
345 | { "hash_chains", KSTAT_DATA_UINT64 }, | |
346 | { "hash_chain_max", KSTAT_DATA_UINT64 }, | |
347 | { "p", KSTAT_DATA_UINT64 }, | |
348 | { "c", KSTAT_DATA_UINT64 }, | |
349 | { "c_min", KSTAT_DATA_UINT64 }, | |
350 | { "c_max", KSTAT_DATA_UINT64 }, | |
351 | { "size", KSTAT_DATA_UINT64 }, | |
352 | { "hdr_size", KSTAT_DATA_UINT64 }, | |
d164b209 BB |
353 | { "data_size", KSTAT_DATA_UINT64 }, |
354 | { "other_size", KSTAT_DATA_UINT64 }, | |
13be560d BB |
355 | { "anon_size", KSTAT_DATA_UINT64 }, |
356 | { "anon_evict_data", KSTAT_DATA_UINT64 }, | |
357 | { "anon_evict_metadata", KSTAT_DATA_UINT64 }, | |
358 | { "mru_size", KSTAT_DATA_UINT64 }, | |
359 | { "mru_evict_data", KSTAT_DATA_UINT64 }, | |
360 | { "mru_evict_metadata", KSTAT_DATA_UINT64 }, | |
361 | { "mru_ghost_size", KSTAT_DATA_UINT64 }, | |
362 | { "mru_ghost_evict_data", KSTAT_DATA_UINT64 }, | |
363 | { "mru_ghost_evict_metadata", KSTAT_DATA_UINT64 }, | |
364 | { "mfu_size", KSTAT_DATA_UINT64 }, | |
365 | { "mfu_evict_data", KSTAT_DATA_UINT64 }, | |
366 | { "mfu_evict_metadata", KSTAT_DATA_UINT64 }, | |
367 | { "mfu_ghost_size", KSTAT_DATA_UINT64 }, | |
368 | { "mfu_ghost_evict_data", KSTAT_DATA_UINT64 }, | |
369 | { "mfu_ghost_evict_metadata", KSTAT_DATA_UINT64 }, | |
34dc7c2f BB |
370 | { "l2_hits", KSTAT_DATA_UINT64 }, |
371 | { "l2_misses", KSTAT_DATA_UINT64 }, | |
372 | { "l2_feeds", KSTAT_DATA_UINT64 }, | |
373 | { "l2_rw_clash", KSTAT_DATA_UINT64 }, | |
d164b209 BB |
374 | { "l2_read_bytes", KSTAT_DATA_UINT64 }, |
375 | { "l2_write_bytes", KSTAT_DATA_UINT64 }, | |
34dc7c2f BB |
376 | { "l2_writes_sent", KSTAT_DATA_UINT64 }, |
377 | { "l2_writes_done", KSTAT_DATA_UINT64 }, | |
378 | { "l2_writes_error", KSTAT_DATA_UINT64 }, | |
379 | { "l2_writes_hdr_miss", KSTAT_DATA_UINT64 }, | |
380 | { "l2_evict_lock_retry", KSTAT_DATA_UINT64 }, | |
381 | { "l2_evict_reading", KSTAT_DATA_UINT64 }, | |
382 | { "l2_free_on_write", KSTAT_DATA_UINT64 }, | |
383 | { "l2_abort_lowmem", KSTAT_DATA_UINT64 }, | |
384 | { "l2_cksum_bad", KSTAT_DATA_UINT64 }, | |
385 | { "l2_io_error", KSTAT_DATA_UINT64 }, | |
386 | { "l2_size", KSTAT_DATA_UINT64 }, | |
387 | { "l2_hdr_size", KSTAT_DATA_UINT64 }, | |
1834f2d8 | 388 | { "memory_throttle_count", KSTAT_DATA_UINT64 }, |
7cb67b45 BB |
389 | { "memory_direct_count", KSTAT_DATA_UINT64 }, |
390 | { "memory_indirect_count", KSTAT_DATA_UINT64 }, | |
1834f2d8 BB |
391 | { "arc_no_grow", KSTAT_DATA_UINT64 }, |
392 | { "arc_tempreserve", KSTAT_DATA_UINT64 }, | |
393 | { "arc_loaned_bytes", KSTAT_DATA_UINT64 }, | |
ab26409d | 394 | { "arc_prune", KSTAT_DATA_UINT64 }, |
1834f2d8 BB |
395 | { "arc_meta_used", KSTAT_DATA_UINT64 }, |
396 | { "arc_meta_limit", KSTAT_DATA_UINT64 }, | |
397 | { "arc_meta_max", KSTAT_DATA_UINT64 }, | |
34dc7c2f BB |
398 | }; |
399 | ||
400 | #define ARCSTAT(stat) (arc_stats.stat.value.ui64) | |
401 | ||
402 | #define ARCSTAT_INCR(stat, val) \ | |
403 | atomic_add_64(&arc_stats.stat.value.ui64, (val)); | |
404 | ||
428870ff | 405 | #define ARCSTAT_BUMP(stat) ARCSTAT_INCR(stat, 1) |
34dc7c2f BB |
406 | #define ARCSTAT_BUMPDOWN(stat) ARCSTAT_INCR(stat, -1) |
407 | ||
408 | #define ARCSTAT_MAX(stat, val) { \ | |
409 | uint64_t m; \ | |
410 | while ((val) > (m = arc_stats.stat.value.ui64) && \ | |
411 | (m != atomic_cas_64(&arc_stats.stat.value.ui64, m, (val)))) \ | |
412 | continue; \ | |
413 | } | |
414 | ||
415 | #define ARCSTAT_MAXSTAT(stat) \ | |
416 | ARCSTAT_MAX(stat##_max, arc_stats.stat.value.ui64) | |
417 | ||
418 | /* | |
419 | * We define a macro to allow ARC hits/misses to be easily broken down by | |
420 | * two separate conditions, giving a total of four different subtypes for | |
421 | * each of hits and misses (so eight statistics total). | |
422 | */ | |
423 | #define ARCSTAT_CONDSTAT(cond1, stat1, notstat1, cond2, stat2, notstat2, stat) \ | |
424 | if (cond1) { \ | |
425 | if (cond2) { \ | |
426 | ARCSTAT_BUMP(arcstat_##stat1##_##stat2##_##stat); \ | |
427 | } else { \ | |
428 | ARCSTAT_BUMP(arcstat_##stat1##_##notstat2##_##stat); \ | |
429 | } \ | |
430 | } else { \ | |
431 | if (cond2) { \ | |
432 | ARCSTAT_BUMP(arcstat_##notstat1##_##stat2##_##stat); \ | |
433 | } else { \ | |
434 | ARCSTAT_BUMP(arcstat_##notstat1##_##notstat2##_##stat);\ | |
435 | } \ | |
436 | } | |
437 | ||
438 | kstat_t *arc_ksp; | |
428870ff | 439 | static arc_state_t *arc_anon; |
34dc7c2f BB |
440 | static arc_state_t *arc_mru; |
441 | static arc_state_t *arc_mru_ghost; | |
442 | static arc_state_t *arc_mfu; | |
443 | static arc_state_t *arc_mfu_ghost; | |
444 | static arc_state_t *arc_l2c_only; | |
445 | ||
446 | /* | |
447 | * There are several ARC variables that are critical to export as kstats -- | |
448 | * but we don't want to have to grovel around in the kstat whenever we wish to | |
449 | * manipulate them. For these variables, we therefore define them to be in | |
450 | * terms of the statistic variable. This assures that we are not introducing | |
451 | * the possibility of inconsistency by having shadow copies of the variables, | |
452 | * while still allowing the code to be readable. | |
453 | */ | |
454 | #define arc_size ARCSTAT(arcstat_size) /* actual total arc size */ | |
455 | #define arc_p ARCSTAT(arcstat_p) /* target size of MRU */ | |
456 | #define arc_c ARCSTAT(arcstat_c) /* target size of cache */ | |
457 | #define arc_c_min ARCSTAT(arcstat_c_min) /* min target cache size */ | |
458 | #define arc_c_max ARCSTAT(arcstat_c_max) /* max target cache size */ | |
1834f2d8 BB |
459 | #define arc_no_grow ARCSTAT(arcstat_no_grow) |
460 | #define arc_tempreserve ARCSTAT(arcstat_tempreserve) | |
461 | #define arc_loaned_bytes ARCSTAT(arcstat_loaned_bytes) | |
462 | #define arc_meta_used ARCSTAT(arcstat_meta_used) | |
463 | #define arc_meta_limit ARCSTAT(arcstat_meta_limit) | |
464 | #define arc_meta_max ARCSTAT(arcstat_meta_max) | |
34dc7c2f BB |
465 | |
466 | typedef struct l2arc_buf_hdr l2arc_buf_hdr_t; | |
467 | ||
468 | typedef struct arc_callback arc_callback_t; | |
469 | ||
470 | struct arc_callback { | |
471 | void *acb_private; | |
472 | arc_done_func_t *acb_done; | |
34dc7c2f BB |
473 | arc_buf_t *acb_buf; |
474 | zio_t *acb_zio_dummy; | |
475 | arc_callback_t *acb_next; | |
476 | }; | |
477 | ||
478 | typedef struct arc_write_callback arc_write_callback_t; | |
479 | ||
480 | struct arc_write_callback { | |
481 | void *awcb_private; | |
482 | arc_done_func_t *awcb_ready; | |
483 | arc_done_func_t *awcb_done; | |
484 | arc_buf_t *awcb_buf; | |
485 | }; | |
486 | ||
487 | struct arc_buf_hdr { | |
488 | /* protected by hash lock */ | |
489 | dva_t b_dva; | |
490 | uint64_t b_birth; | |
491 | uint64_t b_cksum0; | |
492 | ||
493 | kmutex_t b_freeze_lock; | |
494 | zio_cksum_t *b_freeze_cksum; | |
428870ff | 495 | void *b_thawed; |
34dc7c2f BB |
496 | |
497 | arc_buf_hdr_t *b_hash_next; | |
498 | arc_buf_t *b_buf; | |
499 | uint32_t b_flags; | |
500 | uint32_t b_datacnt; | |
501 | ||
502 | arc_callback_t *b_acb; | |
503 | kcondvar_t b_cv; | |
504 | ||
505 | /* immutable */ | |
506 | arc_buf_contents_t b_type; | |
507 | uint64_t b_size; | |
d164b209 | 508 | uint64_t b_spa; |
34dc7c2f BB |
509 | |
510 | /* protected by arc state mutex */ | |
511 | arc_state_t *b_state; | |
512 | list_node_t b_arc_node; | |
513 | ||
514 | /* updated atomically */ | |
515 | clock_t b_arc_access; | |
516 | ||
517 | /* self protecting */ | |
518 | refcount_t b_refcnt; | |
519 | ||
520 | l2arc_buf_hdr_t *b_l2hdr; | |
521 | list_node_t b_l2node; | |
522 | }; | |
523 | ||
ab26409d BB |
524 | static list_t arc_prune_list; |
525 | static kmutex_t arc_prune_mtx; | |
34dc7c2f BB |
526 | static arc_buf_t *arc_eviction_list; |
527 | static kmutex_t arc_eviction_mtx; | |
528 | static arc_buf_hdr_t arc_eviction_hdr; | |
529 | static void arc_get_data_buf(arc_buf_t *buf); | |
530 | static void arc_access(arc_buf_hdr_t *buf, kmutex_t *hash_lock); | |
531 | static int arc_evict_needed(arc_buf_contents_t type); | |
d164b209 | 532 | static void arc_evict_ghost(arc_state_t *state, uint64_t spa, int64_t bytes); |
34dc7c2f | 533 | |
428870ff BB |
534 | static boolean_t l2arc_write_eligible(uint64_t spa_guid, arc_buf_hdr_t *ab); |
535 | ||
34dc7c2f BB |
536 | #define GHOST_STATE(state) \ |
537 | ((state) == arc_mru_ghost || (state) == arc_mfu_ghost || \ | |
538 | (state) == arc_l2c_only) | |
539 | ||
540 | /* | |
541 | * Private ARC flags. These flags are private ARC only flags that will show up | |
542 | * in b_flags in the arc_hdr_buf_t. Some flags are publicly declared, and can | |
543 | * be passed in as arc_flags in things like arc_read. However, these flags | |
544 | * should never be passed and should only be set by ARC code. When adding new | |
545 | * public flags, make sure not to smash the private ones. | |
546 | */ | |
547 | ||
548 | #define ARC_IN_HASH_TABLE (1 << 9) /* this buffer is hashed */ | |
549 | #define ARC_IO_IN_PROGRESS (1 << 10) /* I/O in progress for buf */ | |
550 | #define ARC_IO_ERROR (1 << 11) /* I/O failed for buf */ | |
551 | #define ARC_FREED_IN_READ (1 << 12) /* buf freed while in read */ | |
552 | #define ARC_BUF_AVAILABLE (1 << 13) /* block not in active use */ | |
553 | #define ARC_INDIRECT (1 << 14) /* this is an indirect block */ | |
554 | #define ARC_FREE_IN_PROGRESS (1 << 15) /* hdr about to be freed */ | |
b128c09f BB |
555 | #define ARC_L2_WRITING (1 << 16) /* L2ARC write in progress */ |
556 | #define ARC_L2_EVICTED (1 << 17) /* evicted during I/O */ | |
557 | #define ARC_L2_WRITE_HEAD (1 << 18) /* head of write list */ | |
34dc7c2f BB |
558 | |
559 | #define HDR_IN_HASH_TABLE(hdr) ((hdr)->b_flags & ARC_IN_HASH_TABLE) | |
560 | #define HDR_IO_IN_PROGRESS(hdr) ((hdr)->b_flags & ARC_IO_IN_PROGRESS) | |
561 | #define HDR_IO_ERROR(hdr) ((hdr)->b_flags & ARC_IO_ERROR) | |
d164b209 | 562 | #define HDR_PREFETCH(hdr) ((hdr)->b_flags & ARC_PREFETCH) |
34dc7c2f BB |
563 | #define HDR_FREED_IN_READ(hdr) ((hdr)->b_flags & ARC_FREED_IN_READ) |
564 | #define HDR_BUF_AVAILABLE(hdr) ((hdr)->b_flags & ARC_BUF_AVAILABLE) | |
565 | #define HDR_FREE_IN_PROGRESS(hdr) ((hdr)->b_flags & ARC_FREE_IN_PROGRESS) | |
b128c09f BB |
566 | #define HDR_L2CACHE(hdr) ((hdr)->b_flags & ARC_L2CACHE) |
567 | #define HDR_L2_READING(hdr) ((hdr)->b_flags & ARC_IO_IN_PROGRESS && \ | |
568 | (hdr)->b_l2hdr != NULL) | |
34dc7c2f BB |
569 | #define HDR_L2_WRITING(hdr) ((hdr)->b_flags & ARC_L2_WRITING) |
570 | #define HDR_L2_EVICTED(hdr) ((hdr)->b_flags & ARC_L2_EVICTED) | |
571 | #define HDR_L2_WRITE_HEAD(hdr) ((hdr)->b_flags & ARC_L2_WRITE_HEAD) | |
572 | ||
573 | /* | |
574 | * Other sizes | |
575 | */ | |
576 | ||
577 | #define HDR_SIZE ((int64_t)sizeof (arc_buf_hdr_t)) | |
578 | #define L2HDR_SIZE ((int64_t)sizeof (l2arc_buf_hdr_t)) | |
579 | ||
580 | /* | |
581 | * Hash table routines | |
582 | */ | |
583 | ||
00b46022 BB |
584 | #define HT_LOCK_ALIGN 64 |
585 | #define HT_LOCK_PAD (P2NPHASE(sizeof (kmutex_t), (HT_LOCK_ALIGN))) | |
34dc7c2f BB |
586 | |
587 | struct ht_lock { | |
588 | kmutex_t ht_lock; | |
589 | #ifdef _KERNEL | |
00b46022 | 590 | unsigned char pad[HT_LOCK_PAD]; |
34dc7c2f BB |
591 | #endif |
592 | }; | |
593 | ||
594 | #define BUF_LOCKS 256 | |
595 | typedef struct buf_hash_table { | |
596 | uint64_t ht_mask; | |
597 | arc_buf_hdr_t **ht_table; | |
598 | struct ht_lock ht_locks[BUF_LOCKS]; | |
599 | } buf_hash_table_t; | |
600 | ||
601 | static buf_hash_table_t buf_hash_table; | |
602 | ||
603 | #define BUF_HASH_INDEX(spa, dva, birth) \ | |
604 | (buf_hash(spa, dva, birth) & buf_hash_table.ht_mask) | |
605 | #define BUF_HASH_LOCK_NTRY(idx) (buf_hash_table.ht_locks[idx & (BUF_LOCKS-1)]) | |
606 | #define BUF_HASH_LOCK(idx) (&(BUF_HASH_LOCK_NTRY(idx).ht_lock)) | |
428870ff BB |
607 | #define HDR_LOCK(hdr) \ |
608 | (BUF_HASH_LOCK(BUF_HASH_INDEX(hdr->b_spa, &hdr->b_dva, hdr->b_birth))) | |
34dc7c2f BB |
609 | |
610 | uint64_t zfs_crc64_table[256]; | |
611 | ||
612 | /* | |
613 | * Level 2 ARC | |
614 | */ | |
615 | ||
616 | #define L2ARC_WRITE_SIZE (8 * 1024 * 1024) /* initial write max */ | |
d164b209 BB |
617 | #define L2ARC_HEADROOM 2 /* num of writes */ |
618 | #define L2ARC_FEED_SECS 1 /* caching interval secs */ | |
619 | #define L2ARC_FEED_MIN_MS 200 /* min caching interval ms */ | |
34dc7c2f BB |
620 | |
621 | #define l2arc_writes_sent ARCSTAT(arcstat_l2_writes_sent) | |
622 | #define l2arc_writes_done ARCSTAT(arcstat_l2_writes_done) | |
623 | ||
624 | /* | |
625 | * L2ARC Performance Tunables | |
626 | */ | |
abd8610c BB |
627 | unsigned long l2arc_write_max = L2ARC_WRITE_SIZE; /* def max write size */ |
628 | unsigned long l2arc_write_boost = L2ARC_WRITE_SIZE; /* extra warmup write */ | |
629 | unsigned long l2arc_headroom = L2ARC_HEADROOM; /* # of dev writes */ | |
630 | unsigned long l2arc_feed_secs = L2ARC_FEED_SECS; /* interval seconds */ | |
631 | unsigned long l2arc_feed_min_ms = L2ARC_FEED_MIN_MS; /* min interval msecs */ | |
632 | int l2arc_noprefetch = B_TRUE; /* don't cache prefetch bufs */ | |
633 | int l2arc_feed_again = B_TRUE; /* turbo warmup */ | |
634 | int l2arc_norw = B_TRUE; /* no reads during writes */ | |
34dc7c2f BB |
635 | |
636 | /* | |
637 | * L2ARC Internals | |
638 | */ | |
639 | typedef struct l2arc_dev { | |
640 | vdev_t *l2ad_vdev; /* vdev */ | |
641 | spa_t *l2ad_spa; /* spa */ | |
642 | uint64_t l2ad_hand; /* next write location */ | |
643 | uint64_t l2ad_write; /* desired write size, bytes */ | |
b128c09f | 644 | uint64_t l2ad_boost; /* warmup write boost, bytes */ |
34dc7c2f BB |
645 | uint64_t l2ad_start; /* first addr on device */ |
646 | uint64_t l2ad_end; /* last addr on device */ | |
647 | uint64_t l2ad_evict; /* last addr eviction reached */ | |
648 | boolean_t l2ad_first; /* first sweep through */ | |
d164b209 | 649 | boolean_t l2ad_writing; /* currently writing */ |
34dc7c2f BB |
650 | list_t *l2ad_buflist; /* buffer list */ |
651 | list_node_t l2ad_node; /* device list node */ | |
652 | } l2arc_dev_t; | |
653 | ||
654 | static list_t L2ARC_dev_list; /* device list */ | |
655 | static list_t *l2arc_dev_list; /* device list pointer */ | |
656 | static kmutex_t l2arc_dev_mtx; /* device list mutex */ | |
657 | static l2arc_dev_t *l2arc_dev_last; /* last device used */ | |
658 | static kmutex_t l2arc_buflist_mtx; /* mutex for all buflists */ | |
659 | static list_t L2ARC_free_on_write; /* free after write buf list */ | |
660 | static list_t *l2arc_free_on_write; /* free after write list ptr */ | |
661 | static kmutex_t l2arc_free_on_write_mtx; /* mutex for list */ | |
662 | static uint64_t l2arc_ndev; /* number of devices */ | |
663 | ||
664 | typedef struct l2arc_read_callback { | |
665 | arc_buf_t *l2rcb_buf; /* read buffer */ | |
666 | spa_t *l2rcb_spa; /* spa */ | |
667 | blkptr_t l2rcb_bp; /* original blkptr */ | |
668 | zbookmark_t l2rcb_zb; /* original bookmark */ | |
669 | int l2rcb_flags; /* original flags */ | |
670 | } l2arc_read_callback_t; | |
671 | ||
672 | typedef struct l2arc_write_callback { | |
673 | l2arc_dev_t *l2wcb_dev; /* device info */ | |
674 | arc_buf_hdr_t *l2wcb_head; /* head of write buflist */ | |
675 | } l2arc_write_callback_t; | |
676 | ||
677 | struct l2arc_buf_hdr { | |
678 | /* protected by arc_buf_hdr mutex */ | |
679 | l2arc_dev_t *b_dev; /* L2ARC device */ | |
9babb374 | 680 | uint64_t b_daddr; /* disk address, offset byte */ |
34dc7c2f BB |
681 | }; |
682 | ||
683 | typedef struct l2arc_data_free { | |
684 | /* protected by l2arc_free_on_write_mtx */ | |
685 | void *l2df_data; | |
686 | size_t l2df_size; | |
687 | void (*l2df_func)(void *, size_t); | |
688 | list_node_t l2df_list_node; | |
689 | } l2arc_data_free_t; | |
690 | ||
691 | static kmutex_t l2arc_feed_thr_lock; | |
692 | static kcondvar_t l2arc_feed_thr_cv; | |
693 | static uint8_t l2arc_thread_exit; | |
694 | ||
695 | static void l2arc_read_done(zio_t *zio); | |
696 | static void l2arc_hdr_stat_add(void); | |
697 | static void l2arc_hdr_stat_remove(void); | |
698 | ||
699 | static uint64_t | |
d164b209 | 700 | buf_hash(uint64_t spa, const dva_t *dva, uint64_t birth) |
34dc7c2f | 701 | { |
34dc7c2f BB |
702 | uint8_t *vdva = (uint8_t *)dva; |
703 | uint64_t crc = -1ULL; | |
704 | int i; | |
705 | ||
706 | ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY); | |
707 | ||
708 | for (i = 0; i < sizeof (dva_t); i++) | |
709 | crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ vdva[i]) & 0xFF]; | |
710 | ||
d164b209 | 711 | crc ^= (spa>>8) ^ birth; |
34dc7c2f BB |
712 | |
713 | return (crc); | |
714 | } | |
715 | ||
716 | #define BUF_EMPTY(buf) \ | |
717 | ((buf)->b_dva.dva_word[0] == 0 && \ | |
718 | (buf)->b_dva.dva_word[1] == 0 && \ | |
719 | (buf)->b_birth == 0) | |
720 | ||
721 | #define BUF_EQUAL(spa, dva, birth, buf) \ | |
722 | ((buf)->b_dva.dva_word[0] == (dva)->dva_word[0]) && \ | |
723 | ((buf)->b_dva.dva_word[1] == (dva)->dva_word[1]) && \ | |
724 | ((buf)->b_birth == birth) && ((buf)->b_spa == spa) | |
725 | ||
428870ff BB |
726 | static void |
727 | buf_discard_identity(arc_buf_hdr_t *hdr) | |
728 | { | |
729 | hdr->b_dva.dva_word[0] = 0; | |
730 | hdr->b_dva.dva_word[1] = 0; | |
731 | hdr->b_birth = 0; | |
732 | hdr->b_cksum0 = 0; | |
733 | } | |
734 | ||
34dc7c2f | 735 | static arc_buf_hdr_t * |
d164b209 | 736 | buf_hash_find(uint64_t spa, const dva_t *dva, uint64_t birth, kmutex_t **lockp) |
34dc7c2f BB |
737 | { |
738 | uint64_t idx = BUF_HASH_INDEX(spa, dva, birth); | |
739 | kmutex_t *hash_lock = BUF_HASH_LOCK(idx); | |
740 | arc_buf_hdr_t *buf; | |
741 | ||
742 | mutex_enter(hash_lock); | |
743 | for (buf = buf_hash_table.ht_table[idx]; buf != NULL; | |
744 | buf = buf->b_hash_next) { | |
745 | if (BUF_EQUAL(spa, dva, birth, buf)) { | |
746 | *lockp = hash_lock; | |
747 | return (buf); | |
748 | } | |
749 | } | |
750 | mutex_exit(hash_lock); | |
751 | *lockp = NULL; | |
752 | return (NULL); | |
753 | } | |
754 | ||
755 | /* | |
756 | * Insert an entry into the hash table. If there is already an element | |
757 | * equal to elem in the hash table, then the already existing element | |
758 | * will be returned and the new element will not be inserted. | |
759 | * Otherwise returns NULL. | |
760 | */ | |
761 | static arc_buf_hdr_t * | |
762 | buf_hash_insert(arc_buf_hdr_t *buf, kmutex_t **lockp) | |
763 | { | |
764 | uint64_t idx = BUF_HASH_INDEX(buf->b_spa, &buf->b_dva, buf->b_birth); | |
765 | kmutex_t *hash_lock = BUF_HASH_LOCK(idx); | |
766 | arc_buf_hdr_t *fbuf; | |
767 | uint32_t i; | |
768 | ||
769 | ASSERT(!HDR_IN_HASH_TABLE(buf)); | |
770 | *lockp = hash_lock; | |
771 | mutex_enter(hash_lock); | |
772 | for (fbuf = buf_hash_table.ht_table[idx], i = 0; fbuf != NULL; | |
773 | fbuf = fbuf->b_hash_next, i++) { | |
774 | if (BUF_EQUAL(buf->b_spa, &buf->b_dva, buf->b_birth, fbuf)) | |
775 | return (fbuf); | |
776 | } | |
777 | ||
778 | buf->b_hash_next = buf_hash_table.ht_table[idx]; | |
779 | buf_hash_table.ht_table[idx] = buf; | |
780 | buf->b_flags |= ARC_IN_HASH_TABLE; | |
781 | ||
782 | /* collect some hash table performance data */ | |
783 | if (i > 0) { | |
784 | ARCSTAT_BUMP(arcstat_hash_collisions); | |
785 | if (i == 1) | |
786 | ARCSTAT_BUMP(arcstat_hash_chains); | |
787 | ||
788 | ARCSTAT_MAX(arcstat_hash_chain_max, i); | |
789 | } | |
790 | ||
791 | ARCSTAT_BUMP(arcstat_hash_elements); | |
792 | ARCSTAT_MAXSTAT(arcstat_hash_elements); | |
793 | ||
794 | return (NULL); | |
795 | } | |
796 | ||
797 | static void | |
798 | buf_hash_remove(arc_buf_hdr_t *buf) | |
799 | { | |
800 | arc_buf_hdr_t *fbuf, **bufp; | |
801 | uint64_t idx = BUF_HASH_INDEX(buf->b_spa, &buf->b_dva, buf->b_birth); | |
802 | ||
803 | ASSERT(MUTEX_HELD(BUF_HASH_LOCK(idx))); | |
804 | ASSERT(HDR_IN_HASH_TABLE(buf)); | |
805 | ||
806 | bufp = &buf_hash_table.ht_table[idx]; | |
807 | while ((fbuf = *bufp) != buf) { | |
808 | ASSERT(fbuf != NULL); | |
809 | bufp = &fbuf->b_hash_next; | |
810 | } | |
811 | *bufp = buf->b_hash_next; | |
812 | buf->b_hash_next = NULL; | |
813 | buf->b_flags &= ~ARC_IN_HASH_TABLE; | |
814 | ||
815 | /* collect some hash table performance data */ | |
816 | ARCSTAT_BUMPDOWN(arcstat_hash_elements); | |
817 | ||
818 | if (buf_hash_table.ht_table[idx] && | |
819 | buf_hash_table.ht_table[idx]->b_hash_next == NULL) | |
820 | ARCSTAT_BUMPDOWN(arcstat_hash_chains); | |
821 | } | |
822 | ||
823 | /* | |
824 | * Global data structures and functions for the buf kmem cache. | |
825 | */ | |
826 | static kmem_cache_t *hdr_cache; | |
827 | static kmem_cache_t *buf_cache; | |
828 | ||
829 | static void | |
830 | buf_fini(void) | |
831 | { | |
832 | int i; | |
833 | ||
00b46022 BB |
834 | #if defined(_KERNEL) && defined(HAVE_SPL) |
835 | /* Large allocations which do not require contiguous pages | |
836 | * should be using vmem_free() in the linux kernel */ | |
837 | vmem_free(buf_hash_table.ht_table, | |
838 | (buf_hash_table.ht_mask + 1) * sizeof (void *)); | |
839 | #else | |
34dc7c2f BB |
840 | kmem_free(buf_hash_table.ht_table, |
841 | (buf_hash_table.ht_mask + 1) * sizeof (void *)); | |
00b46022 | 842 | #endif |
34dc7c2f BB |
843 | for (i = 0; i < BUF_LOCKS; i++) |
844 | mutex_destroy(&buf_hash_table.ht_locks[i].ht_lock); | |
845 | kmem_cache_destroy(hdr_cache); | |
846 | kmem_cache_destroy(buf_cache); | |
847 | } | |
848 | ||
849 | /* | |
850 | * Constructor callback - called when the cache is empty | |
851 | * and a new buf is requested. | |
852 | */ | |
853 | /* ARGSUSED */ | |
854 | static int | |
855 | hdr_cons(void *vbuf, void *unused, int kmflag) | |
856 | { | |
857 | arc_buf_hdr_t *buf = vbuf; | |
858 | ||
859 | bzero(buf, sizeof (arc_buf_hdr_t)); | |
860 | refcount_create(&buf->b_refcnt); | |
861 | cv_init(&buf->b_cv, NULL, CV_DEFAULT, NULL); | |
862 | mutex_init(&buf->b_freeze_lock, NULL, MUTEX_DEFAULT, NULL); | |
98f72a53 BB |
863 | list_link_init(&buf->b_arc_node); |
864 | list_link_init(&buf->b_l2node); | |
d164b209 | 865 | arc_space_consume(sizeof (arc_buf_hdr_t), ARC_SPACE_HDRS); |
34dc7c2f | 866 | |
34dc7c2f BB |
867 | return (0); |
868 | } | |
869 | ||
b128c09f BB |
870 | /* ARGSUSED */ |
871 | static int | |
872 | buf_cons(void *vbuf, void *unused, int kmflag) | |
873 | { | |
874 | arc_buf_t *buf = vbuf; | |
875 | ||
876 | bzero(buf, sizeof (arc_buf_t)); | |
428870ff BB |
877 | mutex_init(&buf->b_evict_lock, NULL, MUTEX_DEFAULT, NULL); |
878 | rw_init(&buf->b_data_lock, NULL, RW_DEFAULT, NULL); | |
d164b209 BB |
879 | arc_space_consume(sizeof (arc_buf_t), ARC_SPACE_HDRS); |
880 | ||
b128c09f BB |
881 | return (0); |
882 | } | |
883 | ||
34dc7c2f BB |
884 | /* |
885 | * Destructor callback - called when a cached buf is | |
886 | * no longer required. | |
887 | */ | |
