diff options
| author | David Howells <dhowells@redhat.com> | 2021-11-11 23:14:29 +0000 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2022-01-07 09:22:19 +0000 |
| commit | cdf262f29488e6c3432911ec487ea41918fcbcd7 (patch) | |
| tree | f01398a62b4f4c9e9c29e08b6e583a063aacb7e2 /fs/fscache | |
| parent | d64f4554dd177c5891c02424a8d9e80590b55b35 (diff) | |
fscache: Count data storage objects in a cache
Count the data storage objects that are currently allocated in a cache.
This is used to pin certain cache structures until cache withdrawal is
complete.
Three helpers are provided to manage and make use of the count:
(1) void fscache_count_object(struct fscache_cache *cache);
This should be called by the cache backend to note that an object has
been allocated and attached to the cache.
(2) void fscache_uncount_object(struct fscache_cache *cache);
This should be called by the backend to note that an object has been
destroyed. This sends a wakeup event that allows cache withdrawal to
proceed if it was waiting for that object.
(3) void fscache_wait_for_objects(struct fscache_cache *cache);
This can be used by the backend to wait for all outstanding cache
object to be destroyed.
Each cache's counter is displayed as part of /proc/fs/fscache/caches.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819608594.215744.1812706538117388252.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906911646.143852.168184059935530127.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967111846.1823006.9868154941573671255.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021516219.640689.4934796654308958158.stgit@warthog.procyon.org.uk/ # v4
Diffstat (limited to 'fs/fscache')
| -rw-r--r-- | fs/fscache/cache.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/fscache/cache.c b/fs/fscache/cache.c index 25eac61f1c29..2749933852a9 100644 --- a/fs/fscache/cache.c +++ b/fs/fscache/cache.c @@ -13,6 +13,8 @@ static LIST_HEAD(fscache_caches); DECLARE_RWSEM(fscache_addremove_sem); EXPORT_SYMBOL(fscache_addremove_sem); +DECLARE_WAIT_QUEUE_HEAD(fscache_clearance_waiters); +EXPORT_SYMBOL(fscache_clearance_waiters); static atomic_t fscache_cache_debug_id; |