Blame view
fs/mbcache.c
24.1 KB
1da177e4c Linux-2.6.12-rc2 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 |
/* * linux/fs/mbcache.c * (C) 2001-2002 Andreas Gruenbacher, <a.gruenbacher@computer.org> */ /* * Filesystem Meta Information Block Cache (mbcache) * * The mbcache caches blocks of block devices that need to be located * by their device/block number, as well as by other criteria (such * as the block's contents). * * There can only be one cache entry in a cache per device and block number. * Additional indexes need not be unique in this sense. The number of * additional indexes (=other criteria) can be hardwired at compile time * or specified at cache create time. * * Each cache entry is of fixed size. An entry may be `valid' or `invalid' * in the cache. A valid entry is in the main hash tables of the cache, * and may also be in the lru list. An invalid entry is not in any hashes * or lists. * * A valid cache entry is only in the lru list if no handles refer to it. * Invalid cache entries will be freed when the last handle to the cache * entry is released. Entries that cannot be freed immediately are put * back on the lru list. */ |
1f3e55fe0 fs/mbcache.c: dou... |
28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 |
/* * Lock descriptions and usage: * * Each hash chain of both the block and index hash tables now contains * a built-in lock used to serialize accesses to the hash chain. * * Accesses to global data structures mb_cache_list and mb_cache_lru_list * are serialized via the global spinlock mb_cache_spinlock. * * Each mb_cache_entry contains a spinlock, e_entry_lock, to serialize * accesses to its local data, such as e_used and e_queued. * * Lock ordering: * * Each block hash chain's lock has the highest lock order, followed by an * index hash chain's lock, mb_cache_bg_lock (used to implement mb_cache_entry's * lock), and mb_cach_spinlock, with the lowest order. While holding * either a block or index hash chain lock, a thread can acquire an * mc_cache_bg_lock, which in turn can also acquire mb_cache_spinlock. * * Synchronization: * * Since both mb_cache_entry_get and mb_cache_entry_find scan the block and * index hash chian, it needs to lock the corresponding hash chain. For each * mb_cache_entry within the chain, it needs to lock the mb_cache_entry to * prevent either any simultaneous release or free on the entry and also * to serialize accesses to either the e_used or e_queued member of the entry. * * To avoid having a dangling reference to an already freed * mb_cache_entry, an mb_cache_entry is only freed when it is not on a * block hash chain and also no longer being referenced, both e_used, * and e_queued are 0's. When an mb_cache_entry is explicitly freed it is * first removed from a block hash chain. */ |
1da177e4c Linux-2.6.12-rc2 |
62 63 64 65 66 67 68 69 |
#include <linux/kernel.h> #include <linux/module.h> #include <linux/hash.h> #include <linux/fs.h> #include <linux/mm.h> #include <linux/slab.h> #include <linux/sched.h> |
3e037e521 fs/mbcache.c: cha... |
70 |
#include <linux/list_bl.h> |
1da177e4c Linux-2.6.12-rc2 |
71 |
#include <linux/mbcache.h> |
3e037e521 fs/mbcache.c: cha... |
72 |
#include <linux/init.h> |
1f3e55fe0 fs/mbcache.c: dou... |
73 |
#include <linux/blockgroup_lock.h> |
1da177e4c Linux-2.6.12-rc2 |
74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 |
#ifdef MB_CACHE_DEBUG # define mb_debug(f...) do { \ printk(KERN_DEBUG f); \ printk(" "); \ } while (0) #define mb_assert(c) do { if (!(c)) \ printk(KERN_ERR "assertion " #c " failed "); \ } while(0) #else # define mb_debug(f...) do { } while(0) # define mb_assert(c) do { } while(0) #endif #define mb_error(f...) do { \ printk(KERN_ERR f); \ printk(" "); \ } while(0) #define MB_CACHE_WRITER ((unsigned short)~0U >> 1) |
1f3e55fe0 fs/mbcache.c: dou... |
96 97 98 |
#define MB_CACHE_ENTRY_LOCK_BITS __builtin_log2(NR_BG_LOCKS) #define MB_CACHE_ENTRY_LOCK_INDEX(ce) \ (hash_long((unsigned long)ce, MB_CACHE_ENTRY_LOCK_BITS)) |
75c96f858 [PATCH] make some... |
99 |
static DECLARE_WAIT_QUEUE_HEAD(mb_cache_queue); |
1f3e55fe0 fs/mbcache.c: dou... |
100 |
static struct blockgroup_lock *mb_cache_bg_lock; |
9c191f701 ext4: each filesy... |
101 |
static struct kmem_cache *mb_cache_kmem_cache; |
1f3e55fe0 fs/mbcache.c: dou... |
102 |
|
1da177e4c Linux-2.6.12-rc2 |
103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 |
