On Mon, Oct 8, 2012 at 9:11 PM, Shaohua Li <[email protected]> wrote: > 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))
That plug looks rather coarse-grained. Any adverse affects when mkfs discards an entire (large) raid0 device? (I suspect not but figured I'd ask) -- 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/
