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FS-Cache: Handle pages pending storage that get evicted under OOM conditions
[net-next-2.6.git] / 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
1bccf513 20 * - cookie->stores_lock
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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
0e04d4ce 31/*
348ca102 32 * cache.c
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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
955d0091 40/*
348ca102 41 * cookie.c
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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
a6891645 48/*
348ca102 49 * fsdef.c
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50 */
51extern struct fscache_cookie fscache_fsdef_index;
52extern struct fscache_cookie_def fscache_fsdef_netfs_def;
53
7394daa8 54/*
348ca102 55 * histogram.c
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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
06b3db1b 78/*
348ca102 79 * main.c
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80 */
81extern unsigned fscache_defer_lookup;
82extern unsigned fscache_defer_create;
83extern unsigned fscache_debug;
84extern struct kobject *fscache_root;
85
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86extern int fscache_wait_bit(void *);
87extern int fscache_wait_bit_interruptible(void *);
88
36c95590 89/*
348ca102 90 * object.c
36c95590 91 */
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92extern const char fscache_object_states_short[FSCACHE_OBJECT__NSTATES][5];
93
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94extern void fscache_withdrawing_object(struct fscache_cache *,
95 struct fscache_object *);
96extern void fscache_enqueue_object(struct fscache_object *);
97
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98/*
99 * object-list.c
100 */
101#ifdef CONFIG_FSCACHE_OBJECT_LIST
102extern const struct file_operations fscache_objlist_fops;
103
104extern void fscache_objlist_add(struct fscache_object *);
105#else
106#define fscache_objlist_add(object) do {} while(0)
107#endif
108
36c95590 109/*
348ca102 110 * operation.c
36c95590 111 */
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112extern int fscache_submit_exclusive_op(struct fscache_object *,
113 struct fscache_operation *);
114extern int fscache_submit_op(struct fscache_object *,
115 struct fscache_operation *);
5753c441 116extern int fscache_cancel_op(struct fscache_operation *);
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117extern void fscache_abort_object(struct fscache_object *);
118extern void fscache_start_operations(struct fscache_object *);
119extern void fscache_operation_gc(struct work_struct *);
36c95590 120
7394daa8 121/*
348ca102 122 * proc.c
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123 */
124#ifdef CONFIG_PROC_FS
125extern int __init fscache_proc_init(void);
126extern void fscache_proc_cleanup(void);
127#else
128#define fscache_proc_init() (0)
129#define fscache_proc_cleanup() do {} while (0)
130#endif
131
132/*
348ca102 133 * stats.c
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134 */
135#ifdef CONFIG_FSCACHE_STATS
136extern atomic_t fscache_n_ops_processed[FSCACHE_MAX_THREADS];
137extern atomic_t fscache_n_objs_processed[FSCACHE_MAX_THREADS];
138
139extern atomic_t fscache_n_op_pend;
140extern atomic_t fscache_n_op_run;
141extern atomic_t fscache_n_op_enqueue;
142extern atomic_t fscache_n_op_deferred_release;
143extern atomic_t fscache_n_op_release;
144extern atomic_t fscache_n_op_gc;
5753c441 145extern atomic_t fscache_n_op_cancelled;
e3d4d28b 146extern atomic_t fscache_n_op_rejected;
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147
148extern atomic_t fscache_n_attr_changed;
149extern atomic_t fscache_n_attr_changed_ok;
150extern atomic_t fscache_n_attr_changed_nobufs;
151extern atomic_t fscache_n_attr_changed_nomem;
152extern atomic_t fscache_n_attr_changed_calls;
153
154extern atomic_t fscache_n_allocs;
155extern atomic_t fscache_n_allocs_ok;
156extern atomic_t fscache_n_allocs_wait;
157extern atomic_t fscache_n_allocs_nobufs;
5753c441 158extern atomic_t fscache_n_allocs_intr;
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159extern atomic_t fscache_n_alloc_ops;
160extern atomic_t fscache_n_alloc_op_waits;
161
162extern atomic_t fscache_n_retrievals;
163extern atomic_t fscache_n_retrievals_ok;
164extern atomic_t fscache_n_retrievals_wait;
165extern atomic_t fscache_n_retrievals_nodata;
166extern atomic_t fscache_n_retrievals_nobufs;
167extern atomic_t fscache_n_retrievals_intr;
168extern atomic_t fscache_n_retrievals_nomem;
169extern atomic_t fscache_n_retrieval_ops;
170extern atomic_t fscache_n_retrieval_op_waits;
171
172extern atomic_t fscache_n_stores;
173extern atomic_t fscache_n_stores_ok;
174extern atomic_t fscache_n_stores_again;
175extern atomic_t fscache_n_stores_nobufs;
176extern atomic_t fscache_n_stores_oom;
177extern atomic_t fscache_n_store_ops;
178extern atomic_t fscache_n_store_calls;