MODULE_AUTHOR("Andreas Gruenbacher <a.gruenbacher@computer.org>"); MODULE_DESCRIPTION("Meta block cache (for extended attributes)"); MODULE_LICENSE("GPL"); EXPORT_SYMBOL(mb_cache_create); EXPORT_SYMBOL(mb_cache_shrink); EXPORT_SYMBOL(mb_cache_destroy); EXPORT_SYMBOL(mb_cache_entry_alloc); EXPORT_SYMBOL(mb_cache_entry_insert); EXPORT_SYMBOL(mb_cache_entry_release); EXPORT_SYMBOL(mb_cache_entry_free); EXPORT_SYMBOL(mb_cache_entry_get); #if !defined(MB_CACHE_INDEXES_COUNT) || (MB_CACHE_INDEXES_COUNT > 0) EXPORT_SYMBOL(mb_cache_entry_find_first); EXPORT_SYMBOL(mb_cache_entry_find_next); #endif |
1da177e4c Linux-2.6.12-rc2 |
119 120 121 122 123 124 125 126 127 |
/* * Global data: list of all mbcache's, lru list, and a spinlock for * accessing cache data structures on SMP machines. The lru list is * global across all mbcaches. */ static LIST_HEAD(mb_cache_list); static LIST_HEAD(mb_cache_lru_list); static DEFINE_SPINLOCK(mb_cache_spinlock); |
1da177e4c Linux-2.6.12-rc2 |
128 |
|
1f3e55fe0 fs/mbcache.c: dou... |
129 130 131 132 133 134 135 136 137 138 139 140 141 |
static inline void __spin_lock_mb_cache_entry(struct mb_cache_entry *ce) { spin_lock(bgl_lock_ptr(mb_cache_bg_lock, MB_CACHE_ENTRY_LOCK_INDEX(ce))); } static inline void __spin_unlock_mb_cache_entry(struct mb_cache_entry *ce) { spin_unlock(bgl_lock_ptr(mb_cache_bg_lock, MB_CACHE_ENTRY_LOCK_INDEX(ce))); } |
1da177e4c Linux-2.6.12-rc2 |
142 |
static inline int |
3e037e521 fs/mbcache.c: cha... |
143 |
__mb_cache_entry_is_block_hashed(struct mb_cache_entry *ce) |
1da177e4c Linux-2.6.12-rc2 |
144 |
{ |
3e037e521 fs/mbcache.c: cha... |
145 |
return !hlist_bl_unhashed(&ce->e_block_list); |
1da177e4c Linux-2.6.12-rc2 |
146 |
} |
3e037e521 fs/mbcache.c: cha... |
147 148 |
static inline void __mb_cache_entry_unhash_block(struct mb_cache_entry *ce) |
1da177e4c Linux-2.6.12-rc2 |
149 |
{ |
3e037e521 fs/mbcache.c: cha... |
150 151 152 153 154 155 156 157 |
if (__mb_cache_entry_is_block_hashed(ce)) hlist_bl_del_init(&ce->e_block_list); } static inline int __mb_cache_entry_is_index_hashed(struct mb_cache_entry *ce) { return !hlist_bl_unhashed(&ce->e_index.o_list); |
1da177e4c Linux-2.6.12-rc2 |
158 |
} |
3e037e521 fs/mbcache.c: cha... |
159 160 161 162 163 164 |
static inline void __mb_cache_entry_unhash_index(struct mb_cache_entry *ce) { if (__mb_cache_entry_is_index_hashed(ce)) hlist_bl_del_init(&ce->e_index.o_list); } |
1f3e55fe0 fs/mbcache.c: dou... |
165 166 167 168 169 170 171 172 |
/* * __mb_cache_entry_unhash_unlock() * * This function is called to unhash both the block and index hash * chain. * It assumes both the block and index hash chain is locked upon entry. * It also unlock both hash chains both exit */ |
3e037e521 fs/mbcache.c: cha... |
173 |
static inline void |
1f3e55fe0 fs/mbcache.c: dou... |
174 |
__mb_cache_entry_unhash_unlock(struct mb_cache_entry *ce) |
3e037e521 fs/mbcache.c: cha... |
175 176 |
{ __mb_cache_entry_unhash_index(ce); |
1f3e55fe0 fs/mbcache.c: dou... |
177 |
hlist_bl_unlock(ce->e_index_hash_p); |
3e037e521 fs/mbcache.c: cha... |
178 |
__mb_cache_entry_unhash_block(ce); |
1f3e55fe0 fs/mbcache.c: dou... |
179 |
hlist_bl_unlock(ce->e_block_hash_p); |
3e037e521 fs/mbcache.c: cha... |
180 |
} |
1da177e4c Linux-2.6.12-rc2 |
181 |
|
858119e15 [PATCH] Unlinline... |
182 |
static void |
27496a8c6 [PATCH] gfp_t: fs/* |
183 |
__mb_cache_entry_forget(struct mb_cache_entry *ce, gfp_t gfp_mask) |
1da177e4c Linux-2.6.12-rc2 |
184 185 |
{ struct mb_cache *cache = ce->e_cache; |
1f3e55fe0 fs/mbcache.c: dou... |
186 |
mb_assert(!(ce->e_used || ce->e_queued || atomic_read(&ce->e_refcnt))); |
2aec7c523 mbcache: Remove u... |
187 188 |
kmem_cache_free(cache->c_entry_cache, ce); atomic_dec(&cache->c_entry_count); |
1da177e4c Linux-2.6.12-rc2 |
189 |
} |
858119e15 [PATCH] Unlinline... |
190 |
static void |
1f3e55fe0 fs/mbcache.c: dou... |
191 |
__mb_cache_entry_release(struct mb_cache_entry *ce) |
1da177e4c Linux-2.6.12-rc2 |
192 |
{ |
1f3e55fe0 fs/mbcache.c: dou... |
193 194 |
/* First lock the entry to serialize access to its local data. */ __spin_lock_mb_cache_entry(ce); |
1da177e4c Linux-2.6.12-rc2 |
195 196 197 198 199 |
/* Wake up all processes queuing for this cache entry. */ if (ce->e_queued) wake_up_all(&mb_cache_queue); if (ce->e_used >= MB_CACHE_WRITER) ce->e_used -= MB_CACHE_WRITER; |
1f3e55fe0 fs/mbcache.c: dou... |
200 201 202 203 |
/* * Make sure that all cache entries on lru_list have * both e_used and e_qued of 0s. */ |
