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  * - fscache_thread_lock
  21  *
  22  */
  23
  24 #include <linux/fscache-cache.h>
  25 #include <linux/sched.h>
  26
  27 #define FSCACHE_MIN_THREADS     4
  28 #define FSCACHE_MAX_THREADS     32
  29
  30 /*
  31  * cache.c
  32  */
  33 extern struct list_head fscache_cache_list;
  34 extern struct rw_semaphore fscache_addremove_sem;
  35
  36 extern struct fscache_cache *fscache_select_cache_for_object(
  37         struct fscache_cookie *);
  38
  39 /*
  40  * cookie.c
  41  */
  42 extern struct kmem_cache *fscache_cookie_jar;
  43
  44 extern void fscache_cookie_init_once(void *);
  45 extern void __fscache_cookie_put(struct fscache_cookie *);
  46
  47 /*
  48  * fsdef.c
  49  */
  50 extern struct fscache_cookie fscache_fsdef_index;
  51 extern struct fscache_cookie_def fscache_fsdef_netfs_def;
  52
  53 /*
  54  * histogram.c
  55  */
  56 #ifdef CONFIG_FSCACHE_HISTOGRAM
  57 extern atomic_t fscache_obj_instantiate_histogram[HZ];
  58 extern atomic_t fscache_objs_histogram[HZ];
  59 extern atomic_t fscache_ops_histogram[HZ];
  60 extern atomic_t fscache_retrieval_delay_histogram[HZ];
  61 extern atomic_t fscache_retrieval_histogram[HZ];
  62
  63 static inline void fscache_hist(atomic_t histogram[], unsigned long start_jif)
  64 {
  65         unsigned long jif = jiffies - start_jif;
  66         if (jif >= HZ)
  67                 jif = HZ - 1;
  68         atomic_inc(&histogram[jif]);
  69 }
  70
  71 extern const struct file_operations fscache_histogram_fops;
  72
  73 #else
  74 #define fscache_hist(hist, start_jif) do {} while (0)
  75 #endif
  76
  77 /*
  78  * main.c
  79  */
  80 extern unsigned fscache_defer_lookup;
  81 extern unsigned fscache_defer_create;
  82 extern unsigned fscache_debug;
  83 extern struct kobject *fscache_root;
  84
  85 extern int fscache_wait_bit(void *);
  86 extern int fscache_wait_bit_interruptible(void *);
  87
  88 /*
  89  * object.c
  90  */
  91 extern void fscache_withdrawing_object(struct fscache_cache *,
  92                                        struct fscache_object *);
  93 extern void fscache_enqueue_object(struct fscache_object *);
  94
  95 /*
  96  * operation.c
  97  */
  98 extern int fscache_submit_exclusive_op(struct fscache_object *,
  99                                        struct fscache_operation *);
 100 extern int fscache_submit_op(struct fscache_object *,
 101                              struct fscache_operation *);
 102 extern void fscache_abort_object(struct fscache_object *);
 103 extern void fscache_start_operations(struct fscache_object *);
 104 extern void fscache_operation_gc(struct work_struct *);
 105
 106 /*
 107  * proc.c
 108  */
 109 #ifdef CONFIG_PROC_FS
 110 extern int __init fscache_proc_init(void);
 111 extern void fscache_proc_cleanup(void);
 112 #else
 113 #define fscache_proc_init()     (0)
 114 #define fscache_proc_cleanup()  do {} while (0)
 115 #endif
 116
 117 /*
 118  * stats.c
 119  */
 120 #ifdef CONFIG_FSCACHE_STATS
 121 extern atomic_t fscache_n_ops_processed[FSCACHE_MAX_THREADS];
 122 extern atomic_t fscache_n_objs_processed[FSCACHE_MAX_THREADS];
 123
 124 extern atomic_t fscache_n_op_pend;
 125 extern atomic_t fscache_n_op_run;
 126 extern atomic_t fscache_n_op_enqueue;
 127 extern atomic_t fscache_n_op_deferred_release;
 128 extern atomic_t fscache_n_op_release;
 129 extern atomic_t fscache_n_op_gc;
 130
 131 extern atomic_t fscache_n_attr_changed;
 132 extern atomic_t fscache_n_attr_changed_ok;
 133 extern atomic_t fscache_n_attr_changed_nobufs;
 134 extern atomic_t fscache_n_attr_changed_nomem;
 135 extern atomic_t fscache_n_attr_changed_calls;
 136
 137 extern atomic_t fscache_n_allocs;
 138 extern atomic_t fscache_n_allocs_ok;
 139 extern atomic_t fscache_n_allocs_wait;
 140 extern atomic_t fscache_n_allocs_nobufs;
 141 extern atomic_t fscache_n_alloc_ops;
 142 extern atomic_t fscache_n_alloc_op_waits;
 143
 144 extern atomic_t fscache_n_retrievals;
 145 extern atomic_t fscache_n_retrievals_ok;
 146 extern atomic_t fscache_n_retrievals_wait;