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179extern atomic_t fscache_n_store_pages;
180extern atomic_t fscache_n_store_radix_deletes;
181extern atomic_t fscache_n_store_pages_over_limit;
7394daa8 182
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183extern atomic_t fscache_n_store_vmscan_not_storing;
184extern atomic_t fscache_n_store_vmscan_gone;
185extern atomic_t fscache_n_store_vmscan_busy;
186extern atomic_t fscache_n_store_vmscan_cancelled;
187
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188extern atomic_t fscache_n_marks;
189extern atomic_t fscache_n_uncaches;
190
191extern atomic_t fscache_n_acquires;
192extern atomic_t fscache_n_acquires_null;
193extern atomic_t fscache_n_acquires_no_cache;
194extern atomic_t fscache_n_acquires_ok;
195extern atomic_t fscache_n_acquires_nobufs;
196extern atomic_t fscache_n_acquires_oom;
197
198extern atomic_t fscache_n_updates;
199extern atomic_t fscache_n_updates_null;
200extern atomic_t fscache_n_updates_run;
201
202extern atomic_t fscache_n_relinquishes;
203extern atomic_t fscache_n_relinquishes_null;
204extern atomic_t fscache_n_relinquishes_waitcrt;
205
206extern atomic_t fscache_n_cookie_index;
207extern atomic_t fscache_n_cookie_data;
208extern atomic_t fscache_n_cookie_special;
209
210extern atomic_t fscache_n_object_alloc;
211extern atomic_t fscache_n_object_no_alloc;
212extern atomic_t fscache_n_object_lookups;
213extern atomic_t fscache_n_object_lookups_negative;
214extern atomic_t fscache_n_object_lookups_positive;
215extern atomic_t fscache_n_object_created;
216extern atomic_t fscache_n_object_avail;
217extern atomic_t fscache_n_object_dead;
218
219extern atomic_t fscache_n_checkaux_none;
220extern atomic_t fscache_n_checkaux_okay;
221extern atomic_t fscache_n_checkaux_update;
222extern atomic_t fscache_n_checkaux_obsolete;
223
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224extern atomic_t fscache_n_cop_alloc_object;
225extern atomic_t fscache_n_cop_lookup_object;
226extern atomic_t fscache_n_cop_lookup_complete;
227extern atomic_t fscache_n_cop_grab_object;
228extern atomic_t fscache_n_cop_update_object;
229extern atomic_t fscache_n_cop_drop_object;
230extern atomic_t fscache_n_cop_put_object;
231extern atomic_t fscache_n_cop_sync_cache;
232extern atomic_t fscache_n_cop_attr_changed;
233extern atomic_t fscache_n_cop_read_or_alloc_page;
234extern atomic_t fscache_n_cop_read_or_alloc_pages;
235extern atomic_t fscache_n_cop_allocate_page;
236extern atomic_t fscache_n_cop_allocate_pages;
237extern atomic_t fscache_n_cop_write_page;
238extern atomic_t fscache_n_cop_uncache_page;
239extern atomic_t fscache_n_cop_dissociate_pages;
240
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241static inline void fscache_stat(atomic_t *stat)
242{
243 atomic_inc(stat);
244}
245
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246static inline void fscache_stat_d(atomic_t *stat)
247{
248 atomic_dec(stat);
249}
250
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251extern const struct file_operations fscache_stats_fops;
252#else
253
254#define fscache_stat(stat) do {} while (0)
255#endif
256
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257/*
258 * raise an event on an object
259 * - if the event is not masked for that object, then the object is
260 * queued for attention by the thread pool.
261 */
262static inline void fscache_raise_event(struct fscache_object *object,
263 unsigned event)
264{
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DH
265 if (!test_and_set_bit(event, &object->events) &&
266 test_bit(event, &object->event_mask))
267 fscache_enqueue_object(object);
268}
269
270/*
271 * drop a reference to a cookie
272 */
273static inline void fscache_cookie_put(struct fscache_cookie *cookie)
274{
275 BUG_ON(atomic_read(&cookie->usage) <= 0);
276 if (atomic_dec_and_test(&cookie->usage))
277 __fscache_cookie_put(cookie);
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278}
279
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280/*
281 * get an extra reference to a netfs retrieval context
282 */
283static inline
284void *fscache_get_context(struct fscache_cookie *cookie, void *context)
285{
286 if (cookie->def->get_context)
287 cookie->def->get_context(cookie->netfs_data, context);
288 return context;
289}
290
291/*
292 * release a reference to a netfs retrieval context
293 */
294static inline
295void fscache_put_context(struct fscache_cookie *cookie, void *context)
296{
297 if (cookie->def->put_context)
298 cookie->def->put_context(cookie->netfs_data, context);
299}
300
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301/*****************************************************************************/
302/*
303 * debug tracing
304 */
305#define dbgprintk(FMT, ...) \
306 printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
307
308/* make sure we maintain the format strings, even when debugging is disabled */
309static inline __attribute__((format(printf, 1, 2)))
310void _dbprintk(const char *fmt, ...)
