fs/fscache/internal.h

   1 /* Internal definitions for FS-Cache
   2  *
   3  * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 /*
  13  * Lock order, in the order in which multiple locks should be obtained:
  14  * - fscache_addremove_sem
  15  * - cookie->lock
  16  * - cookie->parent->lock
  17  * - cache->object_list_lock
  18  * - object->lock
  19  * - object->parent->lock
  20  * - cookie->stores_lock
  21  * - fscache_thread_lock
  22  *
  23  */
  24
  25 #include <linux/fscache-cache.h>
  26 #include <linux/sched.h>
  27
  28 #define FSCACHE_MIN_THREADS     4
  29 #define FSCACHE_MAX_THREADS     32
  30
  31 /*
  32  * cache.c
  33  */
  34 extern struct list_head fscache_cache_list;
  35 extern struct rw_semaphore fscache_addremove_sem;
  36
  37 extern struct fscache_cache *fscache_select_cache_for_object(
  38         struct fscache_cookie *);
  39
  40 /*
  41  * cookie.c
  42  */
  43 extern struct kmem_cache *fscache_cookie_jar;
  44
  45 extern void fscache_cookie_init_once(void *);
  46 extern void __fscache_cookie_put(struct fscache_cookie *);
  47
  48 /*
  49  * fsdef.c
  50  */
  51 extern struct fscache_cookie fscache_fsdef_index;
  52 extern struct fscache_cookie_def fscache_fsdef_netfs_def;
  53
  54 /*
  55  * histogram.c
  56  */
  57 #ifdef CONFIG_FSCACHE_HISTOGRAM
  58 extern atomic_t fscache_obj_instantiate_histogram[HZ];
  59 extern atomic_t fscache_objs_histogram[HZ];
  60 extern atomic_t fscache_ops_histogram[HZ];
  61 extern atomic_t fscache_retrieval_delay_histogram[HZ];
  62 extern atomic_t fscache_retrieval_histogram[HZ];
  63
  64 static inline void fscache_hist(atomic_t histogram[], unsigned long start_jif)
  65 {
  66         unsigned long jif = jiffies - start_jif;
  67         if (jif >= HZ)
  68                 jif = HZ - 1;
  69         atomic_inc(&histogram[jif]);
  70 }
  71
  72 extern const struct file_operations fscache_histogram_fops;
  73
  74 #else
  75 #define fscache_hist(hist, start_jif) do {} while (0)
  76 #endif
  77
  78 /*
  79  * main.c
  80  */
  81 extern unsigned fscache_defer_lookup;
  82 extern unsigned fscache_defer_create;
  83 extern unsigned fscache_debug;
  84 extern struct kobject *fscache_root;
  85 extern struct workqueue_struct *fscache_object_wq;
  86 extern struct workqueue_struct *fscache_op_wq;
  87 DECLARE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);
  88
  89 static inline bool fscache_object_congested(void)
  90 {
  91         return workqueue_congested(WORK_CPU_UNBOUND, fscache_object_wq);
  92 }
  93
  94 extern int fscache_wait_bit(void *);
  95 extern int fscache_wait_bit_interruptible(void *);
  96
  97 /*
  98  * object.c
  99  */
 100 extern const char fscache_object_states_short[FSCACHE_OBJECT__NSTATES][5];
 101
 102 extern void fscache_withdrawing_object(struct fscache_cache *,
 103                                        struct fscache_object *);
 104 extern void fscache_enqueue_object(struct fscache_object *);
 105
 106 /*
 107  * object-list.c
 108  */
 109 #ifdef CONFIG_FSCACHE_OBJECT_LIST
 110 extern const struct file_operations fscache_objlist_fops;
 111
 112 extern void fscache_objlist_add(struct fscache_object *);
 113 #else
 114 #define fscache_objlist_add(object) do {} while(0)
 115 #endif
 116
 117 /*
 118  * operation.c
 119  */
 120 extern int fscache_submit_exclusive_op(struct fscache_object *,
 121                                        struct fscache_operation *);
 122 extern int fscache_submit_op(struct fscache_object *,
 123                              struct fscache_operation *);
 124 extern int fscache_cancel_op(struct fscache_operation *);
 125 extern void fscache_abort_object(struct fscache_object *);
 126 extern void fscache_start_operations(struct fscache_object *);
 127 extern void fscache_operation_gc(struct work_struct *);
 128
 129 /*
 130  * proc.c
 131  */
 132 #ifdef CONFIG_PROC_FS
 133 extern int __init fscache_proc_init(void);
 134 extern void fscache_proc_cleanup(void);
 135 #else
 136 #define fscache_proc_init()     (0)
 137 #define fscache_proc_cleanup()  do {} while (0)
