path: root/block
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authorJens Axboe <jens.axboe@oracle.com>2009-04-06 14:48:07 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2009-04-06 08:04:54 -0700
commitaeb6fafb8fa53266d70ca7474fcda2bdaf96524a (patch)
treeebe8e0c616a9dbfdfe5184b64d0150ea02d3d1b2 /block
parent644b2d99b7a8677a56909a7b1fde31677eba4471 (diff)
block: Add flag for telling the IO schedulers NOT to anticipate more IO
By default, CFQ will anticipate more IO from a given io context if the previously completed IO was sync. This used to be fine, since the only sync IO was reads and O_DIRECT writes. But with more "normal" sync writes being used now, we don't want to anticipate for those. Add a bio/request flag that informs the IO scheduler that this is a sync request that we should not idle for. Introduce WRITE_ODIRECT specifically for O_DIRECT writes, and make sure that the other sync writes set this flag. Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'block')
2 files changed, 5 insertions, 1 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index c4198f083e5..25572802dac 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1128,6 +1128,8 @@ void init_request_from_bio(struct request *req, struct bio *bio)
req->cmd_flags |= REQ_UNPLUG;
if (bio_rw_meta(bio))
req->cmd_flags |= REQ_RW_META;
+ if (bio_noidle(bio))
+ req->cmd_flags |= REQ_NOIDLE;
req->errors = 0;
req->hard_sector = req->sector = bio->bi_sector;
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 664ebfd092e..9e809345f71 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1992,8 +1992,10 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq))
cfq_slice_expired(cfqd, 1);
- else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list))
+ else if (sync && !rq_noidle(rq) &&
+ RB_EMPTY_ROOT(&cfqq->sort_list)) {
+ }
if (!cfqd->rq_in_driver)