linux/fs/fscache/internal.h
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   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 */
  34extern struct list_head fscache_cache_list;
  35extern struct rw_semaphore fscache_addremove_sem;
  36
  37extern struct fscache_cache *fscache_select_cache_for_object(
  38        struct fscache_cookie *);
  39
  40/*
  41 * cookie.c
  42 */
  43extern struct kmem_cache *fscache_cookie_jar;
  44
  45extern void fscache_cookie_init_once(void *);
  46extern void __fscache_cookie_put(struct fscache_cookie *);
  47
  48/*
  49 * fsdef.c
  50 */
  51extern struct fscache_cookie fscache_fsdef_index;
  52extern struct fscache_cookie_def fscache_fsdef_netfs_def;
  53
  54/*
  55 * histogram.c
  56 */
  57#ifdef CONFIG_FSCACHE_HISTOGRAM
  58extern atomic_t fscache_obj_instantiate_histogram[HZ];
  59extern atomic_t fscache_objs_histogram[HZ];
  60extern atomic_t fscache_ops_histogram[HZ];
  61extern atomic_t fscache_retrieval_delay_histogram[HZ];
  62extern atomic_t fscache_retrieval_histogram[HZ];
  63
  64static 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
  72extern 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 */
  81extern unsigned fscache_defer_lookup;
  82extern unsigned fscache_defer_create;
  83extern unsigned fscache_debug;
  84extern struct kobject *fscache_root;
  85extern struct workqueue_struct *fscache_object_wq;
  86extern struct workqueue_struct *fscache_op_wq;
  87DECLARE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);
  88
  89static inline bool fscache_object_congested(void)
  90{
  91        return workqueue_congested(WORK_CPU_UNBOUND, fscache_object_wq);
  92}
  93
  94extern int fscache_wait_bit(void *);
  95extern int fscache_wait_bit_interruptible(void *);
  96
  97/*
  98 * object.c
  99 */
 100extern const char fscache_object_states_short[FSCACHE_OBJECT__NSTATES][5];
 101
 102extern void fscache_withdrawing_object(struct fscache_cache *,
 103                                       struct fscache_object *);
 104extern void fscache_enqueue_object(struct fscache_object *);
 105
 106/*
 107 * object-list.c
 108 */
 109#ifdef CONFIG_FSCACHE_OBJECT_LIST
 110extern const struct file_operations fscache_objlist_fops;
 111
 112extern 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 */
 120extern int fscache_submit_exclusive_op(struct fscache_object *,
 121                                       struct fscache_operation *);
 122extern int fscache_submit_op(struct fscache_object *,
 123                             struct fscache_operation *);
 124extern int fscache_cancel_op(struct fscache_operation *);
 125extern void fscache_abort_object(struct fscache_object *);
 126extern void fscache_start_operations(struct fscache_object *);
 127extern void fscache_operation_gc(struct work_struct *);
 128
 129/*
 130 * proc.c
 131 */
 132#ifdef CONFIG_PROC_FS
 133extern int __init fscache_proc_init(void);
 134extern 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
 144extern atomic_t fscache_n_ops_processed[FSCACHE_MAX_THREADS];
 145extern atomic_t fscache_n_objs_processed[FSCACHE_MAX_THREADS];
 146
 147extern atomic_t fscache_n_op_pend;
 148extern atomic_t fscache_n_op_run;
 149extern atomic_t fscache_n_op_enqueue;
 150extern atomic_t fscache_n_op_deferred_release;
 151extern atomic_t fscache_n_op_release;
 152extern atomic_t fscache_n_op_gc;
 153extern atomic_t fscache_n_op_cancelled;
 154extern atomic_t fscache_n_op_rejected;
 155
 156extern atomic_t fscache_n_attr_changed;
 157extern atomic_t fscache_n_attr_changed_ok;
 158extern atomic_t fscache_n_attr_changed_nobufs;
 159extern atomic_t fscache_n_attr_changed_nomem;
 160extern atomic_t fscache_n_attr_changed_calls;
 161
 162extern atomic_t fscache_n_allocs;
 163extern atomic_t fscache_n_allocs_ok;
 164extern atomic_t fscache_n_allocs_wait;
 165extern atomic_t fscache_n_allocs_nobufs;
 166extern atomic_t fscache_n_allocs_intr;
 167extern atomic_t fscache_n_allocs_object_dead;
 168extern atomic_t fscache_n_alloc_ops;
 169extern atomic_t fscache_n_alloc_op_waits;
 170
 171extern atomic_t fscache_n_retrievals;
 172extern atomic_t fscache_n_retrievals_ok;
 173extern atomic_t fscache_n_retrievals_wait;
 174extern atomic_t fscache_n_retrievals_nodata;
 175extern atomic_t fscache_n_retrievals_nobufs;
 176extern atomic_t fscache_n_retrievals_intr;
 177extern atomic_t fscache_n_retrievals_nomem;
 178extern atomic_t fscache_n_retrievals_object_dead;
 179extern atomic_t fscache_n_retrieval_ops;
 180extern atomic_t fscache_n_retrieval_op_waits;
 181
 182extern atomic_t fscache_n_stores;
 183extern atomic_t fscache_n_stores_ok;
 184extern atomic_t fscache_n_stores_again;
 185extern atomic_t fscache_n_stores_nobufs;
 186extern atomic_t fscache_n_stores_oom;
