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| author | Tang Junhui <tang.junhui@zte.com.cn> | 2017-09-06 09:25:52 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-09-27 15:43:21 +0300 |
| commit | 07f18ca7da27748f136dce482ec1ba2be71f0c24 (patch) | |
| tree | 6eddd5cfeba0e67a57287f1187a2b3c1c9cc1b78 | |
| parent | bf8702bf049edbc0b2a1c900473523f582d24706 (diff) | |
| download | linux-07f18ca7da27748f136dce482ec1ba2be71f0c24.tar.xz | |
bcache: fix sequential large write IO bypass
commit c81ffa32a214c84b08900fbc9d432187bd948eba upstream.
Sequential write IOs were tested with bs=1M by FIO in writeback cache
mode, these IOs were expected to be bypassed, but actually they did not.
We debug the code, and find in check_should_bypass():
if (!congested &&
mode == CACHE_MODE_WRITEBACK &&
op_is_write(bio_op(bio)) &&
(bio-＞bi_opf & REQ_SYNC))
goto rescale
that means, If in writeback mode, a write IO with REQ_SYNC flag will not
be bypassed though it is a sequential large IO, It's not a correct thing
to do actually, so this patch remove these codes.
Signed-off-by: tang.junhui <tang.junhui@zte.com.cn>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Eric Wheeler <bcache@linux.ewheeler.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/md/bcache/request.c | 6 |
1 files changed, 0 insertions, 6 deletions
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c index c53cc00202c8..4b413db99276 100644 --- a/drivers/md/bcache/request.c +++ b/drivers/md/bcache/request.c @@ -400,12 +400,6 @@ static bool check_should_bypass(struct cached_dev *dc, struct bio *bio) if (!congested && !dc->sequential_cutoff) goto rescale; - if (!congested && - mode == CACHE_MODE_WRITEBACK && - op_is_write(bio->bi_opf) && - op_is_sync(bio->bi_opf)) - goto rescale; - spin_lock(&dc->io_lock); hlist_for_each_entry(i, iohash(dc, bio->bi_iter.bi_sector), hash) |