 147 extern atomic_t fscache_n_retrievals_nodata;
 148 extern atomic_t fscache_n_retrievals_nobufs;
 149 extern atomic_t fscache_n_retrievals_intr;
 150 extern atomic_t fscache_n_retrievals_nomem;
 151 extern atomic_t fscache_n_retrieval_ops;
 152 extern atomic_t fscache_n_retrieval_op_waits;
 153
 154 extern atomic_t fscache_n_stores;
 155 extern atomic_t fscache_n_stores_ok;
 156 extern atomic_t fscache_n_stores_again;
 157 extern atomic_t fscache_n_stores_nobufs;
 158 extern atomic_t fscache_n_stores_oom;
 159 extern atomic_t fscache_n_store_ops;
 160 extern atomic_t fscache_n_store_calls;
 161
 162 extern atomic_t fscache_n_marks;
 163 extern atomic_t fscache_n_uncaches;
 164
 165 extern atomic_t fscache_n_acquires;
 166 extern atomic_t fscache_n_acquires_null;
 167 extern atomic_t fscache_n_acquires_no_cache;
 168 extern atomic_t fscache_n_acquires_ok;
 169 extern atomic_t fscache_n_acquires_nobufs;
 170 extern atomic_t fscache_n_acquires_oom;
 171
 172 extern atomic_t fscache_n_updates;
 173 extern atomic_t fscache_n_updates_null;
 174 extern atomic_t fscache_n_updates_run;
 175
 176 extern atomic_t fscache_n_relinquishes;
 177 extern atomic_t fscache_n_relinquishes_null;
 178 extern atomic_t fscache_n_relinquishes_waitcrt;
 179
 180 extern atomic_t fscache_n_cookie_index;
 181 extern atomic_t fscache_n_cookie_data;
 182 extern atomic_t fscache_n_cookie_special;
 183
 184 extern atomic_t fscache_n_object_alloc;
 185 extern atomic_t fscache_n_object_no_alloc;
 186 extern atomic_t fscache_n_object_lookups;
 187 extern atomic_t fscache_n_object_lookups_negative;
 188 extern atomic_t fscache_n_object_lookups_positive;
 189 extern atomic_t fscache_n_object_created;
 190 extern atomic_t fscache_n_object_avail;
 191 extern atomic_t fscache_n_object_dead;
 192
 193 extern atomic_t fscache_n_checkaux_none;
 194 extern atomic_t fscache_n_checkaux_okay;
 195 extern atomic_t fscache_n_checkaux_update;
 196 extern atomic_t fscache_n_checkaux_obsolete;
 197
 198 static inline void fscache_stat(atomic_t *stat)
 199 {
 200         atomic_inc(stat);
 201 }
 202
 203 extern const struct file_operations fscache_stats_fops;
 204 #else
 205
 206 #define fscache_stat(stat) do {} while (0)
 207 #endif
 208
 209 /*
 210  * raise an event on an object
 211  * - if the event is not masked for that object, then the object is
 212  *   queued for attention by the thread pool.
 213  */
 214 static inline void fscache_raise_event(struct fscache_object *object,
 215                                        unsigned event)
 216 {
 217         if (!test_and_set_bit(event, &object->events) &&
 218             test_bit(event, &object->event_mask))
 219                 fscache_enqueue_object(object);
 220 }
 221
 222 /*
 223  * drop a reference to a cookie
 224  */
 225 static inline void fscache_cookie_put(struct fscache_cookie *cookie)
 226 {
 227         BUG_ON(atomic_read(&cookie->usage) <= 0);
 228         if (atomic_dec_and_test(&cookie->usage))
 229                 __fscache_cookie_put(cookie);
 230 }
 231
 232 /*
 233  * get an extra reference to a netfs retrieval context
 234  */
 235 static inline
 236 void *fscache_get_context(struct fscache_cookie *cookie, void *context)
 237 {
 238         if (cookie->def->get_context)
 239                 cookie->def->get_context(cookie->netfs_data, context);
 240         return context;
 241 }
 242
 243 /*
 244  * release a reference to a netfs retrieval context
 245  */
 246 static inline
 247 void fscache_put_context(struct fscache_cookie *cookie, void *context)
 248 {
 249         if (cookie->def->put_context)
 250                 cookie->def->put_context(cookie->netfs_data, context);
 251 }
 252
 253 /*****************************************************************************/
 254 /*
 255  * debug tracing
 256  */
 257 #define dbgprintk(FMT, ...) \
 258         printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
 259
 260 /* make sure we maintain the format strings, even when debugging is disabled */
 261 static inline __attribute__((format(printf, 1, 2)))
 262 void _dbprintk(const char *fmt, ...)