888 | /* ARGSUSED */ | |
889 | static void | |
890 | hdr_dest(void *vbuf, void *unused) | |
891 | { | |
892 | arc_buf_hdr_t *buf = vbuf; | |
893 | ||
428870ff | 894 | ASSERT(BUF_EMPTY(buf)); |
34dc7c2f BB |
895 | refcount_destroy(&buf->b_refcnt); |
896 | cv_destroy(&buf->b_cv); | |
897 | mutex_destroy(&buf->b_freeze_lock); | |
d164b209 | 898 | arc_space_return(sizeof (arc_buf_hdr_t), ARC_SPACE_HDRS); |
34dc7c2f BB |
899 | } |
900 | ||
b128c09f BB |
901 | /* ARGSUSED */ |
902 | static void | |
903 | buf_dest(void *vbuf, void *unused) | |
904 | { | |
905 | arc_buf_t *buf = vbuf; | |
906 | ||
428870ff BB |
907 | mutex_destroy(&buf->b_evict_lock); |
908 | rw_destroy(&buf->b_data_lock); | |
d164b209 | 909 | arc_space_return(sizeof (arc_buf_t), ARC_SPACE_HDRS); |
b128c09f BB |
910 | } |
911 | ||
34dc7c2f BB |
912 | /* |
913 | * Reclaim callback -- invoked when memory is low. | |
914 | */ | |
915 | /* ARGSUSED */ | |
916 | static void | |
917 | hdr_recl(void *unused) | |
918 | { | |
34dc7c2f BB |
919 | /* |
920 | * umem calls the reclaim func when we destroy the buf cache, | |
921 | * which is after we do arc_fini(). | |
922 | */ | |
923 | if (!arc_dead) | |
924 | cv_signal(&arc_reclaim_thr_cv); | |
925 | } | |
926 | ||
927 | static void | |
928 | buf_init(void) | |
929 | { | |
930 | uint64_t *ct; | |
931 | uint64_t hsize = 1ULL << 12; | |
932 | int i, j; | |
933 | ||
934 | /* | |
935 | * The hash table is big enough to fill all of physical memory | |
936 | * with an average 64K block size. The table will take up | |
937 | * totalmem*sizeof(void*)/64K (eg. 128KB/GB with 8-byte pointers). | |
938 | */ | |
939 | while (hsize * 65536 < physmem * PAGESIZE) | |
940 | hsize <<= 1; | |
941 | retry: | |
942 | buf_hash_table.ht_mask = hsize - 1; | |
00b46022 BB |
943 | #if defined(_KERNEL) && defined(HAVE_SPL) |
944 | /* Large allocations which do not require contiguous pages | |
945 | * should be using vmem_alloc() in the linux kernel */ | |
946 | buf_hash_table.ht_table = | |
947 | vmem_zalloc(hsize * sizeof (void*), KM_SLEEP); | |
948 | #else | |
34dc7c2f BB |
949 | buf_hash_table.ht_table = |
950 | kmem_zalloc(hsize * sizeof (void*), KM_NOSLEEP); | |
00b46022 | 951 | #endif |
34dc7c2f BB |
952 | if (buf_hash_table.ht_table == NULL) { |
953 | ASSERT(hsize > (1ULL << 8)); | |
954 | hsize >>= 1; | |
955 | goto retry; | |
956 | } | |
957 | ||
958 | hdr_cache = kmem_cache_create("arc_buf_hdr_t", sizeof (arc_buf_hdr_t), | |
959 | 0, hdr_cons, hdr_dest, hdr_recl, NULL, NULL, 0); | |
960 | buf_cache = kmem_cache_create("arc_buf_t", sizeof (arc_buf_t), | |
b128c09f | 961 | 0, buf_cons, buf_dest, NULL, NULL, NULL, 0); |
34dc7c2f BB |
962 | |
963 | for (i = 0; i < 256; i++) | |
964 | for (ct = zfs_crc64_table + i, *ct = i, j = 8; j > 0; j--) | |
965 | *ct = (*ct >> 1) ^ (-(*ct & 1) & ZFS_CRC64_POLY); | |
966 | ||
967 | for (i = 0; i < BUF_LOCKS; i++) { | |
968 | mutex_init(&buf_hash_table.ht_locks[i].ht_lock, | |
969 | NULL, MUTEX_DEFAULT, NULL); | |
970 | } | |
971 | } | |
972 | ||
973 | #define ARC_MINTIME (hz>>4) /* 62 ms */ | |
974 | ||
975 | static void | |
976 | arc_cksum_verify(arc_buf_t *buf) | |
977 | { | |
978 | zio_cksum_t zc; | |
979 | ||
980 | if (!(zfs_flags & ZFS_DEBUG_MODIFY)) | |
981 | return; | |
982 | ||
983 | mutex_enter(&buf->b_hdr->b_freeze_lock); | |
984 | if (buf->b_hdr->b_freeze_cksum == NULL || | |
985 | (buf->b_hdr->b_flags & ARC_IO_ERROR)) { | |
986 | mutex_exit(&buf->b_hdr->b_freeze_lock); | |
987 | return; | |
988 | } | |
989 | fletcher_2_native(buf->b_data, buf->b_hdr->b_size, &zc); | |
990 | if (!ZIO_CHECKSUM_EQUAL(*buf->b_hdr->b_freeze_cksum, zc)) | |
991 | panic("buffer modified while frozen!"); | |
992 | mutex_exit(&buf->b_hdr->b_freeze_lock); | |
993 | } | |
994 | ||
995 | static int | |
996 | arc_cksum_equal(arc_buf_t *buf) | |
997 | { | |
998 | zio_cksum_t zc; | |
999 | int equal; | |
1000 | ||
1001 | mutex_enter(&buf->b_hdr->b_freeze_lock); | |
1002 | fletcher_2_native(buf->b_data, buf->b_hdr->b_size, &zc); | |
1003 | equal = ZIO_CHECKSUM_EQUAL(*buf->b_hdr->b_freeze_cksum, zc); | |
1004 | mutex_exit(&buf->b_hdr->b_freeze_lock); | |
1005 | ||
1006 | return (equal); | |
1007 | } | |
1008 | ||
1009 | static void | |
1010 | arc_cksum_compute(arc_buf_t *buf, boolean_t force) | |
1011 | { | |
1012 | if (!force && !(zfs_flags & ZFS_DEBUG_MODIFY)) | |
1013 | return; | |
1014 | ||
1015 | mutex_enter(&buf->b_hdr->b_freeze_lock); | |
1016 | if (buf->b_hdr->b_freeze_cksum != NULL) { | |
1017 | mutex_exit(&buf->b_hdr->b_freeze_lock); | |
1018 | return; | |
1019 | } | |
409dc1a5 PS |
1020 | buf->b_hdr->b_freeze_cksum = kmem_alloc(sizeof (zio_cksum_t), |
1021 | KM_PUSHPAGE); | |
34dc7c2f BB |
1022 | fletcher_2_native(buf->b_data, buf->b_hdr->b_size, |
1023 | buf->b_hdr->b_freeze_cksum); | |
1024 | mutex_exit(&buf->b_hdr->b_freeze_lock); | |
1025 | } | |
1026 | ||
1027 | void | |
1028 | arc_buf_thaw(arc_buf_t *buf) | |
1029 | { | |
1030 | if (zfs_flags & ZFS_DEBUG_MODIFY) { | |
1031 | if (buf->b_hdr->b_state != arc_anon) | |
1032 | panic("modifying non-anon buffer!"); | |
1033 | if (buf->b_hdr->b_flags & ARC_IO_IN_PROGRESS) | |
1034 | panic("modifying buffer while i/o in progress!"); | |
1035 | arc_cksum_verify(buf); | |
1036 | } | |
1037 | ||
1038 | mutex_enter(&buf->b_hdr->b_freeze_lock); | |
1039 | if (buf->b_hdr->b_freeze_cksum != NULL) { | |
1040 | kmem_free(buf->b_hdr->b_freeze_cksum, sizeof (zio_cksum_t)); | |
1041 | buf->b_hdr->b_freeze_cksum = NULL; | |
1042 | } | |
428870ff BB |
1043 | |
1044 | if (zfs_flags & ZFS_DEBUG_MODIFY) { | |
1045 | if (buf->b_hdr->b_thawed) | |
1046 | kmem_free(buf->b_hdr->b_thawed, 1); | |
1047 | buf->b_hdr->b_thawed = kmem_alloc(1, KM_SLEEP); | |
1048 | } | |
1049 | ||
34dc7c2f BB |
1050 | mutex_exit(&buf->b_hdr->b_freeze_lock); |
1051 | } | |
1052 | ||
1053 | void | |
1054 | arc_buf_freeze(arc_buf_t *buf) | |
1055 | { | |
428870ff BB |
1056 | kmutex_t *hash_lock; |
1057 | ||
34dc7c2f BB |
1058 | if (!(zfs_flags & ZFS_DEBUG_MODIFY)) |
1059 | return; | |
1060 | ||
428870ff BB |
1061 | hash_lock = HDR_LOCK(buf->b_hdr); |
1062 | mutex_enter(hash_lock); | |
1063 | ||
34dc7c2f BB |
1064 | ASSERT(buf->b_hdr->b_freeze_cksum != NULL || |
1065 | buf->b_hdr->b_state == arc_anon); | |
1066 | arc_cksum_compute(buf, B_FALSE); | |
428870ff | 1067 | mutex_exit(hash_lock); |
34dc7c2f BB |
1068 | } |
1069 | ||
1070 | static void | |
1071 | add_reference(arc_buf_hdr_t *ab, kmutex_t *hash_lock, void *tag) | |
1072 | { | |
1073 | ASSERT(MUTEX_HELD(hash_lock)); | |
1074 | ||
1075 | if ((refcount_add(&ab->b_refcnt, tag) == 1) && | |
1076 | (ab->b_state != arc_anon)) { | |
1077 | uint64_t delta = ab->b_size * ab->b_datacnt; | |
1078 | list_t *list = &ab->b_state->arcs_list[ab->b_type]; | |
1079 | uint64_t *size = &ab->b_state->arcs_lsize[ab->b_type]; | |
1080 | ||
1081 | ASSERT(!MUTEX_HELD(&ab->b_state->arcs_mtx)); | |
1082 | mutex_enter(&ab->b_state->arcs_mtx); | |
1083 | ASSERT(list_link_active(&ab->b_arc_node)); | |
1084 | list_remove(list, ab); | |
1085 | if (GHOST_STATE(ab->b_state)) { | |
1086 | ASSERT3U(ab->b_datacnt, ==, 0); | |
1087 | ASSERT3P(ab->b_buf, ==, NULL); | |
1088 | delta = ab->b_size; | |
1089 | } | |
1090 | ASSERT(delta > 0); | |
1091 | ASSERT3U(*size, >=, delta); | |
1092 | atomic_add_64(size, -delta); | |
1093 | mutex_exit(&ab->b_state->arcs_mtx); | |
b128c09f | 1094 | /* remove the prefetch flag if we get a reference */ |
34dc7c2f BB |
1095 | if (ab->b_flags & ARC_PREFETCH) |
1096 | ab->b_flags &= ~ARC_PREFETCH; | |
1097 | } | |
1098 | } | |
1099 | ||
1100 | static int | |
1101 | remove_reference(arc_buf_hdr_t *ab, kmutex_t *hash_lock, void *tag) | |
1102 | { | |
1103 | int cnt; | |
1104 | arc_state_t *state = ab->b_state; | |
1105 | ||
1106 | ASSERT(state == arc_anon || MUTEX_HELD(hash_lock)); | |
1107 | ASSERT(!GHOST_STATE(state)); | |
1108 | ||
1109 | if (((cnt = refcount_remove(&ab->b_refcnt, tag)) == 0) && | |
1110 | (state != arc_anon)) { | |
1111 | uint64_t *size = &state->arcs_lsize[ab->b_type]; | |
1112 | ||
1113 | ASSERT(!MUTEX_HELD(&state->arcs_mtx)); | |
1114 | mutex_enter(&state->arcs_mtx); | |
1115 | ASSERT(!list_link_active(&ab->b_arc_node)); | |
1116 | list_insert_head(&state->arcs_list[ab->b_type], ab); | |
1117 | ASSERT(ab->b_datacnt > 0); | |
1118 | atomic_add_64(size, ab->b_size * ab->b_datacnt); | |
1119 | mutex_exit(&state->arcs_mtx); | |
1120 | } | |
1121 | return (cnt); | |
1122 | } | |
1123 | ||
1124 | /* | |
1125 | * Move the supplied buffer to the indicated state. The mutex | |
1126 | * for the buffer must be held by the caller. | |
1127 | */ | |
1128 | static void | |
1129 | arc_change_state(arc_state_t *new_state, arc_buf_hdr_t *ab, kmutex_t *hash_lock) | |
1130 | { | |
1131 | arc_state_t *old_state = ab->b_state; | |
1132 | int64_t refcnt = refcount_count(&ab->b_refcnt); | |
1133 | uint64_t from_delta, to_delta; | |
1134 | ||
1135 | ASSERT(MUTEX_HELD(hash_lock)); | |
1136 | ASSERT(new_state != old_state); | |
1137 | ASSERT(refcnt == 0 || ab->b_datacnt > 0); | |
1138 | ASSERT(ab->b_datacnt == 0 || !GHOST_STATE(new_state)); | |
428870ff | 1139 | ASSERT(ab->b_datacnt <= 1 || old_state != arc_anon); |
34dc7c2f BB |
1140 | |
1141 | from_delta = to_delta = ab->b_datacnt * ab->b_size; | |
1142 | ||
1143 | /* | |
1144 | * If this buffer is evictable, transfer it from the | |
1145 | * old state list to the new state list. | |
1146 | */ | |
1147 | if (refcnt == 0) { | |
1148 | if (old_state != arc_anon) { | |
1149 | int use_mutex = !MUTEX_HELD(&old_state->arcs_mtx); | |
1150 | uint64_t *size = &old_state->arcs_lsize[ab->b_type]; | |
1151 | ||
1152 | if (use_mutex) | |
1153 | mutex_enter(&old_state->arcs_mtx); | |
1154 | ||
1155 | ASSERT(list_link_active(&ab->b_arc_node)); | |
1156 | list_remove(&old_state->arcs_list[ab->b_type], ab); | |
1157 | ||
1158 | /* | |
1159 | * If prefetching out of the ghost cache, | |
428870ff | 1160 | * we will have a non-zero datacnt. |
34dc7c2f BB |
1161 | */ |
1162 | if (GHOST_STATE(old_state) && ab->b_datacnt == 0) { | |
1163 | /* ghost elements have a ghost size */ | |
1164 | ASSERT(ab->b_buf == NULL); | |
1165 | from_delta = ab->b_size; | |
1166 | } | |
1167 | ASSERT3U(*size, >=, from_delta); | |
1168 | atomic_add_64(size, -from_delta); | |
1169 | ||
1170 | if (use_mutex) | |
1171 | mutex_exit(&old_state->arcs_mtx); | |
1172 | } | |
1173 | if (new_state != arc_anon) { | |
1174 | int use_mutex = !MUTEX_HELD(&new_state->arcs_mtx); | |
1175 | uint64_t *size = &new_state->arcs_lsize[ab->b_type]; | |
1176 | ||
1177 | if (use_mutex) | |
1178 | mutex_enter(&new_state->arcs_mtx); | |
1179 | ||
1180 | list_insert_head(&new_state->arcs_list[ab->b_type], ab); | |
1181 | ||
1182 | /* ghost elements have a ghost size */ | |
1183 | if (GHOST_STATE(new_state)) { | |
1184 | ASSERT(ab->b_datacnt == 0); | |
1185 | ASSERT(ab->b_buf == NULL); | |
1186 | to_delta = ab->b_size; | |
1187 | } | |
1188 | atomic_add_64(size, to_delta); | |
1189 | ||
1190 | if (use_mutex) | |
1191 | mutex_exit(&new_state->arcs_mtx); | |
1192 | } | |
1193 | } | |
1194 | ||
1195 | ASSERT(!BUF_EMPTY(ab)); | |
428870ff | 1196 | if (new_state == arc_anon && HDR_IN_HASH_TABLE(ab)) |
34dc7c2f | 1197 | buf_hash_remove(ab); |
34dc7c2f BB |
1198 | |
1199 | /* adjust state sizes */ | |
1200 | if (to_delta) | |
1201 | atomic_add_64(&new_state->arcs_size, to_delta); | |
1202 | if (from_delta) { | |
1203 | ASSERT3U(old_state->arcs_size, >=, from_delta); | |
1204 | atomic_add_64(&old_state->arcs_size, -from_delta); | |
1205 | } | |
1206 | ab->b_state = new_state; | |
1207 | ||
1208 | /* adjust l2arc hdr stats */ | |
1209 | if (new_state == arc_l2c_only) | |
1210 | l2arc_hdr_stat_add(); | |
1211 | else if (old_state == arc_l2c_only) | |
1212 | l2arc_hdr_stat_remove(); | |
1213 | } | |
1214 | ||
1215 | void | |
d164b209 | 1216 | arc_space_consume(uint64_t space, arc_space_type_t type) |
34dc7c2f | 1217 | { |
d164b209 BB |
1218 | ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES); |
1219 | ||
1220 | switch (type) { | |
e75c13c3 BB |
1221 | default: |
1222 | break; | |
d164b209 BB |
1223 | case ARC_SPACE_DATA: |
1224 | ARCSTAT_INCR(arcstat_data_size, space); | |
1225 | break; | |
1226 | case ARC_SPACE_OTHER: | |
1227 | ARCSTAT_INCR(arcstat_other_size, space); | |
1228 | break; | |
1229 | case ARC_SPACE_HDRS: | |
1230 | ARCSTAT_INCR(arcstat_hdr_size, space); | |
1231 | break; | |
1232 | case ARC_SPACE_L2HDRS: | |
1233 | ARCSTAT_INCR(arcstat_l2_hdr_size, space); | |
1234 | break; | |
1235 | } | |
1236 | ||
34dc7c2f BB |
1237 | atomic_add_64(&arc_meta_used, space); |
1238 | atomic_add_64(&arc_size, space); | |
1239 | } | |
1240 | ||
1241 | void | |
d164b209 | 1242 | arc_space_return(uint64_t space, arc_space_type_t type) |
34dc7c2f | 1243 | { |
d164b209 BB |
1244 | ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES); |
1245 | ||
1246 | switch (type) { | |
e75c13c3 BB |
1247 | default: |
1248 | break; | |
d164b209 BB |
1249 | case ARC_SPACE_DATA: |
1250 | ARCSTAT_INCR(arcstat_data_size, -space); | |
1251 | break; | |
1252 | case ARC_SPACE_OTHER: | |
1253 | ARCSTAT_INCR(arcstat_other_size, -space); | |
1254 | break; | |
1255 | case ARC_SPACE_HDRS: | |
1256 | ARCSTAT_INCR(arcstat_hdr_size, -space); | |
1257 | break; | |
1258 | case ARC_SPACE_L2HDRS: | |
1259 | ARCSTAT_INCR(arcstat_l2_hdr_size, -space); | |
1260 | break; | |
1261 | } | |
1262 | ||
34dc7c2f BB |
1263 | ASSERT(arc_meta_used >= space); |
1264 | if (arc_meta_max < arc_meta_used) | |
1265 | arc_meta_max = arc_meta_used; | |
1266 | atomic_add_64(&arc_meta_used, -space); | |
1267 | ASSERT(arc_size >= space); | |
1268 | atomic_add_64(&arc_size, -space); | |
1269 | } | |
1270 | ||
1271 | void * | |
1272 | arc_data_buf_alloc(uint64_t size) | |
1273 | { | |
1274 | if (arc_evict_needed(ARC_BUFC_DATA)) | |
1275 | cv_signal(&arc_reclaim_thr_cv); | |
1276 | atomic_add_64(&arc_size, size); | |
1277 | return (zio_data_buf_alloc(size)); | |
1278 | } | |
1279 | ||
1280 | void | |
1281 | arc_data_buf_free(void *buf, uint64_t size) | |
1282 | { | |
1283 | zio_data_buf_free(buf, size); | |
1284 | ASSERT(arc_size >= size); | |
1285 | atomic_add_64(&arc_size, -size); | |
1286 | } | |
1287 | ||
1288 | arc_buf_t * | |
1289 | arc_buf_alloc(spa_t *spa, int size, void *tag, arc_buf_contents_t type) | |
1290 | { | |
1291 | arc_buf_hdr_t *hdr; | |
1292 | arc_buf_t *buf; | |
1293 | ||
1294 | ASSERT3U(size, >, 0); | |
1295 | hdr = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); | |
1296 | ASSERT(BUF_EMPTY(hdr)); | |
1297 | hdr->b_size = size; | |
1298 | hdr->b_type = type; | |
d164b209 | 1299 | hdr->b_spa = spa_guid(spa); |
34dc7c2f BB |
1300 | hdr->b_state = arc_anon; |
1301 | hdr->b_arc_access = 0; | |
1302 | buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); | |
1303 | buf->b_hdr = hdr; | |
1304 | buf->b_data = NULL; | |
1305 | buf->b_efunc = NULL; | |
1306 | buf->b_private = NULL; | |
1307 | buf->b_next = NULL; | |
1308 | hdr->b_buf = buf; | |
1309 | arc_get_data_buf(buf); | |
1310 | hdr->b_datacnt = 1; | |
1311 | hdr->b_flags = 0; | |
1312 | ASSERT(refcount_is_zero(&hdr->b_refcnt)); | |
1313 | (void) refcount_add(&hdr->b_refcnt, tag); | |
1314 | ||
1315 | return (buf); | |
1316 | } | |
1317 | ||
9babb374 BB |
1318 | static char *arc_onloan_tag = "onloan"; |
1319 | ||
1320 | /* | |
1321 | * Loan out an anonymous arc buffer. Loaned buffers are not counted as in | |
1322 | * flight data by arc_tempreserve_space() until they are "returned". Loaned | |
1323 | * buffers must be returned to the arc before they can be used by the DMU or | |
1324 | * freed. | |
1325 | */ | |
1326 | arc_buf_t * | |
1327 | arc_loan_buf(spa_t *spa, int size) | |
1328 | { | |
1329 | arc_buf_t *buf; | |
1330 | ||
1331 | buf = arc_buf_alloc(spa, size, arc_onloan_tag, ARC_BUFC_DATA); | |
1332 | ||
1333 | atomic_add_64(&arc_loaned_bytes, size); | |
1334 | return (buf); | |
1335 | } | |
1336 | ||
1337 | /* | |
1338 | * Return a loaned arc buffer to the arc. | |
1339 | */ | |
1340 | void | |
1341 | arc_return_buf(arc_buf_t *buf, void *tag) | |
1342 | { | |
1343 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
1344 | ||
9babb374 | 1345 | ASSERT(buf->b_data != NULL); |
428870ff BB |
1346 | (void) refcount_add(&hdr->b_refcnt, tag); |
1347 | (void) refcount_remove(&hdr->b_refcnt, arc_onloan_tag); | |
9babb374 BB |
1348 | |
1349 | atomic_add_64(&arc_loaned_bytes, -hdr->b_size); | |
1350 | } | |
1351 | ||
428870ff BB |
1352 | /* Detach an arc_buf from a dbuf (tag) */ |
1353 | void | |
1354 | arc_loan_inuse_buf(arc_buf_t *buf, void *tag) | |
1355 | { | |
1356 | arc_buf_hdr_t *hdr; | |
1357 | ||
1358 | ASSERT(buf->b_data != NULL); | |
1359 | hdr = buf->b_hdr; | |
1360 | (void) refcount_add(&hdr->b_refcnt, arc_onloan_tag); | |
1361 | (void) refcount_remove(&hdr->b_refcnt, tag); | |
1362 | buf->b_efunc = NULL; | |
1363 | buf->b_private = NULL; | |
1364 | ||
1365 | atomic_add_64(&arc_loaned_bytes, hdr->b_size); | |
1366 | } | |
1367 | ||
34dc7c2f BB |
1368 | static arc_buf_t * |
1369 | arc_buf_clone(arc_buf_t *from) | |
1370 | { | |
1371 | arc_buf_t *buf; | |
1372 | arc_buf_hdr_t *hdr = from->b_hdr; | |
1373 | uint64_t size = hdr->b_size; | |
1374 | ||
428870ff BB |
1375 | ASSERT(hdr->b_state != arc_anon); |
1376 | ||
34dc7c2f BB |
1377 | buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); |
1378 | buf->b_hdr = hdr; | |
1379 | buf->b_data = NULL; | |
1380 | buf->b_efunc = NULL; | |
1381 | buf->b_private = NULL; | |
1382 | buf->b_next = hdr->b_buf; | |
1383 | hdr->b_buf = buf; | |
1384 | arc_get_data_buf(buf); | |
1385 | bcopy(from->b_data, buf->b_data, size); | |
1386 | hdr->b_datacnt += 1; | |
1387 | return (buf); | |
1388 | } | |
1389 | ||
1390 | void | |
1391 | arc_buf_add_ref(arc_buf_t *buf, void* tag) | |
1392 | { | |
1393 | arc_buf_hdr_t *hdr; | |
1394 | kmutex_t *hash_lock; | |
1395 | ||
1396 | /* | |
b128c09f BB |
1397 | * Check to see if this buffer is evicted. Callers |
1398 | * must verify b_data != NULL to know if the add_ref | |
1399 | * was successful. | |
34dc7c2f | 1400 | */ |
428870ff | 1401 | mutex_enter(&buf->b_evict_lock); |
b128c09f | 1402 | if (buf->b_data == NULL) { |
428870ff | 1403 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
1404 | return; |
1405 | } | |
428870ff | 1406 | hash_lock = HDR_LOCK(buf->b_hdr); |
34dc7c2f | 1407 | mutex_enter(hash_lock); |
428870ff BB |
1408 | hdr = buf->b_hdr; |
1409 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
1410 | mutex_exit(&buf->b_evict_lock); | |
34dc7c2f | 1411 | |
34dc7c2f BB |
1412 | ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); |
1413 | add_reference(hdr, hash_lock, tag); | |
d164b209 | 1414 | DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr); |
34dc7c2f BB |
1415 | arc_access(hdr, hash_lock); |
1416 | mutex_exit(hash_lock); | |
1417 | ARCSTAT_BUMP(arcstat_hits); | |
1418 | ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), | |
1419 | demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, | |
1420 | data, metadata, hits); | |
1421 | } | |
1422 | ||
1423 | /* | |
1424 | * Free the arc data buffer. If it is an l2arc write in progress, | |
1425 | * the buffer is placed on l2arc_free_on_write to be freed later. | |
1426 | */ | |
1427 | static void | |
1428 | arc_buf_data_free(arc_buf_hdr_t *hdr, void (*free_func)(void *, size_t), | |
1429 | void *data, size_t size) | |
1430 | { | |
1431 | if (HDR_L2_WRITING(hdr)) { | |
1432 | l2arc_data_free_t *df; | |
1433 | df = kmem_alloc(sizeof (l2arc_data_free_t), KM_SLEEP); | |
1434 | df->l2df_data = data; | |
1435 | df->l2df_size = size; | |
1436 | df->l2df_func = free_func; | |
1437 | mutex_enter(&l2arc_free_on_write_mtx); | |
1438 | list_insert_head(l2arc_free_on_write, df); | |
1439 | mutex_exit(&l2arc_free_on_write_mtx); | |
1440 | ARCSTAT_BUMP(arcstat_l2_free_on_write); | |
1441 | } else { | |
1442 | free_func(data, size); | |
1443 | } | |
1444 | } | |
1445 | ||
1446 | static void | |
1447 | arc_buf_destroy(arc_buf_t *buf, boolean_t recycle, boolean_t all) | |
1448 | { | |
1449 | arc_buf_t **bufp; | |
1450 | ||
1451 | /* free up data associated with the buf */ | |
1452 | if (buf->b_data) { | |
1453 | arc_state_t *state = buf->b_hdr->b_state; | |
1454 | uint64_t size = buf->b_hdr->b_size; | |
1455 | arc_buf_contents_t type = buf->b_hdr->b_type; | |
1456 | ||
1457 | arc_cksum_verify(buf); | |
428870ff | 1458 | |
34dc7c2f BB |
1459 | if (!recycle) { |
1460 | if (type == ARC_BUFC_METADATA) { | |
1461 | arc_buf_data_free(buf->b_hdr, zio_buf_free, | |
1462 | buf->b_data, size); | |
d164b209 | 1463 | arc_space_return(size, ARC_SPACE_DATA); |
34dc7c2f BB |
1464 | } else { |
1465 | ASSERT(type == ARC_BUFC_DATA); | |
1466 | arc_buf_data_free(buf->b_hdr, | |
1467 | zio_data_buf_free, buf->b_data, size); | |
d164b209 | 1468 | ARCSTAT_INCR(arcstat_data_size, -size); |
34dc7c2f BB |
1469 | atomic_add_64(&arc_size, -size); |
1470 | } | |
1471 | } | |
1472 | if (list_link_active(&buf->b_hdr->b_arc_node)) { | |
1473 | uint64_t *cnt = &state->arcs_lsize[type]; | |
1474 | ||
1475 | ASSERT(refcount_is_zero(&buf->b_hdr->b_refcnt)); | |
1476 | ASSERT(state != arc_anon); | |
1477 | ||
1478 | ASSERT3U(*cnt, >=, size); | |
1479 | atomic_add_64(cnt, -size); | |
1480 | } | |
1481 | ASSERT3U(state->arcs_size, >=, size); | |
1482 | atomic_add_64(&state->arcs_size, -size); | |
1483 | buf->b_data = NULL; | |
1484 | ASSERT(buf->b_hdr->b_datacnt > 0); | |
1485 | buf->b_hdr->b_datacnt -= 1; | |
1486 | } | |
1487 | ||
1488 | /* only remove the buf if requested */ | |
1489 | if (!all) | |
1490 | return; | |
1491 | ||
1492 | /* remove the buf from the hdr list */ | |
1493 | for (bufp = &buf->b_hdr->b_buf; *bufp != buf; bufp = &(*bufp)->b_next) | |
1494 | continue; | |
1495 | *bufp = buf->b_next; | |
428870ff | 1496 | buf->b_next = NULL; |
34dc7c2f BB |
1497 | |
1498 | ASSERT(buf->b_efunc == NULL); | |
1499 | ||
1500 | /* clean up the buf */ | |
1501 | buf->b_hdr = NULL; | |
1502 | kmem_cache_free(buf_cache, buf); | |
1503 | } | |
1504 | ||
1505 | static void | |
1506 | arc_hdr_destroy(arc_buf_hdr_t *hdr) | |
1507 | { | |
d6320ddb BB |
1508 | l2arc_buf_hdr_t *l2hdr = hdr->b_l2hdr; |
1509 | ||
34dc7c2f BB |
1510 | ASSERT(refcount_is_zero(&hdr->b_refcnt)); |
1511 | ASSERT3P(hdr->b_state, ==, arc_anon); | |
1512 | ASSERT(!HDR_IO_IN_PROGRESS(hdr)); | |
1513 | ||
428870ff BB |
1514 | if (l2hdr != NULL) { |
1515 | boolean_t buflist_held = MUTEX_HELD(&l2arc_buflist_mtx); | |
1516 | /* | |
1517 | * To prevent arc_free() and l2arc_evict() from | |
1518 | * attempting to free the same buffer at the same time, | |
1519 | * a FREE_IN_PROGRESS flag is given to arc_free() to | |
