The patch titled
md: pass down BIO_RW_SYNC in raid{1,10}
has been added to the -mm tree. Its filename is
md-pass-down-bio_rw_sync-in-raid110.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: md: pass down BIO_RW_SYNC in raid{1,10}
From: Lars Ellenberg <Lars.Ellenberg@xxxxxxxxxx>
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@xxxxxxx>
Signed-off-by: Lars Ellenberg <lars@xxxxxxxxxx>
Cc: Jens Axboe <jens.axboe@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/md/raid1.c | 13 +++++++++----
drivers/md/raid10.c | 11 ++++++++---
2 files changed, 17 insertions(+), 7 deletions(-)
diff -puN drivers/md/raid1.c~md-pass-down-bio_rw_sync-in-raid110 drivers/md/raid1.c
--- a/drivers/md/raid1.c~md-pass-down-bio_rw_sync-in-raid110
+++ a/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);
diff -puN drivers/md/raid10.c~md-pass-down-bio_rw_sync-in-raid110 drivers/md/raid10.c
--- a/drivers/md/raid10.c~md-pass-down-bio_rw_sync-in-raid110
+++ a/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;
_
Patches currently in -mm which might be from Lars.Ellenberg@xxxxxxxxxx are
md-pass-down-bio_rw_sync-in-raid110.patch
-
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