 263 {
 264 }
 265
 266 #define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
 267 #define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
 268 #define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
 269
 270 #define kjournal(FMT, ...) _dbprintk(FMT, ##__VA_ARGS__)
 271
 272 #ifdef __KDEBUG
 273 #define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
 274 #define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
 275 #define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
 276
 277 #elif defined(CONFIG_FSCACHE_DEBUG)
 278 #define _enter(FMT, ...)                        \
 279 do {                                            \
 280         if (__do_kdebug(ENTER))                 \
 281                 kenter(FMT, ##__VA_ARGS__);     \
 282 } while (0)
 283
 284 #define _leave(FMT, ...)                        \
 285 do {                                            \
 286         if (__do_kdebug(LEAVE))                 \
 287                 kleave(FMT, ##__VA_ARGS__);     \
 288 } while (0)
 289
 290 #define _debug(FMT, ...)                        \
 291 do {                                            \
 292         if (__do_kdebug(DEBUG))                 \
 293                 kdebug(FMT, ##__VA_ARGS__);     \
 294 } while (0)
 295
 296 #else
 297 #define _enter(FMT, ...) _dbprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
 298 #define _leave(FMT, ...) _dbprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
 299 #define _debug(FMT, ...) _dbprintk(FMT, ##__VA_ARGS__)
 300 #endif
 301
 302 /*
 303  * determine whether a particular optional debugging point should be logged
 304  * - we need to go through three steps to persuade cpp to correctly join the
 305  *   shorthand in FSCACHE_DEBUG_LEVEL with its prefix
 306  */
 307 #define ____do_kdebug(LEVEL, POINT) \
 308         unlikely((fscache_debug & \
 309                   (FSCACHE_POINT_##POINT << (FSCACHE_DEBUG_ ## LEVEL * 3))))
 310 #define ___do_kdebug(LEVEL, POINT) \
 311         ____do_kdebug(LEVEL, POINT)
 312 #define __do_kdebug(POINT) \
 313         ___do_kdebug(FSCACHE_DEBUG_LEVEL, POINT)
 314
 315 #define FSCACHE_DEBUG_CACHE     0
 316 #define FSCACHE_DEBUG_COOKIE    1
 317 #define FSCACHE_DEBUG_PAGE      2
 318 #define FSCACHE_DEBUG_OPERATION 3
 319
 320 #define FSCACHE_POINT_ENTER     1
 321 #define FSCACHE_POINT_LEAVE     2
 322 #define FSCACHE_POINT_DEBUG     4
 323
 324 #ifndef FSCACHE_DEBUG_LEVEL
 325 #define FSCACHE_DEBUG_LEVEL CACHE
 326 #endif
 327
 328 /*
 329  * assertions
 330  */
 331 #if 1 /* defined(__KDEBUGALL) */
 332
 333 #define ASSERT(X)                                                       \
 334 do {                                                                    \
 335         if (unlikely(!(X))) {                                           \
 336                 printk(KERN_ERR "\n");                                  \
 337                 printk(KERN_ERR "FS-Cache: Assertion failed\n");        \
 338                 BUG();                                                  \
 339         }                                                               \
 340 } while (0)
 341
 342 #define ASSERTCMP(X, OP, Y)                                             \
 343 do {                                                                    \
 344         if (unlikely(!((X) OP (Y)))) {                                  \
 345                 printk(KERN_ERR "\n");                                  \
 346                 printk(KERN_ERR "FS-Cache: Assertion failed\n");        \
 347                 printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
 348                        (unsigned long)(X), (unsigned long)(Y));         \
 349                 BUG();                                                  \
 350         }                                                               \
 351 } while (0)
 352
 353 #define ASSERTIF(C, X)                                                  \
 354 do {                                                                    \
 355         if (unlikely((C) && !(X))) {                                    \
 356                 printk(KERN_ERR "\n");                                  \
 357                 printk(KERN_ERR "FS-Cache: Assertion failed\n");        \
 358                 BUG();                                                  \
 359         }                                                               \
 360 } while (0)
 361
 362 #define ASSERTIFCMP(C, X, OP, Y)                                        \
 363 do {                                                                    \
 364         if (unlikely((C) && !((X) OP (Y)))) {                           \
 365                 printk(KERN_ERR "\n");                                  \
 366                 printk(KERN_ERR "FS-Cache: Assertion failed\n");        \
 367                 printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
 368                        (unsigned long)(X), (unsigned long)(Y));         \
 369                 BUG();                                                  \
 370         }                                                               \
 371 } while (0)
 372
 373 #else
 374
 375 #define ASSERT(X)                       do {} while (0)
 376 #define ASSERTCMP(X, OP, Y)             do {} while (0)
 377 #define ASSERTIF(C, X)                  do {} while (0)
 378 #define ASSERTIFCMP(C, X, OP, Y)        do {} while (0)
 379
 380 #endif /* assert or not */