1520 | * give it priority. l2arc_evict() can't destroy this | |
1521 | * header while we are waiting on l2arc_buflist_mtx. | |
1522 | * | |
1523 | * The hdr may be removed from l2ad_buflist before we | |
1524 | * grab l2arc_buflist_mtx, so b_l2hdr is rechecked. | |
1525 | */ | |
1526 | if (!buflist_held) { | |
34dc7c2f | 1527 | mutex_enter(&l2arc_buflist_mtx); |
428870ff | 1528 | l2hdr = hdr->b_l2hdr; |
34dc7c2f | 1529 | } |
428870ff BB |
1530 | |
1531 | if (l2hdr != NULL) { | |
1532 | list_remove(l2hdr->b_dev->l2ad_buflist, hdr); | |
1533 | ARCSTAT_INCR(arcstat_l2_size, -hdr->b_size); | |
1534 | kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t)); | |
1535 | if (hdr->b_state == arc_l2c_only) | |
1536 | l2arc_hdr_stat_remove(); | |
1537 | hdr->b_l2hdr = NULL; | |
1538 | } | |
1539 | ||
1540 | if (!buflist_held) | |
1541 | mutex_exit(&l2arc_buflist_mtx); | |
34dc7c2f BB |
1542 | } |
1543 | ||
1544 | if (!BUF_EMPTY(hdr)) { | |
1545 | ASSERT(!HDR_IN_HASH_TABLE(hdr)); | |
428870ff | 1546 | buf_discard_identity(hdr); |
34dc7c2f BB |
1547 | } |
1548 | while (hdr->b_buf) { | |
1549 | arc_buf_t *buf = hdr->b_buf; | |
1550 | ||
1551 | if (buf->b_efunc) { | |
1552 | mutex_enter(&arc_eviction_mtx); | |
428870ff | 1553 | mutex_enter(&buf->b_evict_lock); |
34dc7c2f BB |
1554 | ASSERT(buf->b_hdr != NULL); |
1555 | arc_buf_destroy(hdr->b_buf, FALSE, FALSE); | |
1556 | hdr->b_buf = buf->b_next; | |
1557 | buf->b_hdr = &arc_eviction_hdr; | |
1558 | buf->b_next = arc_eviction_list; | |
1559 | arc_eviction_list = buf; | |
428870ff | 1560 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
1561 | mutex_exit(&arc_eviction_mtx); |
1562 | } else { | |
1563 | arc_buf_destroy(hdr->b_buf, FALSE, TRUE); | |
1564 | } | |
1565 | } | |
1566 | if (hdr->b_freeze_cksum != NULL) { | |
1567 | kmem_free(hdr->b_freeze_cksum, sizeof (zio_cksum_t)); | |
1568 | hdr->b_freeze_cksum = NULL; | |
1569 | } | |
428870ff BB |
1570 | if (hdr->b_thawed) { |
1571 | kmem_free(hdr->b_thawed, 1); | |
1572 | hdr->b_thawed = NULL; | |
1573 | } | |
34dc7c2f BB |
1574 | |
1575 | ASSERT(!list_link_active(&hdr->b_arc_node)); | |
1576 | ASSERT3P(hdr->b_hash_next, ==, NULL); | |
1577 | ASSERT3P(hdr->b_acb, ==, NULL); | |
1578 | kmem_cache_free(hdr_cache, hdr); | |
1579 | } | |
1580 | ||
1581 | void | |
1582 | arc_buf_free(arc_buf_t *buf, void *tag) | |
1583 | { | |
1584 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
1585 | int hashed = hdr->b_state != arc_anon; | |
1586 | ||
1587 | ASSERT(buf->b_efunc == NULL); | |
1588 | ASSERT(buf->b_data != NULL); | |
1589 | ||
1590 | if (hashed) { | |
1591 | kmutex_t *hash_lock = HDR_LOCK(hdr); | |
1592 | ||
1593 | mutex_enter(hash_lock); | |
428870ff BB |
1594 | hdr = buf->b_hdr; |
1595 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
1596 | ||
34dc7c2f | 1597 | (void) remove_reference(hdr, hash_lock, tag); |
428870ff | 1598 | if (hdr->b_datacnt > 1) { |
34dc7c2f | 1599 | arc_buf_destroy(buf, FALSE, TRUE); |
428870ff BB |
1600 | } else { |
1601 | ASSERT(buf == hdr->b_buf); | |
1602 | ASSERT(buf->b_efunc == NULL); | |
34dc7c2f | 1603 | hdr->b_flags |= ARC_BUF_AVAILABLE; |
428870ff | 1604 | } |
34dc7c2f BB |
1605 | mutex_exit(hash_lock); |
1606 | } else if (HDR_IO_IN_PROGRESS(hdr)) { | |
1607 | int destroy_hdr; | |
1608 | /* | |
1609 | * We are in the middle of an async write. Don't destroy | |
1610 | * this buffer unless the write completes before we finish | |
1611 | * decrementing the reference count. | |
1612 | */ | |
1613 | mutex_enter(&arc_eviction_mtx); | |
1614 | (void) remove_reference(hdr, NULL, tag); | |
1615 | ASSERT(refcount_is_zero(&hdr->b_refcnt)); | |
1616 | destroy_hdr = !HDR_IO_IN_PROGRESS(hdr); | |
1617 | mutex_exit(&arc_eviction_mtx); | |
1618 | if (destroy_hdr) | |
1619 | arc_hdr_destroy(hdr); | |
1620 | } else { | |
428870ff | 1621 | if (remove_reference(hdr, NULL, tag) > 0) |
34dc7c2f | 1622 | arc_buf_destroy(buf, FALSE, TRUE); |
428870ff | 1623 | else |
34dc7c2f | 1624 | arc_hdr_destroy(hdr); |
34dc7c2f BB |
1625 | } |
1626 | } | |
1627 | ||
1628 | int | |
1629 | arc_buf_remove_ref(arc_buf_t *buf, void* tag) | |
1630 | { | |
1631 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
1632 | kmutex_t *hash_lock = HDR_LOCK(hdr); | |
1633 | int no_callback = (buf->b_efunc == NULL); | |
1634 | ||
1635 | if (hdr->b_state == arc_anon) { | |
428870ff | 1636 | ASSERT(hdr->b_datacnt == 1); |
34dc7c2f BB |
1637 | arc_buf_free(buf, tag); |
1638 | return (no_callback); | |
1639 | } | |
1640 | ||
1641 | mutex_enter(hash_lock); | |
428870ff BB |
1642 | hdr = buf->b_hdr; |
1643 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
34dc7c2f BB |
1644 | ASSERT(hdr->b_state != arc_anon); |
1645 | ASSERT(buf->b_data != NULL); | |
1646 | ||
1647 | (void) remove_reference(hdr, hash_lock, tag); | |
1648 | if (hdr->b_datacnt > 1) { | |
1649 | if (no_callback) | |
1650 | arc_buf_destroy(buf, FALSE, TRUE); | |
1651 | } else if (no_callback) { | |
1652 | ASSERT(hdr->b_buf == buf && buf->b_next == NULL); | |
428870ff | 1653 | ASSERT(buf->b_efunc == NULL); |
34dc7c2f BB |
1654 | hdr->b_flags |= ARC_BUF_AVAILABLE; |
1655 | } | |
1656 | ASSERT(no_callback || hdr->b_datacnt > 1 || | |
1657 | refcount_is_zero(&hdr->b_refcnt)); | |
1658 | mutex_exit(hash_lock); | |
1659 | return (no_callback); | |
1660 | } | |
1661 | ||
1662 | int | |
1663 | arc_buf_size(arc_buf_t *buf) | |
1664 | { | |
1665 | return (buf->b_hdr->b_size); | |
1666 | } | |
1667 | ||
1668 | /* | |
1669 | * Evict buffers from list until we've removed the specified number of | |
1670 | * bytes. Move the removed buffers to the appropriate evict state. | |
1671 | * If the recycle flag is set, then attempt to "recycle" a buffer: | |
1672 | * - look for a buffer to evict that is `bytes' long. | |
1673 | * - return the data block from this buffer rather than freeing it. | |
1674 | * This flag is used by callers that are trying to make space for a | |
1675 | * new buffer in a full arc cache. | |
1676 | * | |
1677 | * This function makes a "best effort". It skips over any buffers | |
1678 | * it can't get a hash_lock on, and so may not catch all candidates. | |
1679 | * It may also return without evicting as much space as requested. | |
1680 | */ | |
1681 | static void * | |
d164b209 | 1682 | arc_evict(arc_state_t *state, uint64_t spa, int64_t bytes, boolean_t recycle, |
34dc7c2f BB |
1683 | arc_buf_contents_t type) |
1684 | { | |
1685 | arc_state_t *evicted_state; | |
1686 | uint64_t bytes_evicted = 0, skipped = 0, missed = 0; | |
1687 | arc_buf_hdr_t *ab, *ab_prev = NULL; | |
1688 | list_t *list = &state->arcs_list[type]; | |
1689 | kmutex_t *hash_lock; | |
1690 | boolean_t have_lock; | |
1691 | void *stolen = NULL; | |
1692 | ||
1693 | ASSERT(state == arc_mru || state == arc_mfu); | |
1694 | ||
1695 | evicted_state = (state == arc_mru) ? arc_mru_ghost : arc_mfu_ghost; | |
1696 | ||
1697 | mutex_enter(&state->arcs_mtx); | |
1698 | mutex_enter(&evicted_state->arcs_mtx); | |
1699 | ||
1700 | for (ab = list_tail(list); ab; ab = ab_prev) { | |
1701 | ab_prev = list_prev(list, ab); | |
1702 | /* prefetch buffers have a minimum lifespan */ | |
1703 | if (HDR_IO_IN_PROGRESS(ab) || | |
1704 | (spa && ab->b_spa != spa) || | |
1705 | (ab->b_flags & (ARC_PREFETCH|ARC_INDIRECT) && | |
428870ff BB |
1706 | ddi_get_lbolt() - ab->b_arc_access < |
1707 | arc_min_prefetch_lifespan)) { | |
34dc7c2f BB |
1708 | skipped++; |
1709 | continue; | |
1710 | } | |
1711 | /* "lookahead" for better eviction candidate */ | |
1712 | if (recycle && ab->b_size != bytes && | |
1713 | ab_prev && ab_prev->b_size == bytes) | |
1714 | continue; | |
1715 | hash_lock = HDR_LOCK(ab); | |
1716 | have_lock = MUTEX_HELD(hash_lock); | |
1717 | if (have_lock || mutex_tryenter(hash_lock)) { | |
1718 | ASSERT3U(refcount_count(&ab->b_refcnt), ==, 0); | |
1719 | ASSERT(ab->b_datacnt > 0); | |
1720 | while (ab->b_buf) { | |
1721 | arc_buf_t *buf = ab->b_buf; | |
428870ff | 1722 | if (!mutex_tryenter(&buf->b_evict_lock)) { |
b128c09f BB |
1723 | missed += 1; |
1724 | break; | |
1725 | } | |
34dc7c2f BB |
1726 | if (buf->b_data) { |
1727 | bytes_evicted += ab->b_size; | |
1728 | if (recycle && ab->b_type == type && | |
1729 | ab->b_size == bytes && | |
1730 | !HDR_L2_WRITING(ab)) { | |
1731 | stolen = buf->b_data; | |
1732 | recycle = FALSE; | |
1733 | } | |
1734 | } | |
1735 | if (buf->b_efunc) { | |
1736 | mutex_enter(&arc_eviction_mtx); | |
1737 | arc_buf_destroy(buf, | |
1738 | buf->b_data == stolen, FALSE); | |
1739 | ab->b_buf = buf->b_next; | |
1740 | buf->b_hdr = &arc_eviction_hdr; | |
1741 | buf->b_next = arc_eviction_list; | |
1742 | arc_eviction_list = buf; | |
1743 | mutex_exit(&arc_eviction_mtx); | |
428870ff | 1744 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f | 1745 | } else { |
428870ff | 1746 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
1747 | arc_buf_destroy(buf, |
1748 | buf->b_data == stolen, TRUE); | |
1749 | } | |
1750 | } | |
428870ff BB |
1751 | |
1752 | if (ab->b_l2hdr) { | |
1753 | ARCSTAT_INCR(arcstat_evict_l2_cached, | |
1754 | ab->b_size); | |
1755 | } else { | |
1756 | if (l2arc_write_eligible(ab->b_spa, ab)) { | |
1757 | ARCSTAT_INCR(arcstat_evict_l2_eligible, | |
1758 | ab->b_size); | |
1759 | } else { | |
1760 | ARCSTAT_INCR( | |
1761 | arcstat_evict_l2_ineligible, | |
1762 | ab->b_size); | |
1763 | } | |
1764 | } | |
1765 | ||
b128c09f BB |
1766 | if (ab->b_datacnt == 0) { |
1767 | arc_change_state(evicted_state, ab, hash_lock); | |
1768 | ASSERT(HDR_IN_HASH_TABLE(ab)); | |
1769 | ab->b_flags |= ARC_IN_HASH_TABLE; | |
1770 | ab->b_flags &= ~ARC_BUF_AVAILABLE; | |
1771 | DTRACE_PROBE1(arc__evict, arc_buf_hdr_t *, ab); | |
1772 | } | |
34dc7c2f BB |
1773 | if (!have_lock) |
1774 | mutex_exit(hash_lock); | |
1775 | if (bytes >= 0 && bytes_evicted >= bytes) | |
1776 | break; | |
1777 | } else { | |
1778 | missed += 1; | |
1779 | } | |
1780 | } | |
1781 | ||
1782 | mutex_exit(&evicted_state->arcs_mtx); | |
1783 | mutex_exit(&state->arcs_mtx); | |
1784 | ||
1785 | if (bytes_evicted < bytes) | |
3f504482 | 1786 | dprintf("only evicted %lld bytes from %x\n", |
34dc7c2f BB |
1787 | (longlong_t)bytes_evicted, state); |
1788 | ||
1789 | if (skipped) | |
1790 | ARCSTAT_INCR(arcstat_evict_skip, skipped); | |
1791 | ||
1792 | if (missed) | |
1793 | ARCSTAT_INCR(arcstat_mutex_miss, missed); | |
1794 | ||
1795 | /* | |
1796 | * We have just evicted some date into the ghost state, make | |
1797 | * sure we also adjust the ghost state size if necessary. | |
1798 | */ | |
1799 | if (arc_no_grow && | |
1800 | arc_mru_ghost->arcs_size + arc_mfu_ghost->arcs_size > arc_c) { | |
1801 | int64_t mru_over = arc_anon->arcs_size + arc_mru->arcs_size + | |
1802 | arc_mru_ghost->arcs_size - arc_c; | |
1803 | ||
1804 | if (mru_over > 0 && arc_mru_ghost->arcs_lsize[type] > 0) { | |
1805 | int64_t todelete = | |
1806 | MIN(arc_mru_ghost->arcs_lsize[type], mru_over); | |
b8864a23 | 1807 | arc_evict_ghost(arc_mru_ghost, 0, todelete); |
34dc7c2f BB |
1808 | } else if (arc_mfu_ghost->arcs_lsize[type] > 0) { |
1809 | int64_t todelete = MIN(arc_mfu_ghost->arcs_lsize[type], | |
1810 | arc_mru_ghost->arcs_size + | |
1811 | arc_mfu_ghost->arcs_size - arc_c); | |
b8864a23 | 1812 | arc_evict_ghost(arc_mfu_ghost, 0, todelete); |
34dc7c2f BB |
1813 | } |
1814 | } | |
1815 | ||
1816 | return (stolen); | |
1817 | } | |
1818 | ||
1819 | /* | |
1820 | * Remove buffers from list until we've removed the specified number of | |
1821 | * bytes. Destroy the buffers that are removed. | |
1822 | */ | |
1823 | static void | |
d164b209 | 1824 | arc_evict_ghost(arc_state_t *state, uint64_t spa, int64_t bytes) |
34dc7c2f BB |
1825 | { |
1826 | arc_buf_hdr_t *ab, *ab_prev; | |
2598c001 | 1827 | arc_buf_hdr_t marker; |
34dc7c2f BB |
1828 | list_t *list = &state->arcs_list[ARC_BUFC_DATA]; |
1829 | kmutex_t *hash_lock; | |
1830 | uint64_t bytes_deleted = 0; | |
1831 | uint64_t bufs_skipped = 0; | |
1832 | ||
1833 | ASSERT(GHOST_STATE(state)); | |
2598c001 | 1834 | bzero(&marker, sizeof(marker)); |
34dc7c2f BB |
1835 | top: |
1836 | mutex_enter(&state->arcs_mtx); | |
1837 | for (ab = list_tail(list); ab; ab = ab_prev) { | |
1838 | ab_prev = list_prev(list, ab); | |
1839 | if (spa && ab->b_spa != spa) | |
1840 | continue; | |
572e2857 BB |
1841 | |
1842 | /* ignore markers */ | |
1843 | if (ab->b_spa == 0) | |
1844 | continue; | |
1845 | ||
34dc7c2f | 1846 | hash_lock = HDR_LOCK(ab); |
428870ff BB |
1847 | /* caller may be trying to modify this buffer, skip it */ |
1848 | if (MUTEX_HELD(hash_lock)) | |
1849 | continue; | |
34dc7c2f BB |
1850 | if (mutex_tryenter(hash_lock)) { |
1851 | ASSERT(!HDR_IO_IN_PROGRESS(ab)); | |
1852 | ASSERT(ab->b_buf == NULL); | |
1853 | ARCSTAT_BUMP(arcstat_deleted); | |
1854 | bytes_deleted += ab->b_size; | |
1855 | ||
1856 | if (ab->b_l2hdr != NULL) { | |
1857 | /* | |
1858 | * This buffer is cached on the 2nd Level ARC; | |
1859 | * don't destroy the header. | |
1860 | */ | |
1861 | arc_change_state(arc_l2c_only, ab, hash_lock); | |
1862 | mutex_exit(hash_lock); | |
1863 | } else { | |
1864 | arc_change_state(arc_anon, ab, hash_lock); | |
1865 | mutex_exit(hash_lock); | |
1866 | arc_hdr_destroy(ab); | |
1867 | } | |
1868 | ||
1869 | DTRACE_PROBE1(arc__delete, arc_buf_hdr_t *, ab); | |
1870 | if (bytes >= 0 && bytes_deleted >= bytes) | |
1871 | break; | |
572e2857 BB |
1872 | } else if (bytes < 0) { |
1873 | /* | |
1874 | * Insert a list marker and then wait for the | |
1875 | * hash lock to become available. Once its | |
1876 | * available, restart from where we left off. | |
1877 | */ | |
1878 | list_insert_after(list, ab, &marker); | |
1879 | mutex_exit(&state->arcs_mtx); | |
1880 | mutex_enter(hash_lock); | |
1881 | mutex_exit(hash_lock); | |
1882 | mutex_enter(&state->arcs_mtx); | |
1883 | ab_prev = list_prev(list, &marker); | |
1884 | list_remove(list, &marker); | |
1885 | } else | |
34dc7c2f | 1886 | bufs_skipped += 1; |
34dc7c2f BB |
1887 | } |
1888 | mutex_exit(&state->arcs_mtx); | |
1889 | ||
1890 | if (list == &state->arcs_list[ARC_BUFC_DATA] && | |
1891 | (bytes < 0 || bytes_deleted < bytes)) { | |
1892 | list = &state->arcs_list[ARC_BUFC_METADATA]; | |
1893 | goto top; | |
1894 | } | |
1895 | ||
1896 | if (bufs_skipped) { | |
1897 | ARCSTAT_INCR(arcstat_mutex_miss, bufs_skipped); | |
1898 | ASSERT(bytes >= 0); | |
1899 | } | |
1900 | ||
1901 | if (bytes_deleted < bytes) | |
3f504482 | 1902 | dprintf("only deleted %lld bytes from %p\n", |
34dc7c2f BB |
1903 | (longlong_t)bytes_deleted, state); |
1904 | } | |
1905 | ||
1906 | static void | |
1907 | arc_adjust(void) | |
1908 | { | |
d164b209 BB |
1909 | int64_t adjustment, delta; |
1910 | ||
1911 | /* | |
1912 | * Adjust MRU size | |
1913 | */ | |
34dc7c2f | 1914 | |
572e2857 BB |
1915 | adjustment = MIN((int64_t)(arc_size - arc_c), |
1916 | (int64_t)(arc_anon->arcs_size + arc_mru->arcs_size + arc_meta_used - | |
1917 | arc_p)); | |
34dc7c2f | 1918 | |
d164b209 BB |
1919 | if (adjustment > 0 && arc_mru->arcs_lsize[ARC_BUFC_DATA] > 0) { |
1920 | delta = MIN(arc_mru->arcs_lsize[ARC_BUFC_DATA], adjustment); | |
b8864a23 | 1921 | (void) arc_evict(arc_mru, 0, delta, FALSE, ARC_BUFC_DATA); |
d164b209 | 1922 | adjustment -= delta; |
34dc7c2f BB |
1923 | } |
1924 | ||
d164b209 BB |
1925 | if (adjustment > 0 && arc_mru->arcs_lsize[ARC_BUFC_METADATA] > 0) { |
1926 | delta = MIN(arc_mru->arcs_lsize[ARC_BUFC_METADATA], adjustment); | |
b8864a23 | 1927 | (void) arc_evict(arc_mru, 0, delta, FALSE, |
34dc7c2f | 1928 | ARC_BUFC_METADATA); |
34dc7c2f BB |
1929 | } |
1930 | ||
d164b209 BB |
1931 | /* |
1932 | * Adjust MFU size | |
1933 | */ | |
34dc7c2f | 1934 | |
d164b209 BB |
1935 | adjustment = arc_size - arc_c; |
1936 | ||
1937 | if (adjustment > 0 && arc_mfu->arcs_lsize[ARC_BUFC_DATA] > 0) { | |
1938 | delta = MIN(adjustment, arc_mfu->arcs_lsize[ARC_BUFC_DATA]); | |
b8864a23 | 1939 | (void) arc_evict(arc_mfu, 0, delta, FALSE, ARC_BUFC_DATA); |
d164b209 | 1940 | adjustment -= delta; |
34dc7c2f BB |
1941 | } |
1942 | ||
d164b209 BB |
1943 | if (adjustment > 0 && arc_mfu->arcs_lsize[ARC_BUFC_METADATA] > 0) { |
1944 | int64_t delta = MIN(adjustment, | |
1945 | arc_mfu->arcs_lsize[ARC_BUFC_METADATA]); | |
b8864a23 | 1946 | (void) arc_evict(arc_mfu, 0, delta, FALSE, |
d164b209 BB |
1947 | ARC_BUFC_METADATA); |
1948 | } | |
34dc7c2f | 1949 | |
d164b209 BB |
1950 | /* |
1951 | * Adjust ghost lists | |
1952 | */ | |
34dc7c2f | 1953 | |
d164b209 BB |
1954 | adjustment = arc_mru->arcs_size + arc_mru_ghost->arcs_size - arc_c; |
1955 | ||
1956 | if (adjustment > 0 && arc_mru_ghost->arcs_size > 0) { | |
1957 | delta = MIN(arc_mru_ghost->arcs_size, adjustment); | |
b8864a23 | 1958 | arc_evict_ghost(arc_mru_ghost, 0, delta); |
d164b209 | 1959 | } |
34dc7c2f | 1960 | |
d164b209 BB |
1961 | adjustment = |
1962 | arc_mru_ghost->arcs_size + arc_mfu_ghost->arcs_size - arc_c; | |
34dc7c2f | 1963 | |
d164b209 BB |
1964 | if (adjustment > 0 && arc_mfu_ghost->arcs_size > 0) { |
1965 | delta = MIN(arc_mfu_ghost->arcs_size, adjustment); | |
b8864a23 | 1966 | arc_evict_ghost(arc_mfu_ghost, 0, delta); |
34dc7c2f BB |
1967 | } |
1968 | } | |
1969 | ||
ab26409d BB |
1970 | /* |
1971 | * Request that arc user drop references so that N bytes can be released | |
1972 | * from the cache. This provides a mechanism to ensure the arc can honor | |
1973 | * the arc_meta_limit and reclaim buffers which are pinned in the cache | |
1974 | * by higher layers. (i.e. the zpl) | |
1975 | */ | |
1976 | static void | |
1977 | arc_do_user_prune(int64_t adjustment) | |
1978 | { | |
1979 | arc_prune_func_t *func; | |
1980 | void *private; | |
1981 | arc_prune_t *cp, *np; | |
1982 | ||
1983 | mutex_enter(&arc_prune_mtx); | |
1984 | ||
1985 | cp = list_head(&arc_prune_list); | |
1986 | while (cp != NULL) { | |
1987 | func = cp->p_pfunc; | |
1988 | private = cp->p_private; | |
1989 | np = list_next(&arc_prune_list, cp); | |
1990 | refcount_add(&cp->p_refcnt, func); | |
1991 | mutex_exit(&arc_prune_mtx); | |
1992 | ||
1993 | if (func != NULL) | |
1994 | func(adjustment, private); | |
1995 | ||
1996 | mutex_enter(&arc_prune_mtx); | |
1997 | ||
1998 | /* User removed prune callback concurrently with execution */ | |
1999 | if (refcount_remove(&cp->p_refcnt, func) == 0) { | |
2000 | ASSERT(!list_link_active(&cp->p_node)); | |
2001 | refcount_destroy(&cp->p_refcnt); | |
2002 | kmem_free(cp, sizeof (*cp)); | |
2003 | } | |
2004 | ||
2005 | cp = np; | |
2006 | } | |
2007 | ||
2008 | ARCSTAT_BUMP(arcstat_prune); | |
2009 | mutex_exit(&arc_prune_mtx); | |
2010 | } | |
2011 | ||
34dc7c2f BB |
2012 | static void |
2013 | arc_do_user_evicts(void) | |
2014 | { | |
2015 | mutex_enter(&arc_eviction_mtx); | |
2016 | while (arc_eviction_list != NULL) { | |
2017 | arc_buf_t *buf = arc_eviction_list; | |
2018 | arc_eviction_list = buf->b_next; | |
428870ff | 2019 | mutex_enter(&buf->b_evict_lock); |
34dc7c2f | 2020 | buf->b_hdr = NULL; |
428870ff | 2021 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
2022 | mutex_exit(&arc_eviction_mtx); |
2023 | ||
2024 | if (buf->b_efunc != NULL) | |
2025 | VERIFY(buf->b_efunc(buf) == 0); | |
2026 | ||
2027 | buf->b_efunc = NULL; | |
2028 | buf->b_private = NULL; | |
2029 | kmem_cache_free(buf_cache, buf); | |
2030 | mutex_enter(&arc_eviction_mtx); | |
2031 | } | |
2032 | mutex_exit(&arc_eviction_mtx); | |
2033 | } | |
2034 | ||
ab26409d BB |
2035 | /* |
2036 | * Evict only meta data objects from the cache leaving the data objects. | |
2037 | * This is only used to enforce the tunable arc_meta_limit, if we are | |
2038 | * unable to evict enough buffers notify the user via the prune callback. | |
2039 | */ | |
2040 | void | |
2041 | arc_adjust_meta(int64_t adjustment, boolean_t may_prune) | |
2042 | { | |
2043 | int64_t delta; | |
2044 | ||
2045 | if (adjustment > 0 && arc_mru->arcs_lsize[ARC_BUFC_METADATA] > 0) { | |
2046 | delta = MIN(arc_mru->arcs_lsize[ARC_BUFC_METADATA], adjustment); | |
2047 | arc_evict(arc_mru, 0, delta, FALSE, ARC_BUFC_METADATA); | |
2048 | adjustment -= delta; | |
2049 | } | |
2050 | ||
2051 | if (adjustment > 0 && arc_mfu->arcs_lsize[ARC_BUFC_METADATA] > 0) { | |
2052 | delta = MIN(arc_mfu->arcs_lsize[ARC_BUFC_METADATA], adjustment); | |
2053 | arc_evict(arc_mfu, 0, delta, FALSE, ARC_BUFC_METADATA); | |
2054 | adjustment -= delta; | |
2055 | } | |
2056 | ||
2057 | if (may_prune && (adjustment > 0) && (arc_meta_used > arc_meta_limit)) | |
2058 | arc_do_user_prune(arc_meta_prune); | |
2059 | } | |
2060 | ||
34dc7c2f BB |
2061 | /* |
2062 | * Flush all *evictable* data from the cache for the given spa. | |
2063 | * NOTE: this will not touch "active" (i.e. referenced) data. | |
2064 | */ | |
2065 | void | |
2066 | arc_flush(spa_t *spa) | |
2067 | { | |
d164b209 BB |
2068 | uint64_t guid = 0; |
2069 | ||
2070 | if (spa) | |
2071 | guid = spa_guid(spa); | |
2072 | ||
34dc7c2f | 2073 | while (list_head(&arc_mru->arcs_list[ARC_BUFC_DATA])) { |
d164b209 | 2074 | (void) arc_evict(arc_mru, guid, -1, FALSE, ARC_BUFC_DATA); |
34dc7c2f BB |
2075 | if (spa) |
2076 | break; | |
2077 | } | |
2078 | while (list_head(&arc_mru->arcs_list[ARC_BUFC_METADATA])) { | |
d164b209 | 2079 | (void) arc_evict(arc_mru, guid, -1, FALSE, ARC_BUFC_METADATA); |
34dc7c2f BB |
2080 | if (spa) |
2081 | break; | |
2082 | } | |
2083 | while (list_head(&arc_mfu->arcs_list[ARC_BUFC_DATA])) { | |
d164b209 | 2084 | (void) arc_evict(arc_mfu, guid, -1, FALSE, ARC_BUFC_DATA); |
34dc7c2f BB |
2085 | if (spa) |
2086 | break; | |
2087 | } | |
2088 | while (list_head(&arc_mfu->arcs_list[ARC_BUFC_METADATA])) { | |
d164b209 | 2089 | (void) arc_evict(arc_mfu, guid, -1, FALSE, ARC_BUFC_METADATA); |
34dc7c2f BB |
2090 | if (spa) |
2091 | break; | |
2092 | } | |
2093 | ||
d164b209 BB |
2094 | arc_evict_ghost(arc_mru_ghost, guid, -1); |
2095 | arc_evict_ghost(arc_mfu_ghost, guid, -1); | |
34dc7c2f BB |
2096 | |
2097 | mutex_enter(&arc_reclaim_thr_lock); | |
2098 | arc_do_user_evicts(); | |
2099 | mutex_exit(&arc_reclaim_thr_lock); | |
2100 | ASSERT(spa || arc_eviction_list == NULL); | |
2101 | } | |
2102 | ||
34dc7c2f BB |
2103 | void |
2104 | arc_shrink(void) | |
2105 | { | |
2106 | if (arc_c > arc_c_min) { | |
2107 | uint64_t to_free; | |
2108 | ||
2109 | #ifdef _KERNEL | |
2110 | to_free = MAX(arc_c >> arc_shrink_shift, ptob(needfree)); | |
2111 | #else | |
2112 | to_free = arc_c >> arc_shrink_shift; | |
2113 | #endif | |
2114 | if (arc_c > arc_c_min + to_free) | |
2115 | atomic_add_64(&arc_c, -to_free); | |
2116 | else | |
2117 | arc_c = arc_c_min; | |
2118 | ||
2119 | atomic_add_64(&arc_p, -(arc_p >> arc_shrink_shift)); | |
2120 | if (arc_c > arc_size) | |
