Now discard merge works, add plug for blkdev_issue_discard. This will help discard request merge especially for raid0 case. In raid0, a big discard request is split to small requests, and if correct plug is added, such small requests can be merged in low layer.
Signed-off-by: Shaohua Li <[email protected]> --- block/blk-lib.c | 3 +++ 1 file changed, 3 insertions(+) Index: linux/block/blk-lib.c =================================================================== --- linux.orig/block/blk-lib.c 2012-09-28 15:09:38.655327319 +0800 +++ linux/block/blk-lib.c 2012-10-09 08:45:04.358598888 +0800 @@ -48,6 +48,7 @@ int blkdev_issue_discard(struct block_de struct bio_batch bb; struct bio *bio; int ret = 0; + struct blk_plug plug; if (!q) return -ENXIO; @@ -81,6 +82,7 @@ int blkdev_issue_discard(struct block_de bb.flags = 1 << BIO_UPTODATE; bb.wait = &wait; + blk_start_plug(&plug); while (nr_sects) { unsigned int req_sects; sector_t end_sect; @@ -117,6 +119,7 @@ int blkdev_issue_discard(struct block_de atomic_inc(&bb.done); submit_bio(type, bio); } + blk_finish_plug(&plug); /* Wait for bios in-flight */ if (!atomic_dec_and_test(&bb.done)) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
