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 straight forward 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@xxxxxxx>
Signed-off-by: Lars Ellenberg <lars@xxxxxxxxxx>
---
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 @@ 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 @@ #endif
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 @@ #endif
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);
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index f014191..a9401c0 100644
--- a/drivers/md/raid10.c
+++ b/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;
--
: Lars Ellenberg Tel +43-1-8178292-55 :
: LINBIT Information Technologies GmbH Fax +43-1-8178292-82 :
: Vivenotgasse 48, A-1120 Vienna/Europe http://www.linbit.com :
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