2121 | arc_c = MAX(arc_size, arc_c_min); | |
2122 | if (arc_p > arc_c) | |
2123 | arc_p = (arc_c >> 1); | |
2124 | ASSERT(arc_c >= arc_c_min); | |
2125 | ASSERT((int64_t)arc_p >= 0); | |
2126 | } | |
2127 | ||
2128 | if (arc_size > arc_c) | |
2129 | arc_adjust(); | |
2130 | } | |
2131 | ||
2132 | static int | |
2133 | arc_reclaim_needed(void) | |
2134 | { | |
34dc7c2f | 2135 | #ifdef _KERNEL |
1fde1e37 | 2136 | uint64_t extra; |
34dc7c2f BB |
2137 | |
2138 | if (needfree) | |
2139 | return (1); | |
2140 | ||
2141 | /* | |
2142 | * take 'desfree' extra pages, so we reclaim sooner, rather than later | |
2143 | */ | |
2144 | extra = desfree; | |
2145 | ||
2146 | /* | |
2147 | * check that we're out of range of the pageout scanner. It starts to | |
2148 | * schedule paging if freemem is less than lotsfree and needfree. | |
2149 | * lotsfree is the high-water mark for pageout, and needfree is the | |
2150 | * number of needed free pages. We add extra pages here to make sure | |
2151 | * the scanner doesn't start up while we're freeing memory. | |
2152 | */ | |
2153 | if (freemem < lotsfree + needfree + extra) | |
2154 | return (1); | |
2155 | ||
2156 | /* | |
2157 | * check to make sure that swapfs has enough space so that anon | |
2158 | * reservations can still succeed. anon_resvmem() checks that the | |
2159 | * availrmem is greater than swapfs_minfree, and the number of reserved | |
2160 | * swap pages. We also add a bit of extra here just to prevent | |
2161 | * circumstances from getting really dire. | |
2162 | */ | |
2163 | if (availrmem < swapfs_minfree + swapfs_reserve + extra) | |
2164 | return (1); | |
2165 | ||
2166 | #if defined(__i386) | |
2167 | /* | |
2168 | * If we're on an i386 platform, it's possible that we'll exhaust the | |
2169 | * kernel heap space before we ever run out of available physical | |
2170 | * memory. Most checks of the size of the heap_area compare against | |
2171 | * tune.t_minarmem, which is the minimum available real memory that we | |
2172 | * can have in the system. However, this is generally fixed at 25 pages | |
2173 | * which is so low that it's useless. In this comparison, we seek to | |
2174 | * calculate the total heap-size, and reclaim if more than 3/4ths of the | |
2175 | * heap is allocated. (Or, in the calculation, if less than 1/4th is | |
2176 | * free) | |
2177 | */ | |
2178 | if (btop(vmem_size(heap_arena, VMEM_FREE)) < | |
2179 | (btop(vmem_size(heap_arena, VMEM_FREE | VMEM_ALLOC)) >> 2)) | |
2180 | return (1); | |
2181 | #endif | |
2182 | ||
2183 | #else | |
2184 | if (spa_get_random(100) == 0) | |
2185 | return (1); | |
2186 | #endif | |
2187 | return (0); | |
2188 | } | |
2189 | ||
2190 | static void | |
2191 | arc_kmem_reap_now(arc_reclaim_strategy_t strat) | |
2192 | { | |
2193 | size_t i; | |
2194 | kmem_cache_t *prev_cache = NULL; | |
2195 | kmem_cache_t *prev_data_cache = NULL; | |
2196 | extern kmem_cache_t *zio_buf_cache[]; | |
2197 | extern kmem_cache_t *zio_data_buf_cache[]; | |
34dc7c2f BB |
2198 | |
2199 | /* | |
2200 | * An aggressive reclamation will shrink the cache size as well as | |
2201 | * reap free buffers from the arc kmem caches. | |
2202 | */ | |
2203 | if (strat == ARC_RECLAIM_AGGR) | |
2204 | arc_shrink(); | |
2205 | ||
2206 | for (i = 0; i < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; i++) { | |
2207 | if (zio_buf_cache[i] != prev_cache) { | |
2208 | prev_cache = zio_buf_cache[i]; | |
2209 | kmem_cache_reap_now(zio_buf_cache[i]); | |
2210 | } | |
2211 | if (zio_data_buf_cache[i] != prev_data_cache) { | |
2212 | prev_data_cache = zio_data_buf_cache[i]; | |
2213 | kmem_cache_reap_now(zio_data_buf_cache[i]); | |
2214 | } | |
2215 | } | |
ab26409d | 2216 | |
34dc7c2f BB |
2217 | kmem_cache_reap_now(buf_cache); |
2218 | kmem_cache_reap_now(hdr_cache); | |
2219 | } | |
2220 | ||
2221 | static void | |
2222 | arc_reclaim_thread(void) | |
2223 | { | |
2224 | clock_t growtime = 0; | |
2225 | arc_reclaim_strategy_t last_reclaim = ARC_RECLAIM_CONS; | |
2226 | callb_cpr_t cpr; | |
ab26409d | 2227 | int64_t prune; |
34dc7c2f BB |
2228 | |
2229 | CALLB_CPR_INIT(&cpr, &arc_reclaim_thr_lock, callb_generic_cpr, FTAG); | |
2230 | ||
2231 | mutex_enter(&arc_reclaim_thr_lock); | |
2232 | while (arc_thread_exit == 0) { | |
2233 | if (arc_reclaim_needed()) { | |
2234 | ||
2235 | if (arc_no_grow) { | |
2236 | if (last_reclaim == ARC_RECLAIM_CONS) { | |
2237 | last_reclaim = ARC_RECLAIM_AGGR; | |
2238 | } else { | |
2239 | last_reclaim = ARC_RECLAIM_CONS; | |
2240 | } | |
2241 | } else { | |
2242 | arc_no_grow = TRUE; | |
2243 | last_reclaim = ARC_RECLAIM_AGGR; | |
2244 | membar_producer(); | |
2245 | } | |
2246 | ||
2247 | /* reset the growth delay for every reclaim */ | |
428870ff | 2248 | growtime = ddi_get_lbolt() + (arc_grow_retry * hz); |
34dc7c2f BB |
2249 | |
2250 | arc_kmem_reap_now(last_reclaim); | |
b128c09f | 2251 | arc_warm = B_TRUE; |
34dc7c2f | 2252 | |
428870ff | 2253 | } else if (arc_no_grow && ddi_get_lbolt() >= growtime) { |
34dc7c2f BB |
2254 | arc_no_grow = FALSE; |
2255 | } | |
2256 | ||
ab26409d BB |
2257 | /* |
2258 | * Keep meta data usage within limits, arc_shrink() is not | |
2259 | * used to avoid collapsing the arc_c value when only the | |
2260 | * arc_meta_limit is being exceeded. | |
2261 | */ | |
2262 | prune = (int64_t)arc_meta_used - (int64_t)arc_meta_limit; | |
2263 | if (prune > 0) | |
2264 | arc_adjust_meta(prune, B_TRUE); | |
6a8f9b6b | 2265 | |
572e2857 | 2266 | arc_adjust(); |
34dc7c2f BB |
2267 | |
2268 | if (arc_eviction_list != NULL) | |
2269 | arc_do_user_evicts(); | |
2270 | ||
2271 | /* block until needed, or one second, whichever is shorter */ | |
2272 | CALLB_CPR_SAFE_BEGIN(&cpr); | |
5b63b3eb | 2273 | (void) cv_timedwait_interruptible(&arc_reclaim_thr_cv, |
428870ff | 2274 | &arc_reclaim_thr_lock, (ddi_get_lbolt() + hz)); |
34dc7c2f BB |
2275 | CALLB_CPR_SAFE_END(&cpr, &arc_reclaim_thr_lock); |
2276 | } | |
2277 | ||
2278 | arc_thread_exit = 0; | |
2279 | cv_broadcast(&arc_reclaim_thr_cv); | |
2280 | CALLB_CPR_EXIT(&cpr); /* drops arc_reclaim_thr_lock */ | |
2281 | thread_exit(); | |
2282 | } | |
2283 | ||
7cb67b45 BB |
2284 | #ifdef _KERNEL |
2285 | /* | |
2286 | * Under Linux the arc shrinker may be called for synchronous (direct) | |
2287 | * reclaim, or asynchronous (indirect) reclaim. When called by kswapd | |
2288 | * for indirect reclaim we take a conservative approach and just reap | |
2289 | * free slabs from the ARC caches. If this proves to be insufficient | |
2290 | * direct reclaim will be trigger. In direct reclaim a more aggressive | |
2291 | * strategy is used, data is evicted from the ARC and free slabs reaped. | |
2292 | */ | |
7e7baeca BB |
2293 | static int |
2294 | __arc_shrinker_func(struct shrinker *shrink, struct shrink_control *sc) | |
7cb67b45 BB |
2295 | { |
2296 | arc_reclaim_strategy_t strategy; | |
2297 | int arc_reclaim; | |
2298 | ||
7cb67b45 | 2299 | /* Return number of reclaimable pages based on arc_shrink_shift */ |
3fd70ee6 BB |
2300 | arc_reclaim = MAX(btop(((int64_t)arc_size - (int64_t)arc_c_min)) |
2301 | >> arc_shrink_shift, 0); | |
7e7baeca | 2302 | if (sc->nr_to_scan == 0) |
7cb67b45 BB |
2303 | return (arc_reclaim); |
2304 | ||
3fd70ee6 BB |
2305 | /* Prevent reclaim below arc_c_min */ |
2306 | if (arc_reclaim <= 0) | |
2307 | return (-1); | |
2308 | ||
2309 | /* Not allowed to perform filesystem reclaim */ | |
7e7baeca | 2310 | if (!(sc->gfp_mask & __GFP_FS)) |
3fd70ee6 BB |
2311 | return (-1); |
2312 | ||
7cb67b45 BB |
2313 | /* Reclaim in progress */ |
2314 | if (mutex_tryenter(&arc_reclaim_thr_lock) == 0) | |
2315 | return (-1); | |
2316 | ||
2317 | if (current_is_kswapd()) { | |
2318 | strategy = ARC_RECLAIM_CONS; | |
2319 | ARCSTAT_INCR(arcstat_memory_indirect_count, 1); | |
2320 | } else { | |
2321 | strategy = ARC_RECLAIM_AGGR; | |
2322 | ARCSTAT_INCR(arcstat_memory_direct_count, 1); | |
2323 | } | |
2324 | ||
2325 | arc_kmem_reap_now(strategy); | |
3fd70ee6 BB |
2326 | arc_reclaim = MAX(btop(((int64_t)arc_size - (int64_t)arc_c_min)) |
2327 | >> arc_shrink_shift, 0); | |
7cb67b45 BB |
2328 | mutex_exit(&arc_reclaim_thr_lock); |
2329 | ||
2330 | return (arc_reclaim); | |
2331 | } | |
7e7baeca | 2332 | SPL_SHRINKER_CALLBACK_WRAPPER(arc_shrinker_func); |
7cb67b45 BB |
2333 | |
2334 | SPL_SHRINKER_DECLARE(arc_shrinker, arc_shrinker_func, DEFAULT_SEEKS); | |
2335 | #endif /* _KERNEL */ | |
2336 | ||
34dc7c2f BB |
2337 | /* |
2338 | * Adapt arc info given the number of bytes we are trying to add and | |
2339 | * the state that we are comming from. This function is only called | |
2340 | * when we are adding new content to the cache. | |
2341 | */ | |
2342 | static void | |
2343 | arc_adapt(int bytes, arc_state_t *state) | |
2344 | { | |
2345 | int mult; | |
d164b209 | 2346 | uint64_t arc_p_min = (arc_c >> arc_p_min_shift); |
34dc7c2f BB |
2347 | |
2348 | if (state == arc_l2c_only) | |
2349 | return; | |
2350 | ||
2351 | ASSERT(bytes > 0); | |
2352 | /* | |
2353 | * Adapt the target size of the MRU list: | |
2354 | * - if we just hit in the MRU ghost list, then increase | |
2355 | * the target size of the MRU list. | |
2356 | * - if we just hit in the MFU ghost list, then increase | |
2357 | * the target size of the MFU list by decreasing the | |
2358 | * target size of the MRU list. | |
2359 | */ | |
2360 | if (state == arc_mru_ghost) { | |
2361 | mult = ((arc_mru_ghost->arcs_size >= arc_mfu_ghost->arcs_size) ? | |
2362 | 1 : (arc_mfu_ghost->arcs_size/arc_mru_ghost->arcs_size)); | |
572e2857 | 2363 | mult = MIN(mult, 10); /* avoid wild arc_p adjustment */ |
34dc7c2f | 2364 | |
d164b209 | 2365 | arc_p = MIN(arc_c - arc_p_min, arc_p + bytes * mult); |
34dc7c2f | 2366 | } else if (state == arc_mfu_ghost) { |
d164b209 BB |
2367 | uint64_t delta; |
2368 | ||
34dc7c2f BB |
2369 | mult = ((arc_mfu_ghost->arcs_size >= arc_mru_ghost->arcs_size) ? |
2370 | 1 : (arc_mru_ghost->arcs_size/arc_mfu_ghost->arcs_size)); | |
572e2857 | 2371 | mult = MIN(mult, 10); |
34dc7c2f | 2372 | |
d164b209 BB |
2373 | delta = MIN(bytes * mult, arc_p); |
2374 | arc_p = MAX(arc_p_min, arc_p - delta); | |
34dc7c2f BB |
2375 | } |
2376 | ASSERT((int64_t)arc_p >= 0); | |
2377 | ||
2378 | if (arc_reclaim_needed()) { | |
2379 | cv_signal(&arc_reclaim_thr_cv); | |
2380 | return; | |
2381 | } | |
2382 | ||
2383 | if (arc_no_grow) | |
2384 | return; | |
2385 | ||
2386 | if (arc_c >= arc_c_max) | |
2387 | return; | |
2388 | ||
2389 | /* | |
2390 | * If we're within (2 * maxblocksize) bytes of the target | |
2391 | * cache size, increment the target cache size | |
2392 | */ | |
2393 | if (arc_size > arc_c - (2ULL << SPA_MAXBLOCKSHIFT)) { | |
2394 | atomic_add_64(&arc_c, (int64_t)bytes); | |
2395 | if (arc_c > arc_c_max) | |
2396 | arc_c = arc_c_max; | |
2397 | else if (state == arc_anon) | |
2398 | atomic_add_64(&arc_p, (int64_t)bytes); | |
2399 | if (arc_p > arc_c) | |
2400 | arc_p = arc_c; | |
2401 | } | |
2402 | ASSERT((int64_t)arc_p >= 0); | |
2403 | } | |
2404 | ||
2405 | /* | |
2406 | * Check if the cache has reached its limits and eviction is required | |
2407 | * prior to insert. | |
2408 | */ | |
2409 | static int | |
2410 | arc_evict_needed(arc_buf_contents_t type) | |
2411 | { | |
2412 | if (type == ARC_BUFC_METADATA && arc_meta_used >= arc_meta_limit) | |
2413 | return (1); | |
2414 | ||
2415 | #ifdef _KERNEL | |
2416 | /* | |
2417 | * If zio data pages are being allocated out of a separate heap segment, | |
2418 | * then enforce that the size of available vmem for this area remains | |
2419 | * above about 1/32nd free. | |
2420 | */ | |
2421 | if (type == ARC_BUFC_DATA && zio_arena != NULL && | |
2422 | vmem_size(zio_arena, VMEM_FREE) < | |
2423 | (vmem_size(zio_arena, VMEM_ALLOC) >> 5)) | |
2424 | return (1); | |
2425 | #endif | |
2426 | ||
2427 | if (arc_reclaim_needed()) | |
2428 | return (1); | |
2429 | ||
2430 | return (arc_size > arc_c); | |
2431 | } | |
2432 | ||
2433 | /* | |
2434 | * The buffer, supplied as the first argument, needs a data block. | |
2435 | * So, if we are at cache max, determine which cache should be victimized. | |
2436 | * We have the following cases: | |
2437 | * | |
2438 | * 1. Insert for MRU, p > sizeof(arc_anon + arc_mru) -> | |
2439 | * In this situation if we're out of space, but the resident size of the MFU is | |
2440 | * under the limit, victimize the MFU cache to satisfy this insertion request. | |
2441 | * | |
2442 | * 2. Insert for MRU, p <= sizeof(arc_anon + arc_mru) -> | |
2443 | * Here, we've used up all of the available space for the MRU, so we need to | |
2444 | * evict from our own cache instead. Evict from the set of resident MRU | |
2445 | * entries. | |
2446 | * | |
2447 | * 3. Insert for MFU (c - p) > sizeof(arc_mfu) -> | |
2448 | * c minus p represents the MFU space in the cache, since p is the size of the | |
2449 | * cache that is dedicated to the MRU. In this situation there's still space on | |
2450 | * the MFU side, so the MRU side needs to be victimized. | |
2451 | * | |
2452 | * 4. Insert for MFU (c - p) < sizeof(arc_mfu) -> | |
2453 | * MFU's resident set is consuming more space than it has been allotted. In | |
2454 | * this situation, we must victimize our own cache, the MFU, for this insertion. | |
2455 | */ | |
2456 | static void | |
2457 | arc_get_data_buf(arc_buf_t *buf) | |
2458 | { | |
2459 | arc_state_t *state = buf->b_hdr->b_state; | |
2460 | uint64_t size = buf->b_hdr->b_size; | |
2461 | arc_buf_contents_t type = buf->b_hdr->b_type; | |
2462 | ||
2463 | arc_adapt(size, state); | |
2464 | ||
2465 | /* | |
2466 | * We have not yet reached cache maximum size, | |
2467 | * just allocate a new buffer. | |
2468 | */ | |
2469 | if (!arc_evict_needed(type)) { | |
2470 | if (type == ARC_BUFC_METADATA) { | |
2471 | buf->b_data = zio_buf_alloc(size); | |
d164b209 | 2472 | arc_space_consume(size, ARC_SPACE_DATA); |
34dc7c2f BB |
2473 | } else { |
2474 | ASSERT(type == ARC_BUFC_DATA); | |
2475 | buf->b_data = zio_data_buf_alloc(size); | |
d164b209 | 2476 | ARCSTAT_INCR(arcstat_data_size, size); |
34dc7c2f BB |
2477 | atomic_add_64(&arc_size, size); |
2478 | } | |
2479 | goto out; | |
2480 | } | |
2481 | ||
2482 | /* | |
2483 | * If we are prefetching from the mfu ghost list, this buffer | |
2484 | * will end up on the mru list; so steal space from there. | |
2485 | */ | |
2486 | if (state == arc_mfu_ghost) | |
2487 | state = buf->b_hdr->b_flags & ARC_PREFETCH ? arc_mru : arc_mfu; | |
2488 | else if (state == arc_mru_ghost) | |
2489 | state = arc_mru; | |
2490 | ||
2491 | if (state == arc_mru || state == arc_anon) { | |
2492 | uint64_t mru_used = arc_anon->arcs_size + arc_mru->arcs_size; | |
d164b209 | 2493 | state = (arc_mfu->arcs_lsize[type] >= size && |
34dc7c2f BB |
2494 | arc_p > mru_used) ? arc_mfu : arc_mru; |
2495 | } else { | |
2496 | /* MFU cases */ | |
2497 | uint64_t mfu_space = arc_c - arc_p; | |
d164b209 | 2498 | state = (arc_mru->arcs_lsize[type] >= size && |
34dc7c2f BB |
2499 | mfu_space > arc_mfu->arcs_size) ? arc_mru : arc_mfu; |
2500 | } | |
ab26409d | 2501 | |
b8864a23 | 2502 | if ((buf->b_data = arc_evict(state, 0, size, TRUE, type)) == NULL) { |
34dc7c2f BB |
2503 | if (type == ARC_BUFC_METADATA) { |
2504 | buf->b_data = zio_buf_alloc(size); | |
d164b209 | 2505 | arc_space_consume(size, ARC_SPACE_DATA); |
ab26409d BB |
2506 | |
2507 | /* | |
2508 | * If we are unable to recycle an existing meta buffer | |
2509 | * signal the reclaim thread. It will notify users | |
2510 | * via the prune callback to drop references. The | |
2511 | * prune callback in run in the context of the reclaim | |
2512 | * thread to avoid deadlocking on the hash_lock. | |
2513 | */ | |
2514 | cv_signal(&arc_reclaim_thr_cv); | |
34dc7c2f BB |
2515 | } else { |
2516 | ASSERT(type == ARC_BUFC_DATA); | |
2517 | buf->b_data = zio_data_buf_alloc(size); | |
d164b209 | 2518 | ARCSTAT_INCR(arcstat_data_size, size); |
34dc7c2f BB |
2519 | atomic_add_64(&arc_size, size); |
2520 | } | |
ab26409d | 2521 | |
34dc7c2f BB |
2522 | ARCSTAT_BUMP(arcstat_recycle_miss); |
2523 | } | |
2524 | ASSERT(buf->b_data != NULL); | |
2525 | out: | |
2526 | /* | |
2527 | * Update the state size. Note that ghost states have a | |
2528 | * "ghost size" and so don't need to be updated. | |
2529 | */ | |
2530 | if (!GHOST_STATE(buf->b_hdr->b_state)) { | |
2531 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
2532 | ||
2533 | atomic_add_64(&hdr->b_state->arcs_size, size); | |
2534 | if (list_link_active(&hdr->b_arc_node)) { | |
2535 | ASSERT(refcount_is_zero(&hdr->b_refcnt)); | |
2536 | atomic_add_64(&hdr->b_state->arcs_lsize[type], size); | |
2537 | } | |
2538 | /* | |
2539 | * If we are growing the cache, and we are adding anonymous | |
2540 | * data, and we have outgrown arc_p, update arc_p | |
2541 | */ | |
2542 | if (arc_size < arc_c && hdr->b_state == arc_anon && | |
2543 | arc_anon->arcs_size + arc_mru->arcs_size > arc_p) | |
2544 | arc_p = MIN(arc_c, arc_p + size); | |
2545 | } | |
2546 | } | |
2547 | ||
2548 | /* | |
2549 | * This routine is called whenever a buffer is accessed. | |
2550 | * NOTE: the hash lock is dropped in this function. | |
2551 | */ | |
2552 | static void | |
2553 | arc_access(arc_buf_hdr_t *buf, kmutex_t *hash_lock) | |
2554 | { | |
428870ff BB |
2555 | clock_t now; |
2556 | ||
34dc7c2f BB |
2557 | ASSERT(MUTEX_HELD(hash_lock)); |
2558 | ||
2559 | if (buf->b_state == arc_anon) { | |
2560 | /* | |
2561 | * This buffer is not in the cache, and does not | |
2562 | * appear in our "ghost" list. Add the new buffer | |
2563 | * to the MRU state. | |
2564 | */ | |
2565 | ||
2566 | ASSERT(buf->b_arc_access == 0); | |
428870ff | 2567 | buf->b_arc_access = ddi_get_lbolt(); |
34dc7c2f BB |
2568 | DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, buf); |
2569 | arc_change_state(arc_mru, buf, hash_lock); | |
2570 | ||
2571 | } else if (buf->b_state == arc_mru) { | |
428870ff BB |
2572 | now = ddi_get_lbolt(); |
2573 | ||
34dc7c2f BB |
2574 | /* |
2575 | * If this buffer is here because of a prefetch, then either: | |
2576 | * - clear the flag if this is a "referencing" read | |
2577 | * (any subsequent access will bump this into the MFU state). | |
2578 | * or | |
2579 | * - move the buffer to the head of the list if this is | |
2580 | * another prefetch (to make it less likely to be evicted). | |
2581 | */ | |
2582 | if ((buf->b_flags & ARC_PREFETCH) != 0) { | |
2583 | if (refcount_count(&buf->b_refcnt) == 0) { | |
2584 | ASSERT(list_link_active(&buf->b_arc_node)); | |
2585 | } else { | |
2586 | buf->b_flags &= ~ARC_PREFETCH; | |
2587 | ARCSTAT_BUMP(arcstat_mru_hits); | |
2588 | } | |
428870ff | 2589 | buf->b_arc_access = now; |
34dc7c2f BB |
2590 | return; |
2591 | } | |
2592 | ||
2593 | /* | |
2594 | * This buffer has been "accessed" only once so far, | |
2595 | * but it is still in the cache. Move it to the MFU | |
2596 | * state. | |
2597 | */ | |
428870ff | 2598 | if (now > buf->b_arc_access + ARC_MINTIME) { |
34dc7c2f BB |
2599 | /* |
2600 | * More than 125ms have passed since we | |
2601 | * instantiated this buffer. Move it to the | |
2602 | * most frequently used state. | |
2603 | */ | |
428870ff | 2604 | buf->b_arc_access = now; |
34dc7c2f BB |
2605 | DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); |
2606 | arc_change_state(arc_mfu, buf, hash_lock); | |
2607 | } | |
2608 | ARCSTAT_BUMP(arcstat_mru_hits); | |
2609 | } else if (buf->b_state == arc_mru_ghost) { | |
2610 | arc_state_t *new_state; | |
2611 | /* | |
2612 | * This buffer has been "accessed" recently, but | |
2613 | * was evicted from the cache. Move it to the | |
2614 | * MFU state. | |
2615 | */ | |
2616 | ||
2617 | if (buf->b_flags & ARC_PREFETCH) { | |
2618 | new_state = arc_mru; | |
2619 | if (refcount_count(&buf->b_refcnt) > 0) | |
2620 | buf->b_flags &= ~ARC_PREFETCH; | |
2621 | DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, buf); | |
2622 | } else { | |
2623 | new_state = arc_mfu; | |
2624 | DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); | |
2625 | } | |
2626 | ||
428870ff | 2627 | buf->b_arc_access = ddi_get_lbolt(); |
34dc7c2f BB |
2628 | arc_change_state(new_state, buf, hash_lock); |
2629 | ||
2630 | ARCSTAT_BUMP(arcstat_mru_ghost_hits); | |
2631 | } else if (buf->b_state == arc_mfu) { | |
2632 | /* | |
2633 | * This buffer has been accessed more than once and is | |
2634 | * still in the cache. Keep it in the MFU state. | |
2635 | * | |
2636 | * NOTE: an add_reference() that occurred when we did | |
2637 | * the arc_read() will have kicked this off the list. | |
2638 | * If it was a prefetch, we will explicitly move it to | |
2639 | * the head of the list now. | |
2640 | */ | |
2641 | if ((buf->b_flags & ARC_PREFETCH) != 0) { | |
2642 | ASSERT(refcount_count(&buf->b_refcnt) == 0); | |
2643 | ASSERT(list_link_active(&buf->b_arc_node)); | |
2644 | } | |
2645 | ARCSTAT_BUMP(arcstat_mfu_hits); | |
428870ff | 2646 | buf->b_arc_access = ddi_get_lbolt(); |
34dc7c2f BB |
2647 | } else if (buf->b_state == arc_mfu_ghost) { |
2648 | arc_state_t *new_state = arc_mfu; | |
2649 | /* | |
2650 | * This buffer has been accessed more than once but has | |
2651 | * been evicted from the cache. Move it back to the | |
2652 | * MFU state. | |
2653 | */ | |
2654 | ||
2655 | if (buf->b_flags & ARC_PREFETCH) { | |
2656 | /* | |
2657 | * This is a prefetch access... | |
2658 | * move this block back to the MRU state. | |
2659 | */ | |
2660 | ASSERT3U(refcount_count(&buf->b_refcnt), ==, 0); | |
2661 | new_state = arc_mru; | |
2662 | } | |
2663 | ||
428870ff | 2664 | buf->b_arc_access = ddi_get_lbolt(); |
34dc7c2f BB |
2665 | DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); |
2666 | arc_change_state(new_state, buf, hash_lock); | |
2667 | ||
2668 | ARCSTAT_BUMP(arcstat_mfu_ghost_hits); | |
2669 | } else if (buf->b_state == arc_l2c_only) { | |
2670 | /* | |
2671 | * This buffer is on the 2nd Level ARC. | |
2672 | */ | |
2673 | ||
428870ff | 2674 | buf->b_arc_access = ddi_get_lbolt(); |
34dc7c2f BB |
2675 | DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); |
2676 | arc_change_state(arc_mfu, buf, hash_lock); | |
2677 | } else { | |
2678 | ASSERT(!"invalid arc state"); | |
2679 | } | |
2680 | } | |
2681 | ||
2682 | /* a generic arc_done_func_t which you can use */ | |
2683 | /* ARGSUSED */ | |
2684 | void | |
2685 | arc_bcopy_func(zio_t *zio, arc_buf_t *buf, void *arg) | |
2686 | { | |
428870ff BB |
2687 | if (zio == NULL || zio->io_error == 0) |
2688 | bcopy(buf->b_data, arg, buf->b_hdr->b_size); | |
34dc7c2f BB |
2689 | VERIFY(arc_buf_remove_ref(buf, arg) == 1); |