 138 #endif
 139
 140 /*
 141  * stats.c
 142  */
 143 #ifdef CONFIG_FSCACHE_STATS
 144 extern atomic_t fscache_n_ops_processed[FSCACHE_MAX_THREADS];
 145 extern atomic_t fscache_n_objs_processed[FSCACHE_MAX_THREADS];
 146
 147 extern atomic_t fscache_n_op_pend;
 148 extern atomic_t fscache_n_op_run;
 149 extern atomic_t fscache_n_op_enqueue;
 150 extern atomic_t fscache_n_op_deferred_release;
 151 extern atomic_t fscache_n_op_release;
 152 extern atomic_t fscache_n_op_gc;
 153 extern atomic_t fscache_n_op_cancelled;
 154 extern atomic_t fscache_n_op_rejected;
 155
 156 extern atomic_t fscache_n_attr_changed;
 157 extern atomic_t fscache_n_attr_changed_ok;
 158 extern atomic_t fscache_n_attr_changed_nobufs;
 159 extern atomic_t fscache_n_attr_changed_nomem;
 160 extern atomic_t fscache_n_attr_changed_calls;
 161
 162 extern atomic_t fscache_n_allocs;
 163 extern atomic_t fscache_n_allocs_ok;
 164 extern atomic_t fscache_n_allocs_wait;
 165 extern atomic_t fscache_n_allocs_nobufs;
 166 extern atomic_t fscache_n_allocs_intr;
 167 extern atomic_t fscache_n_allocs_object_dead;
 168 extern atomic_t fscache_n_alloc_ops;
 169 extern atomic_t fscache_n_alloc_op_waits;
 170
 171 extern atomic_t fscache_n_retrievals;
 172 extern atomic_t fscache_n_retrievals_ok;
 173 extern atomic_t fscache_n_retrievals_wait;
 174 extern atomic_t fscache_n_retrievals_nodata;
 175 extern atomic_t fscache_n_retrievals_nobufs;
 176 extern atomic_t fscache_n_retrievals_intr;
 177 extern atomic_t fscache_n_retrievals_nomem;
 178 extern atomic_t fscache_n_retrievals_object_dead;
 179 extern atomic_t fscache_n_retrieval_ops;
 180 extern atomic_t fscache_n_retrieval_op_waits;
 181
 182 extern atomic_t fscache_n_stores;
 183 extern atomic_t fscache_n_stores_ok;
 184 extern atomic_t fscache_n_stores_again;
 185 extern atomic_t fscache_n_stores_nobufs;
 186 extern atomic_t fscache_n_stores_oom;
 187 extern atomic_t fscache_n_store_ops;
 188 extern atomic_t fscache_n_store_calls;
 189 extern atomic_t fscache_n_store_pages;
 190 extern atomic_t fscache_n_store_radix_deletes;
 191 extern atomic_t fscache_n_store_pages_over_limit;
 192
 193 extern atomic_t fscache_n_store_vmscan_not_storing;
 194 extern atomic_t fscache_n_store_vmscan_gone;
 195 extern atomic_t fscache_n_store_vmscan_busy;
 196 extern atomic_t fscache_n_store_vmscan_cancelled;
 197
 198 extern atomic_t fscache_n_marks;
 199 extern atomic_t fscache_n_uncaches;
 200
 201 extern atomic_t fscache_n_acquires;
 202 extern atomic_t fscache_n_acquires_null;
 203 extern atomic_t fscache_n_acquires_no_cache;
 204 extern atomic_t fscache_n_acquires_ok;
 205 extern atomic_t fscache_n_acquires_nobufs;
 206 extern atomic_t fscache_n_acquires_oom;
 207
 208 extern atomic_t fscache_n_updates;
 209 extern atomic_t fscache_n_updates_null;
 210 extern atomic_t fscache_n_updates_run;
 211
 212 extern atomic_t fscache_n_relinquishes;
 213 extern atomic_t fscache_n_relinquishes_null;
 214 extern atomic_t fscache_n_relinquishes_waitcrt;
 215 extern atomic_t fscache_n_relinquishes_retire;
 216
 217 extern atomic_t fscache_n_cookie_index;
 218 extern atomic_t fscache_n_cookie_data;
 219 extern atomic_t fscache_n_cookie_special;
 220
 221 extern atomic_t fscache_n_object_alloc;
 222 extern atomic_t fscache_n_object_no_alloc;
 223 extern atomic_t fscache_n_object_lookups;
 224 extern atomic_t fscache_n_object_lookups_negative;
 225 extern atomic_t fscache_n_object_lookups_positive;
 226 extern atomic_t fscache_n_object_lookups_timed_out;
 227 extern atomic_t fscache_n_object_created;
 228 extern atomic_t fscache_n_object_avail;
 229 extern atomic_t fscache_n_object_dead;
 230
 231 extern atomic_t fscache_n_checkaux_none;
 232 extern atomic_t fscache_n_checkaux_okay;
 233 extern atomic_t fscache_n_checkaux_update;
 234 extern atomic_t fscache_n_checkaux_obsolete;
 235
 236 extern atomic_t fscache_n_cop_alloc_object;
 237 extern atomic_t fscache_n_cop_lookup_object;
 238 extern atomic_t fscache_n_cop_lookup_complete;
 239 extern atomic_t fscache_n_cop_grab_object;
 240 extern atomic_t fscache_n_cop_update_object;
