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