Add stat counters of no-space events that caused caching not to happen and display in /proc/fs/fscache/stats. Signed-off-by: David Howells <dhowells@xxxxxxxxxx> cc: linux-cachefs@xxxxxxxxxx Link: https://lore.kernel.org/r/163819653216.215744.17210522251617386509.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # v1 --- fs/cachefiles/cache.c | 18 +++++++++++++++--- fs/cachefiles/daemon.c | 2 +- fs/cachefiles/internal.h | 11 +++++++++-- fs/cachefiles/io.c | 7 +++++-- fs/cachefiles/namei.c | 6 ++++-- fs/fscache/stats.c | 8 ++++++++ include/linux/fscache-cache.h | 6 ++++++ 7 files changed, 48 insertions(+), 10 deletions(-) diff --git a/fs/cachefiles/cache.c b/fs/cachefiles/cache.c index 2f7f5381afbe..327cea71557f 100644 --- a/fs/cachefiles/cache.c +++ b/fs/cachefiles/cache.c @@ -147,7 +147,7 @@ int cachefiles_add_cache(struct cachefiles_cache *cache) pr_info("File cache on %s registered\n", cache_cookie->name); /* check how much space the cache has */ - cachefiles_has_space(cache, 0, 0); + cachefiles_has_space(cache, 0, 0, cachefiles_has_space_check); cachefiles_end_secure(cache, saved_cred); _leave(" = 0 [%px]", cache->cache); return 0; @@ -175,7 +175,8 @@ int cachefiles_add_cache(struct cachefiles_cache *cache) * cache */ int cachefiles_has_space(struct cachefiles_cache *cache, - unsigned fnr, unsigned bnr) + unsigned fnr, unsigned bnr, + enum cachefiles_has_space_for reason) { struct kstatfs stats; u64 b_avail, b_writing; @@ -233,7 +234,7 @@ int cachefiles_has_space(struct cachefiles_cache *cache, ret = -ENOBUFS; if (stats.f_ffree < cache->fstop || b_avail < cache->bstop) - goto begin_cull; + goto stop_and_begin_cull; ret = 0; if (stats.f_ffree < cache->fcull || @@ -252,6 +253,17 @@ int cachefiles_has_space(struct cachefiles_cache *cache, //_leave(" = 0"); return 0; +stop_and_begin_cull: + switch (reason) { + case cachefiles_has_space_for_write: + fscache_count_no_write_space(); + break; + case cachefiles_has_space_for_create: + fscache_count_no_create_space(); + break; + default: + break; + } begin_cull: if (!test_and_set_bit(CACHEFILES_CULLING, &cache->flags)) { _debug("### CULL CACHE ###"); diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c index 45af558a696e..40a792421fc1 100644 --- a/fs/cachefiles/daemon.c +++ b/fs/cachefiles/daemon.c @@ -170,7 +170,7 @@ static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer, return 0; /* check how much space the cache has */ - cachefiles_has_space(cache, 0, 0); + cachefiles_has_space(cache, 0, 0, cachefiles_has_space_check); /* summarise */ f_released = atomic_xchg(&cache->f_released, 0); diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h index 77c899b3eaa5..5396baad45ed 100644 --- a/fs/cachefiles/internal.h +++ b/fs/cachefiles/internal.h @@ -130,10 +130,17 @@ static inline void cachefiles_state_changed(struct cachefiles_cache *cache) * cache.c */ extern int cachefiles_add_cache(struct cachefiles_cache *cache); -extern int cachefiles_has_space(struct cachefiles_cache *cache, - unsigned fnr, unsigned bnr); extern void cachefiles_withdraw_cache(struct cachefiles_cache *cache); +enum cachefiles_has_space_for { + cachefiles_has_space_check, + cachefiles_has_space_for_write, + cachefiles_has_space_for_create, +}; +extern int cachefiles_has_space(struct cachefiles_cache *cache, + unsigned fnr, unsigned bnr, + enum cachefiles_has_space_for reason); + /* * daemon.c */ diff --git a/fs/cachefiles/io.c b/fs/cachefiles/io.c index 6f4dce0cfc36..60b1eac2ce78 100644 --- a/fs/cachefiles/io.c +++ b/fs/cachefiles/io.c @@ -468,7 +468,8 @@ static int __cachefiles_prepare_write(struct netfs_cache_resources *cres, * space, we