 241 extern atomic_t fscache_n_cop_drop_object;
 242 extern atomic_t fscache_n_cop_put_object;
 243 extern atomic_t fscache_n_cop_sync_cache;
 244 extern atomic_t fscache_n_cop_attr_changed;
 245 extern atomic_t fscache_n_cop_read_or_alloc_page;
 246 extern atomic_t fscache_n_cop_read_or_alloc_pages;
 247 extern atomic_t fscache_n_cop_allocate_page;
 248 extern atomic_t fscache_n_cop_allocate_pages;
 249 extern atomic_t fscache_n_cop_write_page;
 250 extern atomic_t fscache_n_cop_uncache_page;
 251 extern atomic_t fscache_n_cop_dissociate_pages;
 252
 253 static inline void fscache_stat(atomic_t *stat)
 254 {
 255         atomic_inc(stat);
 256 }
 257
 258 static inline void fscache_stat_d(atomic_t *stat)
 259 {
 260         atomic_dec(stat);
 261 }
 262
 263 #define __fscache_stat(stat) (stat)
 264
 265 extern const struct file_operations fscache_stats_fops;
 266 #else
 267
 268 #define __fscache_stat(stat) (NULL)
 269 #define fscache_stat(stat) do {} while (0)
 270 #define fscache_stat_d(stat) do {} while (0)
 271 #endif
 272
 273 /*
 274  * raise an event on an object
 275  * - if the event is not masked for that object, then the object is
 276  *   queued for attention by the thread pool.
 277  */
 278 static inline void fscache_raise_event(struct fscache_object *object,
 279                                        unsigned event)
 280 {
 281         if (!test_and_set_bit(event, &object->events) &&
 282             test_bit(event, &object->event_mask))
 283                 fscache_enqueue_object(object);
 284 }
 285
 286 /*
 287  * drop a reference to a cookie
 288  */
 289 static inline void fscache_cookie_put(struct fscache_cookie *cookie)
 290 {
 291         BUG_ON(atomic_read(&cookie->usage) <= 0);
 292         if (atomic_dec_and_test(&cookie->usage))
 293                 __fscache_cookie_put(cookie);
 294 }
 295
 296 /*
 297  * get an extra reference to a netfs retrieval context
 298  */
 299 static inline
 300 void *fscache_get_context(struct fscache_cookie *cookie, void *context)
 301 {
 302         if (cookie->def->get_context)
 303                 cookie->def->get_context(cookie->netfs_data, context);
 304         return context;
 305 }
 306
 307 /*
 308  * release a reference to a netfs retrieval context
 309  */
 310 static inline
 311 void fscache_put_context(struct fscache_cookie *cookie, void *context)
 312 {
 313         if (cookie->def->put_context)
 314                 cookie->def->put_context(cookie->netfs_data, context);
 315 }
 316
 317 /*****************************************************************************/
 318 /*
 319  * debug tracing
 320  */
 321 #define dbgprintk(FMT, ...) \
 322         printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
 323
 324 #define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
 325 #define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
 326 #define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
 327
 328 #define kjournal(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
 329
 330 #ifdef __KDEBUG
 331 #define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
 332 #define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
 333 #define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
 334
 335 #elif defined(CONFIG_FSCACHE_DEBUG)
 336 #define _enter(FMT, ...)                        \
 337 do {                                            \
 338         if (__do_kdebug(ENTER))                 \
 339                 kenter(FMT, ##__VA_ARGS__);     \
 340 } while (0)
 341
 342 #define _leave(FMT, ...)                        \
 343 do {                                            \
 344         if (__do_kdebug(LEAVE))                 \
 345                 kleave(FMT, ##__VA_ARGS__);     \
 346 } while (0)
 347
 348 #define _debug(FMT, ...)                        \
 349 do {                                            \
 350         if (__do_kdebug(DEBUG))                 \
 351                 kdebug(FMT, ##__VA_ARGS__);     \
 352 } while (0)
 353
 354 #else
 355 #define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
