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Commit a852d7b8 authored by NeilBrown's avatar NeilBrown
Browse files

Revert "md/raid5: For odirect-write performance, do not set STRIPE_PREREAD_ACTIVE." 



This reverts commit 895e3c5c.

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: default avatarShaohua Li <shli@kernel.org>
Tested-by: default avatarJianpeng Ma <majianpeng@gmail.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent 55d512e2

drivers/md/raid5.c

+1 −1
Original line number Diff line number Diff line
@@ -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);