From 3d7a641e544e428191667e8b1f83f96fa46dbd65 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 19 Nov 2009 18:10:23 +0000 Subject: SLOW_WORK: Wait for outstanding work items belonging to a module to clear Wait for outstanding slow work items belonging to a module to clear when unregistering that module as a user of the facility. This prevents the put_ref code of a work item from being taken away before it returns. Signed-off-by: David Howells --- fs/fscache/object.c | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/fscache/object.c') diff --git a/fs/fscache/object.c b/fs/fscache/object.c index 392a41b1b79d..d236eb1d6f37 100644 --- a/fs/fscache/object.c +++ b/fs/fscache/object.c @@ -45,6 +45,7 @@ static void fscache_enqueue_dependents(struct fscache_object *); static void fscache_dequeue_object(struct fscache_object *); const struct slow_work_ops fscache_object_slow_work_ops = { + .owner = THIS_MODULE, .get_ref = fscache_object_slow_work_get_ref, .put_ref = fscache_object_slow_work_put_ref, .execute = fscache_object_slow_work_execute, -- cgit v1.2.3 From 440f0affe247e9990c8f8778f1861da4fd7d5e50 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 19 Nov 2009 18:11:01 +0000 Subject: FS-Cache: Annotate slow-work runqueue proc lines for FS-Cache work items Annotate slow-work runqueue proc lines for FS-Cache work items. Objects include the object ID and the state. Operations include the object ID, the operation ID and the operation type and state. Signed-off-by: David Howells --- fs/fscache/object.c | 41 ++++++++++++++++++++++++++++++++++++++++- fs/fscache/operation.c | 29 +++++++++++++++++++++++++++++ fs/fscache/page.c | 27 ++++++++++++++++++++++----- include/linux/fscache-cache.h | 12 ++++++++++++ 4 files changed, 103 insertions(+), 6 deletions(-) (limited to 'fs/fscache/object.c') diff --git a/fs/fscache/object.c b/fs/fscache/object.c index d236eb1d6f37..615b63dd9ecc 100644 --- a/fs/fscache/object.c +++ b/fs/fscache/object.c @@ -14,9 +14,10 @@ #define FSCACHE_DEBUG_LEVEL COOKIE #include +#include #include "internal.h" -const char *fscache_object_states[] = { +const char *fscache_object_states[FSCACHE_OBJECT__NSTATES] = { [FSCACHE_OBJECT_INIT] = "OBJECT_INIT", [FSCACHE_OBJECT_LOOKING_UP] = "OBJECT_LOOKING_UP", [FSCACHE_OBJECT_CREATING] = "OBJECT_CREATING", @@ -33,9 +34,28 @@ const char *fscache_object_states[] = { }; EXPORT_SYMBOL(fscache_object_states); +static const char fscache_object_states_short[FSCACHE_OBJECT__NSTATES][5] = { + [FSCACHE_OBJECT_INIT] = "INIT", + [FSCACHE_OBJECT_LOOKING_UP] = "LOOK", + [FSCACHE_OBJECT_CREATING] = "CRTN", + [FSCACHE_OBJECT_AVAILABLE] = "AVBL", + [FSCACHE_OBJECT_ACTIVE] = "ACTV", + [FSCACHE_OBJECT_UPDATING] = "UPDT", + [FSCACHE_OBJECT_DYING] = "DYNG", + [FSCACHE_OBJECT_LC_DYING] = "LCDY", + [FSCACHE_OBJECT_ABORT_INIT] = "ABTI", + [FSCACHE_OBJECT_RELEASING] = "RELS", + [FSCACHE_OBJECT_RECYCLING] = "RCYC", + [FSCACHE_OBJECT_WITHDRAWING] = "WTHD", + [FSCACHE_OBJECT_DEAD] = "DEAD", +}; + static void fscache_object_slow_work_put_ref(struct slow_work *); static int fscache_object_slow_work_get_ref(struct slow_work *); static void fscache_object_slow_work_execute(struct slow_work *); +#ifdef CONFIG_SLOW_WORK_PROC +static void fscache_object_slow_work_desc(struct slow_work *, struct seq_file *); +#endif static void fscache_initialise_object(struct fscache_object *); static void fscache_lookup_object(struct fscache_object *); static void fscache_object_available(struct fscache_object *); @@ -49,6 +69,9 @@ const struct slow_work_ops fscache_object_slow_work_ops = { .get_ref = fscache_object_slow_work_get_ref, .put_ref = fscache_object_slow_work_put_ref, .execute = fscache_object_slow_work_execute, +#ifdef CONFIG_SLOW_WORK_PROC + .desc = fscache_object_slow_work_desc, +#endif }; EXPORT_SYMBOL(fscache_object_slow_work_ops); @@ -326,6 +349,22 @@ static void fscache_object_slow_work_execute(struct slow_work *work) fscache_enqueue_object(object); } +/* + * describe an object for slow-work debugging + */ +#ifdef CONFIG_SLOW_WORK_PROC +static void fscache_object_slow_work_desc(struct slow_work *work, + struct seq_file *m) +{ + struct fscache_object *object = + container_of(work, struct fscache_object, work); + + seq_printf(m, "FSC: OBJ%x: %s", + object->debug_id, + fscache_object_states_short[object->state]); +} +#endif + /* * initialise an object * - check the specified object's parent to see if we can make use of it diff --git a/fs/fscache/operation.c b/fs/fscache/operation.c index f1a2857b2ff5..91bbe6f0377c 100644 --- a/fs/fscache/operation.c +++ b/fs/fscache/operation.c @@ -13,6 +13,7 @@ #define FSCACHE_DEBUG_LEVEL OPERATION #include +#include #include "internal.h" atomic_t fscache_op_debug_id; @@ -31,6 +32,8 @@ void fscache_enqueue_operation(struct fscache_operation *op) _enter("{OBJ%x OP%x,%u}", op->object->debug_id, op->debug_id, atomic_read(&op->usage)); + fscache_set_op_state(op, "EnQ"); + ASSERT(op->processor != NULL); ASSERTCMP(op->object->state, >=, FSCACHE_OBJECT_AVAILABLE); ASSERTCMP(atomic_read(&op->usage), >, 0); @@ -67,6 +70,8 @@ EXPORT_SYMBOL(fscache_enqueue_operation); static void fscache_run_op(struct fscache_object *object, struct fscache_operation *op) { + fscache_set_op_state(op, "Run"); + object->n_in_progress++; if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags)) wake_up_bit(&op->flags, FSCACHE_OP_WAITING); @@ -87,6 +92,8 @@ int fscache_submit_exclusive_op(struct fscache_object *object, _enter("{OBJ%x OP%x},", object->debug_id, op->debug_id); + fscache_set_op_state(op, "SubmitX"); + spin_lock(&object->lock); ASSERTCMP(object->n_ops, >=, object->n_in_progress); ASSERTCMP(object->n_ops, >=, object->n_exclusive); @@ -190,6 +197,8 @@ int fscache_submit_op(struct fscache_object *object, ASSERTCMP(atomic_read(&op->usage), >, 0); + fscache_set_op_state(op, "Submit"); + spin_lock(&object->lock); ASSERTCMP(object->n_ops, >=, object->n_in_progress); ASSERTCMP(object->n_ops, >=, object->n_exclusive); @@ -298,6 +307,8 @@ void fscache_put_operation(struct fscache_operation *op) if (!atomic_dec_and_test(&op->usage)) return; + fscache_set_op_state(op, "Put"); + _debug("PUT OP"); if (test_and_set_bit(FSCACHE_OP_DEAD, &op->flags)) BUG(); @@ -452,9 +463,27 @@ static void fscache_op_execute(struct slow_work *work) _leave(""); } +/* + * describe an operation for slow-work debugging + */ +#ifdef CONFIG_SLOW_WORK_PROC +static void fscache_op_desc(struct slow_work *work, struct seq_file *m) +{ + struct fscache_operation *op = + container_of(work, struct fscache_operation, slow_work); + + seq_printf(m, "FSC: OBJ%x OP%x: %s/%s fl=%lx", + op->object->debug_id, op->debug_id, + op->name, op->state, op->flags); +} +#endif + const struct slow_work_ops fscache_op_slow_work_ops = { .owner = THIS_MODULE, .get_ref = fscache_op_get_ref, .put_ref = fscache_op_put_ref, .execute = fscache_op_execute, +#ifdef CONFIG_SLOW_WORK_PROC + .desc = fscache_op_desc, +#endif }; diff --git a/fs/fscache/page.c b/fs/fscache/page.c index 2568e0eb644f..e8bbc395cef6 100644 --- a/fs/fscache/page.c +++ b/fs/fscache/page.c @@ -63,14 +63,19 @@ static void fscache_end_page_write(struct fscache_cookie *cookie, struct page *p static void fscache_attr_changed_op(struct fscache_operation *op) { struct fscache_object *object = op->object; + int ret; _enter("{OBJ%x OP%x}", object->debug_id, op->debug_id); fscache_stat(&fscache_n_attr_changed_calls); - if (fscache_object_is_active(object) && - object->cache->ops->attr_changed(object) < 0) - fscache_abort_object(object); + if (fscache_object_is_active(object)) { + fscache_set_op_state(op, "CallFS"); + ret = object->cache->ops->attr_changed(object); + fscache_set_op_state(op, "Done"); + if (ret < 0) + fscache_abort_object(object); + } _leave(""); } @@ -99,6 +104,7 @@ int __fscache_attr_changed(struct fscache_cookie *cookie) fscache_operation_init(op, NULL); fscache_operation_init_slow(op, fscache_attr_changed_op); op->flags = FSCACHE_OP_SLOW | (1 << FSCACHE_OP_EXCLUSIVE); + fscache_set_op_name(op, "Attr"); spin_lock(&cookie->lock); @@ -184,6 +190,7 @@ static struct fscache_retrieval *fscache_alloc_retrieval( op->start_time = jiffies; INIT_WORK(&op->op.fast_work, fscache_retrieval_work); INIT_LIST_HEAD(&op->to_do); + fscache_set_op_name(&op->op, "Retr"); return op; } @@ -257,6 +264,7 @@ int __fscache_read_or_alloc_page(struct fscache_cookie *cookie, _leave(" = -ENOMEM"); return -ENOMEM; } + fscache_set_op_name(&op->op, "RetrRA1"); spin_lock(&cookie->lock); @@ -369,6 +377,7 @@ int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie, op = fscache_alloc_retrieval(mapping, end_io_func, context); if (!op) return -ENOMEM; + fscache_set_op_name(&op->op, "RetrRAN"); spin_lock(&cookie->lock); @@ -461,6 +470,7 @@ int __fscache_alloc_page(struct fscache_cookie *cookie, op = fscache_alloc_retrieval(page->mapping, NULL, NULL); if (!op) return -ENOMEM; + fscache_set_op_name(&op->op, "RetrAL1"); spin_lock(&cookie->lock); @@ -529,6 +539,8 @@ static void fscache_write_op(struct fscache_operation *_op) _enter("{OP%x,%d}", op->op.debug_id, atomic_read(&op->op.usage)); + fscache_set_op_state(&op->op, "GetPage"); + spin_lock(&cookie->lock); spin_lock(&object->lock); @@ -559,13 +571,17 @@ static void fscache_write_op(struct fscache_operation *_op) spin_unlock(&cookie->lock); if (page) { + fscache_set_op_state(&op->op, "Store"); ret = object->cache->ops->write_page(op, page); + fscache_set_op_state(&op->op, "EndWrite"); fscache_end_page_write(cookie, page); page_cache_release(page); - if (ret < 0) + if (ret < 0) { + fscache_set_op_state(&op->op, "Abort"); fscache_abort_object(object); - else + } else { fscache_enqueue_operation(&op->op); + } } _leave(""); @@ -634,6 +650,7 @@ int __fscache_write_page(struct fscache_cookie *cookie, fscache_operation_init(&op->op, fscache_release_write_op); fscache_operation_init_slow(&op->op, fscache_write_op); op->op.flags = FSCACHE_OP_SLOW | (1 << FSCACHE_OP_WAITING); + fscache_set_op_name(&op->op, "Write1"); ret = radix_tree_preload(gfp & ~__GFP_HIGHMEM); if (ret < 0) diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h index 84d3532dd3ea..7a9847ccd192 100644 --- a/include/linux/fscache-cache.h +++ b/include/linux/fscache-cache.h @@ -102,6 +102,16 @@ struct fscache_operation { /* operation releaser */ fscache_operation_release_t release; + +#ifdef CONFIG_SLOW_WORK_PROC + const char *name; /* operation name */ + const char *state; /* operation state */ +#define fscache_set_op_name(OP, N) do { (OP)->name = (N); } while(0) +#define fscache_set_op_state(OP, S) do { (OP)->state = (S); } while(0) +#else +#define fscache_set_op_name(OP, N) do { } while(0) +#define fscache_set_op_state(OP, S) do { } while(0) +#endif }; extern atomic_t fscache_op_debug_id; @@ -125,6 +135,7 @@ static inline void fscache_operation_init(struct fscache_operation *op, op->debug_id = atomic_inc_return(&fscache_op_debug_id); op->release = release; INIT_LIST_HEAD(&op->pend_link); + fscache_set_op_state(op, "Init"); } /** @@ -337,6 +348,7 @@ struct fscache_object { FSCACHE_OBJECT_RECYCLING, /* retiring object */ FSCACHE_OBJECT_WITHDRAWING, /* withdrawing object */ FSCACHE_OBJECT_DEAD, /* object is now dead */ + FSCACHE_OBJECT__NSTATES } state; int debug_id; /* debugging ID */ -- cgit v1.2.3 From 4fbf4291aa15926cd4fdca0ffe9122e89d0459db Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 19 Nov 2009 18:11:04 +0000 Subject: FS-Cache: Allow the current state of all objects to be dumped Allow the current state of all fscache objects to be dumped by doing: cat /proc/fs/fscache/objects By default, all objects and all fields will be shown. This can be restricted by adding a suitable key to one of the caller's keyrings (such as the session keyring): keyctl add user fscache:objlist "" @s The are: K Show hexdump of object key (don't show if not given) A Show hexdump of object aux data (don't show if not given) And paired restrictions: C Show objects that have a cookie c Show objects that don't have a cookie B Show objects that are busy b Show objects that aren't busy W Show objects that have pending writes w Show objects that don't have pending writes R Show objects that have outstanding reads r Show objects that don't have outstanding reads S Show objects that have slow work queued s Show objects that don't have slow work queued If neither side of a restriction pair is given, then both are implied. For example: keyctl add user fscache:objlist KB @s shows objects that are busy, and lists their object keys, but does not dump their auxiliary data. It also implies "CcWwRrSs", but as 'B' is given, 'b' is not implied. Signed-off-by: David Howells --- Documentation/filesystems/caching/fscache.txt | 81 +++++ fs/cachefiles/interface.c | 1 + fs/cachefiles/rdwr.c | 6 +- fs/fscache/Kconfig | 7 + fs/fscache/Makefile | 1 + fs/fscache/cache.c | 1 + fs/fscache/cookie.c | 2 + fs/fscache/internal.h | 13 + fs/fscache/object-list.c | 432 ++++++++++++++++++++++++++ fs/fscache/object.c | 2 +- fs/fscache/operation.c | 3 + fs/fscache/page.c | 6 + fs/fscache/proc.c | 13 + include/linux/fscache-cache.h | 13 + 14 files changed, 578 insertions(+), 3 deletions(-) create mode 100644 fs/fscache/object-list.c (limited to 'fs/fscache/object.c') diff --git a/Documentation/filesystems/caching/fscache.txt b/Documentation/filesystems/caching/fscache.txt index 9e94b9491d89..cac09e11ca30 100644 --- a/Documentation/filesystems/caching/fscache.txt +++ b/Documentation/filesystems/caching/fscache.txt @@ -299,6 +299,87 @@ proc files. jiffy range covered, and the SECS field the equivalent number of seconds. +=========== +OBJECT LIST +=========== + +If CONFIG_FSCACHE_OBJECT_LIST is enabled, the FS-Cache facility will maintain a +list of all the objects currently allocated and allow them to be viewed +through: + + /proc/fs/fscache/objects + +This will look something like: + + [root@andromeda ~]# head /proc/fs/fscache/objects + OBJECT PARENT STAT CHLDN OPS OOP IPR EX READS EM EV F S | NETFS_COOKIE_DEF TY FL NETFS_DATA OBJECT_KEY, AUX_DATA + ======== ======== ==== ===== === === === == ===== == == = = | ================ == == ================ ================ + 17e4b 2 ACTV 0 0 0 0 0 0 7b 4 0 8 | NFS.fh DT 0 ffff88001dd82820 010006017edcf8bbc93b43298fdfbe71e50b57b13a172c0117f38472, e567634700000000000000000000000063f2404a000000000000000000000000c9030000000000000000000063f2404a + 1693a 2 ACTV 0 0 0 0 0 0 7b 4 0 8 | NFS.fh DT 0 ffff88002db23380 010006017edcf8bbc93b43298fdfbe71e50b57b1e0162c01a2df0ea6, 420ebc4a000000000000000000000000420ebc4a0000000000000000000000000e1801000000000000000000420ebc4a + +where the first set of columns before the '|' describe the object: + + COLUMN DESCRIPTION + ======= =============================================================== + OBJECT Object debugging ID (appears as OBJ%x in some debug messages) + PARENT Debugging ID of parent object + STAT Object state + CHLDN Number of child objects of this object + OPS Number of outstanding operations on this object + OOP Number of outstanding child object management operations + IPR + EX Number of outstanding exclusive operations + READS Number of outstanding read operations + EM Object's event mask + EV Events raised on this object + F Object flags + S Object slow-work work item flags + +and the second set of columns describe the object's cookie, if present: + + COLUMN DESCRIPTION + =============== ======================================================= + NETFS_COOKIE_DEF Name of netfs cookie definition + TY Cookie type (IX - index, DT - data, hex - special) + FL Cookie flags + NETFS_DATA Netfs private data stored in the cookie + OBJECT_KEY Object key } 1 column, with separating comma + AUX_DATA Object aux data } presence may be configured + +The data shown may be filtered by attaching the a key to an appropriate keyring +before viewing the file. Something like: + + keyctl add user fscache:objlist @s + +where are a selection of the following letters: + + K Show hexdump of object key (don't show if not given) + A Show hexdump of object aux data (don't show if not given) + +and the following paired letters: + + C Show objects that have a cookie + c Show objects that don't have a cookie + B Show objects that are busy + b Show objects that aren't busy + W Show objects that have pending writes + w Show objects that don't have pending writes + R Show objects that have outstanding reads + r Show objects that don't have outstanding reads + S Show objects that have slow work queued + s Show objects that don't have slow work queued + +If neither side of a letter pair is given, then both are implied. For example: + + keyctl add user fscache:objlist KB @s + +shows objects that are busy, and lists their object keys, but does not dump +their auxiliary data. It also implies "CcWwRrSs", but as 'B' is given, 'b' is +not implied. + +By default all objects and all fields will be shown. + + ========= DEBUGGING ========= diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c index 431accd475a7..dd7f852746cb 100644 --- a/fs/cachefiles/interface.c +++ b/fs/cachefiles/interface.c @@ -331,6 +331,7 @@ static void cachefiles_put_object(struct fscache_object *_object) } cache = object->fscache.cache; + fscache_object_destroy(&object->fscache); kmem_cache_free(cachefiles_object_jar, object); fscache_object_destroyed(cache); } diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c index a69787e7dd96..3304646dae84 100644 --- a/fs/cachefiles/rdwr.c +++ b/fs/cachefiles/rdwr.c @@ -333,7 +333,8 @@ int cachefiles_read_or_alloc_page(struct fscache_retrieval *op, shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits; - op->op.flags = FSCACHE_OP_FAST; + op->op.flags &= FSCACHE_OP_KEEP_FLAGS; + op->op.flags |= FSCACHE_OP_FAST; op->op.processor = cachefiles_read_copier; pagevec_init(&pagevec, 0); @@ -639,7 +640,8 @@ int cachefiles_read_or_alloc_pages(struct fscache_retrieval *op, pagevec_init(&pagevec, 0); - op->op.flags = FSCACHE_OP_FAST; + op->op.flags &= FSCACHE_OP_KEEP_FLAGS; + op->op.flags |= FSCACHE_OP_FAST; op->op.processor = cachefiles_read_copier; INIT_LIST_HEAD(&backpages); diff --git a/fs/fscache/Kconfig b/fs/fscache/Kconfig index 9bbb8ce7bea0..864dac20a242 100644 --- a/fs/fscache/Kconfig +++ b/fs/fscache/Kconfig @@ -54,3 +54,10 @@ config FSCACHE_DEBUG enabled by setting bits in /sys/modules/fscache/parameter/debug. See Documentation/filesystems/caching/fscache.txt for more information. + +config FSCACHE_OBJECT_LIST + bool "Maintain global object list for debugging purposes" + depends on FSCACHE && PROC_FS + help + Maintain a global list of active fscache objects that can be + retrieved through /proc/fs/fscache/objects for debugging purposes diff --git a/fs/fscache/Makefile b/fs/fscache/Makefile index 91571b95aacc..6d561531cb36 100644 --- a/fs/fscache/Makefile +++ b/fs/fscache/Makefile @@ -15,5 +15,6 @@ fscache-y := \ fscache-$(CONFIG_PROC_FS) += proc.o fscache-$(CONFIG_FSCACHE_STATS) += stats.o fscache-$(CONFIG_FSCACHE_HISTOGRAM) += histogram.o +fscache-$(CONFIG_FSCACHE_OBJECT_LIST) += object-list.o obj-$(CONFIG_FSCACHE) := fscache.o diff --git a/fs/fscache/cache.c b/fs/fscache/cache.c index e21985bbb1fb..724384ef96de 100644 --- a/fs/fscache/cache.c +++ b/fs/fscache/cache.c @@ -263,6 +263,7 @@ int fscache_add_cache(struct fscache_cache *cache, spin_lock(&cache->object_list_lock); list_add_tail(&ifsdef->cache_link, &cache->object_list); spin_unlock(&cache->object_list_lock); + fscache_objlist_add(ifsdef); /* add the cache's netfs definition index object to the top level index * cookie as a known backing object */ diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c index 72fd18f6c71f..9b5187328230 100644 --- a/fs/fscache/cookie.c +++ b/fs/fscache/cookie.c @@ -349,6 +349,8 @@ static int fscache_attach_object(struct fscache_cookie *cookie, object->cookie = cookie; atomic_inc(&cookie->usage); hlist_add_head(&object->cookie_link, &cookie->backing_objects); + + fscache_objlist_add(object); ret = 