 356 #define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
 357 #define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
 358 #endif
 359
 360 /*
 361  * determine whether a particular optional debugging point should be logged
 362  * - we need to go through three steps to persuade cpp to correctly join the
 363  *   shorthand in FSCACHE_DEBUG_LEVEL with its prefix
 364  */
 365 #define ____do_kdebug(LEVEL, POINT) \
 366         unlikely((fscache_debug & \
 367                   (FSCACHE_POINT_##POINT << (FSCACHE_DEBUG_ ## LEVEL * 3))))
 368 #define ___do_kdebug(LEVEL, POINT) \
 369         ____do_kdebug(LEVEL, POINT)
 370 #define __do_kdebug(POINT) \
 371         ___do_kdebug(FSCACHE_DEBUG_LEVEL, POINT)
 372
 373 #define FSCACHE_DEBUG_CACHE     0
 374 #define FSCACHE_DEBUG_COOKIE    1
 375 #define FSCACHE_DEBUG_PAGE      2
 376 #define FSCACHE_DEBUG_OPERATION 3
 377
 378 #define FSCACHE_POINT_ENTER     1
 379 #define FSCACHE_POINT_LEAVE     2
 380 #define FSCACHE_POINT_DEBUG     4
 381
 382 #ifndef FSCACHE_DEBUG_LEVEL
 383 #define FSCACHE_DEBUG_LEVEL CACHE
 384 #endif
 385
 386 /*
 387  * assertions
 388  */
 389 #if 1 /* defined(__KDEBUGALL) */
 390
 391 #define ASSERT(X)                                                       \
 392 do {                                                                    \
 393         if (unlikely(!(X))) {                                           \
 394                 printk(KERN_ERR "\n");                                  \
 395                 printk(KERN_ERR "FS-Cache: Assertion failed\n");        \
 396                 BUG();                                                  \
 397         }                                                               \
 398 } while (0)
 399
 400 #define ASSERTCMP(X, OP, Y)                                             \
 401 do {                                                                    \
 402         if (unlikely(!((X) OP (Y)))) {                                  \
 403                 printk(KERN_ERR "\n");                                  \
 404                 printk(KERN_ERR "FS-Cache: Assertion failed\n");        \
 405                 printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
 406                        (unsigned long)(X), (unsigned long)(Y));         \
 407                 BUG();                                                  \
 408         }                                                               \
 409 } while (0)
 410
 411 #define ASSERTIF(C, X)                                                  \
 412 do {                                                                    \
 413         if (unlikely((C) && !(X))) {                                    \
 414                 printk(KERN_ERR "\n");                                  \
 415                 printk(KERN_ERR "FS-Cache: Assertion failed\n");        \
 416                 BUG();                                                  \
 417         }                                                               \
 418 } while (0)
 419
 420 #define ASSERTIFCMP(C, X, OP, Y)                                        \
 421 do {                                                                    \
 422         if (unlikely((C) && !((X) OP (Y)))) {                           \
 423                 printk(KERN_ERR "\n");                                  \
 424                 printk(KERN_ERR "FS-Cache: Assertion failed\n");        \
 425                 printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
 426                        (unsigned long)(X), (unsigned long)(Y));         \
 427                 BUG();                                                  \
 428         }                                                               \
 429 } while (0)
 430
 431 #else
 432
 433 #define ASSERT(X)                       do {} while (0)
 434 #define ASSERTCMP(X, OP, Y)             do {} while (0)
 435 #define ASSERTIF(C, X)                  do {} while (0)
 436 #define ASSERTIFCMP(C, X, OP, Y)        do {} while (0)
 437
 438 #endif /* assert or not */