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 *);
  96extern int fscache_wait_atomic_t(atomic_t *);
  97
  98/*
  99 * object.c
 100 */
 101extern void fscache_enqueue_object(struct fscache_object *);
 102
 103/*
 104 * object-list.c
 105 */
 106#ifdef CONFIG_FSCACHE_OBJECT_LIST
 107extern const struct file_operations fscache_objlist_fops;
 108
 109extern void fscache_objlist_add(struct fscache_object *);
 110extern void fscache_objlist_remove(struct fscache_object *);
 111#else
 112#define fscache_objlist_add(object) do {} while(0)
 113#define fscache_objlist_remove(object) do {} while(0)
 114#endif
 115
 116/*
 117 * operation.c
 118 */
 119extern int fscache_submit_exclusive_op(struct fscache_object *,
 120                                       struct fscache_operation *);
 121extern int fscache_submit_op(struct fscache_object *,
 122                             struct fscache_operation *);
 123extern int fscache_cancel_op(struct fscache_operation *,
 124                             void (*)(struct fscache_operation *));
 125extern void fscache_cancel_all_ops(struct fscache_object *);
 126extern void fscache_abort_object(struct fscache_object *);
 127extern void fscache_start_operations(struct fscache_object *);
 128extern void fscache_operation_gc(struct work_struct *);
 129
 130/*
 131 * page.c
 132 */
 133extern int fscache_wait_for_deferred_lookup(struct fscache_cookie *);
 134extern int fscache_wait_for_operation_activation(struct fscache_object *,
 135                                                 struct fscache_operation *,
 136                                                 atomic_t *,
 137                                                 atomic_t *,
 138                                                 void (*)(struct fscache_operation *));
 139extern void fscache_invalidate_writes(struct fscache_cookie *);
 140
 141/*
 142 * proc.c
 143 */
 144#ifdef CONFIG_PROC_FS
 145extern int __init fscache_proc_init(void);
 146extern void fscache_proc_cleanup(void);
 147#else
 148#define fscache_proc_init()     (0)
 149#define fscache_proc_cleanup()  do {} while (0)
 150#endif
 151
 152/*
 153 * stats.c
 154 */
 155#ifdef CONFIG_FSCACHE_STATS
 156extern atomic_t fscache_n_ops_processed[FSCACHE_MAX_THREADS];
 157extern atomic_t fscache_n_objs_processed[FSCACHE_MAX_THREADS];
 158
 159extern atomic_t fscache_n_op_pend;
 160extern atomic_t fscache_n_op_run;
 161extern atomic_t fscache_n_op_enqueue;
 162extern atomic_t fscache_n_op_deferred_release;
 163extern atomic_t fscache_n_op_release;
 164extern atomic_t fscache_n_op_gc;
 165extern atomic_t fscache_n_op_cancelled;
 166extern atomic_t fscache_n_op_rejected;
 167
 168extern atomic_t fscache_n_attr_changed;
 169extern atomic_t fscache_n_attr_changed_ok;
 170extern atomic_t fscache_n_attr_changed_nobufs;
 171extern atomic_t fscache_n_attr_changed_nomem;
 172extern atomic_t fscache_n_attr_changed_calls;
 173
 174extern atomic_t fscache_n_allocs;
 175extern atomic_t fscache_n_allocs_ok;
 176extern atomic_t fscache_n_allocs_wait;
 177extern atomic_t fscache_n_allocs_nobufs;
 178extern atomic_t fscache_n_allocs_intr;
 179extern atomic_t fscache_n_allocs_object_dead;
 180extern atomic_t fscache_n_alloc_ops;
 181extern atomic_t fscache_n_alloc_op_waits;
 182
 183extern atomic_t fscache_n_retrievals;
 184extern atomic_t fscache_n_retrievals_ok;
 185extern atomic_t fscache_n_retrievals_wait;
 186extern atomic_t fscache_n_retrievals_nodata;
 187extern atomic_t fscache_n_retrievals_nobufs;
 188extern atomic_t fscache_n_retrievals_intr;
 189extern atomic_t fscache_n_retrievals_nomem;
 190extern atomic_t fscache_n_retrievals_object_dead;
 191extern atomic_t fscache_n_retrieval_ops;
 192extern atomic_t fscache_n_retrieval_op_waits;