1da177e4c Linux-2.6.12-rc2 |
204 |
ce->e_used--; |
1f3e55fe0 fs/mbcache.c: dou... |
205 206 207 |
if (!(ce->e_used || ce->e_queued || atomic_read(&ce->e_refcnt))) { if (!__mb_cache_entry_is_block_hashed(ce)) { __spin_unlock_mb_cache_entry(ce); |
1da177e4c Linux-2.6.12-rc2 |
208 |
goto forget; |
1f3e55fe0 fs/mbcache.c: dou... |
209 210 211 212 213 214 215 216 217 |
} /* * Need access to lru list, first drop entry lock, * then reacquire the lock in the proper order. */ spin_lock(&mb_cache_spinlock); if (list_empty(&ce->e_lru_list)) list_add_tail(&ce->e_lru_list, &mb_cache_lru_list); spin_unlock(&mb_cache_spinlock); |
1da177e4c Linux-2.6.12-rc2 |
218 |
} |
1f3e55fe0 fs/mbcache.c: dou... |
219 |
__spin_unlock_mb_cache_entry(ce); |
1da177e4c Linux-2.6.12-rc2 |
220 221 |
return; forget: |
1f3e55fe0 fs/mbcache.c: dou... |
222 |
mb_assert(list_empty(&ce->e_lru_list)); |
1da177e4c Linux-2.6.12-rc2 |
223 224 |
__mb_cache_entry_forget(ce, GFP_KERNEL); } |
1da177e4c Linux-2.6.12-rc2 |
225 |
/* |
1ab6c4997 fs: convert fs sh... |
226 |
* mb_cache_shrink_scan() memory pressure callback |
1da177e4c Linux-2.6.12-rc2 |
227 228 229 230 |
* * This function is called by the kernel memory management when memory * gets low. * |
7f8275d0d mm: add context a... |
231 |
* @shrink: (ignored) |
1495f230f vmscan: change sh... |
232 |
* @sc: shrink_control passed from reclaim |
1da177e4c Linux-2.6.12-rc2 |
233 |
* |
1ab6c4997 fs: convert fs sh... |
234 |
* Returns the number of objects freed. |
1da177e4c Linux-2.6.12-rc2 |
235 |
*/ |
1ab6c4997 fs: convert fs sh... |
236 237 |
static unsigned long mb_cache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) |
1da177e4c Linux-2.6.12-rc2 |
238 239 |
{ LIST_HEAD(free_list); |
e566d48c9 mbcache: fix shri... |
240 |
struct mb_cache_entry *entry, *tmp; |
1495f230f vmscan: change sh... |
241 242 |
int nr_to_scan = sc->nr_to_scan; gfp_t gfp_mask = sc->gfp_mask; |
1ab6c4997 fs: convert fs sh... |
243 |
unsigned long freed = 0; |
1da177e4c Linux-2.6.12-rc2 |
244 |
|
1da177e4c Linux-2.6.12-rc2 |
245 |
mb_debug("trying to free %d entries", nr_to_scan); |
e566d48c9 mbcache: fix shri... |
246 |
spin_lock(&mb_cache_spinlock); |
1f3e55fe0 fs/mbcache.c: dou... |
247 |
while ((nr_to_scan-- > 0) && !list_empty(&mb_cache_lru_list)) { |
1da177e4c Linux-2.6.12-rc2 |
248 249 |
struct mb_cache_entry *ce = list_entry(mb_cache_lru_list.next, |
1f3e55fe0 fs/mbcache.c: dou... |
250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 |
struct mb_cache_entry, e_lru_list); list_del_init(&ce->e_lru_list); if (ce->e_used || ce->e_queued || atomic_read(&ce->e_refcnt)) continue; spin_unlock(&mb_cache_spinlock); /* Prevent any find or get operation on the entry */ hlist_bl_lock(ce->e_block_hash_p); hlist_bl_lock(ce->e_index_hash_p); /* Ignore if it is touched by a find/get */ if (ce->e_used || ce->e_queued || atomic_read(&ce->e_refcnt) || !list_empty(&ce->e_lru_list)) { hlist_bl_unlock(ce->e_index_hash_p); hlist_bl_unlock(ce->e_block_hash_p); spin_lock(&mb_cache_spinlock); continue; } __mb_cache_entry_unhash_unlock(ce); list_add_tail(&ce->e_lru_list, &free_list); spin_lock(&mb_cache_spinlock); |
1ab6c4997 fs: convert fs sh... |
269 270 |
} spin_unlock(&mb_cache_spinlock); |
1f3e55fe0 fs/mbcache.c: dou... |
271 |
|
1ab6c4997 fs: convert fs sh... |
272 273 |
list_for_each_entry_safe(entry, tmp, &free_list, e_lru_list) { __mb_cache_entry_forget(entry, gfp_mask); |
1f3e55fe0 fs/mbcache.c: dou... |
274 |
freed++; |
1da177e4c Linux-2.6.12-rc2 |
275 |
} |
1ab6c4997 fs: convert fs sh... |
276 277 278 279 280 281 282 283 284 285 |
return freed; } static unsigned long mb_cache_shrink_count(struct shrinker *shrink, struct shrink_control *sc) { struct mb_cache *cache; unsigned long count = 0; spin_lock(&mb_cache_spinlock); |
e566d48c9 mbcache: fix shri... |
286 287 288 289 290 |
list_for_each_entry(cache, &mb_cache_list, c_cache_list) { mb_debug("cache %s (%d)", cache->c_name, atomic_read(&cache->c_entry_count)); count += atomic_read(&cache->c_entry_count); } |
1da177e4c Linux-2.6.12-rc2 |
291 |
spin_unlock(&mb_cache_spinlock); |
1ab6c4997 fs: convert fs sh... |
292 |
|
55f841ce9 super: fix calcul... |
293 |
return vfs_pressure_ratio(count); |
1da177e4c Linux-2.6.12-rc2 |
294 |
} |
1ab6c4997 fs: convert fs sh... |
295 296 297 298 299 |
static struct shrinker mb_cache_shrinker = { .count_objects = mb_cache_shrink_count, .scan_objects = mb_cache_shrink_scan, .seeks = DEFAULT_SEEKS, }; |
