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| author | majianpeng <majianpeng@gmail.com> | 2012-07-31 10:05:44 +1000 |
|---|---|---|
| committer | NeilBrown <neilb@suse.de> | 2012-07-31 10:05:44 +1000 |
| commit | 895e3c5c58a80bb9e4e05d9ac38b4f30e0f97d80 (patch) | |
| tree | 0376aaaaf8166e07a052067e5f825ab5b914d758 /drivers/md | |
| parent | b7219ccb33aa0df9949a60c68b5e9f712615e56f (diff) | |
| download | lwn-895e3c5c58a80bb9e4e05d9ac38b4f30e0f97d80.tar.gz lwn-895e3c5c58a80bb9e4e05d9ac38b4f30e0f97d80.zip | |
md/raid5: For odirect-write performance, do not set STRIPE_PREREAD_ACTIVE.
'sync' writes set both REQ_SYNC and REQ_NOIDLE.
O_DIRECT writes set REQ_SYNC but not REQ_NOIDLE.
We currently assume that a REQ_SYNC request will not be followed by
more requests and so set STRIPE_PREREAD_ACTIVE to expedite the
request.
This is appropriate for sync requests, but not for O_DIRECT requests.
So make the setting of STRIPE_PREREAD_ACTIVE conditional on REQ_NOIDLE
rather than REQ_SYNC. This is consistent with the documented meaning
of REQ_NOIDLE:
__REQ_NOIDLE, /* don't anticipate more IO after this one */
Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/raid5.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 29493982dbf5..259f519814ca 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -4135,7 +4135,7 @@ static void make_request(struct mddev *mddev, struct bio * bi) finish_wait(&conf->wait_for_overlap, &w); set_bit(STRIPE_HANDLE, &sh->state); clear_bit(STRIPE_DELAYED, &sh->state); - if ((bi->bi_rw & REQ_SYNC) && + if ((bi->bi_rw & REQ_NOIDLE) && !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) atomic_inc(&conf->preread_active_stripes); mddev_check_plugged(mddev); |