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author | Denis V. Lunev <den@openvz.org> | 2016-07-14 16:33:28 +0300 |
---|---|---|
committer | Jeff Cody <jcody@redhat.com> | 2016-07-19 16:54:46 -0400 |
commit | c7c2769c0e5769eaad9d968fe2161505b657e02a (patch) | |
tree | b11a219e9f09262e7ba0875dabd121e798e52beb /block/mirror.c | |
parent | b7d5062c9cf53f21a555843775392dc03364bbff (diff) | |
download | qemu-c7c2769c0e5769eaad9d968fe2161505b657e02a.zip qemu-c7c2769c0e5769eaad9d968fe2161505b657e02a.tar.gz qemu-c7c2769c0e5769eaad9d968fe2161505b657e02a.tar.bz2 |
mirror: efficiently zero out target
With a bdrv_co_write_zeroes method on a target BDS and when this method
is working as indicated by the bdrv_can_write_zeroes_with_unmap(), zeroes
will not be placed into the wire. Thus the target could be very efficiently
zeroed out. This should be done with the largest chunk possible.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Vladimir Sementsov-Ogievskiy<vsementsov@virtuozzo.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 1468503209-19498-8-git-send-email-den@openvz.org
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Max Reitz <mreitz@redhat.com>
CC: Jeff Cody <jcody@redhat.com>
CC: Eric Blake <eblake@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
Diffstat (limited to 'block/mirror.c')
-rw-r--r-- | block/mirror.c | 28 |
1 files changed, 26 insertions, 2 deletions
diff --git a/block/mirror.c b/block/mirror.c index b7b1ded..0262b03 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -538,8 +538,32 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) end = s->bdev_length / BDRV_SECTOR_SIZE; if (base == NULL && !bdrv_has_zero_init(target_bs)) { - bdrv_set_dirty_bitmap(s->dirty_bitmap, 0, end); - return 0; + if (!bdrv_can_write_zeroes_with_unmap(target_bs)) { + bdrv_set_dirty_bitmap(s->dirty_bitmap, 0, end); + return 0; + } + + for (sector_num = 0; sector_num < end; ) { + int nb_sectors = MIN(end - sector_num, + QEMU_ALIGN_DOWN(INT_MAX, s->granularity) >> BDRV_SECTOR_BITS); + + mirror_throttle(s); + + if (block_job_is_cancelled(&s->common)) { + return 0; + } + + if (s->in_flight >= MAX_IN_FLIGHT) { + trace_mirror_yield(s, s->in_flight, s->buf_free_count, -1); + mirror_wait_for_io(s); + continue; + } + + mirror_do_zero_or_discard(s, sector_num, nb_sectors, false); + sector_num += nb_sectors; + } + + mirror_drain(s); } /* First part, loop on the sectors and initialize the dirty bitmap. */ |