1da177e4c Linux-2.6.12-rc2 |
300 301 302 303 304 305 306 307 308 309 |
/* * mb_cache_create() create a new cache * * All entries in one cache are equal size. Cache entries may be from * multiple devices. If this is the first mbcache created, registers * the cache with kernel memory management. Returns NULL if no more * memory was available. * * @name: name of the cache (informal) |
1da177e4c Linux-2.6.12-rc2 |
310 311 312 |
* @bucket_bits: log2(number of hash buckets) */ struct mb_cache * |
2aec7c523 mbcache: Remove u... |
313 |
mb_cache_create(const char *name, int bucket_bits) |
1da177e4c Linux-2.6.12-rc2 |
314 |
{ |
2aec7c523 mbcache: Remove u... |
315 |
int n, bucket_count = 1 << bucket_bits; |
1da177e4c Linux-2.6.12-rc2 |
316 |
struct mb_cache *cache = NULL; |
1f3e55fe0 fs/mbcache.c: dou... |
317 318 319 320 321 322 323 |
if (!mb_cache_bg_lock) { mb_cache_bg_lock = kmalloc(sizeof(struct blockgroup_lock), GFP_KERNEL); if (!mb_cache_bg_lock) return NULL; bgl_lock_init(mb_cache_bg_lock); } |
2aec7c523 mbcache: Remove u... |
324 |
cache = kmalloc(sizeof(struct mb_cache), GFP_KERNEL); |
1da177e4c Linux-2.6.12-rc2 |
325 |
if (!cache) |
2aec7c523 mbcache: Remove u... |
326 |
return NULL; |
1da177e4c Linux-2.6.12-rc2 |
327 |
cache->c_name = name; |
1da177e4c Linux-2.6.12-rc2 |
328 329 |
atomic_set(&cache->c_entry_count, 0); cache->c_bucket_bits = bucket_bits; |
3e037e521 fs/mbcache.c: cha... |
330 331 |
cache->c_block_hash = kmalloc(bucket_count * sizeof(struct hlist_bl_head), GFP_KERNEL); |
1da177e4c Linux-2.6.12-rc2 |
332 333 334 |
if (!cache->c_block_hash) goto fail; for (n=0; n<bucket_count; n++) |
3e037e521 fs/mbcache.c: cha... |
335 336 337 |
INIT_HLIST_BL_HEAD(&cache->c_block_hash[n]); cache->c_index_hash = kmalloc(bucket_count * sizeof(struct hlist_bl_head), GFP_KERNEL); |
2aec7c523 mbcache: Remove u... |
338 339 340 |
if (!cache->c_index_hash) goto fail; for (n=0; n<bucket_count; n++) |
3e037e521 fs/mbcache.c: cha... |
341 |
INIT_HLIST_BL_HEAD(&cache->c_index_hash[n]); |
9c191f701 ext4: each filesy... |
342 343 344 345 346 347 348 349 |
if (!mb_cache_kmem_cache) { mb_cache_kmem_cache = kmem_cache_create(name, sizeof(struct mb_cache_entry), 0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD, NULL); if (!mb_cache_kmem_cache) goto fail2; } cache->c_entry_cache = mb_cache_kmem_cache; |
1da177e4c Linux-2.6.12-rc2 |
350 |
|
3a48ee8a4 mbcache: Limit th... |
351 352 353 354 355 |
/* * Set an upper limit on the number of cache entries so that the hash * chains won't grow too long. */ cache->c_max_entries = bucket_count << 4; |
1da177e4c Linux-2.6.12-rc2 |
356 357 358 359 |
spin_lock(&mb_cache_spinlock); list_add(&cache->c_cache_list, &mb_cache_list); spin_unlock(&mb_cache_spinlock); return cache; |
2aec7c523 mbcache: Remove u... |
360 361 |
fail2: kfree(cache->c_index_hash); |
1da177e4c Linux-2.6.12-rc2 |
362 |
fail: |
2aec7c523 mbcache: Remove u... |
363 364 |
kfree(cache->c_block_hash); kfree(cache); |
1da177e4c Linux-2.6.12-rc2 |
365 366 367 368 369 370 371 |
return NULL; } /* * mb_cache_shrink() * |
7f927fcc2 [PATCH] Typo fixes |
372 |
* Removes all cache entries of a device from the cache. All cache entries |
1da177e4c Linux-2.6.12-rc2 |
373 374 375 |
* currently in use cannot be freed, and thus remain in the cache. All others * are freed. * |
1da177e4c Linux-2.6.12-rc2 |
376 377 378 |
* @bdev: which device's cache entries to shrink */ void |
8c52ab42c [PATCH] mbcache: ... |
379 |
mb_cache_shrink(struct block_device *bdev) |
1da177e4c Linux-2.6.12-rc2 |
380 381 |
{ LIST_HEAD(free_list); |
1f3e55fe0 fs/mbcache.c: dou... |
382 383 |
struct list_head *l; struct mb_cache_entry *ce, *tmp; |
1da177e4c Linux-2.6.12-rc2 |
384 |
|
1f3e55fe0 fs/mbcache.c: dou... |
385 |
l = &mb_cache_lru_list; |
1da177e4c Linux-2.6.12-rc2 |
386 |
spin_lock(&mb_cache_spinlock); |
1f3e55fe0 fs/mbcache.c: dou... |
387 388 389 |
while (!list_is_last(l, &mb_cache_lru_list)) { l = l->next; ce = list_entry(l, struct mb_cache_entry, e_lru_list); |
1da177e4c Linux-2.6.12-rc2 |
390 |
if (ce->e_bdev == bdev) { |
1f3e55fe0 fs/mbcache.c: dou... |
391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 |
