| Message ID | 20170629222107.D41A5100128@ware.dreamhost.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c index 019b3df..958072a 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)
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> Cc: stable@vger.kernel.org --- drivers/md/bcache/request.c | 6 ------ 1 file changed, 6 deletions(-)