need to see if it's fully allocated. If it's not, we may * want to cull it. */ - if (cachefiles_has_space(cache, 0, *_len / PAGE_SIZE) == 0) + if (cachefiles_has_space(cache, 0, *_len / PAGE_SIZE, + cachefiles_has_space_check) == 0) return 0; /* Enough space to simply overwrite the whole block */ pos = cachefiles_inject_read_error(); @@ -483,6 +484,7 @@ static int __cachefiles_prepare_write(struct netfs_cache_resources *cres, return 0; /* Fully allocated */ /* Partially allocated, but insufficient space: cull. */ + fscache_count_no_write_space(); ret = cachefiles_inject_remove_error(); if (ret == 0) ret = vfs_fallocate(file, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, @@ -498,7 +500,8 @@ static int __cachefiles_prepare_write(struct netfs_cache_resources *cres, return ret; check_space: - return cachefiles_has_space(cache, 0, *_len / PAGE_SIZE); + return cachefiles_has_space(cache, 0, *_len / PAGE_SIZE, + cachefiles_has_space_for_write); } static int cachefiles_prepare_write(struct netfs_cache_resources *cres, diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c index 1e9845b8e939..f31d678159ac 100644 --- a/fs/cachefiles/namei.c +++ b/fs/cachefiles/namei.c @@ -115,7 +115,8 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, /* we need to create the subdir if it doesn't exist yet */ if (d_is_negative(subdir)) { - ret = cachefiles_has_space(cache, 1, 0); + ret = cachefiles_has_space(cache, 1, 0, + cachefiles_has_space_for_create); if (ret < 0) goto mkdir_error; @@ -511,7 +512,8 @@ static bool cachefiles_create_file(struct cachefiles_object *object) struct file *file; int ret; - ret = cachefiles_has_space(object->volume->cache, 1, 0); + ret = cachefiles_has_space(object->volume->cache, 1, 0, + cachefiles_has_space_for_create); if (ret < 0) return false; diff --git a/fs/fscache/stats.c b/fs/fscache/stats.c index 798ee68b3e9d..db2f4e225dd9 100644 --- a/fs/fscache/stats.c +++ b/fs/fscache/stats.c @@ -42,6 +42,10 @@ atomic_t fscache_n_read; EXPORT_SYMBOL(fscache_n_read); atomic_t fscache_n_write; EXPORT_SYMBOL(fscache_n_write); +atomic_t fscache_n_no_write_space; +EXPORT_SYMBOL(fscache_n_no_write_space); +atomic_t fscache_n_no_create_space; +EXPORT_SYMBOL(fscache_n_no_create_space); /* * display the general statistics @@ -82,6 +86,10 @@ int fscache_stats_show(struct seq_file *m, void *v) atomic_read(&fscache_n_relinquishes_retire), atomic_read(&fscache_n_relinquishes_dropped)); + seq_printf(m, "NoSpace: nwr=%u ncr=%u\n", + atomic_read(&fscache_n_no_write_space), + atomic_read(&fscache_n_no_create_space)); + seq_printf(m, "IO : rd=%u wr=%u\n", atomic_read(&fscache_n_read), atomic_read(&fscache_n_write)); diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h index 3fa4902dc87c..007e47f38610 100644 --- a/include/linux/fscache-cache.h +++ b/include/linux/fscache-cache.h @@ -186,11 +186,17 @@ static inline void fscache_wait_for_objects(struct fscache_cache *cache) #ifdef CONFIG_FSCACHE_STATS extern atomic_t fscache_n_read; extern atomic_t fscache_n_write; +extern atomic_t fscache_n_no_write_space; +extern atomic_t fscache_n_no_create_space; #define fscache_count_read() atomic_inc(&fscache_n_read) #define fscache_count_write() atomic_inc(&fscache_n_write) +#define fscache_count_no_write_space() atomic_inc(&fscache_n_no_write_space) +#define fscache_count_no_create_space() atomic_inc(&fscache_n_no_create_space) #else #define fscache_count_read() do {} while(0) #define fscache_count_write() do {} while(0) +#define fscache_count_no_write_space() do {} while(0) +#define fscache_count_no_create_space() do {} while(0) #endif #endif /* _LINUX_FSCACHE_CACHE_H */