 193
 194extern atomic_t fscache_n_stores;
 195extern atomic_t fscache_n_stores_ok;
 196extern atomic_t fscache_n_stores_again;
 197extern atomic_t fscache_n_stores_nobufs;
 198extern atomic_t fscache_n_stores_oom;
 199extern atomic_t fscache_n_store_ops;
 200extern atomic_t fscache_n_store_calls;
 201extern atomic_t fscache_n_store_pages;
 202extern atomic_t fscache_n_store_radix_deletes;
 203extern atomic_t fscache_n_store_pages_over_limit;
 204
 205extern atomic_t fscache_n_store_vmscan_not_storing;
 206extern atomic_t fscache_n_store_vmscan_gone;
 207extern atomic_t fscache_n_store_vmscan_busy;
 208extern atomic_t fscache_n_store_vmscan_cancelled;
 209extern atomic_t fscache_n_store_vmscan_wait;
 210
 211extern atomic_t fscache_n_marks;
 212extern atomic_t fscache_n_uncaches;
 213
 214extern atomic_t fscache_n_acquires;
 215extern atomic_t fscache_n_acquires_null;
 216extern atomic_t fscache_n_acquires_no_cache;
 217extern atomic_t fscache_n_acquires_ok;
 218extern atomic_t fscache_n_acquires_nobufs;
 219extern atomic_t fscache_n_acquires_oom;
 220
 221extern atomic_t fscache_n_invalidates;
 222extern atomic_t fscache_n_invalidates_run;
 223
 224extern atomic_t fscache_n_updates;
 225extern atomic_t fscache_n_updates_null;
 226extern atomic_t fscache_n_updates_run;
 227
 228extern atomic_t fscache_n_relinquishes;
 229extern atomic_t fscache_n_relinquishes_null;
 230extern atomic_t fscache_n_relinquishes_waitcrt;
 231extern atomic_t fscache_n_relinquishes_retire;
 232
 233extern atomic_t fscache_n_cookie_index;
 234extern atomic_t fscache_n_cookie_data;
 235extern atomic_t fscache_n_cookie_special;
 236
 237extern atomic_t fscache_n_object_alloc;
 238extern atomic_t fscache_n_object_no_alloc;
 239extern atomic_t fscache_n_object_lookups;
 240extern atomic_t fscache_n_object_lookups_negative;
 241extern atomic_t fscache_n_object_lookups_positive;
 242extern atomic_t fscache_n_object_lookups_timed_out;
 243extern atomic_t fscache_n_object_created;
 244extern atomic_t fscache_n_object_avail;
 245extern atomic_t fscache_n_object_dead;
 246
 247extern atomic_t fscache_n_checkaux_none;
 248extern atomic_t fscache_n_checkaux_okay;
 249extern atomic_t fscache_n_checkaux_update;
 250extern atomic_t fscache_n_checkaux_obsolete;
 251
 252extern atomic_t fscache_n_cop_alloc_object;
 253extern atomic_t fscache_n_cop_lookup_object;
 254extern atomic_t fscache_n_cop_lookup_complete;
 255extern atomic_t fscache_n_cop_grab_object;
 256extern atomic_t fscache_n_cop_invalidate_object;
 257extern atomic_t fscache_n_cop_update_object;
 258extern atomic_t fscache_n_cop_drop_object;
 259extern atomic_t fscache_n_cop_put_object;
 260extern atomic_t fscache_n_cop_sync_cache;
 261extern atomic_t fscache_n_cop_attr_changed;
 262extern atomic_t fscache_n_cop_read_or_alloc_page;
 263extern atomic_t fscache_n_cop_read_or_alloc_pages;
 264extern atomic_t fscache_n_cop_allocate_page;
 265extern atomic_t fscache_n_cop_allocate_pages;
 266extern atomic_t fscache_n_cop_write_page;
 267extern atomic_t fscache_n_cop_uncache_page;
 268extern atomic_t fscache_n_cop_dissociate_pages;
 269
 270static inline void fscache_stat(atomic_t *stat)
 271{
 272        atomic_inc(stat);
 273}
 274
 275static inline void fscache_stat_d(atomic_t *stat)
 276{
 277        atomic_dec(stat);
 278}
 279
 280#define __fscache_stat(stat) (stat)
 281
 282extern const struct file_operations fscache_stats_fops;
 283#else
 284
 285#define __fscache_stat(stat) (NULL)
 286#define fscache_stat(stat) do {} while (0)
 287#define fscache_stat_d(stat) do {} while (0)
 288#endif
 289
 290/*
 291 * raise an event on an object
 292 * - if the event is not masked for that object, then the object is
 293 *   queued for attention by the thread pool.