2690 | } | |
2691 | ||
2692 | /* a generic arc_done_func_t */ | |
2693 | void | |
2694 | arc_getbuf_func(zio_t *zio, arc_buf_t *buf, void *arg) | |
2695 | { | |
2696 | arc_buf_t **bufp = arg; | |
2697 | if (zio && zio->io_error) { | |
2698 | VERIFY(arc_buf_remove_ref(buf, arg) == 1); | |
2699 | *bufp = NULL; | |
2700 | } else { | |
2701 | *bufp = buf; | |
428870ff | 2702 | ASSERT(buf->b_data); |
34dc7c2f BB |
2703 | } |
2704 | } | |
2705 | ||
2706 | static void | |
2707 | arc_read_done(zio_t *zio) | |
2708 | { | |
2709 | arc_buf_hdr_t *hdr, *found; | |
2710 | arc_buf_t *buf; | |
2711 | arc_buf_t *abuf; /* buffer we're assigning to callback */ | |
2712 | kmutex_t *hash_lock; | |
2713 | arc_callback_t *callback_list, *acb; | |
2714 | int freeable = FALSE; | |
2715 | ||
2716 | buf = zio->io_private; | |
2717 | hdr = buf->b_hdr; | |
2718 | ||
2719 | /* | |
2720 | * The hdr was inserted into hash-table and removed from lists | |
2721 | * prior to starting I/O. We should find this header, since | |
2722 | * it's in the hash table, and it should be legit since it's | |
2723 | * not possible to evict it during the I/O. The only possible | |
2724 | * reason for it not to be found is if we were freed during the | |
2725 | * read. | |
2726 | */ | |
d164b209 | 2727 | found = buf_hash_find(hdr->b_spa, &hdr->b_dva, hdr->b_birth, |
34dc7c2f BB |
2728 | &hash_lock); |
2729 | ||
2730 | ASSERT((found == NULL && HDR_FREED_IN_READ(hdr) && hash_lock == NULL) || | |
2731 | (found == hdr && DVA_EQUAL(&hdr->b_dva, BP_IDENTITY(zio->io_bp))) || | |
2732 | (found == hdr && HDR_L2_READING(hdr))); | |
2733 | ||
b128c09f | 2734 | hdr->b_flags &= ~ARC_L2_EVICTED; |
34dc7c2f | 2735 | if (l2arc_noprefetch && (hdr->b_flags & ARC_PREFETCH)) |
b128c09f | 2736 | hdr->b_flags &= ~ARC_L2CACHE; |
34dc7c2f BB |
2737 | |
2738 | /* byteswap if necessary */ | |
2739 | callback_list = hdr->b_acb; | |
2740 | ASSERT(callback_list != NULL); | |
428870ff | 2741 | if (BP_SHOULD_BYTESWAP(zio->io_bp) && zio->io_error == 0) { |
b128c09f BB |
2742 | arc_byteswap_func_t *func = BP_GET_LEVEL(zio->io_bp) > 0 ? |
2743 | byteswap_uint64_array : | |
2744 | dmu_ot[BP_GET_TYPE(zio->io_bp)].ot_byteswap; | |
2745 | func(buf->b_data, hdr->b_size); | |
2746 | } | |
34dc7c2f BB |
2747 | |
2748 | arc_cksum_compute(buf, B_FALSE); | |
2749 | ||
428870ff BB |
2750 | if (hash_lock && zio->io_error == 0 && hdr->b_state == arc_anon) { |
2751 | /* | |
2752 | * Only call arc_access on anonymous buffers. This is because | |
2753 | * if we've issued an I/O for an evicted buffer, we've already | |
2754 | * called arc_access (to prevent any simultaneous readers from | |
2755 | * getting confused). | |
2756 | */ | |
2757 | arc_access(hdr, hash_lock); | |
2758 | } | |
2759 | ||
34dc7c2f BB |
2760 | /* create copies of the data buffer for the callers */ |
2761 | abuf = buf; | |
2762 | for (acb = callback_list; acb; acb = acb->acb_next) { | |
2763 | if (acb->acb_done) { | |
2764 | if (abuf == NULL) | |
2765 | abuf = arc_buf_clone(buf); | |
2766 | acb->acb_buf = abuf; | |
2767 | abuf = NULL; | |
2768 | } | |
2769 | } | |
2770 | hdr->b_acb = NULL; | |
2771 | hdr->b_flags &= ~ARC_IO_IN_PROGRESS; | |
2772 | ASSERT(!HDR_BUF_AVAILABLE(hdr)); | |
428870ff BB |
2773 | if (abuf == buf) { |
2774 | ASSERT(buf->b_efunc == NULL); | |
2775 | ASSERT(hdr->b_datacnt == 1); | |
34dc7c2f | 2776 | hdr->b_flags |= ARC_BUF_AVAILABLE; |
428870ff | 2777 | } |
34dc7c2f BB |
2778 | |
2779 | ASSERT(refcount_is_zero(&hdr->b_refcnt) || callback_list != NULL); | |
2780 | ||
2781 | if (zio->io_error != 0) { | |
2782 | hdr->b_flags |= ARC_IO_ERROR; | |
2783 | if (hdr->b_state != arc_anon) | |
2784 | arc_change_state(arc_anon, hdr, hash_lock); | |
2785 | if (HDR_IN_HASH_TABLE(hdr)) | |
2786 | buf_hash_remove(hdr); | |
2787 | freeable = refcount_is_zero(&hdr->b_refcnt); | |
34dc7c2f BB |
2788 | } |
2789 | ||
2790 | /* | |
2791 | * Broadcast before we drop the hash_lock to avoid the possibility | |
2792 | * that the hdr (and hence the cv) might be freed before we get to | |
2793 | * the cv_broadcast(). | |
2794 | */ | |
2795 | cv_broadcast(&hdr->b_cv); | |
2796 | ||
2797 | if (hash_lock) { | |
34dc7c2f BB |
2798 | mutex_exit(hash_lock); |
2799 | } else { | |
2800 | /* | |
2801 | * This block was freed while we waited for the read to | |
2802 | * complete. It has been removed from the hash table and | |
2803 | * moved to the anonymous state (so that it won't show up | |
2804 | * in the cache). | |
2805 | */ | |
2806 | ASSERT3P(hdr->b_state, ==, arc_anon); | |
2807 | freeable = refcount_is_zero(&hdr->b_refcnt); | |
2808 | } | |
2809 | ||
2810 | /* execute each callback and free its structure */ | |
2811 | while ((acb = callback_list) != NULL) { | |
2812 | if (acb->acb_done) | |
2813 | acb->acb_done(zio, acb->acb_buf, acb->acb_private); | |
2814 | ||
2815 | if (acb->acb_zio_dummy != NULL) { | |
2816 | acb->acb_zio_dummy->io_error = zio->io_error; | |
2817 | zio_nowait(acb->acb_zio_dummy); | |
2818 | } | |
2819 | ||
2820 | callback_list = acb->acb_next; | |
2821 | kmem_free(acb, sizeof (arc_callback_t)); | |
2822 | } | |
2823 | ||
2824 | if (freeable) | |
2825 | arc_hdr_destroy(hdr); | |
2826 | } | |
2827 | ||
2828 | /* | |
2829 | * "Read" the block block at the specified DVA (in bp) via the | |
2830 | * cache. If the block is found in the cache, invoke the provided | |
2831 | * callback immediately and return. Note that the `zio' parameter | |
2832 | * in the callback will be NULL in this case, since no IO was | |
2833 | * required. If the block is not in the cache pass the read request | |
2834 | * on to the spa with a substitute callback function, so that the | |
2835 | * requested block will be added to the cache. | |
2836 | * | |
2837 | * If a read request arrives for a block that has a read in-progress, | |
2838 | * either wait for the in-progress read to complete (and return the | |
2839 | * results); or, if this is a read with a "done" func, add a record | |
2840 | * to the read to invoke the "done" func when the read completes, | |
2841 | * and return; or just return. | |
2842 | * | |
2843 | * arc_read_done() will invoke all the requested "done" functions | |
2844 | * for readers of this block. | |
b128c09f BB |
2845 | * |
2846 | * Normal callers should use arc_read and pass the arc buffer and offset | |
2847 | * for the bp. But if you know you don't need locking, you can use | |
2848 | * arc_read_bp. | |
34dc7c2f BB |
2849 | */ |
2850 | int | |
428870ff | 2851 | arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp, arc_buf_t *pbuf, |
b128c09f BB |
2852 | arc_done_func_t *done, void *private, int priority, int zio_flags, |
2853 | uint32_t *arc_flags, const zbookmark_t *zb) | |
2854 | { | |
2855 | int err; | |
b128c09f | 2856 | |
428870ff BB |
2857 | if (pbuf == NULL) { |
2858 | /* | |
2859 | * XXX This happens from traverse callback funcs, for | |
2860 | * the objset_phys_t block. | |
2861 | */ | |
2862 | return (arc_read_nolock(pio, spa, bp, done, private, priority, | |
2863 | zio_flags, arc_flags, zb)); | |
2864 | } | |
2865 | ||
b128c09f BB |
2866 | ASSERT(!refcount_is_zero(&pbuf->b_hdr->b_refcnt)); |
2867 | ASSERT3U((char *)bp - (char *)pbuf->b_data, <, pbuf->b_hdr->b_size); | |
428870ff | 2868 | rw_enter(&pbuf->b_data_lock, RW_READER); |
b128c09f BB |
2869 | |
2870 | err = arc_read_nolock(pio, spa, bp, done, private, priority, | |
2871 | zio_flags, arc_flags, zb); | |
428870ff | 2872 | rw_exit(&pbuf->b_data_lock); |
9babb374 | 2873 | |
b128c09f BB |
2874 | return (err); |
2875 | } | |
2876 | ||
2877 | int | |
428870ff | 2878 | arc_read_nolock(zio_t *pio, spa_t *spa, const blkptr_t *bp, |
b128c09f BB |
2879 | arc_done_func_t *done, void *private, int priority, int zio_flags, |
2880 | uint32_t *arc_flags, const zbookmark_t *zb) | |
34dc7c2f BB |
2881 | { |
2882 | arc_buf_hdr_t *hdr; | |
d4ed6673 | 2883 | arc_buf_t *buf = NULL; |
34dc7c2f BB |
2884 | kmutex_t *hash_lock; |
2885 | zio_t *rzio; | |
d164b209 | 2886 | uint64_t guid = spa_guid(spa); |
34dc7c2f BB |
2887 | |
2888 | top: | |
428870ff BB |
2889 | hdr = buf_hash_find(guid, BP_IDENTITY(bp), BP_PHYSICAL_BIRTH(bp), |
2890 | &hash_lock); | |
34dc7c2f BB |
2891 | if (hdr && hdr->b_datacnt > 0) { |
2892 | ||
2893 | *arc_flags |= ARC_CACHED; | |
2894 | ||
2895 | if (HDR_IO_IN_PROGRESS(hdr)) { | |
2896 | ||
2897 | if (*arc_flags & ARC_WAIT) { | |
2898 | cv_wait(&hdr->b_cv, hash_lock); | |
2899 | mutex_exit(hash_lock); | |
2900 | goto top; | |
2901 | } | |
2902 | ASSERT(*arc_flags & ARC_NOWAIT); | |
2903 | ||
2904 | if (done) { | |
2905 | arc_callback_t *acb = NULL; | |
2906 | ||
2907 | acb = kmem_zalloc(sizeof (arc_callback_t), | |
691f6ac4 | 2908 | KM_PUSHPAGE); |
34dc7c2f BB |
2909 | acb->acb_done = done; |
2910 | acb->acb_private = private; | |
34dc7c2f BB |
2911 | if (pio != NULL) |
2912 | acb->acb_zio_dummy = zio_null(pio, | |
d164b209 | 2913 | spa, NULL, NULL, NULL, zio_flags); |
34dc7c2f BB |
2914 | |
2915 | ASSERT(acb->acb_done != NULL); | |
2916 | acb->acb_next = hdr->b_acb; | |
2917 | hdr->b_acb = acb; | |
2918 | add_reference(hdr, hash_lock, private); | |
2919 | mutex_exit(hash_lock); | |
2920 | return (0); | |
2921 | } | |
2922 | mutex_exit(hash_lock); | |
2923 | return (0); | |
2924 | } | |
2925 | ||
2926 | ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); | |
2927 | ||
2928 | if (done) { | |
2929 | add_reference(hdr, hash_lock, private); | |
2930 | /* | |
2931 | * If this block is already in use, create a new | |
2932 | * copy of the data so that we will be guaranteed | |
2933 | * that arc_release() will always succeed. | |
2934 | */ | |
2935 | buf = hdr->b_buf; | |
2936 | ASSERT(buf); | |
2937 | ASSERT(buf->b_data); | |
2938 | if (HDR_BUF_AVAILABLE(hdr)) { | |
2939 | ASSERT(buf->b_efunc == NULL); | |
2940 | hdr->b_flags &= ~ARC_BUF_AVAILABLE; | |
2941 | } else { | |
2942 | buf = arc_buf_clone(buf); | |
2943 | } | |
428870ff | 2944 | |
34dc7c2f BB |
2945 | } else if (*arc_flags & ARC_PREFETCH && |
2946 | refcount_count(&hdr->b_refcnt) == 0) { | |
2947 | hdr->b_flags |= ARC_PREFETCH; | |
2948 | } | |
2949 | DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr); | |
2950 | arc_access(hdr, hash_lock); | |
b128c09f BB |
2951 | if (*arc_flags & ARC_L2CACHE) |
2952 | hdr->b_flags |= ARC_L2CACHE; | |
34dc7c2f BB |
2953 | mutex_exit(hash_lock); |
2954 | ARCSTAT_BUMP(arcstat_hits); | |
2955 | ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), | |
2956 | demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, | |
2957 | data, metadata, hits); | |
2958 | ||
2959 | if (done) | |
2960 | done(NULL, buf, private); | |
2961 | } else { | |
2962 | uint64_t size = BP_GET_LSIZE(bp); | |
2963 | arc_callback_t *acb; | |
b128c09f | 2964 | vdev_t *vd = NULL; |
e06be586 | 2965 | uint64_t addr = -1; |
d164b209 | 2966 | boolean_t devw = B_FALSE; |
34dc7c2f BB |
2967 | |
2968 | if (hdr == NULL) { | |
2969 | /* this block is not in the cache */ | |
2970 | arc_buf_hdr_t *exists; | |
2971 | arc_buf_contents_t type = BP_GET_BUFC_TYPE(bp); | |
2972 | buf = arc_buf_alloc(spa, size, private, type); | |
2973 | hdr = buf->b_hdr; | |
2974 | hdr->b_dva = *BP_IDENTITY(bp); | |
428870ff | 2975 | hdr->b_birth = BP_PHYSICAL_BIRTH(bp); |
34dc7c2f BB |
2976 | hdr->b_cksum0 = bp->blk_cksum.zc_word[0]; |
2977 | exists = buf_hash_insert(hdr, &hash_lock); | |
2978 | if (exists) { | |
2979 | /* somebody beat us to the hash insert */ | |
2980 | mutex_exit(hash_lock); | |
428870ff | 2981 | buf_discard_identity(hdr); |
34dc7c2f BB |
2982 | (void) arc_buf_remove_ref(buf, private); |
2983 | goto top; /* restart the IO request */ | |
2984 | } | |
2985 | /* if this is a prefetch, we don't have a reference */ | |
2986 | if (*arc_flags & ARC_PREFETCH) { | |
2987 | (void) remove_reference(hdr, hash_lock, | |
2988 | private); | |
2989 | hdr->b_flags |= ARC_PREFETCH; | |
2990 | } | |
b128c09f BB |
2991 | if (*arc_flags & ARC_L2CACHE) |
2992 | hdr->b_flags |= ARC_L2CACHE; | |
34dc7c2f BB |
2993 | if (BP_GET_LEVEL(bp) > 0) |
2994 | hdr->b_flags |= ARC_INDIRECT; | |
2995 | } else { | |
2996 | /* this block is in the ghost cache */ | |
2997 | ASSERT(GHOST_STATE(hdr->b_state)); | |
2998 | ASSERT(!HDR_IO_IN_PROGRESS(hdr)); | |
2999 | ASSERT3U(refcount_count(&hdr->b_refcnt), ==, 0); | |
3000 | ASSERT(hdr->b_buf == NULL); | |
3001 | ||
3002 | /* if this is a prefetch, we don't have a reference */ | |
3003 | if (*arc_flags & ARC_PREFETCH) | |
3004 | hdr->b_flags |= ARC_PREFETCH; | |
3005 | else | |
3006 | add_reference(hdr, hash_lock, private); | |
b128c09f BB |
3007 | if (*arc_flags & ARC_L2CACHE) |
3008 | hdr->b_flags |= ARC_L2CACHE; | |
34dc7c2f BB |
3009 | buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); |
3010 | buf->b_hdr = hdr; | |
3011 | buf->b_data = NULL; | |
3012 | buf->b_efunc = NULL; | |
3013 | buf->b_private = NULL; | |
3014 | buf->b_next = NULL; | |
3015 | hdr->b_buf = buf; | |
34dc7c2f BB |
3016 | ASSERT(hdr->b_datacnt == 0); |
3017 | hdr->b_datacnt = 1; | |
428870ff BB |
3018 | arc_get_data_buf(buf); |
3019 | arc_access(hdr, hash_lock); | |
34dc7c2f BB |
3020 | } |
3021 | ||
428870ff BB |
3022 | ASSERT(!GHOST_STATE(hdr->b_state)); |
3023 | ||
691f6ac4 | 3024 | acb = kmem_zalloc(sizeof (arc_callback_t), KM_PUSHPAGE); |
34dc7c2f BB |
3025 | acb->acb_done = done; |
3026 | acb->acb_private = private; | |
34dc7c2f BB |
3027 | |
3028 | ASSERT(hdr->b_acb == NULL); | |
3029 | hdr->b_acb = acb; | |
3030 | hdr->b_flags |= ARC_IO_IN_PROGRESS; | |
3031 | ||
b128c09f BB |
3032 | if (HDR_L2CACHE(hdr) && hdr->b_l2hdr != NULL && |
3033 | (vd = hdr->b_l2hdr->b_dev->l2ad_vdev) != NULL) { | |
d164b209 | 3034 | devw = hdr->b_l2hdr->b_dev->l2ad_writing; |
b128c09f BB |
3035 | addr = hdr->b_l2hdr->b_daddr; |
3036 | /* | |
3037 | * Lock out device removal. | |
3038 | */ | |
3039 | if (vdev_is_dead(vd) || | |
3040 | !spa_config_tryenter(spa, SCL_L2ARC, vd, RW_READER)) | |
3041 | vd = NULL; | |
3042 | } | |
3043 | ||
3044 | mutex_exit(hash_lock); | |
3045 | ||
34dc7c2f | 3046 | ASSERT3U(hdr->b_size, ==, size); |
428870ff BB |
3047 | DTRACE_PROBE4(arc__miss, arc_buf_hdr_t *, hdr, blkptr_t *, bp, |
3048 | uint64_t, size, zbookmark_t *, zb); | |
34dc7c2f BB |
3049 | ARCSTAT_BUMP(arcstat_misses); |
3050 | ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), | |
3051 | demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, | |
3052 | data, metadata, misses); | |
3053 | ||
d164b209 | 3054 | if (vd != NULL && l2arc_ndev != 0 && !(l2arc_norw && devw)) { |
34dc7c2f BB |
3055 | /* |
3056 | * Read from the L2ARC if the following are true: | |
b128c09f BB |
3057 | * 1. The L2ARC vdev was previously cached. |
3058 | * 2. This buffer still has L2ARC metadata. | |
3059 | * 3. This buffer isn't currently writing to the L2ARC. | |
3060 | * 4. The L2ARC entry wasn't evicted, which may | |
3061 | * also have invalidated the vdev. | |
d164b209 | 3062 | * 5. This isn't prefetch and l2arc_noprefetch is set. |
34dc7c2f | 3063 | */ |
b128c09f | 3064 | if (hdr->b_l2hdr != NULL && |
d164b209 BB |
3065 | !HDR_L2_WRITING(hdr) && !HDR_L2_EVICTED(hdr) && |
3066 | !(l2arc_noprefetch && HDR_PREFETCH(hdr))) { | |
34dc7c2f BB |
3067 | l2arc_read_callback_t *cb; |
3068 | ||
3069 | DTRACE_PROBE1(l2arc__hit, arc_buf_hdr_t *, hdr); | |
3070 | ARCSTAT_BUMP(arcstat_l2_hits); | |
3071 | ||
34dc7c2f | 3072 | cb = kmem_zalloc(sizeof (l2arc_read_callback_t), |
691f6ac4 | 3073 | KM_PUSHPAGE); |
34dc7c2f BB |
3074 | cb->l2rcb_buf = buf; |
3075 | cb->l2rcb_spa = spa; | |
3076 | cb->l2rcb_bp = *bp; | |
3077 | cb->l2rcb_zb = *zb; | |
b128c09f | 3078 | cb->l2rcb_flags = zio_flags; |
34dc7c2f BB |
3079 | |
3080 | /* | |
b128c09f BB |
3081 | * l2arc read. The SCL_L2ARC lock will be |
3082 | * released by l2arc_read_done(). | |
34dc7c2f BB |
3083 | */ |
3084 | rzio = zio_read_phys(pio, vd, addr, size, | |
3085 | buf->b_data, ZIO_CHECKSUM_OFF, | |
b128c09f BB |
3086 | l2arc_read_done, cb, priority, zio_flags | |
3087 | ZIO_FLAG_DONT_CACHE | ZIO_FLAG_CANFAIL | | |
3088 | ZIO_FLAG_DONT_PROPAGATE | | |
3089 | ZIO_FLAG_DONT_RETRY, B_FALSE); | |
34dc7c2f BB |
3090 | DTRACE_PROBE2(l2arc__read, vdev_t *, vd, |
3091 | zio_t *, rzio); | |
d164b209 | 3092 | ARCSTAT_INCR(arcstat_l2_read_bytes, size); |
34dc7c2f | 3093 | |
b128c09f BB |
3094 | if (*arc_flags & ARC_NOWAIT) { |
3095 | zio_nowait(rzio); | |
3096 | return (0); | |
3097 | } | |
34dc7c2f | 3098 | |
b128c09f BB |
3099 | ASSERT(*arc_flags & ARC_WAIT); |
3100 | if (zio_wait(rzio) == 0) | |
3101 | return (0); | |
3102 | ||
3103 | /* l2arc read error; goto zio_read() */ | |
34dc7c2f BB |
3104 | } else { |
3105 | DTRACE_PROBE1(l2arc__miss, | |
3106 | arc_buf_hdr_t *, hdr); | |
3107 | ARCSTAT_BUMP(arcstat_l2_misses); | |
3108 | if (HDR_L2_WRITING(hdr)) | |
3109 | ARCSTAT_BUMP(arcstat_l2_rw_clash); | |
b128c09f | 3110 | spa_config_exit(spa, SCL_L2ARC, vd); |
34dc7c2f | 3111 | } |
d164b209 BB |
3112 | } else { |
3113 | if (vd != NULL) | |
3114 | spa_config_exit(spa, SCL_L2ARC, vd); | |
3115 | if (l2arc_ndev != 0) { | |
3116 | DTRACE_PROBE1(l2arc__miss, | |
3117 | arc_buf_hdr_t *, hdr); | |
3118 | ARCSTAT_BUMP(arcstat_l2_misses); | |
3119 | } | |
34dc7c2f | 3120 | } |
34dc7c2f BB |
3121 | |
3122 | rzio = zio_read(pio, spa, bp, buf->b_data, size, | |
b128c09f | 3123 | arc_read_done, buf, priority, zio_flags, zb); |
34dc7c2f BB |
3124 | |
3125 | if (*arc_flags & ARC_WAIT) | |
3126 | return (zio_wait(rzio)); | |
3127 | ||
3128 | ASSERT(*arc_flags & ARC_NOWAIT); | |
3129 | zio_nowait(rzio); | |
3130 | } | |
3131 | return (0); | |
3132 | } | |
3133 | ||
ab26409d BB |
3134 | arc_prune_t * |
3135 | arc_add_prune_callback(arc_prune_func_t *func, void *private) | |
3136 | { | |
3137 | arc_prune_t *p; | |
3138 | ||
3139 | p = kmem_alloc(sizeof(*p), KM_SLEEP); | |
3140 | p->p_pfunc = func; | |
3141 | p->p_private = private; | |
3142 | list_link_init(&p->p_node); | |
3143 | refcount_create(&p->p_refcnt); | |
3144 | ||
3145 | mutex_enter(&arc_prune_mtx); | |
3146 | refcount_add(&p->p_refcnt, &arc_prune_list); | |
3147 | list_insert_head(&arc_prune_list, p); | |
3148 | mutex_exit(&arc_prune_mtx); | |
3149 | ||
3150 | return (p); | |
3151 | } | |
3152 | ||
3153 | void | |
3154 | arc_remove_prune_callback(arc_prune_t *p) | |
3155 | { | |
3156 | mutex_enter(&arc_prune_mtx); | |
3157 | list_remove(&arc_prune_list, p); | |
3158 | if (refcount_remove(&p->p_refcnt, &arc_prune_list) == 0) { | |
3159 | refcount_destroy(&p->p_refcnt); | |
3160 | kmem_free(p, sizeof (*p)); | |
3161 | } | |
3162 | mutex_exit(&arc_prune_mtx); | |
3163 | } | |
3164 | ||
34dc7c2f BB |
3165 | void |
3166 | arc_set_callback(arc_buf_t *buf, arc_evict_func_t *func, void *private) | |
3167 | { | |
3168 | ASSERT(buf->b_hdr != NULL); | |
3169 | ASSERT(buf->b_hdr->b_state != arc_anon); | |
3170 | ASSERT(!refcount_is_zero(&buf->b_hdr->b_refcnt) || func == NULL); | |
428870ff BB |
3171 | ASSERT(buf->b_efunc == NULL); |
3172 | ASSERT(!HDR_BUF_AVAILABLE(buf->b_hdr)); | |
3173 | ||
34dc7c2f BB |
3174 | buf->b_efunc = func; |
3175 | buf->b_private = private; | |
3176 | } | |
3177 | ||
3178 | /* | |
3179 | * This is used by the DMU to let the ARC know that a buffer is | |
3180 | * being evicted, so the ARC should clean up. If this arc buf | |
3181 | * is not yet in the evicted state, it will be put there. | |
3182 | */ | |
3183 | int | |
3184 | arc_buf_evict(arc_buf_t *buf) | |
3185 | { | |
3186 | arc_buf_hdr_t *hdr; | |
3187 | kmutex_t *hash_lock; | |
3188 | arc_buf_t **bufp; | |
3189 | ||
428870ff | 3190 | mutex_enter(&buf->b_evict_lock); |
34dc7c2f BB |
3191 | hdr = buf->b_hdr; |
3192 | if (hdr == NULL) { | |
3193 | /* | |
3194 | * We are in arc_do_user_evicts(). | |
3195 | */ | |
3196 | ASSERT(buf->b_data == NULL); | |
428870ff | 3197 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f | 3198 | return (0); |
b128c09f BB |
3199 | } else if (buf->b_data == NULL) { |
3200 | arc_buf_t copy = *buf; /* structure assignment */ | |
34dc7c2f | 3201 | /* |
b128c09f BB |
3202 | * We are on the eviction list; process this buffer now |
3203 | * but let arc_do_user_evicts() do the reaping. | |
34dc7c2f | 3204 | */ |
b128c09f | 3205 | buf->b_efunc = NULL; |
428870ff | 3206 | mutex_exit(&buf->b_evict_lock); |
b128c09f BB |
3207 | VERIFY(copy.b_efunc(©) == 0); |
3208 | return (1); | |
34dc7c2f | 3209 | } |
b128c09f BB |
3210 | hash_lock = HDR_LOCK(hdr); |
3211 | mutex_enter(hash_lock); | |
428870ff BB |
3212 | hdr = buf->b_hdr; |
3213 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
34dc7c2f | 3214 | |
34dc7c2f BB |
3215 | ASSERT3U(refcount_count(&hdr->b_refcnt), <, hdr->b_datacnt); |
3216 | ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); | |
3217 | ||
3218 | /* | |
3219 | * Pull this buffer off of the hdr | |
3220 | */ | |
3221 | bufp = &hdr->b_buf; | |
3222 | while (*bufp != buf) | |
3223 | bufp = &(*bufp)->b_next; | |
3224 | *bufp = buf->b_next; | |
3225 | ||
3226 | ASSERT(buf->b_data != NULL); | |
3227 | arc_buf_destroy(buf, FALSE, FALSE); | |
3228 | ||
3229 | if (hdr->b_datacnt == 0) { | |
3230 | arc_state_t *old_state = hdr->b_state; | |
3231 | arc_state_t *evicted_state; | |
3232 | ||
428870ff | 3233 | ASSERT(hdr->b_buf == NULL); |
34dc7c2f BB |
3234 | ASSERT(refcount_is_zero(&hdr->b_refcnt)); |
3235 | ||
3236 | evicted_state = | |
3237 | (old_state == arc_mru) ? arc_mru_ghost : arc_mfu_ghost; | |
3238 | ||
3239 | mutex_enter(&old_state->arcs_mtx); | |
3240 | mutex_enter(&evicted_state->arcs_mtx); | |
3241 | ||
3242 | arc_change_state(evicted_state, hdr, hash_lock); | |
3243 | ASSERT(HDR_IN_HASH_TABLE(hdr)); | |
3244 | hdr->b_flags |= ARC_IN_HASH_TABLE; | |
3245 | hdr->b_flags &= ~ARC_BUF_AVAILABLE; | |
3246 | ||
3247 | mutex_exit(&evicted_state->arcs_mtx); | |
3248 | mutex_exit(&old_state->arcs_mtx); | |
3249 | } | |
3250 | mutex_exit(hash_lock); | |
428870ff | 3251 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
3252 | |
3253 | VERIFY(buf->b_efunc(buf) == 0); | |
3254 | buf->b_efunc = NULL; | |
3255 | buf->b_private = NULL; | |
3256 | buf->b_hdr = NULL; | |
428870ff | 3257 | buf->b_next = NULL; |
34dc7c2f BB |
3258 | kmem_cache_free(buf_cache, buf); |
3259 | return (1); | |
3260 | } | |
3261 | ||
3262 | /* | |
3263 | * Release this buffer from the cache. This must be done | |
3264 | * after a read and prior to modifying the buffer contents. | |
3265 | * If the buffer has more than one reference, we must make | |
b128c09f | 3266 | * a new hdr for the buffer. |
34dc7c2f BB |
3267 | */ |
3268 | void | |
3269 | arc_release(arc_buf_t *buf, void *tag) | |
3270 | { | |
b128c09f | 3271 | arc_buf_hdr_t *hdr; |
428870ff | 3272 | kmutex_t *hash_lock = NULL; |
b128c09f | 3273 | l2arc_buf_hdr_t *l2hdr; |