311{
312}
313
314#define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
315#define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
316#define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
317
318#define kjournal(FMT, ...) _dbprintk(FMT, ##__VA_ARGS__)
319
320#ifdef __KDEBUG
321#define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
322#define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
323#define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
324
325#elif defined(CONFIG_FSCACHE_DEBUG)
326#define _enter(FMT, ...) \
327do { \
328 if (__do_kdebug(ENTER)) \
329 kenter(FMT, ##__VA_ARGS__); \
330} while (0)
331
332#define _leave(FMT, ...) \
333do { \
334 if (__do_kdebug(LEAVE)) \
335 kleave(FMT, ##__VA_ARGS__); \
336} while (0)
337
338#define _debug(FMT, ...) \
339do { \
340 if (__do_kdebug(DEBUG)) \
341 kdebug(FMT, ##__VA_ARGS__); \
342} while (0)
343
344#else
345#define _enter(FMT, ...) _dbprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
346#define _leave(FMT, ...) _dbprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
347#define _debug(FMT, ...) _dbprintk(FMT, ##__VA_ARGS__)
348#endif
349
350/*
351 * determine whether a particular optional debugging point should be logged
352 * - we need to go through three steps to persuade cpp to correctly join the
353 * shorthand in FSCACHE_DEBUG_LEVEL with its prefix
354 */
355#define ____do_kdebug(LEVEL, POINT) \
356 unlikely((fscache_debug & \
357 (FSCACHE_POINT_##POINT << (FSCACHE_DEBUG_ ## LEVEL * 3))))
358#define ___do_kdebug(LEVEL, POINT) \
359 ____do_kdebug(LEVEL, POINT)
360#define __do_kdebug(POINT) \
361 ___do_kdebug(FSCACHE_DEBUG_LEVEL, POINT)
362
363#define FSCACHE_DEBUG_CACHE 0
364#define FSCACHE_DEBUG_COOKIE 1
365#define FSCACHE_DEBUG_PAGE 2
366#define FSCACHE_DEBUG_OPERATION 3
367
368#define FSCACHE_POINT_ENTER 1
369#define FSCACHE_POINT_LEAVE 2
370#define FSCACHE_POINT_DEBUG 4
371
372#ifndef FSCACHE_DEBUG_LEVEL
373#define FSCACHE_DEBUG_LEVEL CACHE
374#endif
375
376/*
377 * assertions
378 */
379#if 1 /* defined(__KDEBUGALL) */
380
381#define ASSERT(X) \
382do { \
383 if (unlikely(!(X))) { \
384 printk(KERN_ERR "\n"); \
385 printk(KERN_ERR "FS-Cache: Assertion failed\n"); \
386 BUG(); \
387 } \
388} while (0)
389
390#define ASSERTCMP(X, OP, Y) \
391do { \
392 if (unlikely(!((X) OP (Y)))) { \
393 printk(KERN_ERR "\n"); \
394 printk(KERN_ERR "FS-Cache: Assertion failed\n"); \
395 printk(KERN_ERR "%lx " #OP " %lx is false\n", \
396 (unsigned long)(X), (unsigned long)(Y)); \
397 BUG(); \
398 } \
399} while (0)
400
401#define ASSERTIF(C, X) \
402do { \
403 if (unlikely((C) && !(X))) { \
404 printk(KERN_ERR "\n"); \
405 printk(KERN_ERR "FS-Cache: Assertion failed\n"); \
406 BUG(); \
407 } \
408} while (0)
409
410#define ASSERTIFCMP(C, X, OP, Y) \
411do { \
412 if (unlikely((C) && !((X) OP (Y)))) { \
413 printk(KERN_ERR "\n"); \
414 printk(KERN_ERR "FS-Cache: Assertion failed\n"); \
415 printk(KERN_ERR "%lx " #OP " %lx is false\n", \
416 (unsigned long)(X), (unsigned long)(Y)); \
417 BUG(); \
418 } \
419} while (0)
420
421#else
422
423#define ASSERT(X) do {} while (0)
424#define ASSERTCMP(X, OP, Y) do {} while (0)
425#define ASSERTIF(C, X) do {} while (0)
426#define ASSERTIFCMP(C, X, OP, Y) do {} while (0)
427
428#endif /* assert or not */