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

This reverts commit 895e3c5c58.

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 <shli@kernel.org>
Tested-by: Jianpeng Ma <majianpeng@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2012-09-19 12:48:30 +10:00
parent 55d512e245
commit a852d7b8a0
1 changed files with 1 additions and 1 deletions
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2
drivers/md/raid5.c
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@ -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);