diff options
| -rw-r--r-- | fs/fscache/cookie.c | 29 | ||||
| -rw-r--r-- | include/trace/events/fscache.h | 44 |
2 files changed, 69 insertions, 4 deletions
diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c index a7ea7d1db032..9bb1ab5fe5ed 100644 --- a/fs/fscache/cookie.c +++ b/fs/fscache/cookie.c @@ -556,6 +556,7 @@ void __fscache_use_cookie(struct fscache_cookie *cookie, bool will_modify) { enum fscache_cookie_state state; bool queue = false; + int n_active; _enter("c=%08x", cookie->debug_id); @@ -565,7 +566,11 @@ void __fscache_use_cookie(struct fscache_cookie *cookie, bool will_modify) spin_lock(&cookie->lock); - atomic_inc(&cookie->n_active); + n_active = atomic_inc_return(&cookie->n_active); + trace_fscache_active(cookie->debug_id, refcount_read(&cookie->ref), + n_active, atomic_read(&cookie->n_accesses), + will_modify ? + fscache_active_use_modify : fscache_active_use); again: state = fscache_cookie_state(cookie); @@ -638,13 +643,29 @@ static void fscache_unuse_cookie_locked(struct fscache_cookie *cookie) void __fscache_unuse_cookie(struct fscache_cookie *cookie, const void *aux_data, const loff_t *object_size) { + unsigned int debug_id = cookie->debug_id; + unsigned int r = refcount_read(&cookie->ref); + unsigned int a = atomic_read(&cookie->n_accesses); + unsigned int c; + if (aux_data || object_size) __fscache_update_cookie(cookie, aux_data, object_size); - if (atomic_dec_and_lock(&cookie->n_active, &cookie->lock)) { - fscache_unuse_cookie_locked(cookie); - spin_unlock(&cookie->lock); + /* Subtract 1 from counter unless that drops it to 0 (ie. it was 1) */ + c = atomic_fetch_add_unless(&cookie->n_active, -1, 1); + if (c != 1) { + trace_fscache_active(debug_id, r, c - 1, a, fscache_active_unuse); + return; } + + spin_lock(&cookie->lock); + r = refcount_read(&cookie->ref); + a = atomic_read(&cookie->n_accesses); + c = atomic_dec_return(&cookie->n_active); + trace_fscache_active(debug_id, r, c, a, fscache_active_unuse); + if (c == 0) + fscache_unuse_cookie_locked(cookie); + spin_unlock(&cookie->lock); } EXPORT_SYMBOL(__fscache_unuse_cookie); diff --git a/include/trace/events/fscache.h b/include/trace/events/fscache.h index 1594aefadeac..cb3fb337e880 100644 --- a/include/trace/events/fscache.h +++ b/include/trace/events/fscache.h @@ -71,6 +71,12 @@ enum fscache_cookie_trace { fscache_cookie_see_work, }; +enum fscache_active_trace { + fscache_active_use, + fscache_active_use_modify, + fscache_active_unuse, +}; + enum fscache_access_trace { fscache_access_acquire_volume, fscache_access_acquire_volume_end, @@ -146,6 +152,11 @@ enum fscache_access_trace { EM(fscache_cookie_see_withdraw, "- x-wth") \ E_(fscache_cookie_see_work, "- work ") +#define fscache_active_traces \ + EM(fscache_active_use, "USE ") \ + EM(fscache_active_use_modify, "USE-m ") \ + E_(fscache_active_unuse, "UNUSE ") + #define fscache_access_traces \ EM(fscache_access_acquire_volume, "BEGIN acq_vol") \ EM(fscache_access_acquire_volume_end, "END acq_vol") \ @@ -264,6 +275,39 @@ TRACE_EVENT(fscache_cookie, __entry->ref) ); +TRACE_EVENT(fscache_active, + TP_PROTO(unsigned int cookie_debug_id, + int ref, + int n_active, + int n_accesses, + enum fscache_active_trace why), + + TP_ARGS(cookie_debug_id, ref, n_active, n_accesses, why), + + TP_STRUCT__entry( + __field(unsigned int, cookie ) + __field(int, ref ) + __field(int, n_active ) + __field(int, n_accesses ) + __field(enum fscache_active_trace, why ) + ), + + TP_fast_assign( + __entry->cookie = cookie_debug_id; + __entry->ref = ref; + __entry->n_active = n_active; + __entry->n_accesses = n_accesses; + __entry->why = why; + ), + + TP_printk("c=%08x %s r=%d a=%d c=%d", + __entry->cookie, + __print_symbolic(__entry->why, fscache_active_traces), + __entry->ref, + __entry->n_accesses, + __entry->n_active) + ); + TRACE_EVENT(fscache_access_cache, TP_PROTO(unsigned int cache_debug_id, int ref, |