From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53527) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bNglq-00058p-F3 for qemu-devel@nongnu.org; Thu, 14 Jul 2016 09:33:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bNgln-0007ti-A5 for qemu-devel@nongnu.org; Thu, 14 Jul 2016 09:33:42 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:35122 helo=relay.sw.ru) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bNglm-0007ss-S9 for qemu-devel@nongnu.org; Thu, 14 Jul 2016 09:33:39 -0400 From: "Denis V. Lunev" Date: Thu, 14 Jul 2016 16:33:28 +0300 Message-Id: <1468503209-19498-8-git-send-email-den@openvz.org> In-Reply-To: <1468503209-19498-1-git-send-email-den@openvz.org> References: <1468503209-19498-1-git-send-email-den@openvz.org> Subject: [Qemu-devel] [PATCH v3 7/8] mirror: efficiently zero out target List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org, qemu-devel@nongnu.org Cc: den@openvz.org, Stefan Hajnoczi , Kevin Wolf , Max Reitz , Jeff Cody , Eric Blake 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 Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Fam Zheng CC: Stefan Hajnoczi CC: Kevin Wolf CC: Max Reitz CC: Jeff Cody CC: Eric Blake --- block/mirror.c | 28 ++++++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index d0fa457..ae70c3b 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -536,8 +536,32 @@ 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. */ -- 2.5.0