-stable review patch. If anyone has any objections, please let us know. ------------------ From: Lars Ellenberg 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 Signed-off-by: Lars Ellenberg Acked-by: Jens Axboe Cc: Signed-off-by: Andrew Morton Signed-off-by: Chris Wright --- drivers/md/raid1.c | 13 +++++++++---- drivers/md/raid10.c | 11 ++++++++--- 2 files changed, 17 insertions(+), 7 deletions(-) --- linux-2.6.19.2.orig/drivers/md/raid1.c +++ linux-2.6.19.2/drivers/md/raid1.c @@ -775,6 +775,7 @@ static int make_request(request_queue_t 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 @@ static int make_request(request_queue_t 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 @@ static int make_request(request_queue_t 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 @@ static int make_request(request_queue_t 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 @@ static void raid1d(mddev_t *mddev) * 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 @@ static void raid1d(mddev_t *mddev) 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 @@ static void raid1d(mddev_t *mddev) (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 @@ static void raid1d(mddev_t *mddev) 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); --- linux-2.6.19.2.orig/drivers/md/raid10.c +++ linux-2.6.19.2/drivers/md/raid10.c @@ -782,6 +782,7 @@ static int make_request(request_queue_t int i; int chunk_sects = conf->chunk_mask + 1; const int rw = bio_data_dir(bio); + const int do_sync = bio_sync(bio); struct bio_list bl; unsigned long flags; @@ -863,7 +864,7 @@ static int make_request(request_queue_t mirror->rdev->data_offset; read_bio->bi_bdev = mirror->rdev->bdev; read_bio->bi_end_io = raid10_end_read_request; - read_bio->bi_rw = READ; + read_bio->bi_rw = READ | do_sync; read_bio->bi_private = r10_bio; generic_make_request(read_bio); @@ -909,7 +910,7 @@ static int make_request(request_queue_t conf->mirrors[d].rdev->data_offset; mbio->bi_bdev = conf->mirrors[d].rdev->bdev; mbio->bi_end_io = raid10_end_write_request; - mbio->bi_rw = WRITE; + mbio->bi_rw = WRITE | do_sync; mbio->bi_private = r10_bio; atomic_inc(&r10_bio->remaining); @@ -922,6 +923,9 @@ static int make_request(request_queue_t blk_plug_device(mddev->queue); spin_unlock_irqrestore(&conf->device_lock, flags); + if (do_sync) + md_wakeup_thread(mddev->thread); + return 0; } @@ -1563,6 +1567,7 @@ static void raid10d(mddev_t *mddev) (unsigned long long)r10_bio->sector); raid_end_bio_io(r10_bio); } else { + const int do_sync = bio_sync(r10_bio->master_bio); rdev = conf->mirrors[mirror].rdev; if (printk_ratelimit()) printk(KERN_ERR "raid10: %s: redirecting sector %llu to" @@ -1574,7 +1579,7 @@ static void raid10d(mddev_t *mddev) bio->bi_sector = r10_bio->devs[r10_bio->read_slot].addr + rdev->data_offset; bio->bi_bdev = rdev->bdev; - bio->bi_rw = READ; + bio->bi_rw = READ | do_sync; bio->bi_private = r10_bio; bio->bi_end_io = raid10_end_read_request; unplug = 1; -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/