From b31dc66a54ad986b6b73bdc49c8efc17cbad1833 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 13 Jun 2006 08:26:10 +0200 Subject: [PATCH] Kill PF_SYNCWRITE flag A process flag to indicate whether we are doing sync io is incredibly ugly. It also causes performance problems when one does a lot of async io and then proceeds to sync it. Part of the io will go out as async, and the other part as sync. This causes a disconnect between the previously submitted io and the synced io. For io schedulers such as CFQ, this will cause us lost merges and suboptimal behaviour in scheduling. Remove PF_SYNCWRITE completely from the fsync/msync paths, and let the O_DIRECT path just directly indicate that the writes are sync by using WRITE_SYNC instead. Signed-off-by: Jens Axboe --- block/ll_rw_blk.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'block/ll_rw_blk.c') diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c index 17c42ddd31db..2270bb451385 100644 --- a/block/ll_rw_blk.c +++ b/block/ll_rw_blk.c @@ -2827,6 +2827,9 @@ static void init_request_from_bio(struct request *req, struct bio *bio) if (unlikely(bio_barrier(bio))) req->flags |= (REQ_HARDBARRIER | REQ_NOMERGE); + if (bio_sync(bio)) + req->flags |= REQ_RW_SYNC; + req->errors = 0; req->hard_sector = req->sector = bio->bi_sector; req->hard_nr_sectors = req->nr_sectors = bio_sectors(bio); -- cgit v1.2.3