From a18feb55769b705a44c4107786c4045eae2e87b6 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 4 Apr 2018 13:41:27 +0100 Subject: fscache: Add tracepoints Add some tracepoints to fscache: (*) fscache_cookie - Tracks a cookie's usage count. (*) fscache_netfs - Logs registration of a network filesystem, including the pointer to the cookie allocated. (*) fscache_acquire - Logs cookie acquisition. (*) fscache_relinquish - Logs cookie relinquishment. (*) fscache_enable - Logs enablement of a cookie. (*) fscache_disable - Logs disablement of a cookie. (*) fscache_osm - Tracks execution of states in the object state machine. and cachefiles: (*) cachefiles_ref - Tracks a cachefiles object's usage count. (*) cachefiles_lookup - Logs result of lookup_one_len(). (*) cachefiles_mkdir - Logs result of vfs_mkdir(). (*) cachefiles_create - Logs result of vfs_create(). (*) cachefiles_unlink - Logs calls to vfs_unlink(). (*) cachefiles_rename - Logs calls to vfs_rename(). (*) cachefiles_mark_active - Logs an object becoming active. (*) cachefiles_wait_active - Logs a wait for an old object to be destroyed. (*) cachefiles_mark_inactive - Logs an object becoming inactive. (*) cachefiles_mark_buried - Logs the burial of an object. Signed-off-by: David Howells --- fs/fscache/cookie.c | 46 +++++++++++++++++++++++++++++----------------- fs/fscache/internal.h | 16 ++++++++-------- fs/fscache/main.c | 1 + fs/fscache/netfs.c | 3 ++- fs/fscache/object.c | 36 +++++++++++++++++++++++------------- 5 files changed, 63 insertions(+), 39 deletions(-) (limited to 'fs/fscache') diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c index 98d22f495cd8..20bc3341f113 100644 --- a/fs/fscache/cookie.c +++ b/fs/fscache/cookie.c @@ -101,7 +101,7 @@ struct fscache_cookie *__fscache_acquire_cookie( */ atomic_set(&cookie->n_active, 1); - atomic_inc(&parent->usage); + fscache_cookie_get(parent, fscache_cookie_get_acquire_parent); atomic_inc(&parent->n_children); cookie->def = def; @@ -125,6 +125,8 @@ struct fscache_cookie *__fscache_acquire_cookie( break; } + trace_fscache_acquire(cookie); + if (enable) { /* if the object is an index then we need do nothing more here * - we create indices on disk when we need them as an index @@ -134,7 +136,8 @@ struct fscache_cookie *__fscache_acquire_cookie( set_bit(FSCACHE_COOKIE_ENABLED, &cookie->flags); } else { atomic_dec(&parent->n_children); - __fscache_cookie_put(cookie); + fscache_cookie_put(cookie, + fscache_cookie_put_acquire_nobufs); fscache_stat(&fscache_n_acquires_nobufs); _leave(" = NULL"); return NULL; @@ -159,6 +162,8 @@ void __fscache_enable_cookie(struct fscache_cookie *cookie, { _enter("%p", cookie); + trace_fscache_enable(cookie); + wait_on_bit_lock(&cookie->flags, FSCACHE_COOKIE_ENABLEMENT_LOCK, TASK_UNINTERRUPTIBLE); @@ -318,7 +323,7 @@ static int fscache_alloc_object(struct fscache_cache *cache, * attached to the cookie */ if (fscache_attach_object(cookie, object) < 0) { fscache_stat(&fscache_n_cop_put_object); - cache->ops->put_object(object); + cache->ops->put_object(object, fscache_obj_put_attach_fail); fscache_stat_d(&fscache_n_cop_put_object); } @@ -338,7 +343,7 @@ object_already_extant: error_put: fscache_stat(&fscache_n_cop_put_object); - cache->ops->put_object(object); + cache->ops->put_object(object, fscache_obj_put_alloc_fail); fscache_stat_d(&fscache_n_cop_put_object); error: _leave(" = %d", ret); @@ -398,7 +403,7 @@ static int fscache_attach_object(struct fscache_cookie *cookie, /* attach to the cookie */ object->cookie = cookie; - atomic_inc(&cookie->usage); + fscache_cookie_get(cookie, fscache_cookie_get_attach_object); hlist_add_head(&object->cookie_link, &cookie->backing_objects); fscache_objlist_add(object); @@ -516,6 +521,8 @@ void __fscache_disable_cookie(struct fscache_cookie *cookie, bool invalidate) _enter("%p,%u", cookie, invalidate); + trace_fscache_disable(cookie); + ASSERTCMP(atomic_read(&cookie->n_active), >, 0); if (atomic_read(&cookie->n_children) != 0) { @@ -601,6 +608,8 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie, bool retire) cookie, cookie->def->name, cookie->netfs_data, atomic_read(&cookie->n_active), retire); + trace_fscache_relinquish(cookie, retire); + /* No