list_del_init(&ce->e_lru_list); if (ce->e_used || ce->e_queued || atomic_read(&ce->e_refcnt)) continue; spin_unlock(&mb_cache_spinlock); /* * Prevent any find or get operation on the entry. */ hlist_bl_lock(ce->e_block_hash_p); hlist_bl_lock(ce->e_index_hash_p); /* Ignore if it is touched by a find/get */ if (ce->e_used || ce->e_queued || atomic_read(&ce->e_refcnt) || !list_empty(&ce->e_lru_list)) { hlist_bl_unlock(ce->e_index_hash_p); hlist_bl_unlock(ce->e_block_hash_p); l = &mb_cache_lru_list; spin_lock(&mb_cache_spinlock); continue; } __mb_cache_entry_unhash_unlock(ce); mb_assert(!(ce->e_used || ce->e_queued || atomic_read(&ce->e_refcnt))); list_add_tail(&ce->e_lru_list, &free_list); l = &mb_cache_lru_list; spin_lock(&mb_cache_spinlock); |
1da177e4c Linux-2.6.12-rc2 |
417 418 419 |
} } spin_unlock(&mb_cache_spinlock); |
1f3e55fe0 fs/mbcache.c: dou... |
420 421 422 |
list_for_each_entry_safe(ce, tmp, &free_list, e_lru_list) { __mb_cache_entry_forget(ce, GFP_KERNEL); |
1da177e4c Linux-2.6.12-rc2 |
423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 |
} } /* * mb_cache_destroy() * * Shrinks the cache to its minimum possible size (hopefully 0 entries), * and then destroys it. If this was the last mbcache, un-registers the * mbcache from kernel memory management. */ void mb_cache_destroy(struct mb_cache *cache) { LIST_HEAD(free_list); |
1f3e55fe0 fs/mbcache.c: dou... |
438 |
struct mb_cache_entry *ce, *tmp; |
1da177e4c Linux-2.6.12-rc2 |
439 440 |
spin_lock(&mb_cache_spinlock); |
1f3e55fe0 fs/mbcache.c: dou... |
441 442 |
list_for_each_entry_safe(ce, tmp, &mb_cache_lru_list, e_lru_list) { if (ce->e_cache == cache) |
1da177e4c Linux-2.6.12-rc2 |
443 |
list_move_tail(&ce->e_lru_list, &free_list); |
1da177e4c Linux-2.6.12-rc2 |
444 445 446 |
} list_del(&cache->c_cache_list); spin_unlock(&mb_cache_spinlock); |
1f3e55fe0 fs/mbcache.c: dou... |
447 448 449 450 451 452 453 454 455 456 457 |
list_for_each_entry_safe(ce, tmp, &free_list, e_lru_list) { list_del_init(&ce->e_lru_list); /* * Prevent any find or get operation on the entry. */ hlist_bl_lock(ce->e_block_hash_p); hlist_bl_lock(ce->e_index_hash_p); mb_assert(!(ce->e_used || ce->e_queued || atomic_read(&ce->e_refcnt))); __mb_cache_entry_unhash_unlock(ce); __mb_cache_entry_forget(ce, GFP_KERNEL); |
1da177e4c Linux-2.6.12-rc2 |
458 459 460 461 462 463 464 |
} if (atomic_read(&cache->c_entry_count) > 0) { mb_error("cache %s: %d orphaned entries", cache->c_name, atomic_read(&cache->c_entry_count)); } |
9c191f701 ext4: each filesy... |
465 466 467 468 |
if (list_empty(&mb_cache_list)) { kmem_cache_destroy(mb_cache_kmem_cache); mb_cache_kmem_cache = NULL; } |
2aec7c523 mbcache: Remove u... |
469 |
kfree(cache->c_index_hash); |
1da177e4c Linux-2.6.12-rc2 |
470 471 472 |
kfree(cache->c_block_hash); kfree(cache); } |
1da177e4c Linux-2.6.12-rc2 |
473 474 475 476 477 478 479 480 481 |
/* * mb_cache_entry_alloc() * * Allocates a new cache entry. The new entry will not be valid initially, * and thus cannot be looked up yet. It should be filled with data, and * then inserted into the cache using mb_cache_entry_insert(). Returns NULL * if no more memory was available. */ struct mb_cache_entry * |
335e92e8a vfs: fix possible... |
482 |
mb_cache_entry_alloc(struct mb_cache *cache, gfp_t gfp_flags) |
1da177e4c Linux-2.6.12-rc2 |
483 |
{ |
1f3e55fe0 fs/mbcache.c: dou... |
484 |
struct mb_cache_entry *ce; |
3a48ee8a4 mbcache: Limit th... |
485 486 |
if (atomic_read(&cache->c_entry_count) >= cache->c_max_entries) { |
1f3e55fe0 fs/mbcache.c: dou... |
487 488 489 |
struct list_head *l; l = &mb_cache_lru_list; |
3a48ee8a4 mbcache: Limit th... |
490 |
spin_lock(&mb_cache_spinlock); |
1f3e55fe0 fs/mbcache.c: dou... |
491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 |
while (!list_is_last(l, &mb_cache_lru_list)) { l = l->next; ce = list_entry(l, struct mb_cache_entry, e_lru_list); if (ce->e_cache == cache) { list_del_init(&ce->e_lru_list); if (ce->e_used || ce->e_queued || atomic_read(&ce->e_refcnt)) continue; spin_unlock(&mb_cache_spinlock); /* * Prevent any find or get operation on the * entry. */ hlist_bl_lock(ce->e_block_hash_p); hlist_bl_lock(ce->e_index_hash_p); /* Ignore if it is touched by a find/get */ if (ce->e_used || ce->e_queued || atomic_read(&ce->e_refcnt) || !list_empty(&ce->e_lru_list)) { hlist_bl_unlock(ce->e_index_hash_p); hlist_bl_unlock(ce->e_block_hash_p); l = &mb_cache_lru_list; spin_lock(&mb_cache_spinlock); continue; } mb_assert(list_empty(&ce->e_lru_list)); mb_assert(!(ce->e_used || ce->e_queued || atomic_read(&ce->e_refcnt))); __mb_cache_entry_unhash_unlock(ce); goto found; } |
3a48ee8a4 mbcache: Limit th... |
522 523 524 |
