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
---
fs/cachefiles/bind.c | 2 +-
fs/cachefiles/daemon.c | 18 +++++++++++++++---
fs/cachefiles/internal.h | 8 +++++++-
fs/cachefiles/io.c | 9 ++++++---
fs/cachefiles/namei.c | 6 ++++--
fs/fscache/stats.c | 8 ++++++++
include/linux/fscache-cache.h | 6 ++++++
7 files changed, 47 insertions(+), 10 deletions(-)
diff --git a/fs/cachefiles/bind.c b/fs/cachefiles/bind.c
index 59c9d141f1fe..a62361e82b20 100644
--- a/fs/cachefiles/bind.c
+++ b/fs/cachefiles/bind.c
@@ -211,7 +211,7 @@ static int cachefiles_daemon_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;
diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c
index 50ec292c7213..7a7d521aeb83 100644
--- a/fs/cachefiles/daemon.c
+++ b/fs/cachefiles/daemon.c
@@ -168,7 +168,7 @@ 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);
@@ -668,7 +668,8 @@ static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args)
* 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;
int ret;
@@ -720,7 +721,7 @@ int cachefiles_has_space(struct cachefiles_cache *cache,
ret = -ENOBUFS;
if (stats.f_ffree < cache->fstop ||
stats.f_bavail < cache->bstop)
- goto begin_cull;
+ goto stop_and_begin_cull;
ret = 0;
if (stats.f_ffree < cache->fcull ||
@@ -739,6 +740,17 @@ 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/internal.h b/fs/cachefiles/internal.h
index d3c7db3b058e..8d1b1347abb4 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -152,8 +152,14 @@ extern void cachefiles_daemon_unbind(struct cachefiles_cache *cache);
*/
extern const struct file_operations cachefiles_daemon_fops;
+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);
+ unsigned fnr, unsigned bnr,
+ enum cachefiles_has_space_for reason);
/*
* error_inject.c
diff --git a/fs/cachefiles/io.c b/fs/cachefiles/io.c
index 78e6ef781f73..cb531424a64f 100644
--- a/fs/cachefiles/io.c
+++ b/fs/cachefiles/io.c
@@ -461,7 +461,8 @@ 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();
@@ -476,6 +477,7 @@ 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();
pos = cachefiles_inject_remove_error();
if (pos == 0)
ret = vfs_fallocate(file, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
@@ -491,7 +493,8 @@ 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,
@@ -528,7 +531,7 @@ static int cachefiles_prepare_fallback_write(struct netfs_cache_resources *cres,
_enter("%lx", index);
- return cachefiles_has_space(cache, 0, 1);
+ return cachefiles_has_space(cache, 0, 1, cachefiles_has_space_for_write);
}
/*
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index ad87fb28b602..9b0a14e37cfa 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -309,7 +309,8 @@ 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;
@@ -480,7 +481,8 @@ 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)) {
if (cache->store) {
- 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;
}
diff --git a/fs/fscache/stats.c b/fs/fscache/stats.c
index 225bba60b617..d34fb6e91d57 100644
--- a/fs/fscache/stats.c
+++ b/fs/fscache/stats.c
@@ -44,6 +44,10 @@ 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
@@ -86,6 +90,10 @@ 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 d5f6b636175e..7b3225c6c22f 100644
--- a/include/linux/fscache-cache.h
+++ b/include/linux/fscache-cache.h
@@ -179,11 +179,17 @@ void fscache_end_operation(struct netfs_cache_resources *cres)
#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
extern struct workqueue_struct *fscache_wq;