d4ed6673 | 3274 | uint64_t buf_size = 0; |
34dc7c2f | 3275 | |
428870ff BB |
3276 | /* |
3277 | * It would be nice to assert that if it's DMU metadata (level > | |
3278 | * 0 || it's the dnode file), then it must be syncing context. | |
3279 | * But we don't know that information at this level. | |
3280 | */ | |
3281 | ||
3282 | mutex_enter(&buf->b_evict_lock); | |
b128c09f BB |
3283 | hdr = buf->b_hdr; |
3284 | ||
34dc7c2f BB |
3285 | /* this buffer is not on any list */ |
3286 | ASSERT(refcount_count(&hdr->b_refcnt) > 0); | |
3287 | ||
3288 | if (hdr->b_state == arc_anon) { | |
3289 | /* this buffer is already released */ | |
34dc7c2f | 3290 | ASSERT(buf->b_efunc == NULL); |
9babb374 BB |
3291 | } else { |
3292 | hash_lock = HDR_LOCK(hdr); | |
3293 | mutex_enter(hash_lock); | |
428870ff BB |
3294 | hdr = buf->b_hdr; |
3295 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
34dc7c2f BB |
3296 | } |
3297 | ||
b128c09f BB |
3298 | l2hdr = hdr->b_l2hdr; |
3299 | if (l2hdr) { | |
3300 | mutex_enter(&l2arc_buflist_mtx); | |
3301 | hdr->b_l2hdr = NULL; | |
3302 | buf_size = hdr->b_size; | |
3303 | } | |
3304 | ||
34dc7c2f BB |
3305 | /* |
3306 | * Do we have more than one buf? | |
3307 | */ | |
b128c09f | 3308 | if (hdr->b_datacnt > 1) { |
34dc7c2f BB |
3309 | arc_buf_hdr_t *nhdr; |
3310 | arc_buf_t **bufp; | |
3311 | uint64_t blksz = hdr->b_size; | |
d164b209 | 3312 | uint64_t spa = hdr->b_spa; |
34dc7c2f BB |
3313 | arc_buf_contents_t type = hdr->b_type; |
3314 | uint32_t flags = hdr->b_flags; | |
3315 | ||
b128c09f | 3316 | ASSERT(hdr->b_buf != buf || buf->b_next != NULL); |
34dc7c2f | 3317 | /* |
428870ff BB |
3318 | * Pull the data off of this hdr and attach it to |
3319 | * a new anonymous hdr. | |
34dc7c2f BB |
3320 | */ |
3321 | (void) remove_reference(hdr, hash_lock, tag); | |
3322 | bufp = &hdr->b_buf; | |
3323 | while (*bufp != buf) | |
3324 | bufp = &(*bufp)->b_next; | |
428870ff | 3325 | *bufp = buf->b_next; |
34dc7c2f BB |
3326 | buf->b_next = NULL; |
3327 | ||
3328 | ASSERT3U(hdr->b_state->arcs_size, >=, hdr->b_size); | |
3329 | atomic_add_64(&hdr->b_state->arcs_size, -hdr->b_size); | |
3330 | if (refcount_is_zero(&hdr->b_refcnt)) { | |
3331 | uint64_t *size = &hdr->b_state->arcs_lsize[hdr->b_type]; | |
3332 | ASSERT3U(*size, >=, hdr->b_size); | |
3333 | atomic_add_64(size, -hdr->b_size); | |
3334 | } | |
3335 | hdr->b_datacnt -= 1; | |
34dc7c2f BB |
3336 | arc_cksum_verify(buf); |
3337 | ||
3338 | mutex_exit(hash_lock); | |
3339 | ||
3340 | nhdr = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); | |
3341 | nhdr->b_size = blksz; | |
3342 | nhdr->b_spa = spa; | |
3343 | nhdr->b_type = type; | |
3344 | nhdr->b_buf = buf; | |
3345 | nhdr->b_state = arc_anon; | |
3346 | nhdr->b_arc_access = 0; | |
3347 | nhdr->b_flags = flags & ARC_L2_WRITING; | |
3348 | nhdr->b_l2hdr = NULL; | |
3349 | nhdr->b_datacnt = 1; | |
3350 | nhdr->b_freeze_cksum = NULL; | |
3351 | (void) refcount_add(&nhdr->b_refcnt, tag); | |
3352 | buf->b_hdr = nhdr; | |
428870ff | 3353 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
3354 | atomic_add_64(&arc_anon->arcs_size, blksz); |
3355 | } else { | |
428870ff | 3356 | mutex_exit(&buf->b_evict_lock); |
34dc7c2f BB |
3357 | ASSERT(refcount_count(&hdr->b_refcnt) == 1); |
3358 | ASSERT(!list_link_active(&hdr->b_arc_node)); | |
3359 | ASSERT(!HDR_IO_IN_PROGRESS(hdr)); | |
428870ff BB |
3360 | if (hdr->b_state != arc_anon) |
3361 | arc_change_state(arc_anon, hdr, hash_lock); | |
34dc7c2f | 3362 | hdr->b_arc_access = 0; |
428870ff BB |
3363 | if (hash_lock) |
3364 | mutex_exit(hash_lock); | |
34dc7c2f | 3365 | |
428870ff | 3366 | buf_discard_identity(hdr); |
34dc7c2f BB |
3367 | arc_buf_thaw(buf); |
3368 | } | |
3369 | buf->b_efunc = NULL; | |
3370 | buf->b_private = NULL; | |
3371 | ||
3372 | if (l2hdr) { | |
3373 | list_remove(l2hdr->b_dev->l2ad_buflist, hdr); | |
3374 | kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t)); | |
3375 | ARCSTAT_INCR(arcstat_l2_size, -buf_size); | |
34dc7c2f | 3376 | mutex_exit(&l2arc_buflist_mtx); |
b128c09f | 3377 | } |
34dc7c2f BB |
3378 | } |
3379 | ||
428870ff BB |
3380 | /* |
3381 | * Release this buffer. If it does not match the provided BP, fill it | |
3382 | * with that block's contents. | |
3383 | */ | |
3384 | /* ARGSUSED */ | |
3385 | int | |
3386 | arc_release_bp(arc_buf_t *buf, void *tag, blkptr_t *bp, spa_t *spa, | |
3387 | zbookmark_t *zb) | |
3388 | { | |
3389 | arc_release(buf, tag); | |
3390 | return (0); | |
3391 | } | |
3392 | ||
34dc7c2f BB |
3393 | int |
3394 | arc_released(arc_buf_t *buf) | |
3395 | { | |
b128c09f BB |
3396 | int released; |
3397 | ||
428870ff | 3398 | mutex_enter(&buf->b_evict_lock); |
b128c09f | 3399 | released = (buf->b_data != NULL && buf->b_hdr->b_state == arc_anon); |
428870ff | 3400 | mutex_exit(&buf->b_evict_lock); |
b128c09f | 3401 | return (released); |
34dc7c2f BB |
3402 | } |
3403 | ||
3404 | int | |
3405 | arc_has_callback(arc_buf_t *buf) | |
3406 | { | |
b128c09f BB |
3407 | int callback; |
3408 | ||
428870ff | 3409 | mutex_enter(&buf->b_evict_lock); |
b128c09f | 3410 | callback = (buf->b_efunc != NULL); |
428870ff | 3411 | mutex_exit(&buf->b_evict_lock); |
b128c09f | 3412 | return (callback); |
34dc7c2f BB |
3413 | } |
3414 | ||
3415 | #ifdef ZFS_DEBUG | |
3416 | int | |
3417 | arc_referenced(arc_buf_t *buf) | |
3418 | { | |
b128c09f BB |
3419 | int referenced; |
3420 | ||
428870ff | 3421 | mutex_enter(&buf->b_evict_lock); |
b128c09f | 3422 | referenced = (refcount_count(&buf->b_hdr->b_refcnt)); |
428870ff | 3423 | mutex_exit(&buf->b_evict_lock); |
b128c09f | 3424 | return (referenced); |
34dc7c2f BB |
3425 | } |
3426 | #endif | |
3427 | ||
3428 | static void | |
3429 | arc_write_ready(zio_t *zio) | |
3430 | { | |
3431 | arc_write_callback_t *callback = zio->io_private; | |
3432 | arc_buf_t *buf = callback->awcb_buf; | |
3433 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
3434 | ||
b128c09f BB |
3435 | ASSERT(!refcount_is_zero(&buf->b_hdr->b_refcnt)); |
3436 | callback->awcb_ready(zio, buf, callback->awcb_private); | |
3437 | ||
34dc7c2f BB |
3438 | /* |
3439 | * If the IO is already in progress, then this is a re-write | |
b128c09f BB |
3440 | * attempt, so we need to thaw and re-compute the cksum. |
3441 | * It is the responsibility of the callback to handle the | |
3442 | * accounting for any re-write attempt. | |
34dc7c2f BB |
3443 | */ |
3444 | if (HDR_IO_IN_PROGRESS(hdr)) { | |
34dc7c2f BB |
3445 | mutex_enter(&hdr->b_freeze_lock); |
3446 | if (hdr->b_freeze_cksum != NULL) { | |
3447 | kmem_free(hdr->b_freeze_cksum, sizeof (zio_cksum_t)); | |
3448 | hdr->b_freeze_cksum = NULL; | |
3449 | } | |
3450 | mutex_exit(&hdr->b_freeze_lock); | |
3451 | } | |
3452 | arc_cksum_compute(buf, B_FALSE); | |
3453 | hdr->b_flags |= ARC_IO_IN_PROGRESS; | |
3454 | } | |
3455 | ||
3456 | static void | |
3457 | arc_write_done(zio_t *zio) | |
3458 | { | |
3459 | arc_write_callback_t *callback = zio->io_private; | |
3460 | arc_buf_t *buf = callback->awcb_buf; | |
3461 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
3462 | ||
428870ff BB |
3463 | ASSERT(hdr->b_acb == NULL); |
3464 | ||
3465 | if (zio->io_error == 0) { | |
3466 | hdr->b_dva = *BP_IDENTITY(zio->io_bp); | |
3467 | hdr->b_birth = BP_PHYSICAL_BIRTH(zio->io_bp); | |
3468 | hdr->b_cksum0 = zio->io_bp->blk_cksum.zc_word[0]; | |
3469 | } else { | |
3470 | ASSERT(BUF_EMPTY(hdr)); | |
3471 | } | |
34dc7c2f | 3472 | |
34dc7c2f BB |
3473 | /* |
3474 | * If the block to be written was all-zero, we may have | |
3475 | * compressed it away. In this case no write was performed | |
428870ff BB |
3476 | * so there will be no dva/birth/checksum. The buffer must |
3477 | * therefore remain anonymous (and uncached). | |
34dc7c2f BB |
3478 | */ |
3479 | if (!BUF_EMPTY(hdr)) { | |
3480 | arc_buf_hdr_t *exists; | |
3481 | kmutex_t *hash_lock; | |
3482 | ||
428870ff BB |
3483 | ASSERT(zio->io_error == 0); |
3484 | ||
34dc7c2f BB |
3485 | arc_cksum_verify(buf); |
3486 | ||
3487 | exists = buf_hash_insert(hdr, &hash_lock); | |
3488 | if (exists) { | |
3489 | /* | |
3490 | * This can only happen if we overwrite for | |
3491 | * sync-to-convergence, because we remove | |
3492 | * buffers from the hash table when we arc_free(). | |
3493 | */ | |
428870ff BB |
3494 | if (zio->io_flags & ZIO_FLAG_IO_REWRITE) { |
3495 | if (!BP_EQUAL(&zio->io_bp_orig, zio->io_bp)) | |
3496 | panic("bad overwrite, hdr=%p exists=%p", | |
3497 | (void *)hdr, (void *)exists); | |
3498 | ASSERT(refcount_is_zero(&exists->b_refcnt)); | |
3499 | arc_change_state(arc_anon, exists, hash_lock); | |
3500 | mutex_exit(hash_lock); | |
3501 | arc_hdr_destroy(exists); | |
3502 | exists = buf_hash_insert(hdr, &hash_lock); | |
3503 | ASSERT3P(exists, ==, NULL); | |
3504 | } else { | |
3505 | /* Dedup */ | |
3506 | ASSERT(hdr->b_datacnt == 1); | |
3507 | ASSERT(hdr->b_state == arc_anon); | |
3508 | ASSERT(BP_GET_DEDUP(zio->io_bp)); | |
3509 | ASSERT(BP_GET_LEVEL(zio->io_bp) == 0); | |
3510 | } | |
34dc7c2f BB |
3511 | } |
3512 | hdr->b_flags &= ~ARC_IO_IN_PROGRESS; | |
b128c09f | 3513 | /* if it's not anon, we are doing a scrub */ |
428870ff | 3514 | if (!exists && hdr->b_state == arc_anon) |
b128c09f | 3515 | arc_access(hdr, hash_lock); |
34dc7c2f | 3516 | mutex_exit(hash_lock); |
34dc7c2f BB |
3517 | } else { |
3518 | hdr->b_flags &= ~ARC_IO_IN_PROGRESS; | |
3519 | } | |
3520 | ||
428870ff BB |
3521 | ASSERT(!refcount_is_zero(&hdr->b_refcnt)); |
3522 | callback->awcb_done(zio, buf, callback->awcb_private); | |
34dc7c2f BB |
3523 | |
3524 | kmem_free(callback, sizeof (arc_write_callback_t)); | |
3525 | } | |
3526 | ||
3527 | zio_t * | |
428870ff BB |
3528 | arc_write(zio_t *pio, spa_t *spa, uint64_t txg, |
3529 | blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, const zio_prop_t *zp, | |
3530 | arc_done_func_t *ready, arc_done_func_t *done, void *private, | |
3531 | int priority, int zio_flags, const zbookmark_t *zb) | |
34dc7c2f BB |
3532 | { |
3533 | arc_buf_hdr_t *hdr = buf->b_hdr; | |
3534 | arc_write_callback_t *callback; | |
b128c09f | 3535 | zio_t *zio; |
34dc7c2f | 3536 | |
b128c09f | 3537 | ASSERT(ready != NULL); |
428870ff | 3538 | ASSERT(done != NULL); |
34dc7c2f BB |
3539 | ASSERT(!HDR_IO_ERROR(hdr)); |
3540 | ASSERT((hdr->b_flags & ARC_IO_IN_PROGRESS) == 0); | |
428870ff | 3541 | ASSERT(hdr->b_acb == NULL); |
b128c09f BB |
3542 | if (l2arc) |
3543 | hdr->b_flags |= ARC_L2CACHE; | |
34dc7c2f BB |
3544 | callback = kmem_zalloc(sizeof (arc_write_callback_t), KM_SLEEP); |
3545 | callback->awcb_ready = ready; | |
3546 | callback->awcb_done = done; | |
3547 | callback->awcb_private = private; | |
3548 | callback->awcb_buf = buf; | |
b128c09f | 3549 | |
428870ff | 3550 | zio = zio_write(pio, spa, txg, bp, buf->b_data, hdr->b_size, zp, |
b128c09f | 3551 | arc_write_ready, arc_write_done, callback, priority, zio_flags, zb); |
34dc7c2f BB |
3552 | |
3553 | return (zio); | |
3554 | } | |
3555 | ||
34dc7c2f | 3556 | static int |
9babb374 | 3557 | arc_memory_throttle(uint64_t reserve, uint64_t inflight_data, uint64_t txg) |
34dc7c2f BB |
3558 | { |
3559 | #ifdef _KERNEL | |
34dc7c2f BB |
3560 | uint64_t available_memory = ptob(freemem); |
3561 | static uint64_t page_load = 0; | |
3562 | static uint64_t last_txg = 0; | |
3563 | ||
3564 | #if defined(__i386) | |
3565 | available_memory = | |
3566 | MIN(available_memory, vmem_size(heap_arena, VMEM_FREE)); | |
3567 | #endif | |
3568 | if (available_memory >= zfs_write_limit_max) | |
3569 | return (0); | |
3570 | ||
3571 | if (txg > last_txg) { | |
3572 | last_txg = txg; | |
3573 | page_load = 0; | |
3574 | } | |
3575 | /* | |
3576 | * If we are in pageout, we know that memory is already tight, | |
3577 | * the arc is already going to be evicting, so we just want to | |
3578 | * continue to let page writes occur as quickly as possible. | |
3579 | */ | |
3580 | if (curproc == proc_pageout) { | |
3581 | if (page_load > MAX(ptob(minfree), available_memory) / 4) | |
3582 | return (ERESTART); | |
3583 | /* Note: reserve is inflated, so we deflate */ | |
3584 | page_load += reserve / 8; | |
3585 | return (0); | |
3586 | } else if (page_load > 0 && arc_reclaim_needed()) { | |
3587 | /* memory is low, delay before restarting */ | |
3588 | ARCSTAT_INCR(arcstat_memory_throttle_count, 1); | |
570827e1 | 3589 | DMU_TX_STAT_BUMP(dmu_tx_memory_reclaim); |
34dc7c2f BB |
3590 | return (EAGAIN); |
3591 | } | |
3592 | page_load = 0; | |
3593 | ||
3594 | if (arc_size > arc_c_min) { | |
3595 | uint64_t evictable_memory = | |
3596 | arc_mru->arcs_lsize[ARC_BUFC_DATA] + | |
3597 | arc_mru->arcs_lsize[ARC_BUFC_METADATA] + | |
3598 | arc_mfu->arcs_lsize[ARC_BUFC_DATA] + | |
3599 | arc_mfu->arcs_lsize[ARC_BUFC_METADATA]; | |
3600 | available_memory += MIN(evictable_memory, arc_size - arc_c_min); | |
3601 | } | |
3602 | ||
3603 | if (inflight_data > available_memory / 4) { | |
3604 | ARCSTAT_INCR(arcstat_memory_throttle_count, 1); | |
570827e1 | 3605 | DMU_TX_STAT_BUMP(dmu_tx_memory_inflight); |
34dc7c2f BB |
3606 | return (ERESTART); |
3607 | } | |
3608 | #endif | |
3609 | return (0); | |
3610 | } | |
3611 | ||
3612 | void | |
3613 | arc_tempreserve_clear(uint64_t reserve) | |
3614 | { | |
3615 | atomic_add_64(&arc_tempreserve, -reserve); | |
3616 | ASSERT((int64_t)arc_tempreserve >= 0); | |
3617 | } | |
3618 | ||
3619 | int | |
3620 | arc_tempreserve_space(uint64_t reserve, uint64_t txg) | |
3621 | { | |
3622 | int error; | |
9babb374 | 3623 | uint64_t anon_size; |
34dc7c2f BB |
3624 | |
3625 | #ifdef ZFS_DEBUG | |
3626 | /* | |
3627 | * Once in a while, fail for no reason. Everything should cope. | |
3628 | */ | |
3629 | if (spa_get_random(10000) == 0) { | |
3630 | dprintf("forcing random failure\n"); | |
3631 | return (ERESTART); | |
3632 | } | |
3633 | #endif | |
3634 | if (reserve > arc_c/4 && !arc_no_grow) | |
3635 | arc_c = MIN(arc_c_max, reserve * 4); | |
570827e1 BB |
3636 | if (reserve > arc_c) { |
3637 | DMU_TX_STAT_BUMP(dmu_tx_memory_reserve); | |
34dc7c2f | 3638 | return (ENOMEM); |
570827e1 | 3639 | } |
34dc7c2f | 3640 | |
9babb374 BB |
3641 | /* |
3642 | * Don't count loaned bufs as in flight dirty data to prevent long | |
3643 | * network delays from blocking transactions that are ready to be | |
3644 | * assigned to a txg. | |
3645 | */ | |
3646 | anon_size = MAX((int64_t)(arc_anon->arcs_size - arc_loaned_bytes), 0); | |
3647 | ||
34dc7c2f BB |
3648 | /* |
3649 | * Writes will, almost always, require additional memory allocations | |
3650 | * in order to compress/encrypt/etc the data. We therefor need to | |
3651 | * make sure that there is sufficient available memory for this. | |
3652 | */ | |
c65aa5b2 | 3653 | if ((error = arc_memory_throttle(reserve, anon_size, txg))) |
34dc7c2f BB |
3654 | return (error); |
3655 | ||
3656 | /* | |
3657 | * Throttle writes when the amount of dirty data in the cache | |
3658 | * gets too large. We try to keep the cache less than half full | |
3659 | * of dirty blocks so that our sync times don't grow too large. | |
3660 | * Note: if two requests come in concurrently, we might let them | |
3661 | * both succeed, when one of them should fail. Not a huge deal. | |
3662 | */ | |
9babb374 BB |
3663 | |
3664 | if (reserve + arc_tempreserve + anon_size > arc_c / 2 && | |
3665 | anon_size > arc_c / 4) { | |
34dc7c2f BB |
3666 | dprintf("failing, arc_tempreserve=%lluK anon_meta=%lluK " |
3667 | "anon_data=%lluK tempreserve=%lluK arc_c=%lluK\n", | |
3668 | arc_tempreserve>>10, | |
3669 | arc_anon->arcs_lsize[ARC_BUFC_METADATA]>>10, | |
3670 | arc_anon->arcs_lsize[ARC_BUFC_DATA]>>10, | |
3671 | reserve>>10, arc_c>>10); | |
570827e1 | 3672 | DMU_TX_STAT_BUMP(dmu_tx_dirty_throttle); |
34dc7c2f BB |
3673 | return (ERESTART); |
3674 | } | |
3675 | atomic_add_64(&arc_tempreserve, reserve); | |
3676 | return (0); | |
3677 | } | |
3678 | ||
13be560d BB |
3679 | static void |
3680 | arc_kstat_update_state(arc_state_t *state, kstat_named_t *size, | |
3681 | kstat_named_t *evict_data, kstat_named_t *evict_metadata) | |
3682 | { | |
3683 | size->value.ui64 = state->arcs_size; | |
3684 | evict_data->value.ui64 = state->arcs_lsize[ARC_BUFC_DATA]; | |
3685 | evict_metadata->value.ui64 = state->arcs_lsize[ARC_BUFC_METADATA]; | |
3686 | } | |
3687 | ||
3688 | static int | |
3689 | arc_kstat_update(kstat_t *ksp, int rw) | |
3690 | { | |
3691 | arc_stats_t *as = ksp->ks_data; | |
3692 | ||
3693 | if (rw == KSTAT_WRITE) { | |
3694 | return (EACCES); | |
3695 | } else { | |
3696 | arc_kstat_update_state(arc_anon, | |
3697 | &as->arcstat_anon_size, | |
3698 | &as->arcstat_anon_evict_data, | |
3699 | &as->arcstat_anon_evict_metadata); | |
3700 | arc_kstat_update_state(arc_mru, | |
3701 | &as->arcstat_mru_size, | |
3702 | &as->arcstat_mru_evict_data, | |
3703 | &as->arcstat_mru_evict_metadata); | |
3704 | arc_kstat_update_state(arc_mru_ghost, | |
3705 | &as->arcstat_mru_ghost_size, | |
3706 | &as->arcstat_mru_ghost_evict_data, | |
3707 | &as->arcstat_mru_ghost_evict_metadata); | |
3708 | arc_kstat_update_state(arc_mfu, | |
3709 | &as->arcstat_mfu_size, | |
3710 | &as->arcstat_mfu_evict_data, | |
3711 | &as->arcstat_mfu_evict_metadata); | |
fc41c640 | 3712 | arc_kstat_update_state(arc_mfu_ghost, |
13be560d BB |
3713 | &as->arcstat_mfu_ghost_size, |
3714 | &as->arcstat_mfu_ghost_evict_data, | |
3715 | &as->arcstat_mfu_ghost_evict_metadata); | |
3716 | } | |
3717 | ||
3718 | return (0); | |
3719 | } | |
3720 | ||
34dc7c2f BB |
3721 | void |
3722 | arc_init(void) | |
3723 | { | |
3724 | mutex_init(&arc_reclaim_thr_lock, NULL, MUTEX_DEFAULT, NULL); | |
3725 | cv_init(&arc_reclaim_thr_cv, NULL, CV_DEFAULT, NULL); | |
3726 | ||
3727 | /* Convert seconds to clock ticks */ | |
3728 | arc_min_prefetch_lifespan = 1 * hz; | |
3729 | ||
3730 | /* Start out with 1/8 of all memory */ | |
3731 | arc_c = physmem * PAGESIZE / 8; | |
3732 | ||
3733 | #ifdef _KERNEL | |
3734 | /* | |
3735 | * On architectures where the physical memory can be larger | |
3736 | * than the addressable space (intel in 32-bit mode), we may | |
3737 | * need to limit the cache to 1/8 of VM size. | |
3738 | */ | |
3739 | arc_c = MIN(arc_c, vmem_size(heap_arena, VMEM_ALLOC | VMEM_FREE) / 8); | |
7cb67b45 BB |
3740 | /* |
3741 | * Register a shrinker to support synchronous (direct) memory | |
3742 | * reclaim from the arc. This is done to prevent kswapd from | |
3743 | * swapping out pages when it is preferable to shrink the arc. | |
3744 | */ | |
3745 | spl_register_shrinker(&arc_shrinker); | |
34dc7c2f BB |
3746 | #endif |
3747 | ||
3748 | /* set min cache to 1/32 of all memory, or 64MB, whichever is more */ | |
3749 | arc_c_min = MAX(arc_c / 4, 64<<20); | |
23bdb07d BB |
3750 | /* set max to 1/2 of all memory, or all but 4GB, whichever is more */ |
3751 | if (arc_c * 8 >= ((uint64_t)4<<30)) | |
3752 | arc_c_max = (arc_c * 8) - ((uint64_t)4<<30); | |
34dc7c2f BB |
3753 | else |
3754 | arc_c_max = arc_c_min; | |
23bdb07d | 3755 | arc_c_max = MAX(arc_c * 4, arc_c_max); |
34dc7c2f BB |
3756 | |
3757 | /* | |
3758 | * Allow the tunables to override our calculations if they are | |
3759 | * reasonable (ie. over 64MB) | |
3760 | */ | |
3761 | if (zfs_arc_max > 64<<20 && zfs_arc_max < physmem * PAGESIZE) | |
3762 | arc_c_max = zfs_arc_max; | |
3763 | if (zfs_arc_min > 64<<20 && zfs_arc_min <= arc_c_max) | |
3764 | arc_c_min = zfs_arc_min; | |
3765 | ||
3766 | arc_c = arc_c_max; | |
3767 | arc_p = (arc_c >> 1); | |
3768 | ||
3769 | /* limit meta-data to 1/4 of the arc capacity */ | |
3770 | arc_meta_limit = arc_c_max / 4; | |
1834f2d8 | 3771 | arc_meta_max = 0; |
34dc7c2f BB |
3772 | |
3773 | /* Allow the tunable to override if it is reasonable */ | |
3774 | if (zfs_arc_meta_limit > 0 && zfs_arc_meta_limit <= arc_c_max) | |
3775 | arc_meta_limit = zfs_arc_meta_limit; | |
3776 | ||
3777 | if (arc_c_min < arc_meta_limit / 2 && zfs_arc_min == 0) | |
3778 | arc_c_min = arc_meta_limit / 2; | |
3779 | ||
d164b209 BB |
3780 | if (zfs_arc_grow_retry > 0) |
3781 | arc_grow_retry = zfs_arc_grow_retry; | |
3782 | ||
3783 | if (zfs_arc_shrink_shift > 0) | |
3784 | arc_shrink_shift = zfs_arc_shrink_shift; | |
3785 | ||
3786 | if (zfs_arc_p_min_shift > 0) | |
3787 | arc_p_min_shift = zfs_arc_p_min_shift; | |
3788 | ||
ab26409d BB |
3789 | if (zfs_arc_meta_prune > 0) |
3790 | arc_meta_prune = zfs_arc_meta_prune; | |
6a8f9b6b | 3791 | |
34dc7c2f BB |
3792 | /* if kmem_flags are set, lets try to use less memory */ |
3793 | if (kmem_debugging()) | |
3794 | arc_c = arc_c / 2; | |
3795 | if (arc_c < arc_c_min) | |
3796 | arc_c = arc_c_min; | |
3797 | ||
3798 | arc_anon = &ARC_anon; | |
3799 | arc_mru = &ARC_mru; | |
3800 | arc_mru_ghost = &ARC_mru_ghost; | |
3801 | arc_mfu = &ARC_mfu; | |
3802 | arc_mfu_ghost = &ARC_mfu_ghost; | |
3803 | arc_l2c_only = &ARC_l2c_only; | |
3804 | arc_size = 0; | |
3805 | ||
3806 | mutex_init(&arc_anon->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3807 | mutex_init(&arc_mru->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3808 | mutex_init(&arc_mru_ghost->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3809 | mutex_init(&arc_mfu->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3810 | mutex_init(&arc_mfu_ghost->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3811 | mutex_init(&arc_l2c_only->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); | |
3812 | ||
3813 | list_create(&arc_mru->arcs_list[ARC_BUFC_METADATA], | |
3814 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3815 | list_create(&arc_mru->arcs_list[ARC_BUFC_DATA], | |
3816 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3817 | list_create(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA], | |
3818 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3819 | list_create(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA], | |
3820 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3821 | list_create(&arc_mfu->arcs_list[ARC_BUFC_METADATA], | |
3822 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3823 | list_create(&arc_mfu->arcs_list[ARC_BUFC_DATA], | |
3824 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3825 | list_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA], | |
3826 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3827 | list_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA], | |
3828 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3829 | list_create(&arc_l2c_only->arcs_list[ARC_BUFC_METADATA], | |
3830 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3831 | list_create(&arc_l2c_only->arcs_list[ARC_BUFC_DATA], | |
3832 | sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); | |
