From: NeilBrown Date: Wed, 19 Sep 2012 02:48:30 +0000 (+1000) Subject: Revert "md/raid5: For odirect-write performance, do not set STRIPE_PREREAD_ACTIVE." X-Git-Tag: v3.6~17^2~4 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=a852d7b8a0cf29499905c9243fa6d3fb93898b82;p=profile%2Fivi%2Fkernel-adaptation-intel-automotive.git Revert "md/raid5: For odirect-write performance, do not set STRIPE_PREREAD_ACTIVE." This reverts commit 895e3c5c58a80bb9e4e05d9ac38b4f30e0f97d80. While this patch seemed like a good idea and did help some workloads, it hurts other workloads. Large sequential O_DIRECT writes were faster, Small random O_DIRECT writes were slower. Other changes (batching RAID5 writes) have improved the sequential writes using a different mechanism, so the net result of this patch is definitely negative. So revert it. Reported-by: Shaohua Li Tested-by: Jianpeng Ma Signed-off-by: NeilBrown --- diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index adda94d..380cb68 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -4192,7 +4192,7 @@ 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_NOIDLE) && + if ((bi->bi_rw & REQ_SYNC) && !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) atomic_inc(&conf->preread_active_stripes); release_stripe_plug(mddev, sh);