From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53426) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cxbk7-00062F-Ty for qemu-devel@nongnu.org; Mon, 10 Apr 2017 12:00:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cxbk6-0004Py-SL for qemu-devel@nongnu.org; Mon, 10 Apr 2017 12:00:39 -0400 Date: Mon, 10 Apr 2017 17:00:23 +0100 From: Stefan Hajnoczi Message-ID: <20170410160023.GG3214@stefanha-x1.localdomain> References: <1491741460-10308-1-git-send-email-lidongchen@tencent.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="DWg365Y4B18r8evw" Content-Disposition: inline In-Reply-To: <1491741460-10308-1-git-send-email-lidongchen@tencent.com> Subject: Re: [Qemu-devel] [PATCH v3] migration/block: use blk_pwrite_zeroes for each zero cluster List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: jemmy858585@gmail.com Cc: qemu-devel@nongnu.org, famz@redhat.com, quintela@redhat.com, dgilbert@redhat.com, qemu-block@nongnu.org, Lidong Chen --DWg365Y4B18r8evw Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Apr 09, 2017 at 08:37:40PM +0800, jemmy858585@gmail.com wrote: > From: Lidong Chen >=20 > BLOCK_SIZE is (1 << 20), qcow2 cluster size is 65536 by default, > this maybe cause the qcow2 file size is bigger after migration. > This patch check each cluster, use blk_pwrite_zeroes for each > zero cluster. >=20 > Signed-off-by: Lidong Chen > --- > migration/block.c | 38 ++++++++++++++++++++++++++++++++++++-- > 1 file changed, 36 insertions(+), 2 deletions(-) >=20 > diff --git a/migration/block.c b/migration/block.c > index 7734ff7..fe613db 100644 > --- a/migration/block.c > +++ b/migration/block.c > @@ -885,6 +885,8 @@ static int block_load(QEMUFile *f, void *opaque, int = version_id) > int64_t total_sectors =3D 0; > int nr_sectors; > int ret; > + BlockDriverInfo bdi; > + int cluster_size; > =20 > do { > addr =3D qemu_get_be64(f); > @@ -934,8 +936,40 @@ static int block_load(QEMUFile *f, void *opaque, int= version_id) > } else { > buf =3D g_malloc(BLOCK_SIZE); > qemu_get_buffer(f, buf, BLOCK_SIZE); > - ret =3D blk_pwrite(blk, addr * BDRV_SECTOR_SIZE, buf, > - nr_sectors * BDRV_SECTOR_SIZE, 0); > + > + ret =3D bdrv_get_info(blk_bs(blk), &bdi); > + cluster_size =3D bdi.cluster_size; > + > + if (ret =3D=3D 0 && cluster_size > 0 && > + cluster_size <=3D BLOCK_SIZE && > + BLOCK_SIZE % cluster_size =3D=3D 0) { How about: if (blk !=3D blk_prev) { blk_prev =3D blk; total_sectors =3D blk_nb_sectors(blk); if (total_sectors <=3D 0) { error_report("Error getting length of block device %s", device_name); return -EINVAL; } blk_invalidate_cache(blk, &local_err); if (local_err) { error_report_err(local_err); return -EINVAL; } + ret =3D bdrv_get_info(blk_bs(blk), &bdi); + if (ret =3D=3D 0 && cluster_size > 0 && cluster_size <=3D BLOCK_SIZE = && + BLOCK_SIZE % cluster_size =3D=3D 0) { + zero_cluster_size =3D bdi.cluster_size; + } else { + zero_cluster_size =3D 0; + } } That way we only fetch the cluster size once per device. When processing a block we do without repeatedly fetching the cluster size: if (zero_cluster_size) { ...detect zeroes... } > + int i; > + int64_t cur_addr; > + uint8_t *cur_buf; > + > + for (i =3D 0; i < BLOCK_SIZE / cluster_size; i++) { > + cur_addr =3D addr * BDRV_SECTOR_SIZE > + + i * cluster_size; > + cur_buf =3D buf + i * cluster_size; > + > + if (buffer_is_zero(cur_buf, cluster_size)) { > + ret =3D blk_pwrite_zeroes(blk, cur_addr, > + cluster_size, > + BDRV_REQ_MAY_UNMAP); > + } else { > + ret =3D blk_pwrite(blk, cur_addr, cur_buf, > + cluster_size, 0); Indentation is off here. > + } > + > + if (ret < 0) { > + g_free(buf); > + return ret; > + } > + } > + } else { > + ret =3D blk_pwrite(blk, addr * BDRV_SECTOR_SIZE, buf, > + nr_sectors * BDRV_SECTOR_SIZE, 0); > + } > g_free(buf); > } > =20 > --=20 > 1.8.3.1 >=20 --DWg365Y4B18r8evw Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEcBAEBAgAGBQJY66wXAAoJEJykq7OBq3PIdAoH/2Hi9eT3jHbkhSgxJYJXSa+p U2GDc+Jb6A1MQzHXuY3Tm9u7n9836VwpdAE+3W/zml1gviCjOWFiWj525UfKHnyk YmpdDjgIMqOCIj9QY7x2iIngoeRKTS8QyUMLoHkLr4Kj04oFR+CgN4FGp0IGYA5F 97gV5vm3fYzb4eIksH5IErxWcGeRE/X3uHmjhNqhsUCo13WkreB17OtCA7CngKz8 b/1g55JC1f/NDUgmwexq4kjS6FmkhhbsA3CPld73BgBYlzahAJojGnBy3+toeeYS MNx61jwDtw6NOaaeYJ96L6v4zl1GvhkYFTM3ZfiEfpWGAV8RrSoBiXD40MEQ3tU= =r+nC -----END PGP SIGNATURE----- --DWg365Y4B18r8evw--