further netfs-accessing operations on this cookie permitted */ if (test_and_set_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags)) BUG(); @@ -620,35 +629,38 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie, bool retire) /* Dispose of the netfs's link to the cookie */ ASSERTCMP(atomic_read(&cookie->usage), >, 0); - fscache_cookie_put(cookie); + fscache_cookie_put(cookie, fscache_cookie_put_relinquish); _leave(""); } EXPORT_SYMBOL(__fscache_relinquish_cookie); /* - * destroy a cookie + * Drop a reference to a cookie. */ -void __fscache_cookie_put(struct fscache_cookie *cookie) +void fscache_cookie_put(struct fscache_cookie *cookie, + enum fscache_cookie_trace where) { struct fscache_cookie *parent; + int usage; _enter("%p", cookie); - for (;;) { - _debug("FREE COOKIE %p", cookie); + do { + usage = atomic_dec_return(&cookie->usage); + trace_fscache_cookie(cookie, where, usage); + + if (usage > 0) + return; + BUG_ON(usage < 0); + parent = cookie->parent; BUG_ON(!hlist_empty(&cookie->backing_objects)); kmem_cache_free(fscache_cookie_jar, cookie); - if (!parent) - break; - cookie = parent; - BUG_ON(atomic_read(&cookie->usage) <= 0); - if (!atomic_dec_and_test(&cookie->usage)) - break; - } + where = fscache_cookie_put_parent; + } while (cookie); _leave(""); } diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h index 0ff4b49a0037..c27e2db3004e 100644 --- a/fs/fscache/internal.h +++ b/fs/fscache/internal.h @@ -29,6 +29,7 @@ #define pr_fmt(fmt) "FS-Cache: " fmt #include +#include #include #define FSCACHE_MIN_THREADS 4 @@ -49,7 +50,8 @@ extern struct fscache_cache *fscache_select_cache_for_object( extern struct kmem_cache *fscache_cookie_jar; extern void fscache_cookie_init_once(void *); -extern void __fscache_cookie_put(struct fscache_cookie *); +extern void fscache_cookie_put(struct fscache_cookie *, + enum fscache_cookie_trace); /* * fsdef.c @@ -311,14 +313,12 @@ static inline void fscache_raise_event(struct fscache_object *object, fscache_enqueue_object(object); } -/* - * drop a reference to a cookie - */ -static inline void fscache_cookie_put(struct fscache_cookie *cookie) +static inline void fscache_cookie_get(struct fscache_cookie *cookie, + enum fscache_cookie_trace where) { - BUG_ON(atomic_read(&cookie->usage) <= 0); - if (atomic_dec_and_test(&cookie->usage)) - __fscache_cookie_put(cookie); + int usage = atomic_inc_return(&cookie->usage); + + trace_fscache_cookie(cookie, where, usage); } /* diff --git a/fs/fscache/main.c b/fs/fscache/main.c index 249968dcbf5c..7dce110bf17d 100644 --- a/fs/fscache/main.c +++ b/fs/fscache/main.c @@ -16,6 +16,7 @@ #include #include #include +#define CREATE_TRACE_POINTS #include "internal.h" MODULE_DESCRIPTION("FS Cache Manager"); diff --git a/fs/fscache/netfs.c b/fs/fscache/netfs.c index a8aa00be4444..c816600d1dde 100644 --- a/fs/fscache/netfs.c +++ b/fs/fscache/netfs.c @@ -60,7 +60,7 @@ int __fscache_register_netfs(struct fscache_netfs *netfs) goto already_registered; } - atomic_inc(&cookie->parent->usage); + fscache_cookie_get(cookie->parent, fscache_cookie_get_register_netfs); atomic_inc(&cookie->parent->n_children); netfs->primary_index = cookie; @@ -68,6 +68,7 @@ int __fscache_register_netfs(struct fscache_netfs *netfs) ret = 0; pr_notice("Netfs '%s' registered for caching\n", netfs->name); + trace_fscache_netfs(netfs); already_registered: up_write(&fscache_addremove_sem); diff --git a/fs/fscache/object.c b/fs/fscache/object.c index 7a182c87f378..99afe64352a5 100644 --- a/fs/fscache/object.c +++ b/fs/fscache/object.c @@ -138,8 +138,10 @@ static const struct fscache_transition fscache_osm_run_oob[] = { { 0, NULL } }; -static int fscache_get_object(struct fscache_object *); -static void fscache_put_object(struct fscache_object *); +static int fscache_get_object(struct fscache_object *, + enum fscache_obj_ref_trace); +static void fscache_put_object(struct fscache_object *, + enum fscache_obj_ref_trace); static bool fscache_enqueue_dependents(struct fscache_object *, int); static void fscache_dequeue_object(struct fscache_object *); @@ -170,6 +172,7 @@ static void fscache_object_sm_dispatcher(struct fscache_object *object) const struct fscache_transition *t; const