diff options
| author | Kent Overstreet <kmo@daterainc.com> | 2013-09-23 23:17:31 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-09-24 14:41:43 -0700 |
| commit | c2a4f3183a1248f615a695fbd8905da55ad11bba (patch) | |
| tree | 51233866301869506c0728c812fe3668ae1e94ce /drivers/md/bcache/bcache.h | |
| parent | 61cbd250f867f98bb4738000afc6002d6f2b14bd (diff) | |
bcache: Fix a writeback performance regression
Background writeback works by scanning the btree for dirty data and
adding those keys into a fixed size buffer, then for each dirty key in
the keybuf writing it to the backing device.
When read_dirty() finishes and it's time to scan for more dirty data, we
need to wait for the outstanding writeback IO to finish - they still
take up slots in the keybuf (so that foreground writes can check for
them to avoid races) - without that wait, we'll continually rescan when
we'll be able to add at most a key or two to the keybuf, and that takes
locks that starves foreground IO. Doh.
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: linux-stable <stable@vger.kernel.org> # >= v3.10
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/md/bcache/bcache.h')
| -rw-r--r-- | drivers/md/bcache/bcache.h | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h index b39f6f0b45f..0f12382aa35 100644 --- a/drivers/md/bcache/bcache.h +++ b/drivers/md/bcache/bcache.h @@ -498,7 +498,7 @@ struct cached_dev { */ atomic_t has_dirty; - struct ratelimit writeback_rate; + struct bch_ratelimit writeback_rate; struct delayed_work writeback_rate_update; /* @@ -507,10 +507,9 @@ struct cached_dev { */ sector_t last_read; - /* Number of writeback bios in flight */ - atomic_t in_flight; + /* Limit number of writeback bios in flight */ + struct semaphore in_flight; struct closure_with_timer writeback; - struct closure_waitlist writeback_wait; struct keybuf writeback_keys; |