 294 */
 295static inline void fscache_raise_event(struct fscache_object *object,
 296                                       unsigned event)
 297{
 298        BUG_ON(event >= NR_FSCACHE_OBJECT_EVENTS);
 299#if 0
 300        printk("*** fscache_raise_event(OBJ%d{%lx},%x)\n",
 301               object->debug_id, object->event_mask, (1 << event));
 302#endif
 303        if (!test_and_set_bit(event, &object->events) &&
 304            test_bit(event, &object->event_mask))
 305                fscache_enqueue_object(object);
 306}
 307
 308/*
 309 * drop a reference to a cookie
 310 */
 311static inline void fscache_cookie_put(struct fscache_cookie *cookie)
 312{
 313        BUG_ON(atomic_read(&cookie->usage) <= 0);
 314        if (atomic_dec_and_test(&cookie->usage))
 315                __fscache_cookie_put(cookie);
 316}
 317
 318/*
 319 * get an extra reference to a netfs retrieval context
 320 */
 321static inline
 322void *fscache_get_context(struct fscache_cookie *cookie, void *context)
 323{
 324        if (cookie->def->get_context)
 325                cookie->def->get_context(cookie->netfs_data, context);
 326        return context;
 327}
 328
 329/*
 330 * release a reference to a netfs retrieval context
 331 */
 332static inline
 333void fscache_put_context(struct fscache_cookie *cookie, void *context)
 334{
 335        if (cookie->def->put_context)
 336                cookie->def->put_context(cookie->netfs_data, context);
 337}
 338
 339/*****************************************************************************/
 340/*
 341 * debug tracing
 342 */
 343#define dbgprintk(FMT, ...) \
 344        printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
 345
 346#define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
 347#define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
 348#define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
 349
 350#define kjournal(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
 351
 352#ifdef __KDEBUG
 353#define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
 354#define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
 355#define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
 356
 357#elif defined(CONFIG_FSCACHE_DEBUG)
 358#define _enter(FMT, ...)                        \
 359do {                                            \
 360        if (__do_kdebug(ENTER))                 \
 361                kenter(FMT, ##__VA_ARGS__);     \
 362} while (0)
 363
 364#define _leave(FMT, ...)                        \
 365do {                                            \
 366        if (__do_kdebug(LEAVE))                 \
 367                kleave(FMT, ##__VA_ARGS__);     \
 368} while (0)
 369
 370#define _debug(FMT, ...)                        \
 371do {                                            \
 372        if (__do_kdebug(DEBUG))                 \
 373                kdebug(FMT, ##__VA_ARGS__);     \
 374} while (0)
 375
 376#else
 377#define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
 378#define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
 379#define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
 380#endif
 381
 382/*
 383 * determine whether a particular optional debugging point should be logged
 384 * - we need to go through three steps to persuade cpp to correctly join the
 385 *   shorthand in FSCACHE_DEBUG_LEVEL with its prefix
 386 */
 387#define ____do_kdebug(LEVEL, POINT) \
 388        unlikely((fscache_debug & \
 389                  (FSCACHE_POINT_##POINT << (FSCACHE_DEBUG_ ## LEVEL * 3))))
 390#define ___do_kdebug(LEVEL, POINT) \
 391        ____do_kdebug(LEVEL, POINT)
 392#define __do_kdebug(POINT) \
 393        ___do_kdebug(FSCACHE_DEBUG_LEVEL, POINT)
 394
 395#define FSCACHE_DEBUG_CACHE     0
 396#define FSCACHE_DEBUG_COOKIE    1
 397#define FSCACHE_DEBUG_PAGE      2
 398#define FSCACHE_DEBUG_OPERATION 3
 399
 400#define FSCACHE_POINT_ENTER     1
 401#define FSCACHE_POINT_LEAVE     2
 402#define FSCACHE_POINT_DEBUG     4
 403
 404#ifndef FSCACHE_DEBUG_LEVEL
 405#define FSCACHE_DEBUG_LEVEL CACHE
 406#endif
 407
 408/*
 409 * assertions
 410 */
 411#if 1 /* defined(__KDEBUGALL) */
 412
 413#define ASSERT(X)                                                       \
 414do {                                                                    \
 415        if (unlikely(!(X))) {                                           \
 416                printk(KERN_ERR "\n");                                  \
 417                printk(KERN_ERR "FS-Cache: Assertion failed\n");        \
 418                BUG();                                                  \
 419        }                                                               \
 420} while (0)
 421
 422#define ASSERTCMP(X, OP, Y)                                             \
 423do {                                                                    \
 424        if (unlikely(!((X) OP (Y)))) {                                  \
 425                printk(KERN_ERR "\n");                                  \
 426                printk(KERN_ERR "FS-Cache: Assertion failed\n");        \
 427                printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
 428                       (unsigned long)(X), (unsigned long)(Y));         \
 429                BUG();                                                  \
 430        }                                                               \
 431} while (0)
 432
 433#define ASSERTIF(C, X)                                                  \
 434do {                                                                    \
 435        if (unlikely((C) && !(X))) {                                    \
 436                printk(KERN_ERR "\n");                                  \
 437                printk(KERN_ERR "FS-Cache: Assertion failed\n");        \
 438                BUG();                                                  \
 439        }                                                               \
 440} while (0)
 441
 442#define ASSERTIFCMP(C, X, OP, Y)                                        \
 443do {                                                                    \
 444        if (unlikely((C) && !((X) OP (Y)))) {                           \
 445                printk(KERN_ERR "\n");                                  \
 446                printk(KERN_ERR "FS-Cache: Assertion failed\n");        \
 447                printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
 448                       (unsigned long)(X), (unsigned long)(Y));         \
 449                BUG();                                                  \
 450        }                                                               \
 451} while (0)
 452
 453#else
 454
 455#define ASSERT(X)                       do {} while (0)
 456#define ASSERTCMP(X, OP, Y)             do {} while (0)
 457#define ASSERTIF(C, X)                  do {} while (0)
 458#define ASSERTIFCMP(C, X, OP, Y)        do {} while (0)
 459
 460#endif /* assert or not */
 461