} spin_unlock(&mb_cache_spinlock); } |
1f3e55fe0 fs/mbcache.c: dou... |
525 526 527 528 529 530 531 532 533 534 535 536 |
ce = kmem_cache_alloc(cache->c_entry_cache, gfp_flags); if (!ce) return NULL; atomic_inc(&cache->c_entry_count); INIT_LIST_HEAD(&ce->e_lru_list); INIT_HLIST_BL_NODE(&ce->e_block_list); INIT_HLIST_BL_NODE(&ce->e_index.o_list); ce->e_cache = cache; ce->e_queued = 0; atomic_set(&ce->e_refcnt, 0); found: |
3e037e521 fs/mbcache.c: cha... |
537 538 |
ce->e_block_hash_p = &cache->c_block_hash[0]; ce->e_index_hash_p = &cache->c_index_hash[0]; |
3a48ee8a4 mbcache: Limit th... |
539 |
ce->e_used = 1 + MB_CACHE_WRITER; |
1da177e4c Linux-2.6.12-rc2 |
540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 |
return ce; } /* * mb_cache_entry_insert() * * Inserts an entry that was allocated using mb_cache_entry_alloc() into * the cache. After this, the cache entry can be looked up, but is not yet * in the lru list as the caller still holds a handle to it. Returns 0 on * success, or -EBUSY if a cache entry for that device + inode exists * already (this may happen after a failed lookup, but when another process * has inserted the same cache entry in the meantime). * * @bdev: device the cache entry belongs to * @block: block number |
2aec7c523 mbcache: Remove u... |
556 |
* @key: lookup key |
1da177e4c Linux-2.6.12-rc2 |
557 558 559 |
*/ int mb_cache_entry_insert(struct mb_cache_entry *ce, struct block_device *bdev, |
2aec7c523 mbcache: Remove u... |
560 |
sector_t block, unsigned int key) |
1da177e4c Linux-2.6.12-rc2 |
561 562 563 |
{ struct mb_cache *cache = ce->e_cache; unsigned int bucket; |
3e037e521 fs/mbcache.c: cha... |
564 |
struct hlist_bl_node *l; |
3e037e521 fs/mbcache.c: cha... |
565 566 567 |
struct hlist_bl_head *block_hash_p; struct hlist_bl_head *index_hash_p; struct mb_cache_entry *lce; |
1da177e4c Linux-2.6.12-rc2 |
568 |
|
3e037e521 fs/mbcache.c: cha... |
569 |
mb_assert(ce); |
1da177e4c Linux-2.6.12-rc2 |
570 571 |
bucket = hash_long((unsigned long)bdev + (block & 0xffffffff), cache->c_bucket_bits); |
3e037e521 fs/mbcache.c: cha... |
572 |
block_hash_p = &cache->c_block_hash[bucket]; |
1f3e55fe0 fs/mbcache.c: dou... |
573 |
hlist_bl_lock(block_hash_p); |
3e037e521 fs/mbcache.c: cha... |
574 |
hlist_bl_for_each_entry(lce, l, block_hash_p, e_block_list) { |
1f3e55fe0 fs/mbcache.c: dou... |
575 576 577 578 |
if (lce->e_bdev == bdev && lce->e_block == block) { hlist_bl_unlock(block_hash_p); return -EBUSY; } |
1da177e4c Linux-2.6.12-rc2 |
579 |
} |
3e037e521 fs/mbcache.c: cha... |
580 |
mb_assert(!__mb_cache_entry_is_block_hashed(ce)); |
1f3e55fe0 fs/mbcache.c: dou... |
581 582 |
__mb_cache_entry_unhash_block(ce); __mb_cache_entry_unhash_index(ce); |
1da177e4c Linux-2.6.12-rc2 |
583 584 |
ce->e_bdev = bdev; ce->e_block = block; |
3e037e521 fs/mbcache.c: cha... |
585 |
ce->e_block_hash_p = block_hash_p; |
2aec7c523 mbcache: Remove u... |
586 |
ce->e_index.o_key = key; |
1f3e55fe0 fs/mbcache.c: dou... |
587 588 |
hlist_bl_add_head(&ce->e_block_list, block_hash_p); hlist_bl_unlock(block_hash_p); |
2aec7c523 mbcache: Remove u... |
589 |
bucket = hash_long(key, cache->c_bucket_bits); |
3e037e521 fs/mbcache.c: cha... |
590 |
index_hash_p = &cache->c_index_hash[bucket]; |
1f3e55fe0 fs/mbcache.c: dou... |
591 |
hlist_bl_lock(index_hash_p); |
3e037e521 fs/mbcache.c: cha... |
592 593 |
ce->e_index_hash_p = index_hash_p; hlist_bl_add_head(&ce->e_index.o_list, index_hash_p); |
1f3e55fe0 fs/mbcache.c: dou... |
594 595 |
hlist_bl_unlock(index_hash_p); return 0; |
1da177e4c Linux-2.6.12-rc2 |
596 597 598 599 600 601 602 603 604 605 606 607 608 |
} /* * mb_cache_entry_release() * * Release a handle to a cache entry. When the last handle to a cache entry * is released it is either freed (if it is invalid) or otherwise inserted * in to the lru list. */ void mb_cache_entry_release(struct mb_cache_entry *ce) { |
1f3e55fe0 fs/mbcache.c: dou... |
609 |
__mb_cache_entry_release(ce); |
1da177e4c Linux-2.6.12-rc2 |
610 611 612 613 614 615 |
} /* * mb_cache_entry_free() * |
1da177e4c Linux-2.6.12-rc2 |
616 617 618 619 |
*/ void mb_cache_entry_free(struct mb_cache_entry *ce) { |
1f3e55fe0 fs/mbcache.c: dou... |
620 |
mb_assert(ce); |
1da177e4c Linux-2.6.12-rc2 |
621 |
mb_assert(list_empty(&ce->e_lru_list)); |
1f3e55fe0 fs/mbcache.c: dou... |
622 623 624 625 626 627 628 |