0; cant_attach_object: diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h index 1c341304621f..fe02973a9516 100644 --- a/fs/fscache/internal.h +++ b/fs/fscache/internal.h @@ -88,10 +88,23 @@ extern int fscache_wait_bit_interruptible(void *); /* * object.c */ +extern const char fscache_object_states_short[FSCACHE_OBJECT__NSTATES][5]; + extern void fscache_withdrawing_object(struct fscache_cache *, struct fscache_object *); extern void fscache_enqueue_object(struct fscache_object *); +/* + * object-list.c + */ +#ifdef CONFIG_FSCACHE_OBJECT_LIST +extern const struct file_operations fscache_objlist_fops; + +extern void fscache_objlist_add(struct fscache_object *); +#else +#define fscache_objlist_add(object) do {} while(0) +#endif + /* * operation.c */ diff --git a/fs/fscache/object-list.c b/fs/fscache/object-list.c new file mode 100644 index 000000000000..e590242fa41a --- /dev/null +++ b/fs/fscache/object-list.c @@ -0,0 +1,432 @@ +/* Global fscache object list maintainer and viewer + * + * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define FSCACHE_DEBUG_LEVEL COOKIE +#include +#include +#include +#include +#include "internal.h" + +static struct rb_root fscache_object_list; +static DEFINE_RWLOCK(fscache_object_list_lock); + +struct fscache_objlist_data { + unsigned long config; /* display configuration */ +#define FSCACHE_OBJLIST_CONFIG_KEY 0x00000001 /* show object keys */ +#define FSCACHE_OBJLIST_CONFIG_AUX 0x00000002 /* show object auxdata */ +#define FSCACHE_OBJLIST_CONFIG_COOKIE 0x00000004 /* show objects with cookies */ +#define FSCACHE_OBJLIST_CONFIG_NOCOOKIE 0x00000008 /* show objects without cookies */ +#define FSCACHE_OBJLIST_CONFIG_BUSY 0x00000010 /* show busy objects */ +#define FSCACHE_OBJLIST_CONFIG_IDLE 0x00000020 /* show idle objects */ +#define FSCACHE_OBJLIST_CONFIG_PENDWR 0x00000040 /* show objects with pending writes */ +#define FSCACHE_OBJLIST_CONFIG_NOPENDWR 0x00000080 /* show objects without pending writes */ +#define FSCACHE_OBJLIST_CONFIG_READS 0x00000100 /* show objects with active reads */ +#define FSCACHE_OBJLIST_CONFIG_NOREADS 0x00000200 /* show objects without active reads */ +#define FSCACHE_OBJLIST_CONFIG_EVENTS 0x00000400 /* show objects with events */ +#define FSCACHE_OBJLIST_CONFIG_NOEVENTS 0x00000800 /* show objects without no events */ +#define FSCACHE_OBJLIST_CONFIG_WORK 0x00001000 /* show objects with slow work */ +#define FSCACHE_OBJLIST_CONFIG_NOWORK 0x00002000 /* show objects without slow work */ + + u8 buf[512]; /* key and aux data buffer */ +}; + +/* + * Add an object to the object list + * - we use the address of the fscache_object structure as the key into the + * tree + */ +void fscache_objlist_add(struct fscache_object *obj) +{ + struct fscache_object *xobj; + struct rb_node **p = &fscache_object_list.rb_node, *parent = NULL; + + write_lock(&fscache_object_list_lock); + + while (*p) { + parent = *p; + xobj = rb_entry(parent, struct fscache_object, objlist_link); + + if (obj < xobj) + p = &(*p)->rb_left; + else if (obj > xobj) + p = &(*p)->rb_right; + else + BUG(); + } + + rb_link_node(&obj->objlist_link, parent, p); + rb_insert_color(&obj->objlist_link, &fscache_object_list); + + write_unlock(&fscache_object_list_lock); +} + +/** + * fscache_object_destroy - Note that a cache object is about to be destroyed + * @object: The object to be destroyed + * + * Note the imminent destruction and deallocation of a cache object record. + */ +void fscache_object_destroy(struct fscache_object *obj) +{ + write_lock(&fscache_object_list_lock); + + BUG_ON(RB_EMPTY_ROOT(&fscache_object_list)); + rb_erase(&obj->objlist_link, &fscache_object_list); + + write_unlock(&fscache_object_list_lock); +} +EXPORT_SYMBOL(fscache_object_destroy); + +/* + * find the object in the tree on or after the specified index + */ +static struct fscache_object *fscache_objlist_lookup(loff_t *_pos) +{ + struct fscache_object *pobj, *obj, *minobj = NULL; + struct rb_node *p; + unsigned long pos; + + if (*_pos >= (unsigned long) ERR_PTR(-ENOENT)) + return NULL; + pos = *_pos; + + /* banners (can't represent line 0 by pos 0 as that would involve + * returning a NULL pointer) */ + if (pos == 0) + return (struct fscache_object *) ++(*_pos); + if (pos < 3) + return (struct fscache_object *)pos; + + pobj = (struct fscache_object *)pos; + p = fscache_object_list.rb_node; + while (p) { + obj = rb_entry(p, struct fscache_object, objlist_link); + if (pobj < obj) { + if (!minobj || minobj > obj) + minobj = obj; + p = p->rb_left; + } else if (pobj > obj) { + p = p->rb_right; + } else { + minobj = obj; + break; + } + obj = NULL; + } + + if (!minobj) + *_pos = (unsigned long) ERR_PTR(-ENOENT); + else if (minobj != obj) + *_pos = (unsigned long) minobj; + return minobj; +} + +/* + * set up the iterator to start reading from the first line + */ +static void *fscache_objlist_start(struct seq_file *m, loff_t *_pos) + __acquires(&fscache_object_list_lock) +{ + read_lock(&fscache_object_list_lock); + return fscache_objlist_lookup(_pos); +} + +/* + * move to the next line + */ +static void *fscache_objlist_next(struct seq_file *m, void *v, loff_t *_pos) +{ + (*_pos)++; + return fscache_objlist_lookup(_pos); +} + +/* + * clean up after reading + */ +static void fscache_objlist_stop(struct seq_file *m, void *v) + __releases(&fscache_object_list_lock) +{ + read_unlock(&fscache_object_list_lock); +} + +/* + * display an object + */ +static int fscache_objlist_show(struct seq_file *m, void *v) +{ + struct fscache_objlist_data *data = m->private; + struct fscache_object *obj = v; + unsigned long config = data->config; + uint16_t keylen, auxlen; + char _type[3], *type; + bool no_cookie; + u8 *buf = data->buf, *p; + + if ((unsigned long) v == 1) { + seq_puts(m, "OBJECT PARENT STAT CHLDN OPS OOP IPR EX READS" + " EM EV F S" + " | NETFS_COOKIE_DEF TY FL NETFS_DATA"); + if (config & (FSCACHE_OBJLIST_CONFIG_KEY | + FSCACHE_OBJLIST_CONFIG_AUX)) + seq_puts(m, " "); + if (config & FSCACHE_OBJLIST_CONFIG_KEY) + seq_puts(m, "OBJECT_KEY"); + if ((config & (FSCACHE_OBJLIST_CONFIG_KEY | + FSCACHE_OBJLIST_CONFIG_AUX)) == + (FSCACHE_OBJLIST_CONFIG_KEY | FSCACHE_OBJLIST_CONFIG_AUX)) + seq_puts(m, ", "); + if (config & FSCACHE_OBJLIST_CONFIG_AUX) + seq_puts(m, "AUX_DATA"); + seq_puts(m, "\n"); + return 0; + } + + if ((unsigned long) v == 2) { + seq_puts(m, "======== ======== ==== ===== === === === == =====" + " == == = =" + " | ================ == == ================"); + if (config & (FSCACHE_OBJLIST_CONFIG_KEY | + FSCACHE_OBJLIST_CONFIG_AUX)) + seq_puts(m, " ================"); + seq_puts(m, "\n"); + return 0; + } + + /* filter out any unwanted objects */ +#define FILTER(criterion, _yes, _no) \ + do { \ + unsigned long yes = FSCACHE_OBJLIST_CONFIG_##_yes; \ + unsigned long no = FSCACHE_OBJLIST_CONFIG_##_no; \ + if (criterion) { \ + if (!(config & yes)) \ + return 0; \ + } else { \ + if (!(config & no)) \ + return 0; \ + } \ + } while(0) + + if (~config) { + FILTER(obj->cookie, + COOKIE, NOCOOKIE); + FILTER(obj->state != FSCACHE_OBJECT_ACTIVE || + obj->n_ops != 0 || + obj->n_obj_ops != 0 || + obj->flags || + !list_empty(&obj->dependents), + BUSY, IDLE); + FILTER(test_bit(FSCACHE_OBJECT_PENDING_WRITE, &obj->flags), + PENDWR, NOPENDWR); + FILTER(atomic_read(&obj->n_reads), + READS, NOREADS); + FILTER(obj->events & obj->event_mask, + EVENTS, NOEVENTS); + FILTER(obj->work.flags & ~(1UL << SLOW_WORK_VERY_SLOW), + WORK, NOWORK); + } + + seq_printf(m, + "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %1lx %1lx | ", + obj->debug_id, + obj->parent ? obj->parent->debug_id : -1, + fscache_object_states_short[obj->state], + obj->n_children, + obj->n_ops, + obj->n_obj_ops, + obj->n_in_progress, + obj->n_exclusive, + atomic_read(&obj->n_reads), + obj->event_mask & FSCACHE_OBJECT_EVENTS_MASK, + obj->events, + obj->flags, + obj->work.flags); + + no_cookie = true; + keylen = auxlen = 0; + if (obj->cookie) { + spin_lock(&obj->lock); + if (obj->cookie) { + switch (obj->cookie->def->type) { + case 0: + type = "IX"; + break; + case 1: + type = "DT"; + break; + default: + sprintf(_type, "%02u", + obj->cookie->def->type); + type = _type; + break; + } + + seq_printf(m, "%-16s %s %2lx %16p", + obj->cookie->def->name, + type, + obj->cookie->flags, + obj->cookie->netfs_data); + + if (obj->cookie->def->get_key && + config & FSCACHE_OBJLIST_CONFIG_KEY) + keylen = obj->cookie->def->get_key( + obj->cookie->netfs_data, + buf, 400); + + if (obj->cookie->def->get_aux && + config & FSCACHE_OBJLIST_CONFIG_AUX) + auxlen = obj->cookie->def->get_aux( + obj->cookie->netfs_data, + buf + keylen, 512 - keylen); + + no_cookie = false; + } + spin_unlock(&obj->lock); + + if (!no_cookie && (keylen > 0 || auxlen > 0)) { + seq_printf(m, " "); + for (p = buf; keylen > 0; keylen--) + seq_printf(m, "%02x", *p++); + if (auxlen > 0) { + if (config & FSCACHE_OBJLIST_CONFIG_KEY) + seq_printf(m, ", "); + for (; auxlen > 0; auxlen--) + seq_printf(m, "%02x", *p++); + } + } + } + + if (no_cookie) + seq_printf(m, "\n"); + else + seq_printf(m, "\n"); + return 0; +} + +static const struct seq_operations fscache_objlist_ops = { + .start = fscache_objlist_start, + .stop = fscache_objlist_stop, + .next = fscache_objlist_next, + .show = fscache_objlist_show, +}; + +/* + * get the configuration for filtering the list + */ +static void fscache_objlist_config(struct fscache_objlist_data *data) +{ +#ifdef CONFIG_KEYS + struct user_key_payload *confkey; + unsigned long config; + struct key *key; + const char *buf; + int len; + + key = request_key(&key_type_user, "fscache:objlist", NULL); + if (IS_ERR(key)) + goto no_config; + + config = 0; + rcu_read_lock(); + + confkey = key->payload.data; + buf = confkey->data; + + for (len = confkey->datalen - 1; len >= 0; len--) { + switch (buf[len]) { + case 'K': config |= FSCACHE_OBJLIST_CONFIG_KEY; break; + case 'A': config |= FSCACHE_OBJLIST_CONFIG_AUX; break; + case 'C': config |= FSCACHE_OBJLIST_CONFIG_COOKIE; break; + case 'c': config |= FSCACHE_OBJLIST_CONFIG_NOCOOKIE; break; + case 'B': config |= FSCACHE_OBJLIST_CONFIG_BUSY; break; + case 'b': config |= FSCACHE_OBJLIST_CONFIG_IDLE; break; + case 'W': config |= FSCACHE_OBJLIST_CONFIG_PENDWR; break; + case 'w': config |= FSCACHE_OBJLIST_CONFIG_NOPENDWR; break; + case 'R': config |= FSCACHE_OBJLIST_CONFIG_READS; break; + case 'r': config |= FSCACHE_OBJLIST_CONFIG_NOREADS; break; + case 'S': config |= FSCACHE_OBJLIST_CONFIG_WORK; break; + case 's': config |= FSCACHE_OBJLIST_CONFIG_NOWORK; break; + } + } + + rcu_read_unlock(); + key_put(key); + + if (!