3833 | ||
3834 | buf_init(); | |
3835 | ||
3836 | arc_thread_exit = 0; | |
ab26409d BB |
3837 | list_create(&arc_prune_list, sizeof (arc_prune_t), |
3838 | offsetof(arc_prune_t, p_node)); | |
34dc7c2f | 3839 | arc_eviction_list = NULL; |
ab26409d | 3840 | mutex_init(&arc_prune_mtx, NULL, MUTEX_DEFAULT, NULL); |
34dc7c2f BB |
3841 | mutex_init(&arc_eviction_mtx, NULL, MUTEX_DEFAULT, NULL); |
3842 | bzero(&arc_eviction_hdr, sizeof (arc_buf_hdr_t)); | |
3843 | ||
3844 | arc_ksp = kstat_create("zfs", 0, "arcstats", "misc", KSTAT_TYPE_NAMED, | |
3845 | sizeof (arc_stats) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL); | |
3846 | ||
3847 | if (arc_ksp != NULL) { | |
3848 | arc_ksp->ks_data = &arc_stats; | |
13be560d | 3849 | arc_ksp->ks_update = arc_kstat_update; |
34dc7c2f BB |
3850 | kstat_install(arc_ksp); |
3851 | } | |
3852 | ||
3853 | (void) thread_create(NULL, 0, arc_reclaim_thread, NULL, 0, &p0, | |
3854 | TS_RUN, minclsyspri); | |
3855 | ||
3856 | arc_dead = FALSE; | |
b128c09f | 3857 | arc_warm = B_FALSE; |
34dc7c2f BB |
3858 | |
3859 | if (zfs_write_limit_max == 0) | |
b128c09f | 3860 | zfs_write_limit_max = ptob(physmem) >> zfs_write_limit_shift; |
34dc7c2f BB |
3861 | else |
3862 | zfs_write_limit_shift = 0; | |
b128c09f | 3863 | mutex_init(&zfs_write_limit_lock, NULL, MUTEX_DEFAULT, NULL); |
34dc7c2f BB |
3864 | } |
3865 | ||
3866 | void | |
3867 | arc_fini(void) | |
3868 | { | |
ab26409d BB |
3869 | arc_prune_t *p; |
3870 | ||
34dc7c2f | 3871 | mutex_enter(&arc_reclaim_thr_lock); |
7cb67b45 BB |
3872 | #ifdef _KERNEL |
3873 | spl_unregister_shrinker(&arc_shrinker); | |
3874 | #endif /* _KERNEL */ | |
3875 | ||
34dc7c2f BB |
3876 | arc_thread_exit = 1; |
3877 | while (arc_thread_exit != 0) | |
3878 | cv_wait(&arc_reclaim_thr_cv, &arc_reclaim_thr_lock); | |
3879 | mutex_exit(&arc_reclaim_thr_lock); | |
3880 | ||
3881 | arc_flush(NULL); | |
3882 | ||
3883 | arc_dead = TRUE; | |
3884 | ||
3885 | if (arc_ksp != NULL) { | |
3886 | kstat_delete(arc_ksp); | |
3887 | arc_ksp = NULL; | |
3888 | } | |
3889 | ||
ab26409d BB |
3890 | mutex_enter(&arc_prune_mtx); |
3891 | while ((p = list_head(&arc_prune_list)) != NULL) { | |
3892 | list_remove(&arc_prune_list, p); | |
3893 | refcount_remove(&p->p_refcnt, &arc_prune_list); | |
3894 | refcount_destroy(&p->p_refcnt); | |
3895 | kmem_free(p, sizeof (*p)); | |
3896 | } | |
3897 | mutex_exit(&arc_prune_mtx); | |
3898 | ||
3899 | list_destroy(&arc_prune_list); | |
3900 | mutex_destroy(&arc_prune_mtx); | |
34dc7c2f BB |
3901 | mutex_destroy(&arc_eviction_mtx); |
3902 | mutex_destroy(&arc_reclaim_thr_lock); | |
3903 | cv_destroy(&arc_reclaim_thr_cv); | |
3904 | ||
3905 | list_destroy(&arc_mru->arcs_list[ARC_BUFC_METADATA]); | |
3906 | list_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA]); | |
3907 | list_destroy(&arc_mfu->arcs_list[ARC_BUFC_METADATA]); | |
3908 | list_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA]); | |
3909 | list_destroy(&arc_mru->arcs_list[ARC_BUFC_DATA]); | |
3910 | list_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA]); | |
3911 | list_destroy(&arc_mfu->arcs_list[ARC_BUFC_DATA]); | |
3912 | list_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA]); | |
3913 | ||
3914 | mutex_destroy(&arc_anon->arcs_mtx); | |
3915 | mutex_destroy(&arc_mru->arcs_mtx); | |
3916 | mutex_destroy(&arc_mru_ghost->arcs_mtx); | |
3917 | mutex_destroy(&arc_mfu->arcs_mtx); | |
3918 | mutex_destroy(&arc_mfu_ghost->arcs_mtx); | |
fb5f0bc8 | 3919 | mutex_destroy(&arc_l2c_only->arcs_mtx); |
34dc7c2f | 3920 | |
b128c09f BB |
3921 | mutex_destroy(&zfs_write_limit_lock); |
3922 | ||
34dc7c2f | 3923 | buf_fini(); |
9babb374 BB |
3924 | |
3925 | ASSERT(arc_loaned_bytes == 0); | |
34dc7c2f BB |
3926 | } |
3927 | ||
3928 | /* | |
3929 | * Level 2 ARC | |
3930 | * | |
3931 | * The level 2 ARC (L2ARC) is a cache layer in-between main memory and disk. | |
3932 | * It uses dedicated storage devices to hold cached data, which are populated | |
3933 | * using large infrequent writes. The main role of this cache is to boost | |
3934 | * the performance of random read workloads. The intended L2ARC devices | |
3935 | * include short-stroked disks, solid state disks, and other media with | |
3936 | * substantially faster read latency than disk. | |
3937 | * | |
3938 | * +-----------------------+ | |
3939 | * | ARC | | |
3940 | * +-----------------------+ | |
3941 | * | ^ ^ | |
3942 | * | | | | |
3943 | * l2arc_feed_thread() arc_read() | |
3944 | * | | | | |
3945 | * | l2arc read | | |
3946 | * V | | | |
3947 | * +---------------+ | | |
3948 | * | L2ARC | | | |
3949 | * +---------------+ | | |
3950 | * | ^ | | |
3951 | * l2arc_write() | | | |
3952 | * | | | | |
3953 | * V | | | |
3954 | * +-------+ +-------+ | |
3955 | * | vdev | | vdev | | |
3956 | * | cache | | cache | | |
3957 | * +-------+ +-------+ | |
3958 | * +=========+ .-----. | |
3959 | * : L2ARC : |-_____-| | |
3960 | * : devices : | Disks | | |
3961 | * +=========+ `-_____-' | |
3962 | * | |
3963 | * Read requests are satisfied from the following sources, in order: | |
3964 | * | |
3965 | * 1) ARC | |
3966 | * 2) vdev cache of L2ARC devices | |
3967 | * 3) L2ARC devices | |
3968 | * 4) vdev cache of disks | |
3969 | * 5) disks | |
3970 | * | |
3971 | * Some L2ARC device types exhibit extremely slow write performance. | |
3972 | * To accommodate for this there are some significant differences between | |
3973 | * the L2ARC and traditional cache design: | |
3974 | * | |
3975 | * 1. There is no eviction path from the ARC to the L2ARC. Evictions from | |
3976 | * the ARC behave as usual, freeing buffers and placing headers on ghost | |
3977 | * lists. The ARC does not send buffers to the L2ARC during eviction as | |
3978 | * this would add inflated write latencies for all ARC memory pressure. | |
3979 | * | |
3980 | * 2. The L2ARC attempts to cache data from the ARC before it is evicted. | |
3981 | * It does this by periodically scanning buffers from the eviction-end of | |
3982 | * the MFU and MRU ARC lists, copying them to the L2ARC devices if they are | |
3983 | * not already there. It scans until a headroom of buffers is satisfied, | |
3984 | * which itself is a buffer for ARC eviction. The thread that does this is | |
3985 | * l2arc_feed_thread(), illustrated below; example sizes are included to | |
3986 | * provide a better sense of ratio than this diagram: | |
3987 | * | |
3988 | * head --> tail | |
3989 | * +---------------------+----------+ | |
3990 | * ARC_mfu |:::::#:::::::::::::::|o#o###o###|-->. # already on L2ARC | |
3991 | * +---------------------+----------+ | o L2ARC eligible | |
3992 | * ARC_mru |:#:::::::::::::::::::|#o#ooo####|-->| : ARC buffer | |
3993 | * +---------------------+----------+ | | |
3994 | * 15.9 Gbytes ^ 32 Mbytes | | |
3995 | * headroom | | |
3996 | * l2arc_feed_thread() | |
3997 | * | | |
3998 | * l2arc write hand <--[oooo]--' | |
3999 | * | 8 Mbyte | |
4000 | * | write max | |
4001 | * V | |
4002 | * +==============================+ | |
4003 | * L2ARC dev |####|#|###|###| |####| ... | | |
4004 | * +==============================+ | |
4005 | * 32 Gbytes | |
4006 | * | |
4007 | * 3. If an ARC buffer is copied to the L2ARC but then hit instead of | |
4008 | * evicted, then the L2ARC has cached a buffer much sooner than it probably | |
4009 | * needed to, potentially wasting L2ARC device bandwidth and storage. It is | |
4010 | * safe to say that this is an uncommon case, since buffers at the end of | |
4011 | * the ARC lists have moved there due to inactivity. | |
4012 | * | |
4013 | * 4. If the ARC evicts faster than the L2ARC can maintain a headroom, | |
4014 | * then the L2ARC simply misses copying some buffers. This serves as a | |
4015 | * pressure valve to prevent heavy read workloads from both stalling the ARC | |
4016 | * with waits and clogging the L2ARC with writes. This also helps prevent | |
4017 | * the potential for the L2ARC to churn if it attempts to cache content too | |
4018 | * quickly, such as during backups of the entire pool. | |
4019 | * | |
b128c09f BB |
4020 | * 5. After system boot and before the ARC has filled main memory, there are |
4021 | * no evictions from the ARC and so the tails of the ARC_mfu and ARC_mru | |
4022 | * lists can remain mostly static. Instead of searching from tail of these | |
4023 | * lists as pictured, the l2arc_feed_thread() will search from the list heads | |
4024 | * for eligible buffers, greatly increasing its chance of finding them. | |
4025 | * | |
4026 | * The L2ARC device write speed is also boosted during this time so that | |
4027 | * the L2ARC warms up faster. Since there have been no ARC evictions yet, | |
4028 | * there are no L2ARC reads, and no fear of degrading read performance | |
4029 | * through increased writes. | |
4030 | * | |
4031 | * 6. Writes to the L2ARC devices are grouped and sent in-sequence, so that | |
34dc7c2f BB |
4032 | * the vdev queue can aggregate them into larger and fewer writes. Each |
4033 | * device is written to in a rotor fashion, sweeping writes through | |
4034 | * available space then repeating. | |
4035 | * | |
b128c09f | 4036 | * 7. The L2ARC does not store dirty content. It never needs to flush |
34dc7c2f BB |
4037 | * write buffers back to disk based storage. |
4038 | * | |
b128c09f | 4039 | * 8. If an ARC buffer is written (and dirtied) which also exists in the |
34dc7c2f BB |
4040 | * L2ARC, the now stale L2ARC buffer is immediately dropped. |
4041 | * | |
4042 | * The performance of the L2ARC can be tweaked by a number of tunables, which | |
4043 | * may be necessary for different workloads: | |
4044 | * | |
4045 | * l2arc_write_max max write bytes per interval | |
b128c09f | 4046 | * l2arc_write_boost extra write bytes during device warmup |
34dc7c2f BB |
4047 | * l2arc_noprefetch skip caching prefetched buffers |
4048 | * l2arc_headroom number of max device writes to precache | |
4049 | * l2arc_feed_secs seconds between L2ARC writing | |
4050 | * | |
4051 | * Tunables may be removed or added as future performance improvements are | |
4052 | * integrated, and also may become zpool properties. | |
d164b209 BB |
4053 | * |
4054 | * There are three key functions that control how the L2ARC warms up: | |
4055 | * | |
4056 | * l2arc_write_eligible() check if a buffer is eligible to cache | |
4057 | * l2arc_write_size() calculate how much to write | |
4058 | * l2arc_write_interval() calculate sleep delay between writes | |
4059 | * | |
4060 | * These three functions determine what to write, how much, and how quickly | |
4061 | * to send writes. | |
34dc7c2f BB |
4062 | */ |
4063 | ||
d164b209 BB |
4064 | static boolean_t |
4065 | l2arc_write_eligible(uint64_t spa_guid, arc_buf_hdr_t *ab) | |
4066 | { | |
4067 | /* | |
4068 | * A buffer is *not* eligible for the L2ARC if it: | |
4069 | * 1. belongs to a different spa. | |
428870ff BB |
4070 | * 2. is already cached on the L2ARC. |
4071 | * 3. has an I/O in progress (it may be an incomplete read). | |
4072 | * 4. is flagged not eligible (zfs property). | |
d164b209 | 4073 | */ |
428870ff | 4074 | if (ab->b_spa != spa_guid || ab->b_l2hdr != NULL || |
d164b209 BB |
4075 | HDR_IO_IN_PROGRESS(ab) || !HDR_L2CACHE(ab)) |
4076 | return (B_FALSE); | |
4077 | ||
4078 | return (B_TRUE); | |
4079 | } | |
4080 | ||
4081 | static uint64_t | |
4082 | l2arc_write_size(l2arc_dev_t *dev) | |
4083 | { | |
4084 | uint64_t size; | |
4085 | ||
4086 | size = dev->l2ad_write; | |
4087 | ||
4088 | if (arc_warm == B_FALSE) | |
4089 | size += dev->l2ad_boost; | |
4090 | ||
4091 | return (size); | |
4092 | ||
4093 | } | |
4094 | ||
4095 | static clock_t | |
4096 | l2arc_write_interval(clock_t began, uint64_t wanted, uint64_t wrote) | |
4097 | { | |
428870ff | 4098 | clock_t interval, next, now; |
d164b209 BB |
4099 | |
4100 | /* | |
4101 | * If the ARC lists are busy, increase our write rate; if the | |
4102 | * lists are stale, idle back. This is achieved by checking | |
4103 | * how much we previously wrote - if it was more than half of | |
4104 | * what we wanted, schedule the next write much sooner. | |
4105 | */ | |
4106 | if (l2arc_feed_again && wrote > (wanted / 2)) | |
4107 | interval = (hz * l2arc_feed_min_ms) / 1000; | |
4108 | else | |
4109 | interval = hz * l2arc_feed_secs; | |
4110 | ||
428870ff BB |
4111 | now = ddi_get_lbolt(); |
4112 | next = MAX(now, MIN(now + interval, began + interval)); | |
d164b209 BB |
4113 | |
4114 | return (next); | |
4115 | } | |
4116 | ||
34dc7c2f BB |
4117 | static void |
4118 | l2arc_hdr_stat_add(void) | |
4119 | { | |
4120 | ARCSTAT_INCR(arcstat_l2_hdr_size, HDR_SIZE + L2HDR_SIZE); | |
4121 | ARCSTAT_INCR(arcstat_hdr_size, -HDR_SIZE); | |
4122 | } | |
4123 | ||
4124 | static void | |
4125 | l2arc_hdr_stat_remove(void) | |
4126 | { | |
4127 | ARCSTAT_INCR(arcstat_l2_hdr_size, -(HDR_SIZE + L2HDR_SIZE)); | |
4128 | ARCSTAT_INCR(arcstat_hdr_size, HDR_SIZE); | |
4129 | } | |
4130 | ||
4131 | /* | |
4132 | * Cycle through L2ARC devices. This is how L2ARC load balances. | |
b128c09f | 4133 | * If a device is returned, this also returns holding the spa config lock. |
34dc7c2f BB |
4134 | */ |
4135 | static l2arc_dev_t * | |
4136 | l2arc_dev_get_next(void) | |
4137 | { | |
b128c09f | 4138 | l2arc_dev_t *first, *next = NULL; |
34dc7c2f | 4139 | |
b128c09f BB |
4140 | /* |
4141 | * Lock out the removal of spas (spa_namespace_lock), then removal | |
4142 | * of cache devices (l2arc_dev_mtx). Once a device has been selected, | |
4143 | * both locks will be dropped and a spa config lock held instead. | |
4144 | */ | |
4145 | mutex_enter(&spa_namespace_lock); | |
4146 | mutex_enter(&l2arc_dev_mtx); | |
4147 | ||
4148 | /* if there are no vdevs, there is nothing to do */ | |
4149 | if (l2arc_ndev == 0) | |
4150 | goto out; | |
4151 | ||
4152 | first = NULL; | |
4153 | next = l2arc_dev_last; | |
4154 | do { | |
4155 | /* loop around the list looking for a non-faulted vdev */ | |
4156 | if (next == NULL) { | |
34dc7c2f | 4157 | next = list_head(l2arc_dev_list); |
b128c09f BB |
4158 | } else { |
4159 | next = list_next(l2arc_dev_list, next); | |
4160 | if (next == NULL) | |
4161 | next = list_head(l2arc_dev_list); | |
4162 | } | |
4163 | ||
4164 | /* if we have come back to the start, bail out */ | |
4165 | if (first == NULL) | |
4166 | first = next; | |
4167 | else if (next == first) | |
4168 | break; | |
4169 | ||
4170 | } while (vdev_is_dead(next->l2ad_vdev)); | |
4171 | ||
4172 | /* if we were unable to find any usable vdevs, return NULL */ | |
4173 | if (vdev_is_dead(next->l2ad_vdev)) | |
4174 | next = NULL; | |
34dc7c2f BB |
4175 | |
4176 | l2arc_dev_last = next; | |
4177 | ||
b128c09f BB |
4178 | out: |
4179 | mutex_exit(&l2arc_dev_mtx); | |
4180 | ||
4181 | /* | |
4182 | * Grab the config lock to prevent the 'next' device from being | |
4183 | * removed while we are writing to it. | |
4184 | */ | |
4185 | if (next != NULL) | |
4186 | spa_config_enter(next->l2ad_spa, SCL_L2ARC, next, RW_READER); | |
4187 | mutex_exit(&spa_namespace_lock); | |
4188 | ||
34dc7c2f BB |
4189 | return (next); |
4190 | } | |
4191 | ||
b128c09f BB |
4192 | /* |
4193 | * Free buffers that were tagged for destruction. | |
4194 | */ | |
4195 | static void | |
0bc8fd78 | 4196 | l2arc_do_free_on_write(void) |
b128c09f BB |
4197 | { |
4198 | list_t *buflist; | |
4199 | l2arc_data_free_t *df, *df_prev; | |
4200 | ||
4201 | mutex_enter(&l2arc_free_on_write_mtx); | |
4202 | buflist = l2arc_free_on_write; | |
4203 | ||
4204 | for (df = list_tail(buflist); df; df = df_prev) { | |
4205 | df_prev = list_prev(buflist, df); | |
4206 | ASSERT(df->l2df_data != NULL); | |
4207 | ASSERT(df->l2df_func != NULL); | |
4208 | df->l2df_func(df->l2df_data, df->l2df_size); | |
4209 | list_remove(buflist, df); | |
4210 | kmem_free(df, sizeof (l2arc_data_free_t)); | |
4211 | } | |
4212 | ||
4213 | mutex_exit(&l2arc_free_on_write_mtx); | |
4214 | } | |
4215 | ||
34dc7c2f BB |
4216 | /* |
4217 | * A write to a cache device has completed. Update all headers to allow | |
4218 | * reads from these buffers to begin. | |
4219 | */ | |
4220 | static void | |
4221 | l2arc_write_done(zio_t *zio) | |
4222 | { | |
4223 | l2arc_write_callback_t *cb; | |
4224 | l2arc_dev_t *dev; | |
4225 | list_t *buflist; | |
34dc7c2f | 4226 | arc_buf_hdr_t *head, *ab, *ab_prev; |
b128c09f | 4227 | l2arc_buf_hdr_t *abl2; |
34dc7c2f BB |
4228 | kmutex_t *hash_lock; |
4229 | ||
4230 | cb = zio->io_private; | |
4231 | ASSERT(cb != NULL); | |
4232 | dev = cb->l2wcb_dev; | |
4233 | ASSERT(dev != NULL); | |
4234 | head = cb->l2wcb_head; | |
4235 | ASSERT(head != NULL); | |
4236 | buflist = dev->l2ad_buflist; | |
4237 | ASSERT(buflist != NULL); | |
4238 | DTRACE_PROBE2(l2arc__iodone, zio_t *, zio, | |
4239 | l2arc_write_callback_t *, cb); | |
4240 | ||
4241 | if (zio->io_error != 0) | |
4242 | ARCSTAT_BUMP(arcstat_l2_writes_error); | |
4243 | ||
4244 | mutex_enter(&l2arc_buflist_mtx); | |
4245 | ||
4246 | /* | |
4247 | * All writes completed, or an error was hit. | |
4248 | */ | |
4249 | for (ab = list_prev(buflist, head); ab; ab = ab_prev) { | |
4250 | ab_prev = list_prev(buflist, ab); | |
4251 | ||
4252 | hash_lock = HDR_LOCK(ab); | |
4253 | if (!mutex_tryenter(hash_lock)) { | |
4254 | /* | |
4255 | * This buffer misses out. It may be in a stage | |
4256 | * of eviction. Its ARC_L2_WRITING flag will be | |
4257 | * left set, denying reads to this buffer. | |
4258 | */ | |
4259 | ARCSTAT_BUMP(arcstat_l2_writes_hdr_miss); | |
4260 | continue; | |
4261 | } | |
4262 | ||
4263 | if (zio->io_error != 0) { | |
4264 | /* | |
b128c09f | 4265 | * Error - drop L2ARC entry. |
34dc7c2f | 4266 | */ |
b128c09f BB |
4267 | list_remove(buflist, ab); |
4268 | abl2 = ab->b_l2hdr; | |
34dc7c2f | 4269 | ab->b_l2hdr = NULL; |
b128c09f BB |
4270 | kmem_free(abl2, sizeof (l2arc_buf_hdr_t)); |
4271 | ARCSTAT_INCR(arcstat_l2_size, -ab->b_size); | |
34dc7c2f BB |
4272 | } |
4273 | ||
4274 | /* | |
4275 | * Allow ARC to begin reads to this L2ARC entry. | |
4276 | */ | |
4277 | ab->b_flags &= ~ARC_L2_WRITING; | |
4278 | ||
4279 | mutex_exit(hash_lock); | |
4280 | } | |
4281 | ||
4282 | atomic_inc_64(&l2arc_writes_done); | |
4283 | list_remove(buflist, head); | |
4284 | kmem_cache_free(hdr_cache, head); | |
4285 | mutex_exit(&l2arc_buflist_mtx); | |
4286 | ||
b128c09f | 4287 | l2arc_do_free_on_write(); |
34dc7c2f BB |
4288 | |
4289 | kmem_free(cb, sizeof (l2arc_write_callback_t)); | |
4290 | } | |
4291 | ||
4292 | /* | |
4293 | * A read to a cache device completed. Validate buffer contents before | |
4294 | * handing over to the regular ARC routines. | |
4295 | */ | |
4296 | static void | |
4297 | l2arc_read_done(zio_t *zio) | |
4298 | { | |
4299 | l2arc_read_callback_t *cb; | |
4300 | arc_buf_hdr_t *hdr; | |
4301 | arc_buf_t *buf; | |
34dc7c2f | 4302 | kmutex_t *hash_lock; |
b128c09f BB |
4303 | int equal; |
4304 | ||
4305 | ASSERT(zio->io_vd != NULL); | |
4306 | ASSERT(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE); | |
4307 | ||
4308 | spa_config_exit(zio->io_spa, SCL_L2ARC, zio->io_vd); | |
34dc7c2f BB |
4309 | |
4310 | cb = zio->io_private; | |
4311 | ASSERT(cb != NULL); | |
4312 | buf = cb->l2rcb_buf; | |
4313 | ASSERT(buf != NULL); | |
34dc7c2f | 4314 | |
428870ff | 4315 | hash_lock = HDR_LOCK(buf->b_hdr); |
34dc7c2f | 4316 | mutex_enter(hash_lock); |
428870ff BB |
4317 | hdr = buf->b_hdr; |
4318 | ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); | |
34dc7c2f BB |
4319 | |
4320 | /* | |
4321 | * Check this survived the L2ARC journey. | |
4322 | */ | |
4323 | equal = arc_cksum_equal(buf); | |
4324 | if (equal && zio->io_error == 0 && !HDR_L2_EVICTED(hdr)) { | |
4325 | mutex_exit(hash_lock); | |
4326 | zio->io_private = buf; | |
b128c09f BB |
4327 | zio->io_bp_copy = cb->l2rcb_bp; /* XXX fix in L2ARC 2.0 */ |
4328 | zio->io_bp = &zio->io_bp_copy; /* XXX fix in L2ARC 2.0 */ | |
34dc7c2f BB |
4329 | arc_read_done(zio); |
4330 | } else { | |
4331 | mutex_exit(hash_lock); | |
4332 | /* | |
4333 | * Buffer didn't survive caching. Increment stats and | |
4334 | * reissue to the original storage device. | |
4335 | */ | |
b128c09f | 4336 | if (zio->io_error != 0) { |
34dc7c2f | 4337 | ARCSTAT_BUMP(arcstat_l2_io_error); |
b128c09f BB |
4338 | } else { |
4339 | zio->io_error = EIO; | |
4340 | } | |
34dc7c2f BB |
4341 | if (!equal) |
4342 | ARCSTAT_BUMP(arcstat_l2_cksum_bad); | |
4343 | ||
34dc7c2f | 4344 | /* |
b128c09f BB |
4345 | * If there's no waiter, issue an async i/o to the primary |
4346 | * storage now. If there *is* a waiter, the caller must | |
4347 | * issue the i/o in a context where it's OK to block. | |
34dc7c2f | 4348 | */ |
d164b209 BB |
4349 | if (zio->io_waiter == NULL) { |
4350 | zio_t *pio = zio_unique_parent(zio); | |
4351 | ||
4352 | ASSERT(!pio || pio->io_child_type == ZIO_CHILD_LOGICAL); | |
4353 | ||
4354 | zio_nowait(zio_read(pio, cb->l2rcb_spa, &cb->l2rcb_bp, | |
b128c09f BB |
4355 | buf->b_data, zio->io_size, arc_read_done, buf, |
4356 | zio->io_priority, cb->l2rcb_flags, &cb->l2rcb_zb)); | |
d164b209 | 4357 | } |
34dc7c2f BB |
4358 | } |
4359 | ||
4360 | kmem_free(cb, sizeof (l2arc_read_callback_t)); | |
4361 | } | |
4362 | ||
4363 | /* | |
4364 | * This is the list priority from which the L2ARC will search for pages to | |
4365 | * cache. This is used within loops (0..3) to cycle through lists in the | |
4366 | * desired order. This order can have a significant effect on cache | |
4367 | * performance. | |
4368 | * | |
4369 | * Currently the metadata lists are hit first, MFU then MRU, followed by | |
4370 | * the data lists. This function returns a locked list, and also returns | |
4371 | * the lock pointer. | |
4372 | */ | |
4373 | static list_t * | |
4374 | l2arc_list_locked(int list_num, kmutex_t **lock) | |
4375 | { | |
d4ed6673 | 4376 | list_t *list = NULL; |
34dc7c2f BB |
4377 | |
4378 | ASSERT(list_num >= 0 && list_num <= 3); | |
4379 | ||
4380 | switch (list_num) { | |
4381 | case 0: | |
4382 | list = &arc_mfu->arcs_list[ARC_BUFC_METADATA]; | |
4383 | *lock = &arc_mfu->arcs_mtx; | |
4384 | break; | |
4385 | case 1: | |
4386 | list = &arc_mru->arcs_list[ARC_BUFC_METADATA]; | |
4387 | *lock = &arc_mru->arcs_mtx; | |
4388 | break; | |
4389 | case 2: | |
4390 | list = &arc_mfu->arcs_list[ARC_BUFC_DATA]; | |
4391 | *lock = &arc_mfu->arcs_mtx; | |
4392 | break; | |
4393 | case 3: | |
4394 | list = &arc_mru->arcs_list[ARC_BUFC_DATA]; | |
4395 | *lock = &arc_mru->arcs_mtx; | |
4396 | break; | |
4397 | } | |
4398 | ||
4399 | ASSERT(!(MUTEX_HELD(*lock))); | |
4400 | mutex_enter(*lock); | |
4401 | return (list); | |
