[PATCH] md: pass down BIO_RW_SYNC in raid{1,10}
md raidX make_request functions strip off the BIO_RW_SYNC flag, thus
introducing additional latency.
Fixing this in raid1 and raid10 seems to be straightforward enough.
For our particular usage case in DRBD, passing this flag improved some
initialization time from ~5 minutes to ~5 seconds.
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Lars Ellenberg <lars@linbit.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index b30f74b..164b25d 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -775,6 +775,7 @@
struct bio_list bl;
struct page **behind_pages = NULL;
const int rw = bio_data_dir(bio);
+ const int do_sync = bio_sync(bio);
int do_barriers;
/*
@@ -835,7 +836,7 @@
read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
read_bio->bi_bdev = mirror->rdev->bdev;
read_bio->bi_end_io = raid1_end_read_request;
- read_bio->bi_rw = READ;
+ read_bio->bi_rw = READ | do_sync;
read_bio->bi_private = r1_bio;
generic_make_request(read_bio);
@@ -906,7 +907,7 @@
mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset;
mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
mbio->bi_end_io = raid1_end_write_request;
- mbio->bi_rw = WRITE | do_barriers;
+ mbio->bi_rw = WRITE | do_barriers | do_sync;
mbio->bi_private = r1_bio;
if (behind_pages) {
@@ -941,6 +942,8 @@
blk_plug_device(mddev->queue);
spin_unlock_irqrestore(&conf->device_lock, flags);
+ if (do_sync)
+ md_wakeup_thread(mddev->thread);
#if 0
while ((bio = bio_list_pop(&bl)) != NULL)
generic_make_request(bio);
@@ -1541,6 +1544,7 @@
* We already have a nr_pending reference on these rdevs.
*/
int i;
+ const int do_sync = bio_sync(r1_bio->master_bio);
clear_bit(R1BIO_BarrierRetry, &r1_bio->state);
clear_bit(R1BIO_Barrier, &r1_bio->state);
for (i=0; i < conf->raid_disks; i++)
@@ -1561,7 +1565,7 @@
conf->mirrors[i].rdev->data_offset;
bio->bi_bdev = conf->mirrors[i].rdev->bdev;
bio->bi_end_io = raid1_end_write_request;
- bio->bi_rw = WRITE;
+ bio->bi_rw = WRITE | do_sync;
bio->bi_private = r1_bio;
r1_bio->bios[i] = bio;
generic_make_request(bio);
@@ -1593,6 +1597,7 @@
(unsigned long long)r1_bio->sector);
raid_end_bio_io(r1_bio);
} else {
+ const int do_sync = bio_sync(r1_bio->master_bio);
r1_bio->bios[r1_bio->read_disk] =
mddev->ro ? IO_BLOCKED : NULL;
r1_bio->read_disk = disk;
@@ -1608,7 +1613,7 @@
bio->bi_sector = r1_bio->sector + rdev->data_offset;
bio->bi_bdev = rdev->bdev;
bio->bi_end_io = raid1_end_read_request;
- bio->bi_rw = READ;
+ bio->bi_rw = READ | do_sync;
bio->bi_private = r1_bio;
unplug = 1;
generic_make_request(bio);