(config & (FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE))) + config |= FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE; + if (!(config & (FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE))) + config |= FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE; + if (!(config & (FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR))) + config |= FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR; + if (!(config & (FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS))) + config |= FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS; + if (!(config & (FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS))) + config |= FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS; + if (!(config & (FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK))) + config |= FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK; + + data->config = config; + return; + +no_config: +#endif + data->config = ULONG_MAX; +} + +/* + * open "/proc/fs/fscache/objects" to provide a list of active objects + * - can be configured by a user-defined key added to the caller's keyrings + */ +static int fscache_objlist_open(struct inode *inode, struct file *file) +{ + struct fscache_objlist_data *data; + struct seq_file *m; + int ret; + + ret = seq_open(file, &fscache_objlist_ops); + if (ret < 0) + return ret; + + m = file->private_data; + + /* buffer for key extraction */ + data = kmalloc(sizeof(struct fscache_objlist_data), GFP_KERNEL); + if (!data) { + seq_release(inode, file); + return -ENOMEM; + } + + /* get the configuration key */ + fscache_objlist_config(data); + + m->private = data; + return 0; +} + +/* + * clean up on close + */ +static int fscache_objlist_release(struct inode *inode, struct file *file) +{ + struct seq_file *m = file->private_data; + + kfree(m->private); + m->private = NULL; + return seq_release(inode, file); +} + +const struct file_operations fscache_objlist_fops = { + .owner = THIS_MODULE, + .open = fscache_objlist_open, + .read = seq_read, + .llseek = seq_lseek, + .release = fscache_objlist_release, +}; diff --git a/fs/fscache/object.c b/fs/fscache/object.c index 615b63dd9ecc..ad1644f073bd 100644 --- a/fs/fscache/object.c +++ b/fs/fscache/object.c @@ -34,7 +34,7 @@ const char *fscache_object_states[FSCACHE_OBJECT__NSTATES] = { }; EXPORT_SYMBOL(fscache_object_states); -static const char fscache_object_states_short[FSCACHE_OBJECT__NSTATES][5] = { +const char fscache_object_states_short[FSCACHE_OBJECT__NSTATES][5] = { [FSCACHE_OBJECT_INIT] = "INIT", [FSCACHE_OBJECT_LOOKING_UP] = "LOOK", [FSCACHE_OBJECT_CREATING] = "CRTN", diff --git a/fs/fscache/operation.c b/fs/fscache/operation.c index 91bbe6f0377c..09e43b6e822f 100644 --- a/fs/fscache/operation.c +++ b/fs/fscache/operation.c @@ -322,6 +322,9 @@ void fscache_put_operation(struct fscache_operation *op) object = op->object; + if (test_bit(FSCACHE_OP_DEC_READ_CNT, &op->flags)) + atomic_dec(&object->n_reads); + /* now... we may get called with the object spinlock held, so we * complete the cleanup here only if we can immediately acquire the * lock, and defer it otherwise */ diff --git a/fs/fscache/page.c b/fs/fscache/page.c index e8bbc395cef6..c5973e38ce39 100644 --- a/fs/fscache/page.c +++ b/fs/fscache/page.c @@ -275,6 +275,9 @@ int __fscache_read_or_alloc_page(struct fscache_cookie *cookie, ASSERTCMP(object->state, >, FSCACHE_OBJECT_LOOKING_UP); + atomic_inc(&object->n_reads); + set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags); + if (fscache_submit_op(object, &op->op) < 0) goto nobufs_unlock; spin_unlock(&cookie->lock); @@ -386,6 +389,9 @@ int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie, object = hlist_entry(cookie->backing_objects.first, struct fscache_object, cookie_link); + atomic_inc(&object->n_reads); + set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags); + if (fscache_submit_op(object, &op->op) < 0) goto nobufs_unlock; spin_unlock(&cookie->lock); diff --git a/fs/fscache/proc.c b/fs/fscache/proc.c index beeab44bc31a..1d9e4951a597 100644 --- a/fs/fscache/proc.c +++ b/fs/fscache/proc.c @@ -37,10 +37,20 @@ int __init fscache_proc_init(void) goto error_histogram; #endif +#ifdef CONFIG_FSCACHE_OBJECT_LIST + if (!proc_create("fs/fscache/objects", S_IFREG | 0444, NULL, + &fscache_objlist_fops)) + goto error_objects; +#endif + _leave(" = 0"); return 0; +#ifdef CONFIG_FSCACHE_OBJECT_LIST +error_objects: +#endif #ifdef CONFIG_FSCACHE_HISTOGRAM + remove_proc_entry("fs/fscache/histogram", NULL); error_histogram: #endif #ifdef CONFIG_FSCACHE_STATS @@ -58,6 +68,9 @@ error_dir: */ void fscache_proc_cleanup(void) { +#ifdef CONFIG_FSCACHE_OBJECT_LIST + remove_proc_entry("fs/fscache/objects", NULL); +#endif #ifdef CONFIG_FSCACHE_HISTOGRAM remove_proc_entry("fs/fscache/histogram", NULL); #endif diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h index 7a9847ccd192..184cbdfbcc99 100644 --- a/include/linux/fscache-cache.h +++ b/include/linux/fscache-cache.h @@ -91,6 +91,8 @@ struct fscache_operation { #define FSCACHE_OP_WAITING 4 /* cleared when op is woken */ #define FSCACHE_OP_EXCLUSIVE 5 /* exclusive op, other ops must wait */ #define FSCACHE_OP_DEAD 6 /* op is now dead */ +#define FSCACHE_OP_DEC_READ_CNT 7 /* decrement object->n_reads on destruction */ +#define FSCACHE_OP_KEEP_FLAGS 0xc0 /* flags to keep when repurposing an op */ atomic_t usage; unsigned debug_id; /* debugging ID */ @@ -357,6 +359,7 @@ struct fscache_object { int n_obj_ops; /* number of object ops outstanding on object */ int n_in_progress; /* number of ops in progress */ int n_exclusive; /* number of exclusive ops queued */ + atomic_t n_reads; /* number of read ops in progress */ spinlock_t lock; /* state and operations lock */ unsigned long lookup_jif; /* time at which lookup started */ @@ -370,6 +373,7 @@ struct fscache_object { #define FSCACHE_OBJECT_EV_RELEASE 4 /* T if netfs requested object release */ #define FSCACHE_OBJECT_EV_RETIRE 5 /* T if netfs requested object retirement */ #define FSCACHE_OBJECT_EV_WITHDRAW 6 /* T if cache requested object withdrawal */ +#define FSCACHE_OBJECT_EVENTS_MASK 0x7f /* mask of all events*/ unsigned long flags; #define FSCACHE_OBJECT_LOCK 0 /* T if object is busy being processed */ @@ -385,6 +389,9 @@ struct fscache_object { struct list_head dependents; /* FIFO of dependent objects */ struct list_head dep_link; /* link in parent's dependents list */ struct list_head pending_ops; /* unstarted operations on this object */ +#ifdef CONFIG_FSCACHE_OBJECT_LIST + struct rb_node objlist_link; /* link in global object list */ +#endif pgoff_t store_limit; /* current storage limit */ }; @@ -434,6 +441,12 @@ void fscache_object_init(struct fscache_object *object, extern void fscache_object_lookup_negative(struct fscache_object *object); extern void fscache_obtained_object(struct fscache_object *object); +#ifdef CONFIG_FSCACHE_OBJECT_LIST +extern void fscache_object_destroy(struct fscache_object *object); +#else +#define fscache_object_destroy(object) do {} while(0) +#endif + /** * fscache_object_destroyed - Note destruction of an object in a cache * @cache: The cache from which the object came -- cgit v1.2.3 From 52bd75fdb135d6133d878ae60c6e7e3f4ebc1cfc Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 19 Nov 2009 18:11:08 +0000 Subject: FS-Cache: Add counters for entry/exit to/from cache operation functions Count entries to and exits from cache operation table functions. Maintain these as a single counter that's added to or removed from as appropriate. Signed-off-by: David Howells --- Documentation/filesystems/caching/fscache.txt | 16 ++++++++++++ fs/fscache/cache.c | 4 +++ fs/fscache/cookie.c | 9 ++++++- fs/fscache/internal.h | 22 ++++++++++++++++ fs/fscache/object.c | 26 +++++++++++++++++-- fs/fscache/page.c | 29 ++++++++++++++++----- fs/fscache/stats.c | 37 +++++++++++++++++++++++++++ 7 files changed, 134 insertions(+), 9 deletions(-) (limited to 'fs/fscache/object.c') diff --git a/Documentation/filesystems/caching/fscache.txt b/Documentation/filesystems/caching/fscache.txt index cac09e11ca30..b6c32c080ab1 100644 --- a/Documentation/filesystems/caching/fscache.txt +++ b/Documentation/filesystems/caching/fscache.txt @@ -274,6 +274,22 @@ proc files. dfr=N Number of async ops queued for deferred release rel=N Number of async ops released gc=N Number of deferred-release async ops garbage collected + CacheOp alo=N Number of in-progress alloc_object() cache ops + luo=N Number of in-progress lookup_object() cache ops + luc=N Number of in-progress lookup_complete() cache ops + gro=N Number of in-progress grab_object() cache ops + upo=N Number of in-progress update_object() cache ops + dro=N Number of in-progress drop_object() cache ops + pto=N Number of in-progress put_object() cache ops + syn=N Number of in-progress sync_cache() cache ops + atc=N Number of in-progress attr_changed() cache ops + rap=N Number of in-progress read_or_alloc_page() cache ops + ras=N Number of in-progress read_or_alloc_pages() cache ops + alp=N Number of in-progress allocate_page() cache ops + als=N Number of in-progress allocate_pages() cache ops + wrp=N Number of in-progress write_page() cache ops + ucp=N Number of in-progress uncache_page() cache ops + dsp=N Number of in-progress dissociate_pages() cache ops (*) /proc/fs/fscache/histogram diff --git a/fs/fscache/cache.c b/fs/fscache/cache.c