A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-28 18:51:56 -04:00
Code Issues Projects Releases Packages Wiki Activity

bcache: fix sequential large write IO bypass

Browse source 
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 <[email protected]>
Reviewed-by: Kent Overstreet <[email protected]>
Reviewed-by: Eric Wheeler <[email protected]>
Cc: [email protected]
Signed-off-by: Jens Axboe <[email protected]>
This commit is contained in:
Tang Junhui 2017-09-06 14:25:52 +08:00 • committed by Jens Axboe
commit c81ffa32a2
1 changed files with 0 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

6
drivers/md/bcache/request.c
View file

@ -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)