struct fscache_state *state, *new_state; unsigned long events, event_mask; + bool oob; int event = -1; ASSERT(object != NULL); @@ -188,6 +191,7 @@ restart_masked: if (events & object->oob_event_mask) { _debug("{OBJ%x} oob %lx", object->debug_id, events & object->oob_event_mask); + oob = true; for (t = object->oob_table; t->events; t++) { if (events & t->events) { state = t->transit_to; @@ -199,6 +203,7 @@ restart_masked: } } } + oob = false; /* Wait states are just transition tables */ if (!state->work) { @@ -207,6 +212,8 @@ restart_masked: if (events & t->events) { new_state = t->transit_to; event = fls(events & t->events) - 1; + trace_fscache_osm(object, state, + true, false, event); clear_bit(event, &object->events); _debug("{OBJ%x} ev %d: %s -> %s", object->debug_id, event, @@ -226,6 +233,7 @@ restart_masked: execute_work_state: _debug("{OBJ%x} exec %s", object->debug_id, state->name); + trace_fscache_osm(object, state, false, oob, event); new_state = state->work(object, event); event = -1; if (new_state == NO_TRANSIT) { @@ -279,7 +287,7 @@ static void fscache_object_work_func(struct work_struct *work) start = jiffies; fscache_object_sm_dispatcher(object); fscache_hist(fscache_objs_histogram, start); - fscache_put_object(object); + fscache_put_object(object, fscache_obj_put_work); } /** @@ -397,7 +405,7 @@ static const struct fscache_state *fscache_initialise_object(struct fscache_obje fscache_stat(&fscache_n_cop_grab_object); success = false; if (fscache_object_is_live(parent) && - object->cache->ops->grab_object(object)) { + object->cache->ops->grab_object(object, fscache_obj_get_add_to_deps)) { list_add(&object->dep_link, &parent->dependents); success = true; } @@ -745,7 +753,7 @@ static const struct fscache_state *fscache_drop_object(struct fscache_object *ob } /* this just shifts the object release to the work processor */ - fscache_put_object(object); + fscache_put_object(object, fscache_obj_put_drop_obj); fscache_stat(&fscache_n_object_dead); _leave(""); @@ -755,12 +763,13 @@ static const struct fscache_state *fscache_drop_object(struct fscache_object *ob /* * get a ref on an object */ -static int fscache_get_object(struct fscache_object *object) +static int fscache_get_object(struct fscache_object *object, + enum fscache_obj_ref_trace why) { int ret; fscache_stat(&fscache_n_cop_grab_object); - ret = object->cache->ops->grab_object(object) ? 0 : -EAGAIN; + ret = object->cache->ops->grab_object(object, why) ? 0 : -EAGAIN; fscache_stat_d(&fscache_n_cop_grab_object); return ret; } @@ -768,10 +777,11 @@ static int fscache_get_object(struct fscache_object *object) /* * Discard a ref on an object */ -static void fscache_put_object(struct fscache_object *object) +static void fscache_put_object(struct fscache_object *object, + enum fscache_obj_ref_trace why) { fscache_stat(&fscache_n_cop_put_object); - object->cache->ops->put_object(object); + object->cache->ops->put_object(object, why); fscache_stat_d(&fscache_n_cop_put_object); } @@ -786,7 +796,7 @@ void fscache_object_destroy(struct fscache_object *object) fscache_objlist_remove(object); /* We can get rid of the cookie now */ - fscache_cookie_put(object->cookie); + fscache_cookie_put(object->cookie, fscache_cookie_put_object); object->cookie = NULL; } EXPORT_SYMBOL(fscache_object_destroy); @@ -798,7 +808,7 @@ void fscache_enqueue_object(struct fscache_object *object) { _enter("{OBJ%x}", object->debug_id); - if (fscache_get_object(object) >= 0) { + if (fscache_get_object(object, fscache_obj_get_queue) >= 0) { wait_queue_head_t *cong_wq = &get_cpu_var(fscache_object_cong_wait); @@ -806,7 +816,7 @@ void fscache_enqueue_object(struct fscache_object *object) if (fscache_object_congested()) wake_up(cong_wq); } else - fscache_put_object(object); + fscache_put_object(object, fscache_obj_put_queue); put_cpu_var(fscache_object_cong_wait); } @@ -866,7 +876,7 @@ static bool fscache_enqueue_dependents(struct fscache_object *object, int event) list_del_init(&dep->dep_link); fscache_raise_event(dep, event); - fscache_put_object(dep); + fscache_put_object(dep, fscache_obj_put_enq_dep); if (!list_empty(&object->dependents) && need_resched()) { ret = false; -- cgit v1.2.3-70-g09d2