index 724384ef96de..6a3c48abd677 100644 --- a/fs/fscache/cache.c +++ b/fs/fscache/cache.c @@ -381,11 +381,15 @@ void fscache_withdraw_cache(struct fscache_cache *cache) /* make sure all pages pinned by operations on behalf of the netfs are * written to disk */ + fscache_stat(&fscache_n_cop_sync_cache); cache->ops->sync_cache(cache); + fscache_stat_d(&fscache_n_cop_sync_cache); /* dissociate all the netfs pages backed by this cache from the block * mappings in the cache */ + fscache_stat(&fscache_n_cop_dissociate_pages); cache->ops->dissociate_pages(cache); + fscache_stat_d(&fscache_n_cop_dissociate_pages); /* we now have to destroy all the active objects pertaining to this * cache - which we do by passing them off to thread pool to be diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c index 9b5187328230..432482edc738 100644 --- a/fs/fscache/cookie.c +++ b/fs/fscache/cookie.c @@ -249,7 +249,9 @@ static int fscache_alloc_object(struct fscache_cache *cache, /* ask the cache to allocate an object (we may end up with duplicate * objects at this stage, but we sort that out later) */ + fscache_stat(&fscache_n_cop_alloc_object); object = cache->ops->alloc_object(cache, cookie); + fscache_stat_d(&fscache_n_cop_alloc_object); if (IS_ERR(object)) { fscache_stat(&fscache_n_object_no_alloc); ret = PTR_ERR(object); @@ -270,8 +272,11 @@ static int fscache_alloc_object(struct fscache_cache *cache, /* only attach if we managed to allocate all we needed, otherwise * discard the object we just allocated and instead use the one * attached to the cookie */ - if (fscache_attach_object(cookie, object) < 0) + if (fscache_attach_object(cookie, object) < 0) { + fscache_stat(&fscache_n_cop_put_object); cache->ops->put_object(object); + fscache_stat_d(&fscache_n_cop_put_object); + } _leave(" = 0"); return 0; @@ -287,7 +292,9 @@ object_already_extant: return 0; error_put: + fscache_stat(&fscache_n_cop_put_object); cache->ops->put_object(object); + fscache_stat_d(&fscache_n_cop_put_object); error: _leave(" = %d", ret); return ret; diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h index fe02973a9516..b85cc8906818 100644 --- a/fs/fscache/internal.h +++ b/fs/fscache/internal.h @@ -208,11 +208,33 @@ extern atomic_t fscache_n_checkaux_okay; extern atomic_t fscache_n_checkaux_update; extern atomic_t fscache_n_checkaux_obsolete; +extern atomic_t fscache_n_cop_alloc_object; +extern atomic_t fscache_n_cop_lookup_object; +extern atomic_t fscache_n_cop_lookup_complete; +extern atomic_t fscache_n_cop_grab_object; +extern atomic_t fscache_n_cop_update_object; +extern atomic_t fscache_n_cop_drop_object; +extern atomic_t fscache_n_cop_put_object; +extern atomic_t fscache_n_cop_sync_cache; +extern atomic_t fscache_n_cop_attr_changed; +extern atomic_t fscache_n_cop_read_or_alloc_page; +extern atomic_t fscache_n_cop_read_or_alloc_pages; +extern atomic_t fscache_n_cop_allocate_page; +extern atomic_t fscache_n_cop_allocate_pages; +extern atomic_t fscache_n_cop_write_page; +extern atomic_t fscache_n_cop_uncache_page; +extern atomic_t fscache_n_cop_dissociate_pages; + static inline void fscache_stat(atomic_t *stat) { atomic_inc(stat); } +static inline void fscache_stat_d(atomic_t *stat) +{ + atomic_dec(stat); +} + extern const struct file_operations fscache_stats_fops; #else diff --git a/fs/fscache/object.c b/fs/fscache/object.c index ad1644f073bd..0d65c0c92b46 100644 --- a/fs/fscache/object.c +++ b/fs/fscache/object.c @@ -144,13 +144,17 @@ static void fscache_object_state_machine(struct fscache_object *object) case FSCACHE_OBJECT_UPDATING: clear_bit(FSCACHE_OBJECT_EV_UPDATE, &object->events); fscache_stat(&fscache_n_updates_run); + fscache_stat(&fscache_n_cop_update_object); object->cache->ops->update_object(object); + fscache_stat_d(&fscache_n_cop_update_object); goto active_transit; /* handle an object dying during lookup or creation */ case FSCACHE_OBJECT_LC_DYING: object->event_mask &= ~(1 << FSCACHE_OBJECT_EV_UPDATE); + fscache_stat(&fscache_n_cop_lookup_complete); object->cache->ops->lookup_complete(object); + fscache_stat_d(&fscache_n_cop_lookup_complete); spin_lock(&object->lock); object->state = FSCACHE_OBJECT_DYING; @@ -416,7 +420,9 @@ static void fscache_initialise_object(struct fscache_object *object) * binding on to us, so we need to make sure we don't * add ourself to the list multiple times */ if (list_empty(&object->dep_link)) { + fscache_stat(&fscache_n_cop_grab_object); object->cache->ops->grab_object(object); + fscache_stat_d(&fscache_n_cop_grab_object); list_add(&object->dep_link, &parent->dependents); @@ -478,7 +484,9 @@ static void fscache_lookup_object(struct fscache_object *object) object->cache->tag->name); fscache_stat(&fscache_n_object_lookups); + fscache_stat(&fscache_n_cop_lookup_object); object->cache->ops->lookup_object(object); + fscache_stat_d(&fscache_n_cop_lookup_object); if (test_bit(FSCACHE_OBJECT_EV_ERROR, &object->events)) set_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags); @@ -602,7 +610,9 @@ static void fscache_object_available(struct fscache_object *object) } spin_unlock(&object->lock); + fscache_stat(&fscache_n_cop_lookup_complete); object->cache->ops->lookup_complete(object); + fscache_stat_d(&fscache_n_cop_lookup_complete); fscache_enqueue_dependents(object); fscache_hist(fscache_obj_instantiate_histogram, object->lookup_jif); @@ -625,7 +635,9 @@ static void fscache_drop_object(struct fscache_object *object) list_del_init(&object->cache_link); spin_unlock(&cache->object_list_lock); + fscache_stat(&fscache_n_cop_drop_object); cache->ops->drop_object(object); + fscache_stat_d(&fscache_n_cop_drop_object); if (parent) { _debug("release parent OBJ%x {%d}", @@ -640,7 +652,9 @@ static void fscache_drop_object(struct fscache_object *object) } /* this just shifts the object release to the slow work processor */ + fscache_stat(&fscache_n_cop_put_object); object->cache->ops->put_object(object); + fscache_stat_d(&fscache_n_cop_put_object); _leave(""); } @@ -730,8 +744,12 @@ static int fscache_object_slow_work_get_ref(struct slow_work *work) { struct fscache_object *object = container_of(work, struct fscache_object, work); + int ret; - return object->cache->ops->grab_object(object) ? 0 : -EAGAIN; + fscache_stat(&fscache_n_cop_grab_object); + ret = object->cache->ops->grab_object(object) ? 0 : -EAGAIN; + fscache_stat_d(&fscache_n_cop_grab_object); + return ret; } /* @@ -742,7 +760,9 @@ static void fscache_object_slow_work_put_ref(struct slow_work *work) struct fscache_object *object = container_of(work, struct fscache_object, work); - return object->cache->ops->put_object(object); + fscache_stat(&fscache_n_cop_put_object); + object->cache->ops->put_object(object); + fscache_stat_d(&fscache_n_cop_put_object); } /* @@ -779,7 +799,9 @@ static void fscache_enqueue_dependents(struct fscache_object *object) /* sort onto appropriate lists */ fscache_enqueue_object(dep); + fscache_stat(&fscache_n_cop_put_object); dep->cache->ops->put_object(dep); + fscache_stat_d(&fscache_n_cop_put_object); if (!list_empty(&object->dependents)) cond_resched_lock(&object->lock); diff --git a/fs/fscache/page.c b/fs/fscache/page.c index c5973e38ce39..250dfd34c07b 100644 --- a/fs/fscache/page.c +++ b/fs/fscache/page.c @@ -71,7 +71,9 @@ static void fscache_attr_changed_op(struct fscache_operation *op) if (fscache_object_is_active(object)) { fscache_set_op_state(op, "CallFS"); + fscache_stat(&fscache_n_cop_attr_changed); ret = object->cache->ops->attr_changed(object); + fscache_stat_d(&fscache_n_cop_attr_changed); fscache_set_op_state(op, "Done"); if (ret < 0) fscache_abort_object(object); @@ -300,11 +302,15 @@ int __fscache_read_or_alloc_page(struct fscache_cookie *cookie, /* ask the cache to honour the operation */ if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) { + fscache_stat(&fscache_n_cop_allocate_page); ret = object->cache->ops->allocate_page(op, page, gfp); + fscache_stat_d(&fscache_n_cop_allocate_page); if (ret == 0) ret = -ENODATA; } else { + fscache_stat(&fscache_n_cop_read_or_alloc_page); ret = object->cache->ops->read_or_alloc_page(op, page, gfp); + fscache_stat_d(&fscache_n_cop_read_or_alloc_page); } if (ret == -ENOMEM) @@ -358,7 +364,6 @@ int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie, void *context, gfp_t gfp) { - fscache_pages_retrieval_func_t func; struct fscache_retrieval *op; struct fscache_object *object; int ret; @@ -413,11 +418,17 @@ int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie, } /* ask the cache to honour the operation */ - if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) - func = object->cache->ops->allocate_pages; - else - func = object->cache->ops->read_or_alloc_pages; - ret = func(op, pages, nr_pages, gfp); + if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) { + fscache_stat(&fscache_n_cop_allocate_pages); + ret = object->cache->ops->allocate_pages( + op, pages, nr_pages, gfp); + fscache_stat_d(&fscache_n_cop_allocate_pages); + } else { + fscache_stat(&fscache_n_cop_read_or_alloc_pages); + ret = object->cache->ops->read_or_alloc_pages( + op, pages, nr_pages, gfp); + fscache_stat_d(&fscache_n_cop_read_or_alloc_pages); + } if (ret == -ENOMEM) fscache_stat(&fscache_n_retrievals_nomem); @@ -500,7 +511,9 @@ int __fscache_alloc_page(struct fscache_cookie *cookie, } /* ask the cache to honour the operation */ + fscache_stat(&fscache_n_cop_allocate_page); ret = object->cache->ops->allocate_page(op, page, gfp); + fscache_stat_d(&fscache_n_cop_allocate_page); if (ret < 0) fscache_stat(&fscache_n_allocs_nobufs); @@ -578,7 +591,9 @@ static void fscache_write_op(struct fscache_operation *_op) if (page) { fscache_set_op_state(&op->op, "Store"); + fscache_stat(&fscache_n_cop_write_page); ret = object->cache->ops->write_page(op, page); + fscache_stat_d(&fscache_n_cop_write_page); fscache_set_op_state(&op->op, "EndWrite"); fscache_end_page_write(cookie, page); page_cache_release(page); @@ -786,7 +801,9 @@ void __fscache_uncache_page(struct fscache_cookie *cookie, struct page *page) if (TestClearPageFsCache(page) && object->cache->ops->uncache_page) { /* the cache backend releases the cookie lock */ + fscache_stat(&fscache_n_cop_uncache_page); object->cache->ops->uncache_page(object, page); + fscache_stat_d(&fscache_n_cop_uncache_page); goto done; } diff --git a/fs/fscache/stats.c b/fs/fscache/stats.c index 65deb99e756b..20233fb44bfd 100644 --- a/fs/fscache/stats.c +++ b/fs/fscache/stats.c @@ -93,6 +93,23 @@ atomic_t fscache_n_checkaux_okay; atomic_t fscache_n_checkaux_update; atomic_t fscache_n_checkaux_obsolete; +atomic_t fscache_n_cop_alloc_object; +atomic_t fscache_n_cop_lookup_object; +atomic_t fscache_n_cop_lookup_complete; +atomic_t fscache_n_cop_grab_object; +atomic_t fscache_n_cop_update_object; +atomic_t fscache_n_cop_drop_object; +atomic_t fscache_n_cop_put_object; +atomic_t fscache_n_cop_sync_cache; +atomic_t fscache_n_cop_attr_changed; +atomic_t fscache_n_cop_read_or_alloc_page; +atomic_t fscache_n_cop_read_or_alloc_pages; +atomic_t fscache_n_cop_allocate_page; +atomic_t fscache_n_cop_allocate_pages; +atomic_t fscache_n_cop_write_page; +atomic_t fscache_n_cop_uncache_page; +atomic_t fscache_n_cop_dissociate_pages; + /* * display the general statistics */ @@ -192,6 +209,26 @@ static int fscache_stats_show(struct seq_file *m, void *v) atomic_read(&fscache_n_op_deferred_release), atomic_read(&fscache_n_op_release), atomic_read(&fscache_n_op_gc)); + + seq_printf(m, "CacheOp: alo=%d luo=%d luc=%d gro=%d\n", + atomic_read(&fscache_n_cop_alloc_object), + atomic_read(&fscache_n_cop_lookup_object), + atomic_read(&fscache_n_cop_lookup_complete), + atomic_read(&fscache_n_cop_grab_object)); + seq_printf(m, "CacheOp: upo=%d dro=%d pto=%d atc=%d syn=%d\n", + atomic_read(&fscache_n_cop_update_object), + atomic_read(&fscache_n_cop_drop_object), + atomic_read(&fscache_n_cop_put_object), + atomic_read(&fscache_n_cop_attr_changed), + atomic_read(&fscache_n_cop_sync_cache)); + seq_printf(m, "CacheOp: rap=%d ras=%d alp=%d als=%d wrp=%d ucp=%d dsp=%d\n", + atomic_read(&fscache_n_cop_read_or_alloc_page), + atomic_read(&fscache_n_cop_read_or_alloc_pages), + atomic_read(&fscache_n_cop_allocate_page), + atomic_read(&fscache_n_cop_allocate_pages), + atomic_read(&fscache_n_cop_write_page), + atomic_read(&fscache_n_cop_uncache_page), + atomic_read(&fscache_n_cop_dissociate_pages)); return 0; } -- cgit v1.2.3 From 6897e3df8fc37bd4a58bbcdef8306da7fc175584 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 19 Nov 2009 18:11:22 +0000 Subject: FS-Cache: The object-available state can't rely on the cookie to be available The object-available state in the object processing state machine (as processed by fscache_object_available()) can't rely on the cookie to be available because the FSCACHE_COOKIE_CREATING bit may have been cleared by fscache_obtained_object() prior to the object being put into the FSCACHE_OBJECT_AVAILABLE state. Clearing the FSCACHE_COOKIE_CREATING bit on a cookie permits __fscache_relinquish_cookie() to proceed and detach the cookie from the object. To deal with this, we don't dereference object->cookie in fscache_object_available() if the object has already been detached. In addition, a couple of assertions are added into fscache_drop_object() to make sure the object is unbound from the cookie before it gets there. Signed-off-by: David Howells --- fs/fscache/object.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'fs/fscache/object.c') diff --git a/fs/fscache/object.c b/fs/fscache/object.c index 0d65c0c92b46..1a1afa82f798 100644 --- a/fs/fscache/object.c +++ b/fs/fscache/object.c @@ -158,7 +158,8 @@ static void fscache_object_state_machine(struct fscache_object *object) spin_lock(&object->lock); object->state = FSCACHE_OBJECT_DYING; - if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, + if (object->cookie && + test_and_clear_bit(FSCACHE_COOKIE_CREATING, &object->cookie->flags)) wake_up_bit(&object->cookie->flags, FSCACHE_COOKIE_CREATING); @@ -594,7 +595,8 @@ static void fscache_object_available(struct fscache_object *object) spin_lock(&object->lock); - if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, &object->cookie->flags)) + if (object->cookie && + test_and_clear_bit(FSCACHE_COOKIE_CREATING, &object->cookie->flags)) wake_up_bit(&object->cookie->flags, FSCACHE_COOKIE_CREATING); fscache_done_parent_op(object); @@ -631,6 +633,9 @@ static void fscache_drop_object(struct fscache_object *object) _enter("{OBJ%x,%d}", object->debug_id, object->n_children); + ASSERTCMP(object->cookie, ==, NULL); + ASSERT(hlist_unhashed(&object->cookie_link)); + spin_lock(&cache->object_list_lock); list_del_init(&object->cache_link); spin_unlock(&cache->object_list_lock); -- cgit v1.2.3 From d461d26dde901b0523c46b0317e7fccf574a3933 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 19 Nov 2009 18:11:41 +0000 Subject: FS-Cache: Make sure FSCACHE_COOKIE_LOOKING_UP cleared on lookup failure We must make sure that FSCACHE_COOKIE_LOOKING_UP is cleared on lookup failure (if an object reaches the LC_DYING state), and we should clear it before clearing FSCACHE_COOKIE_CREATING. If this doesn't happen then fscache_wait_for_deferred_lookup() may hold allocation and retrieval operations indefinitely until they're interrupted by signals - which in turn pins the dying object until they go away. Signed-off-by: David Howells --- fs/fscache/object.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) (limited to 'fs/fscache/object.c') diff --git a/fs/fscache/object.c b/fs/fscache/object.c index 1a1afa82f798..74bc562a2cbc 100644 --- a/fs/fscache/object.c +++ b/fs/fscache/object.c @@ -105,6 +105,7 @@ static inline void fscache_done_parent_op(struct fscache_object *object) static void fscache_object_state_machine(struct fscache_object *object) { enum fscache_object_state new_state; + struct fscache_cookie *cookie; ASSERT(object != NULL); @@ -158,11 +159,17 @@ static void fscache_object_state_machine(struct fscache_object *object) spin_lock(&object->lock); object->state = FSCACHE_OBJECT_DYING; - if (object->cookie && - test_and_clear_bit(FSCACHE_COOKIE_CREATING, - &object->cookie->flags)) - wake_up_bit(&object->cookie->flags, - FSCACHE_COOKIE_CREATING); + cookie = object->cookie; + if (cookie) { + if (test_and_clear_bit(FSCACHE_COOKIE_LOOKING_UP, + &cookie->flags)) + wake_up_bit(&cookie->flags, + FSCACHE_COOKIE_LOOKING_UP); + if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, + &cookie->flags)) + wake_up_bit(&cookie->flags, + FSCACHE_COOKIE_CREATING); + } spin_unlock(&object->lock); fscache_done_parent_op(object); -- cgit v1.2.3 From 60d543ca724be155c2b6166e36a00c80b21bd810 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 19 Nov 2009 18:11:45 +0000 Subject: FS-Cache: Start processing an object's operations on that object's death Start processing an object's operations when that object moves into the DYING state as the object cannot be destroyed until all its outstanding operations have completed. Furthermore, make sure that read and allocation operations handle being woken up on a dead object. Such events are recorded in the Allocs.abt and Retrvls.abt statistics as viewable through /proc/fs/fscache/stats. The code for waiting for object activation for the read and allocation operations is also extracted into its own function as it is much the same in all cases, differing only in the stats incremented. Signed-off-by: David Howells --- Documentation/filesystems/caching/fscache.txt | 2 + fs/fscache/internal.h | 5 ++ fs/fscache/object.c | 1 + fs/fscache/page.c | 112 +++++++++++++------------- fs/fscache/stats.c | 12 ++- include/linux/fscache-cache.h | 4 + 6 files changed, 75 insertions(+), 61 deletions(-) (limited to 'fs/fscache/object.c') diff --git a/Documentation/filesystems/caching/fscache.txt b/Documentation/filesystems/caching/fscache.txt index 7097fd29fb3d..3c23411956bb 100644 --- a/Documentation/filesystems/caching/fscache.txt +++ b/Documentation/filesystems/caching/fscache.txt @@ -253,6 +253,7 @@ proc files. int=N Number of alloc reqs aborted -ERESTARTSYS ops=N Number of alloc reqs submitted owt=N Number of alloc reqs waited for CPU time + abt=N Number of alloc reqs aborted due to object death Retrvls n=N Number of retrieval (read) requests seen ok=N Number of successful retr reqs wt=N Number of retr reqs that waited on lookup completion @@ -262,6 +263,7 @@ proc files. oom=N Number of retr reqs failed -ENOMEM ops=N Number of retr reqs submitted owt=N Number of retr reqs waited for CPU time + abt=N Number of retr reqs aborted due to object death Stores n=N Number of storage (write) requests seen ok=N Number of successful store reqs agn=N Number of store reqs on a page already pending storage diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h index 2bf463d26080..5b49a373689b 100644 --- a/fs/fscache/internal.h +++ b/fs/fscache/internal.h @@ -156,6 +156,7 @@ extern atomic_t fscache_n_allocs_ok; extern atomic_t fscache_n_allocs_wait; extern atomic_t fscache_n_allocs_nobufs; extern atomic_t fscache_n_allocs_intr; +extern atomic_t fscache_n_allocs_object_dead; extern atomic_t fscache_n_alloc_ops; extern atomic_t fscache_n_alloc_op_waits; @@ -166,6 +167,7 @@ extern atomic_t fscache_n_retrievals_nodata; extern atomic_t fscache_n_retrievals_nobufs; extern atomic_t fscache_n_retrievals_intr; extern atomic_t fscache_n_retrievals_nomem; +extern atomic_t fscache_n_retrievals_object_dead; extern atomic_t fscache_n_retrieval_ops; extern atomic_t fscache_n_retrieval_op_waits; @@ -249,9 +251,12 @@ static inline void fscache_stat_d(atomic_t *stat) atomic_dec(stat); } +#define __fscache_stat(stat) (stat) + extern const struct file_operations fscache_stats_fops; #else +#define __fscache_stat(stat) (NULL) #define fscache_stat(stat) do {} while (0) #endif diff --git a/fs/fscache/object.c b/fs/fscache/object.c index 74bc562a2cbc..c85c9f582166 100644 --- a/fs/fscache/object.c +++ b/fs/fscache/object.c @@ -201,6 +201,7 @@ static void fscache_object_state_machine(struct fscache_object *object) } spin_unlock(&object->lock); fscache_enqueue_dependents(object); + fscache_start_operations(object); goto terminal_transit; /* handle an abort during initialisation */ diff --git a/fs/fscache/page.c b/fs/fscache/page.c index fc76798bd968..c598ea4c4e7d 100644 --- a/fs/fscache/page.c +++ b/fs/fscache/page.c @@ -313,6 +313,43 @@ static int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie) return 0; } +/* + * wait for an object to become active (or dead) + */ +static int fscache_wait_for_retrieval_activation(struct fscache_object *object, + struct fscache_retrieval *op, + atomic_t *stat_op_waits, + atomic_t *stat_object_dead) +{ + int ret; + + if (!test_bit(FSCACHE_OP_WAITING, &op->op.flags)) + goto check_if_dead; + + _debug(">>> WT"); + fscache_stat(stat_op_waits); + if (wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, + fscache_wait_bit_interruptible, + TASK_INTERRUPTIBLE) < 0) { + ret = fscache_cancel_op(&op->op); + if (ret == 0) + return -ERESTARTSYS; + + /* it's been removed from the pending queue by another party, + * so we should get to run shortly */ + wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, + fscache_wait_bit, TASK_UNINTERRUPTIBLE); + } + _debug("<<< GO"); + +check_if_dead: + if (unlikely(fscache_object_is_dead(object))) { + fscache_stat(stat_object_dead); + return -ENOBUFS; + } + return 0; +} + /* * read a page from the cache or allocate a block in which to store it * - we return: @@ -376,25 +413,12 @@ int __fscache_read_or_alloc_page(struct fscache_cookie *cookie, /* we wait for the operation to become active, and then process it * *here*, in this thread, and not in the thread pool */ - if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) { - _debug(">>> WT"); - fscache_stat(&fscache_n_retrieval_op_waits); - if (wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, - fscache_wait_bit_interruptible, - TASK_INTERRUPTIBLE) < 0) { - ret = fscache_cancel_op(&op->op); - if (ret == 0) { - ret = -ERESTARTSYS; - goto error; - } - - /* it's been removed from the pending queue by another - * party, so we should get to run shortly */ - wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, - fscache_wait_bit, TASK_UNINTERRUPTIBLE); - } - _debug("<<< GO"); - } + ret = fscache_wait_for_retrieval_activation( + object, op, + __fscache_stat(&fscache_n_retrieval_op_waits), + __fscache_stat(&fscache_n_retrievals_object_dead)); + if (ret < 0) + goto error; /* ask the cache to honour the operation */ if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) { @@ -506,25 +530,12 @@ int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie, /* we wait for the operation to become active, and then process it * *here*, in this thread, and not in the thread pool */ - if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) { - _debug(">>> WT"); - fscache_stat(&fscache_n_retrieval_op_waits); - if (wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, - fscache_wait_bit_interruptible, - TASK_INTERRUPTIBLE) < 0) { - ret = fscache_cancel_op(&op->op); - if (ret == 0) { - ret = -ERESTARTSYS; - goto error; - } - - /* it's been removed from the pending queue by another - * party, so we should get to run shortly */ - wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, - fscache_wait_bit, TASK_UNINTERRUPTIBLE); - } - _debug("<<< GO"); - } + ret = fscache_wait_for_retrieval_activation( + object, op, + __fscache_stat(&fscache_n_retrieval_op_waits), + __fscache_stat(&fscache_n_retrievals_object_dead)); + if (ret < 0) + goto error; /* ask the cache to honour the operation */ if (test_bit(FSCACHE_COOKIE_NO_DATA_YET, &object->cookie->flags)) { @@ -612,25 +623,12 @@ int __fscache_alloc_page(struct fscache_cookie *cookie, fscache_stat(&fscache_n_alloc_ops); - if (test_bit(FSCACHE_OP_WAITING, &op->op.flags)) { - _debug(">>> WT"); - fscache_stat(&fscache_n_alloc_op_waits); - if (wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, - fscache_wait_bit_interruptible, - TASK_INTERRUPTIBLE) < 0) { - ret = fscache_cancel_op(&op->op); - if (ret == 0) { - ret = -ERESTARTSYS; - goto error; - } - - /* it's been removed from the pending queue by another - * party, so we should get to run shortly */ - wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING, - fscache_wait_bit, TASK_UNINTERRUPTIBLE); - } - _debug("<<< GO"); - } + ret = fscache_wait_for_retrieval_activation( + object, op, + __fscache_stat(&fscache_n_alloc_op_waits), + __fscache_stat(&fscache_n_allocs_object_dead)); + if (ret < 0) + goto error; /* ask the cache to honour the operation */ fscache_stat(&fscache_n_cop_allocate_page); diff --git a/fs/fscache/stats.c b/fs/fscache/stats.c index 9e15289eb5c1..05f77caf4a2d 100644 --- a/fs/fscache/stats.c +++ b/fs/fscache/stats.c @@ -39,6 +39,7 @@ atomic_t fscache_n_allocs_ok; atomic_t fscache_n_allocs_wait; atomic_t fscache_n_allocs_nobufs; atomic_t fscache_n_allocs_intr; +atomic_t fscache_n_allocs_object_dead; atomic_t fscache_n_alloc_ops; atomic_t fscache_n_alloc_op_waits; @@ -49,6 +50,7 @@ atomic_t fscache_n_retrievals_nodata; atomic_t fscache_n_retrievals_nobufs; atomic_t fscache_n_retrievals_intr; atomic_t fscache_n_retrievals_nomem; +atomic_t fscache_n_retrievals_object_dead; atomic_t fscache_n_retrieval_ops; atomic_t fscache_n_retrieval_op_waits; @@ -188,9 +190,10 @@ static int fscache_stats_show(struct seq_file *m, void *v) atomic_read(&fscache_n_allocs_wait), atomic_read(&fscache_n_allocs_nobufs), atomic_read(&fscache_n_allocs_intr)); - seq_printf(m, "Allocs : ops=%u owt=%u\n", + seq_printf(m, "Allocs : ops=%u owt=%u abt=%u\n", atomic_read(&fscache_n_alloc_ops), - atomic_read(&fscache_n_alloc_op_waits)); + atomic_read(&fscache_n_alloc_op_waits), + atomic_read(&fscache_n_allocs_object_dead)); seq_printf(m, "Retrvls: n=%u ok=%u wt=%u nod=%u nbf=%u" " int=%u oom=%u\n", @@ -201,9 +204,10 @@ static int fscache_stats_show(struct seq_file *m, void *v) atomic_read(&fscache_n_retrievals_nobufs), atomic_read(&fscache_n_retrievals_intr), atomic_read(&fscache_n_retrievals_nomem)); - seq_printf(m, "Retrvls: ops=%u owt=%u\n", + seq_printf(m, "Retrvls: ops=%u owt=%u abt=%u\n", atomic_read(&fscache_n_retrieval_ops), - atomic_read(&fscache_n_retrieval_op_waits)); + atomic_read(&fscache_n_retrieval_op_waits), + atomic_read(&fscache_n_retrievals_object_dead)); seq_printf(m, "Stores : n=%u ok=%u agn=%u nbf=%u oom=%u\n", atomic_read(&fscache_n_stores), diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h index 4750d5fb419f..907bb56c5888 100644 --- a/include/linux/fscache-cache.h +++ b/include/linux/fscache-cache.h @@ -404,6 +404,10 @@ extern const char *fscache_object_states[]; (obj)->state >= FSCACHE_OBJECT_AVAILABLE && \ (obj)->state < FSCACHE_OBJECT_DYING) +#define fscache_object_is_dead(obj) \ + (test_bit(FSCACHE_IOERROR, &(obj)->cache->flags) && \ + (obj)->state >= FSCACHE_OBJECT_DYING) + extern const struct slow_work_ops fscache_object_slow_work_ops; /** -- cgit v1.2.3 From 868411be3f445a83fafbd734f3e426400138add5 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 19 Nov 2009 18:11:48 +0000 Subject: FS-Cache: Actually requeue an object when requested FS-Cache objects have an FSCACHE_OBJECT_EV_REQUEUE event that can theoretically be raised to ask the state machine to requeue the object for further processing before the work function returns to the slow-work facility. However, fscache_object_work_execute() was clearing that bit before checking the event mask to see whether the object has any pending events that require it to be requeued immediately. Instead, the bit should be cleared after the check and enqueue. Signed-off-by: David Howells --- fs/fscache/object.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'fs/fscache/object.c') diff --git a/fs/fscache/object.c b/fs/fscache/object.c index c85c9f582166..f3f952cf887e 100644 --- a/fs/fscache/object.c +++ b/fs/fscache/object.c @@ -353,13 +353,12 @@ static void fscache_object_slow_work_execute(struct slow_work *work) _enter("{OBJ%x}", object->debug_id); - clear_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events); - start = jiffies; fscache_object_state_machine(object); fscache_hist(fscache_objs_histogram, start); if (object->events & object->event_mask) fscache_enqueue_object(object); + clear_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events); } /* -- cgit v1.2.3 From fee096deb4f33897937b974cb2c5168bab7935be Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 19 Nov 2009 18:12:05 +0000 Subject: CacheFiles: Catch an overly long wait for an old active object Catch an overly long wait for an old, dying active object when we want to replace it with a new one. The probability is that all the slow-work threads are hogged, and the delete can't get a look in. What we do instead is: (1) if there's nothing in the slow work queue, we sleep until either the dying object has finished dying or there is something in the slow work queue behind which we can queue our object. (2) if there is something in the slow work queue, we return ETIMEDOUT to fscache_lookup_object(), which then puts us back on the slow work queue, presumably behind the deletion that we're blocked by. We are then deferred for a while until we work our way back through the queue - without blocking a slow-work thread unnecessarily. A backtrace similar to the following may appear in the log without this patch: INFO: task kslowd004:5711 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kslowd004 D 0000000000000000 0 5711 2 0x00000080 ffff88000340bb80 0000000000000046 ffff88002550d000 0000000000000000 ffff88002550d000 0000000000000007 ffff88000340bfd8 ffff88002550d2a8 000000000000ddf0 00000000000118c0 00000000000118c0 ffff88002550d2a8 Call Trace: [] ? trace_hardirqs_on+0xd/0xf [] ? cachefiles_wait_bit+0x0/0xd [cachefiles] [] cachefiles_wait_bit+0x9/0xd [cachefiles] [] __wait_on_bit+0x43/0x76 [] ? ext3_xattr_get+0x1ec/0x270 [] out_of_line_wait_on_bit+0x69/0x74 [] ? cachefiles_wait_bit+0x0/0xd [cachefiles] [] ? wake_bit_function+0x0/0x2e [] cachefiles_mark_object_active+0x203/0x23b [cachefiles] [] cachefiles_walk_to_object+0x558/0x827 [cachefiles] [] cachefiles_lookup_object+0xac/0x12a [cachefiles] [] fscache_lookup_object+0x1c7/0x214 [fscache] [] fscache_object_state_machine+0xa5/0x52d [fscache] [] fscache_object_slow_work_execute+0x5f/0xa0 [fscache] [] slow_work_execute+0x18f/0x2d1 [] slow_work_thread+0x1c5/0x308 [] ? autoremove_wake_function+0x0/0x34 [] ? slow_work_thread+0x0/0x308 [] kthread+0x7a/0x82 [] child_rip+0xa/0x20 [] ? restore_args+0x0/0x30 [] ? kthread+0x0/0x82 [] ? child_rip+0x0/0x20 1 lock held by kslowd004/5711: #0: (&sb->s_type->i_mutex_key#7/1){+.