 187extern atomic_t fscache_n_store_ops;
 188extern atomic_t fscache_n_store_calls;
 189extern atomic_t fscache_n_store_pages;
 190extern atomic_t fscache_n_store_radix_deletes;
 191extern atomic_t fscache_n_store_pages_over_limit;
 192
 193extern atomic_t fscache_n_store_vmscan_not_storing;
 194extern atomic_t fscache_n_store_vmscan_gone;
 195extern atomic_t fscache_n_store_vmscan_busy;
 196extern atomic_t fscache_n_store_vmscan_cancelled;
 197
 198extern atomic_t fscache_n_marks;
 199extern atomic_t fscache_n_uncaches;
 200
 201extern atomic_t fscache_n_acquires;
 202extern atomic_t fscache_n_acquires_null;
 203extern atomic_t fscache_n_acquires_no_cache;
 204extern atomic_t fscache_n_acquires_ok;
 205extern atomic_t fscache_n_acquires_nobufs;
 206extern atomic_t fscache_n_acquires_oom;
 207
 208extern atomic_t fscache_n_updates;
 209extern atomic_t fscache_n_updates_null;
 210extern atomic_t fscache_n_updates_run;
 211
 212extern atomic_t fscache_n_relinquishes;
 213extern atomic_t fscache_n_relinquishes_null;
 214extern atomic_t fscache_n_relinquishes_waitcrt;
 215extern atomic_t fscache_n_relinquishes_retire;
 216
 217extern atomic_t fscache_n_cookie_index;
 218extern atomic_t fscache_n_cookie_data;
 219extern atomic_t fscache_n_cookie_special;
 220
 221extern atomic_t fscache_n_object_alloc;
 222extern atomic_t fscache_n_object_no_alloc;
 223extern atomic_t fscache_n_object_lookups;
 224extern atomic_t fscache_n_object_lookups_negative;
 225extern atomic_t fscache_n_object_lookups_positive;
 226extern atomic_t fscache_n_object_lookups_timed_out;
 227extern atomic_t fscache_n_object_created;
 228extern atomic_t fscache_n_object_avail;
 229extern atomic_t fscache_n_object_dead;
 230
 231extern atomic_t fscache_n_checkaux_none;
 232extern atomic_t fscache_n_checkaux_okay;
 233extern atomic_t fscache_n_checkaux_update;
 234extern atomic_t fscache_n_checkaux_obsolete;
 235
 236extern atomic_t fscache_n_cop_alloc_object;
 237extern atomic_t fscache_n_cop_lookup_object;
 238extern atomic_t fscache_n_cop_lookup_complete;
 239extern atomic_t fscache_n_cop_grab_object;
 240extern atomic_t fscache_n_cop_update_object;
 241extern atomic_t fscache_n_cop_drop_object;
 242extern atomic_t fscache_n_cop_put_object;
 243extern atomic_t fscache_n_cop_sync_cache;
 244extern atomic_t fscache_n_cop_attr_changed;
 245extern atomic_t fscache_n_cop_read_or_alloc_page;
 246extern atomic_t fscache_n_cop_read_or_alloc_pages;
 247extern atomic_t fscache_n_cop_allocate_page;
 248extern atomic_t fscache_n_cop_allocate_pages;
 249extern atomic_t fscache_n_cop_write_page;
 250extern atomic_t fscache_n_cop_uncache_page;
 251extern atomic_t fscache_n_cop_dissociate_pages;
 252
 253static inline void fscache_stat(atomic_t *stat)
 254{
 255        atomic_inc(stat);
 256}
 257
 258static inline void fscache_stat_d(atomic_t *stat)
 259{
 260        atomic_dec(stat);
 261}
 262
 263#define __fscache_stat(stat) (stat)
 264
 265extern 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 */
 278static 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 */
 289static 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 */
 299static inline
 300void *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 */
 310static inline
 311void 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, ...)                        \
 337do {                                            \
 338        if (__do_kdebug(ENTER))                 \
 339                kenter(FMT, ##__VA_ARGS__);     \
 340} while (0)
 341
 342#define _leave(FMT, ...)                        \
 343do {                                            \
 344        if (__do_kdebug(LEAVE))                 \
 345                kleave(FMT, ##__VA_ARGS__);     \
 346} while (0)
 347
 348#define _debug(FMT, ...)                        \
 349do {                                            \
 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)                                                       \
 392do {                                                                    \
 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)                                             \
 401do {                                                                    \
 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)                                                  \
 412do {                                                                    \
 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)                                        \
 421do {                                                                    \
 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 */
 439
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