From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53834) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VmRDE-0003pF-FC for qemu-devel@nongnu.org; Fri, 29 Nov 2013 11:46:45 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VmRD9-0002pB-I1 for qemu-devel@nongnu.org; Fri, 29 Nov 2013 11:46:40 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50090) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VmRD9-0002ox-34 for qemu-devel@nongnu.org; Fri, 29 Nov 2013 11:46:35 -0500 From: Kevin Wolf Date: Fri, 29 Nov 2013 17:45:25 +0100 Message-Id: <1385743555-27888-11-git-send-email-kwolf@redhat.com> In-Reply-To: <1385743555-27888-1-git-send-email-kwolf@redhat.com> References: <1385743555-27888-1-git-send-email-kwolf@redhat.com> Subject: [Qemu-devel] [PULL 10/41] block: honour BlockLimits in bdrv_co_discard List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: anthony@codemonkey.ws Cc: kwolf@redhat.com, qemu-devel@nongnu.org From: Peter Lieven Reviewed-by: Eric Blake Signed-off-by: Peter Lieven Signed-off-by: Stefan Hajnoczi --- block.c | 37 ++++++++++++++++++++++++++++++++++++- 1 file changed, 36 insertions(+), 1 deletion(-) diff --git a/block.c b/block.c index b4194da..df5a603 100644 --- a/block.c +++ b/block.c @@ -4243,6 +4243,11 @@ static void coroutine_fn bdrv_discard_co_entry(void *opaque) rwco->ret = bdrv_co_discard(rwco->bs, rwco->sector_num, rwco->nb_sectors); } +/* if no limit is specified in the BlockLimits use a default + * of 32768 512-byte sectors (16 MiB) per request. + */ +#define MAX_DISCARD_DEFAULT 32768 + int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors) { @@ -4264,7 +4269,37 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, } if (bs->drv->bdrv_co_discard) { - return bs->drv->bdrv_co_discard(bs, sector_num, nb_sectors); + int max_discard = bs->bl.max_discard ? + bs->bl.max_discard : MAX_DISCARD_DEFAULT; + + while (nb_sectors > 0) { + int ret; + int num = nb_sectors; + + /* align request */ + if (bs->bl.discard_alignment && + num >= bs->bl.discard_alignment && + sector_num % bs->bl.discard_alignment) { + if (num > bs->bl.discard_alignment) { + num = bs->bl.discard_alignment; + } + num -= sector_num % bs->bl.discard_alignment; + } + + /* limit request size */ + if (num > max_discard) { + num = max_discard; + } + + ret = bs->drv->bdrv_co_discard(bs, sector_num, num); + if (ret) { + return ret; + } + + sector_num += num; + nb_sectors -= num; + } + return 0; } else if (bs->drv->bdrv_aio_discard) { BlockDriverAIOCB *acb; CoroutineIOCompletion co = { -- 1.8.1.4