+.+.}, at: [] cachefiles_walk_to_object+0x1b3/0x827 [cachefiles] Signed-off-by: David Howells --- Documentation/filesystems/caching/fscache.txt | 1 + fs/cachefiles/interface.c | 6 +- fs/cachefiles/namei.c | 87 +++++++++++++++++++++------ fs/fscache/internal.h | 1 + fs/fscache/object.c | 10 ++- fs/fscache/stats.c | 4 +- include/linux/fscache-cache.h | 6 +- 7 files changed, 90 insertions(+), 25 deletions(-) (limited to 'fs/fscache/object.c') diff --git a/Documentation/filesystems/caching/fscache.txt b/Documentation/filesystems/caching/fscache.txt index 3c23411956bb..a91e2e2095b0 100644 --- a/Documentation/filesystems/caching/fscache.txt +++ b/Documentation/filesystems/caching/fscache.txt @@ -235,6 +235,7 @@ proc files. neg=N Number of negative lookups made pos=N Number of positive lookups made crt=N Number of objects created by lookup + tmo=N Number of lookups timed out and requeued Updates n=N Number of update cookie requests seen nul=N Number of upd reqs given a NULL parent run=N Number of upd reqs granted CPU time diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c index 8e67abf05985..9d3c426044ae 100644 --- a/fs/cachefiles/interface.c +++ b/fs/cachefiles/interface.c @@ -114,8 +114,9 @@ nomem_lookup_data: /* * attempt to look up the nominated node in this cache + * - return -ETIMEDOUT to be scheduled again */ -static void cachefiles_lookup_object(struct fscache_object *_object) +static int cachefiles_lookup_object(struct fscache_object *_object) { struct cachefiles_lookup_data *lookup_data; struct cachefiles_object *parent, *object; @@ -145,13 +146,14 @@ static void cachefiles_lookup_object(struct fscache_object *_object) object->fscache.cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX) cachefiles_attr_changed(&object->fscache); - if (ret < 0) { + if (ret < 0 && ret != -ETIMEDOUT) { printk(KERN_WARNING "CacheFiles: Lookup failed error %d\n", ret); fscache_object_lookup_error(&object->fscache); } _leave(" [%d]", ret); + return ret; } /* diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c index 00a0cda8f47a..14ac4806e291 100644 --- a/fs/cachefiles/namei.c +++ b/fs/cachefiles/namei.c @@ -21,12 +21,6 @@ #include #include "internal.h" -static int cachefiles_wait_bit(void *flags) -{ - schedule(); - return 0; -} - #define CACHEFILES_KEYBUF_SIZE 512 /* @@ -100,8 +94,8 @@ static noinline void cachefiles_printk_object(struct cachefiles_object *object, /* * record the fact that an object is now active */ -static void cachefiles_mark_object_active(struct cachefiles_cache *cache, - struct cachefiles_object *object) +static int cachefiles_mark_object_active(struct cachefiles_cache *cache, + struct cachefiles_object *object) { struct cachefiles_object *xobject; struct rb_node **_p, *_parent = NULL; @@ -139,8 +133,8 @@ try_again: rb_insert_color(&object->active_node, &cache->active_nodes); write_unlock(&cache->active_lock); - _leave(""); - return; + _leave(" = 0"); + return 0; /* an old object from a previous incarnation is hogging the slot - we * need to wait for it to be destroyed */ @@ -155,13 +149,64 @@ wait_for_old_object: atomic_inc(&xobject->usage); write_unlock(&cache->active_lock); - _debug(">>> wait"); - wait_on_bit(&xobject->flags, CACHEFILES_OBJECT_ACTIVE, - cachefiles_wait_bit, TASK_UNINTERRUPTIBLE); - _debug("<<< waited"); + if (test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { + wait_queue_head_t *wq; + + signed long timeout = 60 * HZ; + wait_queue_t wait; + bool requeue; + + /* if the object we're waiting for is queued for processing, + * then just put ourselves on the queue behind it */ + if (slow_work_is_queued(&xobject->fscache.work)) { + _debug("queue OBJ%x behind OBJ%x immediately", + object->fscache.debug_id, + xobject->fscache.debug_id); + goto requeue; + } + + /* otherwise we sleep until either the object we're waiting for + * is done, or the slow-work facility wants the thread back to + * do other work */ + wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE); + init_wait(&wait); + requeue = false; + do { + prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); + if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) + break; + requeue = slow_work_sleep_till_thread_needed( + &object->fscache.work, &timeout); + } while (timeout > 0 && !requeue); + finish_wait(wq, &wait); + + if (requeue && + test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { + _debug("queue OBJ%x behind OBJ%x after wait", + object->fscache.debug_id, + xobject->fscache.debug_id); + goto requeue; + } + + if (timeout <= 0) { + printk(KERN_ERR "\n"); + printk(KERN_ERR "CacheFiles: Error: Overlong" + " wait for old active object to go away\n"); + cachefiles_printk_object(object, xobject); + goto requeue; + } + } + + ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)); cache->cache.ops->put_object(&xobject->fscache); goto try_again; + +requeue: + clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); + cache->cache.ops->put_object(&xobject->fscache); + _leave(" = -ETIMEDOUT"); + return -ETIMEDOUT; } /* @@ -466,12 +511,15 @@ lookup_again: } /* note that we're now using this object */ - cachefiles_mark_object_active(cache, object); + ret = cachefiles_mark_object_active(cache, object); mutex_unlock(&dir->d_inode->i_mutex); dput(dir); dir = NULL; + if (ret == -ETIMEDOUT) + goto mark_active_timed_out; + _debug("=== OBTAINED_OBJECT ==="); if (object->new) { @@ -515,6 +563,10 @@ create_error: cachefiles_io_error(cache, "Create/mkdir failed"); goto error; +mark_active_timed_out: + _debug("mark active timed out"); + goto release_dentry; + check_error: _debug("check error %d", ret); write_lock(&cache->active_lock); @@ -522,7 +574,7 @@ check_error: clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE); write_unlock(&cache->active_lock); - +release_dentry: dput(object->dentry); object->dentry = NULL; goto error_out; @@ -543,9 +595,6 @@ error: error_out2: dput(dir); error_out: - if (ret == -ENOSPC) - ret = -ENOBUFS; - _leave(" = error %d", -ret); return ret; } diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h index 5b49a373689b..0ca2566e038c 100644 --- a/fs/fscache/internal.h +++ b/fs/fscache/internal.h @@ -215,6 +215,7 @@ extern atomic_t fscache_n_object_no_alloc; extern atomic_t fscache_n_object_lookups; extern atomic_t fscache_n_object_lookups_negative; extern atomic_t fscache_n_object_lookups_positive; +extern atomic_t fscache_n_object_lookups_timed_out; extern atomic_t fscache_n_object_created; extern atomic_t fscache_n_object_avail; extern atomic_t fscache_n_object_dead; diff --git a/fs/fscache/object.c b/fs/fscache/object.c index f3f952cf887e..e513ac599c8e 100644 --- a/fs/fscache/object.c +++ b/fs/fscache/object.c @@ -468,6 +468,7 @@ static void fscache_lookup_object(struct fscache_object *object) { struct fscache_cookie *cookie = object->cookie; struct fscache_object *parent; + int ret; _enter(""); @@ -493,12 +494,19 @@ static void fscache_lookup_object(struct fscache_object *object) fscache_stat(&fscache_n_object_lookups); fscache_stat(&fscache_n_cop_lookup_object); - object->cache->ops->lookup_object(object); + ret = object->cache->ops->lookup_object(object); fscache_stat_d(&fscache_n_cop_lookup_object); if (test_bit(FSCACHE_OBJECT_EV_ERROR, &object->events)) set_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags); + if (ret == -ETIMEDOUT) { + /* probably stuck behind another object, so move this one to + * the back of the queue */ + fscache_stat(&fscache_n_object_lookups_timed_out); + set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events); + } + _leave(""); } diff --git a/fs/fscache/stats.c b/fs/fscache/stats.c index 05f77caf4a2d..46435f3aae68 100644 --- a/fs/fscache/stats.c +++ b/fs/fscache/stats.c @@ -98,6 +98,7 @@ atomic_t fscache_n_object_no_alloc; atomic_t fscache_n_object_lookups; atomic_t fscache_n_object_lookups_negative; atomic_t fscache_n_object_lookups_positive; +atomic_t fscache_n_object_lookups_timed_out; atomic_t fscache_n_object_created; atomic_t fscache_n_object_avail; atomic_t fscache_n_object_dead; @@ -160,10 +161,11 @@ static int fscache_stats_show(struct seq_file *m, void *v) atomic_read(&fscache_n_acquires_nobufs), atomic_read(&fscache_n_acquires_oom)); - seq_printf(m, "Lookups: n=%u neg=%u pos=%u crt=%u\n", + seq_printf(m, "Lookups: n=%u neg=%u pos=%u crt=%u tmo=%u\n", atomic_read(&fscache_n_object_lookups), atomic_read(&fscache_n_object_lookups_negative), atomic_read(&fscache_n_object_lookups_positive), + atomic_read(&fscache_n_object_lookups_timed_out), atomic_read(&fscache_n_object_created)); seq_printf(m, "Updates: n=%u nul=%u run=%u\n", diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h index 5db50002f3b5..7be0c6fbe880 100644 --- a/include/linux/fscache-cache.h +++ b/include/linux/fscache-cache.h @@ -234,8 +234,10 @@ struct fscache_cache_ops { struct fscache_object *(*alloc_object)(struct fscache_cache *cache, struct fscache_cookie *cookie); - /* look up the object for a cookie */ - void (*lookup_object)(struct fscache_object *object); + /* look up the object for a cookie + * - return -ETIMEDOUT to be requeued + */ + int (*lookup_object)(struct fscache_object *object); /* finished looking up */ void (*lookup_complete)(struct fscache_object *object); -- cgit v1.2.3