hlist_bl_lock(ce->e_index_hash_p); __mb_cache_entry_unhash_index(ce); hlist_bl_unlock(ce->e_index_hash_p); hlist_bl_lock(ce->e_block_hash_p); __mb_cache_entry_unhash_block(ce); hlist_bl_unlock(ce->e_block_hash_p); __mb_cache_entry_release(ce); |
1da177e4c Linux-2.6.12-rc2 |
629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 |
} /* * mb_cache_entry_get() * * Get a cache entry by device / block number. (There can only be one entry * in the cache per device and block.) Returns NULL if no such cache entry * exists. The returned cache entry is locked for exclusive access ("single * writer"). */ struct mb_cache_entry * mb_cache_entry_get(struct mb_cache *cache, struct block_device *bdev, sector_t block) { unsigned int bucket; |
3e037e521 fs/mbcache.c: cha... |
645 |
struct hlist_bl_node *l; |
1da177e4c Linux-2.6.12-rc2 |
646 |
struct mb_cache_entry *ce; |
3e037e521 fs/mbcache.c: cha... |
647 |
struct hlist_bl_head *block_hash_p; |
1da177e4c Linux-2.6.12-rc2 |
648 649 650 |
bucket = hash_long((unsigned long)bdev + (block & 0xffffffff), cache->c_bucket_bits); |
3e037e521 fs/mbcache.c: cha... |
651 |
block_hash_p = &cache->c_block_hash[bucket]; |
1f3e55fe0 fs/mbcache.c: dou... |
652 653 |
/* First serialize access to the block corresponding hash chain. */ hlist_bl_lock(block_hash_p); |
3e037e521 fs/mbcache.c: cha... |
654 655 |
hlist_bl_for_each_entry(ce, l, block_hash_p, e_block_list) { mb_assert(ce->e_block_hash_p == block_hash_p); |
1da177e4c Linux-2.6.12-rc2 |
656 |
if (ce->e_bdev == bdev && ce->e_block == block) { |
1f3e55fe0 fs/mbcache.c: dou... |
657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 |
/* * Prevent a free from removing the entry. */ atomic_inc(&ce->e_refcnt); hlist_bl_unlock(block_hash_p); __spin_lock_mb_cache_entry(ce); atomic_dec(&ce->e_refcnt); if (ce->e_used > 0) { DEFINE_WAIT(wait); while (ce->e_used > 0) { ce->e_queued++; prepare_to_wait(&mb_cache_queue, &wait, TASK_UNINTERRUPTIBLE); __spin_unlock_mb_cache_entry(ce); schedule(); __spin_lock_mb_cache_entry(ce); ce->e_queued--; } finish_wait(&mb_cache_queue, &wait); } ce->e_used += 1 + MB_CACHE_WRITER; __spin_unlock_mb_cache_entry(ce); |
1da177e4c Linux-2.6.12-rc2 |
679 |
|
1f3e55fe0 fs/mbcache.c: dou... |
680 681 |
if (!list_empty(&ce->e_lru_list)) { spin_lock(&mb_cache_spinlock); |
1da177e4c Linux-2.6.12-rc2 |
682 |
list_del_init(&ce->e_lru_list); |
1da177e4c Linux-2.6.12-rc2 |
683 |
spin_unlock(&mb_cache_spinlock); |
1da177e4c Linux-2.6.12-rc2 |
684 |
} |
3e037e521 fs/mbcache.c: cha... |
685 |
if (!__mb_cache_entry_is_block_hashed(ce)) { |
1f3e55fe0 fs/mbcache.c: dou... |
686 |
__mb_cache_entry_release(ce); |
1da177e4c Linux-2.6.12-rc2 |
687 688 |
return NULL; } |
1f3e55fe0 fs/mbcache.c: dou... |
689 |
return ce; |
1da177e4c Linux-2.6.12-rc2 |
690 691 |
} } |
1f3e55fe0 fs/mbcache.c: dou... |
692 693 |
hlist_bl_unlock(block_hash_p); return NULL; |
1da177e4c Linux-2.6.12-rc2 |
694 695 696 697 698 |
} #if !defined(MB_CACHE_INDEXES_COUNT) || (MB_CACHE_INDEXES_COUNT > 0) static struct mb_cache_entry * |
3e037e521 fs/mbcache.c: cha... |
699 |
__mb_cache_entry_find(struct hlist_bl_node *l, struct hlist_bl_head *head, |
2aec7c523 mbcache: Remove u... |
700 |
struct block_device *bdev, unsigned int key) |
1da177e4c Linux-2.6.12-rc2 |
701 |
{ |
1f3e55fe0 fs/mbcache.c: dou... |
702 703 |
/* The index hash chain is alredy acquire by caller. */ |
3e037e521 fs/mbcache.c: cha... |
704 |
while (l != NULL) { |
1da177e4c Linux-2.6.12-rc2 |
705 |
struct mb_cache_entry *ce = |
3e037e521 fs/mbcache.c: cha... |
706 707 708 |
hlist_bl_entry(l, struct mb_cache_entry, e_index.o_list); mb_assert(ce->e_index_hash_p == head); |
2aec7c523 mbcache: Remove u... |
709 |
if (ce->e_bdev == bdev && ce->e_index.o_key == key) { |
1f3e55fe0 fs/mbcache.c: dou... |
710 711 712 713 714 715 716 717 |
/* * Prevent a free from removing the entry. */ atomic_inc(&ce->e_refcnt); hlist_bl_unlock(head); __spin_lock_mb_cache_entry(ce); atomic_dec(&ce->e_refcnt); ce->e_used++; |
1da177e4c Linux-2.6.12-rc2 |
718 719 |
/* Incrementing before holding the lock gives readers priority over writers. */ |
1f3e55fe0 fs/mbcache.c: dou... |
720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 |
if (ce->e_used >= MB_CACHE_WRITER) { DEFINE_WAIT(wait); while (ce->e_used >= MB_CACHE_WRITER) { ce->e_queued++; prepare_to_wait(&mb_cache_queue, &wait, TASK_UNINTERRUPTIBLE); __spin_unlock_mb_cache_entry(ce); schedule(); __spin_lock_mb_cache_entry(ce); ce->e_queued--; } finish_wait(&mb_cache_queue, &wait); } __spin_unlock_mb_cache_entry(ce); if (!list_empty(&ce->e_lru_list)) { |