4402 | } | |
4403 | ||
4404 | /* | |
4405 | * Evict buffers from the device write hand to the distance specified in | |
4406 | * bytes. This distance may span populated buffers, it may span nothing. | |
4407 | * This is clearing a region on the L2ARC device ready for writing. | |
4408 | * If the 'all' boolean is set, every buffer is evicted. | |
4409 | */ | |
4410 | static void | |
4411 | l2arc_evict(l2arc_dev_t *dev, uint64_t distance, boolean_t all) | |
4412 | { | |
4413 | list_t *buflist; | |
4414 | l2arc_buf_hdr_t *abl2; | |
4415 | arc_buf_hdr_t *ab, *ab_prev; | |
4416 | kmutex_t *hash_lock; | |
4417 | uint64_t taddr; | |
4418 | ||
34dc7c2f BB |
4419 | buflist = dev->l2ad_buflist; |
4420 | ||
4421 | if (buflist == NULL) | |
4422 | return; | |
4423 | ||
4424 | if (!all && dev->l2ad_first) { | |
4425 | /* | |
4426 | * This is the first sweep through the device. There is | |
4427 | * nothing to evict. | |
4428 | */ | |
4429 | return; | |
4430 | } | |
4431 | ||
b128c09f | 4432 | if (dev->l2ad_hand >= (dev->l2ad_end - (2 * distance))) { |
34dc7c2f BB |
4433 | /* |
4434 | * When nearing the end of the device, evict to the end | |
4435 | * before the device write hand jumps to the start. | |
4436 | */ | |
4437 | taddr = dev->l2ad_end; | |
4438 | } else { | |
4439 | taddr = dev->l2ad_hand + distance; | |
4440 | } | |
4441 | DTRACE_PROBE4(l2arc__evict, l2arc_dev_t *, dev, list_t *, buflist, | |
4442 | uint64_t, taddr, boolean_t, all); | |
4443 | ||
4444 | top: | |
4445 | mutex_enter(&l2arc_buflist_mtx); | |
4446 | for (ab = list_tail(buflist); ab; ab = ab_prev) { | |
4447 | ab_prev = list_prev(buflist, ab); | |
4448 | ||
4449 | hash_lock = HDR_LOCK(ab); | |
4450 | if (!mutex_tryenter(hash_lock)) { | |
4451 | /* | |
4452 | * Missed the hash lock. Retry. | |
4453 | */ | |
4454 | ARCSTAT_BUMP(arcstat_l2_evict_lock_retry); | |
4455 | mutex_exit(&l2arc_buflist_mtx); | |
4456 | mutex_enter(hash_lock); | |
4457 | mutex_exit(hash_lock); | |
4458 | goto top; | |
4459 | } | |
4460 | ||
4461 | if (HDR_L2_WRITE_HEAD(ab)) { | |
4462 | /* | |
4463 | * We hit a write head node. Leave it for | |
4464 | * l2arc_write_done(). | |
4465 | */ | |
4466 | list_remove(buflist, ab); | |
4467 | mutex_exit(hash_lock); | |
4468 | continue; | |
4469 | } | |
4470 | ||
4471 | if (!all && ab->b_l2hdr != NULL && | |
4472 | (ab->b_l2hdr->b_daddr > taddr || | |
4473 | ab->b_l2hdr->b_daddr < dev->l2ad_hand)) { | |
4474 | /* | |
4475 | * We've evicted to the target address, | |
4476 | * or the end of the device. | |
4477 | */ | |
4478 | mutex_exit(hash_lock); | |
4479 | break; | |
4480 | } | |
4481 | ||
4482 | if (HDR_FREE_IN_PROGRESS(ab)) { | |
4483 | /* | |
4484 | * Already on the path to destruction. | |
4485 | */ | |
4486 | mutex_exit(hash_lock); | |
4487 | continue; | |
4488 | } | |
4489 | ||
4490 | if (ab->b_state == arc_l2c_only) { | |
4491 | ASSERT(!HDR_L2_READING(ab)); | |
4492 | /* | |
4493 | * This doesn't exist in the ARC. Destroy. | |
4494 | * arc_hdr_destroy() will call list_remove() | |
4495 | * and decrement arcstat_l2_size. | |
4496 | */ | |
4497 | arc_change_state(arc_anon, ab, hash_lock); | |
4498 | arc_hdr_destroy(ab); | |
4499 | } else { | |
b128c09f BB |
4500 | /* |
4501 | * Invalidate issued or about to be issued | |
4502 | * reads, since we may be about to write | |
4503 | * over this location. | |
4504 | */ | |
4505 | if (HDR_L2_READING(ab)) { | |
4506 | ARCSTAT_BUMP(arcstat_l2_evict_reading); | |
4507 | ab->b_flags |= ARC_L2_EVICTED; | |
4508 | } | |
4509 | ||
34dc7c2f BB |
4510 | /* |
4511 | * Tell ARC this no longer exists in L2ARC. | |
4512 | */ | |
4513 | if (ab->b_l2hdr != NULL) { | |
4514 | abl2 = ab->b_l2hdr; | |
4515 | ab->b_l2hdr = NULL; | |
4516 | kmem_free(abl2, sizeof (l2arc_buf_hdr_t)); | |
4517 | ARCSTAT_INCR(arcstat_l2_size, -ab->b_size); | |
4518 | } | |
4519 | list_remove(buflist, ab); | |
4520 | ||
4521 | /* | |
4522 | * This may have been leftover after a | |
4523 | * failed write. | |
4524 | */ | |
4525 | ab->b_flags &= ~ARC_L2_WRITING; | |
34dc7c2f BB |
4526 | } |
4527 | mutex_exit(hash_lock); | |
4528 | } | |
4529 | mutex_exit(&l2arc_buflist_mtx); | |
4530 | ||
428870ff | 4531 | vdev_space_update(dev->l2ad_vdev, -(taddr - dev->l2ad_evict), 0, 0); |
34dc7c2f BB |
4532 | dev->l2ad_evict = taddr; |
4533 | } | |
4534 | ||
4535 | /* | |
4536 | * Find and write ARC buffers to the L2ARC device. | |
4537 | * | |
4538 | * An ARC_L2_WRITING flag is set so that the L2ARC buffers are not valid | |
4539 | * for reading until they have completed writing. | |
4540 | */ | |
d164b209 | 4541 | static uint64_t |
b128c09f | 4542 | l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz) |
34dc7c2f BB |
4543 | { |
4544 | arc_buf_hdr_t *ab, *ab_prev, *head; | |
4545 | l2arc_buf_hdr_t *hdrl2; | |
4546 | list_t *list; | |
b128c09f | 4547 | uint64_t passed_sz, write_sz, buf_sz, headroom; |
34dc7c2f | 4548 | void *buf_data; |
d4ed6673 | 4549 | kmutex_t *hash_lock, *list_lock = NULL; |
34dc7c2f BB |
4550 | boolean_t have_lock, full; |
4551 | l2arc_write_callback_t *cb; | |
4552 | zio_t *pio, *wzio; | |
d164b209 | 4553 | uint64_t guid = spa_guid(spa); |
d6320ddb | 4554 | int try; |
34dc7c2f | 4555 | |
34dc7c2f BB |
4556 | ASSERT(dev->l2ad_vdev != NULL); |
4557 | ||
4558 | pio = NULL; | |
4559 | write_sz = 0; | |
4560 | full = B_FALSE; | |
4561 | head = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); | |
4562 | head->b_flags |= ARC_L2_WRITE_HEAD; | |
4563 | ||
4564 | /* | |
4565 | * Copy buffers for L2ARC writing. | |
4566 | */ | |
4567 | mutex_enter(&l2arc_buflist_mtx); | |
d6320ddb | 4568 | for (try = 0; try <= 3; try++) { |
34dc7c2f BB |
4569 | list = l2arc_list_locked(try, &list_lock); |
4570 | passed_sz = 0; | |
4571 | ||
b128c09f BB |
4572 | /* |
4573 | * L2ARC fast warmup. | |
4574 | * | |
4575 | * Until the ARC is warm and starts to evict, read from the | |
4576 | * head of the ARC lists rather than the tail. | |
4577 | */ | |
4578 | headroom = target_sz * l2arc_headroom; | |
4579 | if (arc_warm == B_FALSE) | |
4580 | ab = list_head(list); | |
4581 | else | |
4582 | ab = list_tail(list); | |
4583 | ||
4584 | for (; ab; ab = ab_prev) { | |
4585 | if (arc_warm == B_FALSE) | |
4586 | ab_prev = list_next(list, ab); | |
4587 | else | |
4588 | ab_prev = list_prev(list, ab); | |
34dc7c2f BB |
4589 | |
4590 | hash_lock = HDR_LOCK(ab); | |
4591 | have_lock = MUTEX_HELD(hash_lock); | |
4592 | if (!have_lock && !mutex_tryenter(hash_lock)) { | |
4593 | /* | |
4594 | * Skip this buffer rather than waiting. | |
4595 | */ | |
4596 | continue; | |
4597 | } | |
4598 | ||
4599 | passed_sz += ab->b_size; | |
4600 | if (passed_sz > headroom) { | |
4601 | /* | |
4602 | * Searched too far. | |
4603 | */ | |
4604 | mutex_exit(hash_lock); | |
4605 | break; | |
4606 | } | |
4607 | ||
d164b209 | 4608 | if (!l2arc_write_eligible(guid, ab)) { |
34dc7c2f BB |
4609 | mutex_exit(hash_lock); |
4610 | continue; | |
4611 | } | |
4612 | ||
4613 | if ((write_sz + ab->b_size) > target_sz) { | |
4614 | full = B_TRUE; | |
4615 | mutex_exit(hash_lock); | |
4616 | break; | |
4617 | } | |
4618 | ||
34dc7c2f BB |
4619 | if (pio == NULL) { |
4620 | /* | |
4621 | * Insert a dummy header on the buflist so | |
4622 | * l2arc_write_done() can find where the | |
4623 | * write buffers begin without searching. | |
4624 | */ | |
4625 | list_insert_head(dev->l2ad_buflist, head); | |
4626 | ||
409dc1a5 PS |
4627 | cb = kmem_alloc(sizeof (l2arc_write_callback_t), |
4628 | KM_PUSHPAGE); | |
34dc7c2f BB |
4629 | cb->l2wcb_dev = dev; |
4630 | cb->l2wcb_head = head; | |
4631 | pio = zio_root(spa, l2arc_write_done, cb, | |
4632 | ZIO_FLAG_CANFAIL); | |
4633 | } | |
4634 | ||
4635 | /* | |
4636 | * Create and add a new L2ARC header. | |
4637 | */ | |
409dc1a5 PS |
4638 | hdrl2 = kmem_zalloc(sizeof (l2arc_buf_hdr_t), |
4639 | KM_PUSHPAGE); | |
34dc7c2f BB |
4640 | hdrl2->b_dev = dev; |
4641 | hdrl2->b_daddr = dev->l2ad_hand; | |
4642 | ||
4643 | ab->b_flags |= ARC_L2_WRITING; | |
4644 | ab->b_l2hdr = hdrl2; | |
4645 | list_insert_head(dev->l2ad_buflist, ab); | |
4646 | buf_data = ab->b_buf->b_data; | |
4647 | buf_sz = ab->b_size; | |
4648 | ||
4649 | /* | |
4650 | * Compute and store the buffer cksum before | |
4651 | * writing. On debug the cksum is verified first. | |
4652 | */ | |
4653 | arc_cksum_verify(ab->b_buf); | |
4654 | arc_cksum_compute(ab->b_buf, B_TRUE); | |
4655 | ||
4656 | mutex_exit(hash_lock); | |
4657 | ||
4658 | wzio = zio_write_phys(pio, dev->l2ad_vdev, | |
4659 | dev->l2ad_hand, buf_sz, buf_data, ZIO_CHECKSUM_OFF, | |
4660 | NULL, NULL, ZIO_PRIORITY_ASYNC_WRITE, | |
4661 | ZIO_FLAG_CANFAIL, B_FALSE); | |
4662 | ||
4663 | DTRACE_PROBE2(l2arc__write, vdev_t *, dev->l2ad_vdev, | |
4664 | zio_t *, wzio); | |
4665 | (void) zio_nowait(wzio); | |
4666 | ||
b128c09f BB |
4667 | /* |
4668 | * Keep the clock hand suitably device-aligned. | |
4669 | */ | |
4670 | buf_sz = vdev_psize_to_asize(dev->l2ad_vdev, buf_sz); | |
4671 | ||
34dc7c2f BB |
4672 | write_sz += buf_sz; |
4673 | dev->l2ad_hand += buf_sz; | |
4674 | } | |
4675 | ||
4676 | mutex_exit(list_lock); | |
4677 | ||
4678 | if (full == B_TRUE) | |
4679 | break; | |
4680 | } | |
4681 | mutex_exit(&l2arc_buflist_mtx); | |
4682 | ||
4683 | if (pio == NULL) { | |
4684 | ASSERT3U(write_sz, ==, 0); | |
4685 | kmem_cache_free(hdr_cache, head); | |
d164b209 | 4686 | return (0); |
34dc7c2f BB |
4687 | } |
4688 | ||
4689 | ASSERT3U(write_sz, <=, target_sz); | |
4690 | ARCSTAT_BUMP(arcstat_l2_writes_sent); | |
d164b209 | 4691 | ARCSTAT_INCR(arcstat_l2_write_bytes, write_sz); |
34dc7c2f | 4692 | ARCSTAT_INCR(arcstat_l2_size, write_sz); |
428870ff | 4693 | vdev_space_update(dev->l2ad_vdev, write_sz, 0, 0); |
34dc7c2f BB |
4694 | |
4695 | /* | |
4696 | * Bump device hand to the device start if it is approaching the end. | |
4697 | * l2arc_evict() will already have evicted ahead for this case. | |
4698 | */ | |
b128c09f | 4699 | if (dev->l2ad_hand >= (dev->l2ad_end - target_sz)) { |
428870ff BB |
4700 | vdev_space_update(dev->l2ad_vdev, |
4701 | dev->l2ad_end - dev->l2ad_hand, 0, 0); | |
34dc7c2f BB |
4702 | dev->l2ad_hand = dev->l2ad_start; |
4703 | dev->l2ad_evict = dev->l2ad_start; | |
4704 | dev->l2ad_first = B_FALSE; | |
4705 | } | |
4706 | ||
d164b209 | 4707 | dev->l2ad_writing = B_TRUE; |
34dc7c2f | 4708 | (void) zio_wait(pio); |
d164b209 BB |
4709 | dev->l2ad_writing = B_FALSE; |
4710 | ||
4711 | return (write_sz); | |
34dc7c2f BB |
4712 | } |
4713 | ||
4714 | /* | |
4715 | * This thread feeds the L2ARC at regular intervals. This is the beating | |
4716 | * heart of the L2ARC. | |
4717 | */ | |
4718 | static void | |
4719 | l2arc_feed_thread(void) | |
4720 | { | |
4721 | callb_cpr_t cpr; | |
4722 | l2arc_dev_t *dev; | |
4723 | spa_t *spa; | |
d164b209 | 4724 | uint64_t size, wrote; |
428870ff | 4725 | clock_t begin, next = ddi_get_lbolt(); |
34dc7c2f BB |
4726 | |
4727 | CALLB_CPR_INIT(&cpr, &l2arc_feed_thr_lock, callb_generic_cpr, FTAG); | |
4728 | ||
4729 | mutex_enter(&l2arc_feed_thr_lock); | |
4730 | ||
4731 | while (l2arc_thread_exit == 0) { | |
34dc7c2f | 4732 | CALLB_CPR_SAFE_BEGIN(&cpr); |
5b63b3eb BB |
4733 | (void) cv_timedwait_interruptible(&l2arc_feed_thr_cv, |
4734 | &l2arc_feed_thr_lock, next); | |
34dc7c2f | 4735 | CALLB_CPR_SAFE_END(&cpr, &l2arc_feed_thr_lock); |
428870ff | 4736 | next = ddi_get_lbolt() + hz; |
34dc7c2f BB |
4737 | |
4738 | /* | |
b128c09f | 4739 | * Quick check for L2ARC devices. |
34dc7c2f BB |
4740 | */ |
4741 | mutex_enter(&l2arc_dev_mtx); | |
4742 | if (l2arc_ndev == 0) { | |
4743 | mutex_exit(&l2arc_dev_mtx); | |
4744 | continue; | |
4745 | } | |
b128c09f | 4746 | mutex_exit(&l2arc_dev_mtx); |
428870ff | 4747 | begin = ddi_get_lbolt(); |
34dc7c2f BB |
4748 | |
4749 | /* | |
b128c09f BB |
4750 | * This selects the next l2arc device to write to, and in |
4751 | * doing so the next spa to feed from: dev->l2ad_spa. This | |
4752 | * will return NULL if there are now no l2arc devices or if | |
4753 | * they are all faulted. | |
4754 | * | |
4755 | * If a device is returned, its spa's config lock is also | |
4756 | * held to prevent device removal. l2arc_dev_get_next() | |
4757 | * will grab and release l2arc_dev_mtx. | |
34dc7c2f | 4758 | */ |
b128c09f | 4759 | if ((dev = l2arc_dev_get_next()) == NULL) |
34dc7c2f | 4760 | continue; |
b128c09f BB |
4761 | |
4762 | spa = dev->l2ad_spa; | |
4763 | ASSERT(spa != NULL); | |
34dc7c2f | 4764 | |
572e2857 BB |
4765 | /* |
4766 | * If the pool is read-only then force the feed thread to | |
4767 | * sleep a little longer. | |
4768 | */ | |
4769 | if (!spa_writeable(spa)) { | |
4770 | next = ddi_get_lbolt() + 5 * l2arc_feed_secs * hz; | |
4771 | spa_config_exit(spa, SCL_L2ARC, dev); | |
4772 | continue; | |
4773 | } | |
4774 | ||
34dc7c2f | 4775 | /* |
b128c09f | 4776 | * Avoid contributing to memory pressure. |
34dc7c2f | 4777 | */ |
b128c09f BB |
4778 | if (arc_reclaim_needed()) { |
4779 | ARCSTAT_BUMP(arcstat_l2_abort_lowmem); | |
4780 | spa_config_exit(spa, SCL_L2ARC, dev); | |
34dc7c2f BB |
4781 | continue; |
4782 | } | |
b128c09f | 4783 | |
34dc7c2f BB |
4784 | ARCSTAT_BUMP(arcstat_l2_feeds); |
4785 | ||
d164b209 | 4786 | size = l2arc_write_size(dev); |
b128c09f | 4787 | |
34dc7c2f BB |
4788 | /* |
4789 | * Evict L2ARC buffers that will be overwritten. | |
4790 | */ | |
b128c09f | 4791 | l2arc_evict(dev, size, B_FALSE); |
34dc7c2f BB |
4792 | |
4793 | /* | |
4794 | * Write ARC buffers. | |
4795 | */ | |
d164b209 BB |
4796 | wrote = l2arc_write_buffers(spa, dev, size); |
4797 | ||
4798 | /* | |
4799 | * Calculate interval between writes. | |
4800 | */ | |
4801 | next = l2arc_write_interval(begin, size, wrote); | |
b128c09f | 4802 | spa_config_exit(spa, SCL_L2ARC, dev); |
34dc7c2f BB |
4803 | } |
4804 | ||
4805 | l2arc_thread_exit = 0; | |
4806 | cv_broadcast(&l2arc_feed_thr_cv); | |
4807 | CALLB_CPR_EXIT(&cpr); /* drops l2arc_feed_thr_lock */ | |
4808 | thread_exit(); | |
4809 | } | |
4810 | ||
b128c09f BB |
4811 | boolean_t |
4812 | l2arc_vdev_present(vdev_t *vd) | |
4813 | { | |
4814 | l2arc_dev_t *dev; | |
4815 | ||
4816 | mutex_enter(&l2arc_dev_mtx); | |
4817 | for (dev = list_head(l2arc_dev_list); dev != NULL; | |
4818 | dev = list_next(l2arc_dev_list, dev)) { | |
4819 | if (dev->l2ad_vdev == vd) | |
4820 | break; | |
4821 | } | |
4822 | mutex_exit(&l2arc_dev_mtx); | |
4823 | ||
4824 | return (dev != NULL); | |
4825 | } | |
4826 | ||
34dc7c2f BB |
4827 | /* |
4828 | * Add a vdev for use by the L2ARC. By this point the spa has already | |
4829 | * validated the vdev and opened it. | |
4830 | */ | |
4831 | void | |
9babb374 | 4832 | l2arc_add_vdev(spa_t *spa, vdev_t *vd) |
34dc7c2f BB |
4833 | { |
4834 | l2arc_dev_t *adddev; | |
4835 | ||
b128c09f BB |
4836 | ASSERT(!l2arc_vdev_present(vd)); |
4837 | ||
34dc7c2f BB |
4838 | /* |
4839 | * Create a new l2arc device entry. | |
4840 | */ | |
4841 | adddev = kmem_zalloc(sizeof (l2arc_dev_t), KM_SLEEP); | |
4842 | adddev->l2ad_spa = spa; | |
4843 | adddev->l2ad_vdev = vd; | |
4844 | adddev->l2ad_write = l2arc_write_max; | |
b128c09f | 4845 | adddev->l2ad_boost = l2arc_write_boost; |
9babb374 BB |
4846 | adddev->l2ad_start = VDEV_LABEL_START_SIZE; |
4847 | adddev->l2ad_end = VDEV_LABEL_START_SIZE + vdev_get_min_asize(vd); | |
34dc7c2f BB |
4848 | adddev->l2ad_hand = adddev->l2ad_start; |
4849 | adddev->l2ad_evict = adddev->l2ad_start; | |
4850 | adddev->l2ad_first = B_TRUE; | |
d164b209 | 4851 | adddev->l2ad_writing = B_FALSE; |
98f72a53 | 4852 | list_link_init(&adddev->l2ad_node); |
34dc7c2f BB |
4853 | ASSERT3U(adddev->l2ad_write, >, 0); |
4854 | ||
4855 | /* | |
4856 | * This is a list of all ARC buffers that are still valid on the | |
4857 | * device. | |
4858 | */ | |
4859 | adddev->l2ad_buflist = kmem_zalloc(sizeof (list_t), KM_SLEEP); | |
4860 | list_create(adddev->l2ad_buflist, sizeof (arc_buf_hdr_t), | |
4861 | offsetof(arc_buf_hdr_t, b_l2node)); | |
4862 | ||
428870ff | 4863 | vdev_space_update(vd, 0, 0, adddev->l2ad_end - adddev->l2ad_hand); |
34dc7c2f BB |
4864 | |
4865 | /* | |
4866 | * Add device to global list | |
4867 | */ | |
4868 | mutex_enter(&l2arc_dev_mtx); | |
4869 | list_insert_head(l2arc_dev_list, adddev); | |
4870 | atomic_inc_64(&l2arc_ndev); | |
4871 | mutex_exit(&l2arc_dev_mtx); | |
4872 | } | |
4873 | ||
4874 | /* | |
4875 | * Remove a vdev from the L2ARC. | |
4876 | */ | |
4877 | void | |
4878 | l2arc_remove_vdev(vdev_t *vd) | |
4879 | { | |
4880 | l2arc_dev_t *dev, *nextdev, *remdev = NULL; | |
4881 | ||
34dc7c2f BB |
4882 | /* |
4883 | * Find the device by vdev | |
4884 | */ | |
4885 | mutex_enter(&l2arc_dev_mtx); | |
4886 | for (dev = list_head(l2arc_dev_list); dev; dev = nextdev) { | |
4887 | nextdev = list_next(l2arc_dev_list, dev); | |
4888 | if (vd == dev->l2ad_vdev) { | |
4889 | remdev = dev; | |
4890 | break; | |
4891 | } | |
4892 | } | |
4893 | ASSERT(remdev != NULL); | |
4894 | ||
4895 | /* | |
4896 | * Remove device from global list | |
4897 | */ | |
4898 | list_remove(l2arc_dev_list, remdev); | |
4899 | l2arc_dev_last = NULL; /* may have been invalidated */ | |
b128c09f BB |
4900 | atomic_dec_64(&l2arc_ndev); |
4901 | mutex_exit(&l2arc_dev_mtx); | |
34dc7c2f BB |
4902 | |
4903 | /* | |
4904 | * Clear all buflists and ARC references. L2ARC device flush. | |
4905 | */ | |
4906 | l2arc_evict(remdev, 0, B_TRUE); | |
4907 | list_destroy(remdev->l2ad_buflist); | |
4908 | kmem_free(remdev->l2ad_buflist, sizeof (list_t)); | |
4909 | kmem_free(remdev, sizeof (l2arc_dev_t)); | |
34dc7c2f BB |
4910 | } |
4911 | ||
4912 | void | |
b128c09f | 4913 | l2arc_init(void) |
34dc7c2f BB |
4914 | { |
4915 | l2arc_thread_exit = 0; | |
4916 | l2arc_ndev = 0; | |
4917 | l2arc_writes_sent = 0; | |
4918 | l2arc_writes_done = 0; | |
4919 | ||
4920 | mutex_init(&l2arc_feed_thr_lock, NULL, MUTEX_DEFAULT, NULL); | |
4921 | cv_init(&l2arc_feed_thr_cv, NULL, CV_DEFAULT, NULL); | |
4922 | mutex_init(&l2arc_dev_mtx, NULL, MUTEX_DEFAULT, NULL); | |
4923 | mutex_init(&l2arc_buflist_mtx, NULL, MUTEX_DEFAULT, NULL); | |
4924 | mutex_init(&l2arc_free_on_write_mtx, NULL, MUTEX_DEFAULT, NULL); | |
4925 | ||
4926 | l2arc_dev_list = &L2ARC_dev_list; | |
4927 | l2arc_free_on_write = &L2ARC_free_on_write; | |
4928 | list_create(l2arc_dev_list, sizeof (l2arc_dev_t), | |
4929 | offsetof(l2arc_dev_t, l2ad_node)); | |
4930 | list_create(l2arc_free_on_write, sizeof (l2arc_data_free_t), | |
4931 | offsetof(l2arc_data_free_t, l2df_list_node)); | |
34dc7c2f BB |
4932 | } |
4933 | ||
4934 | void | |
b128c09f | 4935 | l2arc_fini(void) |
34dc7c2f | 4936 | { |
b128c09f BB |
4937 | /* |
4938 | * This is called from dmu_fini(), which is called from spa_fini(); | |
4939 | * Because of this, we can assume that all l2arc devices have | |
4940 | * already been removed when the pools themselves were removed. | |
4941 | */ | |
4942 | ||
4943 | l2arc_do_free_on_write(); | |
34dc7c2f BB |
4944 | |
4945 | mutex_destroy(&l2arc_feed_thr_lock); | |
4946 | cv_destroy(&l2arc_feed_thr_cv); | |
4947 | mutex_destroy(&l2arc_dev_mtx); | |
4948 | mutex_destroy(&l2arc_buflist_mtx); | |
4949 | mutex_destroy(&l2arc_free_on_write_mtx); | |
4950 | ||
4951 | list_destroy(l2arc_dev_list); | |
4952 | list_destroy(l2arc_free_on_write); | |
4953 | } | |
b128c09f BB |
4954 | |
4955 | void | |
4956 | l2arc_start(void) | |
4957 | { | |
fb5f0bc8 | 4958 | if (!(spa_mode_global & FWRITE)) |
b128c09f BB |
4959 | return; |
4960 | ||
4961 | (void) thread_create(NULL, 0, l2arc_feed_thread, NULL, 0, &p0, | |
4962 | TS_RUN, minclsyspri); | |
4963 | } | |
4964 | ||
4965 | void | |
4966 | l2arc_stop(void) | |
4967 | { | |
fb5f0bc8 | 4968 | if (!(spa_mode_global & FWRITE)) |
b128c09f BB |
4969 | return; |
4970 | ||
4971 | mutex_enter(&l2arc_feed_thr_lock); | |
4972 | cv_signal(&l2arc_feed_thr_cv); /* kick thread out of startup */ | |
4973 | l2arc_thread_exit = 1; | |
4974 | while (l2arc_thread_exit != 0) | |
4975 | cv_wait(&l2arc_feed_thr_cv, &l2arc_feed_thr_lock); | |
4976 | mutex_exit(&l2arc_feed_thr_lock); | |
4977 | } | |
c28b2279 BB |
4978 | |
4979 | #if defined(_KERNEL) && defined(HAVE_SPL) | |
4980 | EXPORT_SYMBOL(arc_read); | |
4981 | EXPORT_SYMBOL(arc_buf_remove_ref); | |
4982 | EXPORT_SYMBOL(arc_getbuf_func); | |
ab26409d BB |
4983 | EXPORT_SYMBOL(arc_add_prune_callback); |
4984 | EXPORT_SYMBOL(arc_remove_prune_callback); | |
c28b2279 | 4985 | |
c409e464 BB |
4986 | module_param(zfs_arc_min, ulong, 0444); |
4987 | MODULE_PARM_DESC(zfs_arc_min, "Min arc size"); | |
c28b2279 | 4988 | |
c409e464 BB |
4989 | module_param(zfs_arc_max, ulong, 0444); |
4990 | MODULE_PARM_DESC(zfs_arc_max, "Max arc size"); | |
c28b2279 | 4991 | |
c409e464 | 4992 | module_param(zfs_arc_meta_limit, ulong, 0444); |
c28b2279 | 4993 | MODULE_PARM_DESC(zfs_arc_meta_limit, "Meta limit for arc size"); |
6a8f9b6b | 4994 | |
ab26409d BB |
4995 | module_param(zfs_arc_meta_prune, int, 0444); |
4996 | MODULE_PARM_DESC(zfs_arc_meta_prune, "Bytes of meta data to prune"); | |
c409e464 BB |
4997 | |
4998 | module_param(zfs_arc_grow_retry, int, 0444); | |
4999 | MODULE_PARM_DESC(zfs_arc_grow_retry, "Seconds before growing arc size"); | |
5000 | ||
5001 | module_param(zfs_arc_shrink_shift, int, 0444); | |
5002 | MODULE_PARM_DESC(zfs_arc_shrink_shift, "log2(fraction of arc to reclaim)"); | |
5003 | ||
5004 | module_param(zfs_arc_p_min_shift, int, 0444); | |
5005 | MODULE_PARM_DESC(zfs_arc_p_min_shift, "arc_c shift to calc min/max arc_p"); | |
5006 | ||
abd8610c BB |
5007 | module_param(l2arc_write_max, ulong, 0444); |
5008 | MODULE_PARM_DESC(l2arc_write_max, "Max write bytes per interval"); | |
5009 | ||
5010 | module_param(l2arc_write_boost, ulong, 0444); | |
5011 | MODULE_PARM_DESC(l2arc_write_boost, "Extra write bytes during device warmup"); | |
5012 | ||
5013 | module_param(l2arc_headroom, ulong, 0444); | |
5014 | MODULE_PARM_DESC(l2arc_headroom, "Number of max device writes to precache"); | |
5015 | ||
5016 | module_param(l2arc_feed_secs, ulong, 0444); | |
5017 | MODULE_PARM_DESC(l2arc_feed_secs, "Seconds between L2ARC writing"); | |
5018 | ||
5019 | module_param(l2arc_feed_min_ms, ulong, 0444); | |
5020 | MODULE_PARM_DESC(l2arc_feed_min_ms, "Min feed interval in milliseconds"); | |
5021 | ||
5022 | module_param(l2arc_noprefetch, int, 0444); | |
5023 | MODULE_PARM_DESC(l2arc_noprefetch, "Skip caching prefetched buffers"); | |
5024 | ||
5025 | module_param(l2arc_feed_again, int, 0444); | |
5026 | MODULE_PARM_DESC(l2arc_feed_again, "Turbo L2ARC warmup"); | |
5027 | ||
5028 | module_param(l2arc_norw, int, 0444); | |
5029 | MODULE_PARM_DESC(l2arc_norw, "No reads during writes"); | |
5030 | ||
c28b2279 | 5031 | #endif |