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/util.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/util.h')
| -rw-r--r-- | drivers/md/bcache/util.h | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/drivers/md/bcache/util.h b/drivers/md/bcache/util.h index 1ae2a73ad85f..ea345c6896f4 100644 --- a/drivers/md/bcache/util.h +++ b/drivers/md/bcache/util.h @@ -450,17 +450,23 @@ read_attribute(name ## _last_ ## frequency_units) (ewma) >> factor; \ }) -struct ratelimit { +struct bch_ratelimit { + /* Next time we want to do some work, in nanoseconds */ uint64_t next; + + /* + * Rate at which we want to do work, in units per nanosecond + * The units here correspond to the units passed to bch_next_delay() + */ unsigned rate; }; -static inline void ratelimit_reset(struct ratelimit *d) +static inline void bch_ratelimit_reset(struct bch_ratelimit *d) { d->next = local_clock(); } -unsigned bch_next_delay(struct ratelimit *d, uint64_t done); +uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done); #define __DIV_SAFE(n, d, zero) \ ({ \ |