1da177e4c Linux-2.6.12-rc2 |
736 |
spin_lock(&mb_cache_spinlock); |
1f3e55fe0 fs/mbcache.c: dou... |
737 738 |
list_del_init(&ce->e_lru_list); spin_unlock(&mb_cache_spinlock); |
1da177e4c Linux-2.6.12-rc2 |
739 |
} |
3e037e521 fs/mbcache.c: cha... |
740 |
if (!__mb_cache_entry_is_block_hashed(ce)) { |
1f3e55fe0 fs/mbcache.c: dou... |
741 |
__mb_cache_entry_release(ce); |
1da177e4c Linux-2.6.12-rc2 |
742 743 744 745 746 747 |
return ERR_PTR(-EAGAIN); } return ce; } l = l->next; } |
1f3e55fe0 fs/mbcache.c: dou... |
748 |
hlist_bl_unlock(head); |
1da177e4c Linux-2.6.12-rc2 |
749 750 751 752 753 754 755 756 |
return NULL; } /* * mb_cache_entry_find_first() * * Find the first cache entry on a given device with a certain key in |
25985edce Fix common misspe... |
757 |
* an additional index. Additional matches can be found with |
1da177e4c Linux-2.6.12-rc2 |
758 759 760 761 |
* mb_cache_entry_find_next(). Returns NULL if no match was found. The * returned cache entry is locked for shared access ("multiple readers"). * * @cache: the cache to search |
1da177e4c Linux-2.6.12-rc2 |
762 763 764 765 |
* @bdev: the device the cache entry should belong to * @key: the key in the index */ struct mb_cache_entry * |
2aec7c523 mbcache: Remove u... |
766 767 |
mb_cache_entry_find_first(struct mb_cache *cache, struct block_device *bdev, unsigned int key) |
1da177e4c Linux-2.6.12-rc2 |
768 769 |
{ unsigned int bucket = hash_long(key, cache->c_bucket_bits); |
3e037e521 fs/mbcache.c: cha... |
770 771 772 |
struct hlist_bl_node *l; struct mb_cache_entry *ce = NULL; struct hlist_bl_head *index_hash_p; |
1da177e4c Linux-2.6.12-rc2 |
773 |
|
3e037e521 fs/mbcache.c: cha... |
774 |
index_hash_p = &cache->c_index_hash[bucket]; |
1f3e55fe0 fs/mbcache.c: dou... |
775 |
hlist_bl_lock(index_hash_p); |
3e037e521 fs/mbcache.c: cha... |
776 777 778 |
if (!hlist_bl_empty(index_hash_p)) { l = hlist_bl_first(index_hash_p); ce = __mb_cache_entry_find(l, index_hash_p, bdev, key); |
1f3e55fe0 fs/mbcache.c: dou... |
779 780 |
} else hlist_bl_unlock(index_hash_p); |
1da177e4c Linux-2.6.12-rc2 |
781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 |
return ce; } /* * mb_cache_entry_find_next() * * Find the next cache entry on a given device with a certain key in an * additional index. Returns NULL if no match could be found. The previous * entry is atomatically released, so that mb_cache_entry_find_next() can * be called like this: * * entry = mb_cache_entry_find_first(); * while (entry) { * ... * entry = mb_cache_entry_find_next(entry, ...); * } * * @prev: The previous match |
1da177e4c Linux-2.6.12-rc2 |
800 801 802 803 |
* @bdev: the device the cache entry should belong to * @key: the key in the index */ struct mb_cache_entry * |
2aec7c523 mbcache: Remove u... |
804 |
mb_cache_entry_find_next(struct mb_cache_entry *prev, |
1da177e4c Linux-2.6.12-rc2 |
805 806 807 808 |
struct block_device *bdev, unsigned int key) { struct mb_cache *cache = prev->e_cache; unsigned int bucket = hash_long(key, cache->c_bucket_bits); |
3e037e521 fs/mbcache.c: cha... |
809 |
struct hlist_bl_node *l; |
1da177e4c Linux-2.6.12-rc2 |
810 |
struct mb_cache_entry *ce; |
3e037e521 fs/mbcache.c: cha... |
811 |
struct hlist_bl_head *index_hash_p; |
1da177e4c Linux-2.6.12-rc2 |
812 |
|
3e037e521 fs/mbcache.c: cha... |
813 814 |
index_hash_p = &cache->c_index_hash[bucket]; mb_assert(prev->e_index_hash_p == index_hash_p); |
1f3e55fe0 fs/mbcache.c: dou... |
815 |
hlist_bl_lock(index_hash_p); |
3e037e521 fs/mbcache.c: cha... |
816 |
mb_assert(!hlist_bl_empty(index_hash_p)); |
2aec7c523 mbcache: Remove u... |
817 |
l = prev->e_index.o_list.next; |
3e037e521 fs/mbcache.c: cha... |
818 |
ce = __mb_cache_entry_find(l, index_hash_p, bdev, key); |
1f3e55fe0 fs/mbcache.c: dou... |
819 |
__mb_cache_entry_release(prev); |
1da177e4c Linux-2.6.12-rc2 |
820 821 822 823 824 825 826 |
return ce; } #endif /* !defined(MB_CACHE_INDEXES_COUNT) || (MB_CACHE_INDEXES_COUNT > 0) */ static int __init init_mbcache(void) { |
8e1f936b7 mm: clean up and ... |
827 |
register_shrinker(&mb_cache_shrinker); |
1da177e4c Linux-2.6.12-rc2 |
828 829 830 831 832 |
return 0; } static void __exit exit_mbcache(void) { |
8e1f936b7 mm: clean up and ... |
833 |
unregister_shrinker(&mb_cache_shrinker); |
1da177e4c Linux-2.6.12-rc2 |
834 835 836 837 |
} module_init(init_mbcache) module_exit(exit_mbcache) |