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.

Signed-off-by: Lars Ellenberg <lars@linbit.com>
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 59cd546cdecbbd90896843466e17bfa91ffc15ae..31e872eb0b923cbde767055e9c28079900996957 100644 (file)
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -751,6 +751,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
        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;
 
        if (unlikely(!mddev->barriers_work && bio_barrier(bio))) {
@@ -805,7 +806,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
                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);
@@ -876,7 +877,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
                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) {
@@ -911,6 +912,8 @@ static int make_request(request_queue_t *q, struct bio * bio)
        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);
@@ -1404,6 +1407,7 @@ static void raid1d(mddev_t *mddev)
                         * all others have had their bios[] entry cleared.
                         */
                        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++)
@@ -1421,7 +1425,7 @@ 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);
@@ -1518,6 +1522,7 @@ 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;
@@ -1533,7 +1538,7 @@ 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 039ed49b3c030462d8cd0e54ab84e97c0d85fc26..0a11d5c20b5b78d5d39976bed9dc6dd3478ffd59 100644 (file)
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -748,6 +748,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
        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;
 
@@ -829,7 +830,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
                        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);
@@ -875,7 +876,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
                        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);
@@ -888,6 +889,9 @@ static int make_request(request_queue_t *q, struct bio * bio)
        blk_plug_device(mddev->queue);
        spin_unlock_irqrestore(&conf->device_lock, flags);
 
+       if (do_sync)
+               md_wakeup_thread(mddev->thread);
+
        return 0;
 }
 
@@ -1488,6 +1492,7 @@ 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"
@@ -1499,7 +1504,7 @@ 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;