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Wed, 7 Aug 2019 18:01:13 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-204-24.brq.redhat.com [10.40.204.24]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B5C2160BE1; Wed, 7 Aug 2019 18:01:06 +0000 (UTC) To: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org References: <20190807080750.15950-1-vsementsov@virtuozzo.com> <20190807080750.15950-5-vsementsov@virtuozzo.com> From: Max Reitz Openpgp: preference=signencrypt Autocrypt: addr=mreitz@redhat.com; prefer-encrypt=mutual; keydata= mQENBFXOJlcBCADEyyhOTsoa/2ujoTRAJj4MKA21dkxxELVj3cuILpLTmtachWj7QW+TVG8U /PsMCFbpwsQR7oEy8eHHZwuGQsNpEtNC2G/L8Yka0BIBzv7dEgrPzIu+W3anZXQW4702+uES U29G8TP/NGfXRRHGlbBIH9KNUnOSUD2vRtpOLXkWsV5CN6vQFYgQfFvmp5ZpPeUe6xNplu8V mcTw8OSEDW/ZnxJc8TekCKZSpdzYoxfzjm7xGmZqB18VFwgJZlIibt1HE0EB4w5GsD7x5ekh awIe3RwoZgZDLQMdOitJ1tUc8aqaxvgA4tz6J6st8D8pS//m1gAoYJWGwwIVj1DjTYLtABEB AAG0HU1heCBSZWl0eiA8bXJlaXR6QHJlZGhhdC5jb20+iQFTBBMBCAA9AhsDBQkSzAMABQsJ CAcCBhUICQoLAgQWAgMBAh4BAheABQJVzie5FRhoa3A6Ly9rZXlzLmdudXBnLm5ldAAKCRD0 B9sAYdXPQDcIB/9uNkbYEex1rHKz3mr12uxYMwLOOFY9fstP5aoVJQ1nWQVB6m2cfKGdcRe1 2/nFaHSNAzT0NnKz2MjhZVmcrpyd2Gp2QyISCfb1FbT82GMtXFj1wiHmPb3CixYmWGQUUh+I AvUqsevLA+WihgBUyaJq/vuDVM1/K9Un+w+Tz5vpeMidlIsTYhcsMhn0L9wlCjoucljvbDy/ 8C9L2DUdgi3XTa0ORKeflUhdL4gucWoAMrKX2nmPjBMKLgU7WLBc8AtV+84b9OWFML6NEyo4 4cP7cM/07VlJK53pqNg5cHtnWwjHcbpGkQvx6RUx6F1My3y52vM24rNUA3+ligVEgPYBuQEN BFXOJlcBCADAmcVUNTWT6yLWQHvxZ0o47KCP8OcLqD+67T0RCe6d0LP8GsWtrJdeDIQk+T+F xO7DolQPS6iQ6Ak2/lJaPX8L0BkEAiMuLCKFU6Bn3lFOkrQeKp3u05wCSV1iKnhg0UPji9V2 W5eNfy8F4ZQHpeGUGy+liGXlxqkeRVhLyevUqfU0WgNqAJpfhHSGpBgihUupmyUg7lfUPeRM DzAN1pIqoFuxnN+BRHdAecpsLcbR8sQddXmDg9BpSKozO/JyBmaS1RlquI8HERQoe6EynJhd 64aICHDfj61rp+/0jTIcevxIIAzW70IadoS/y3DVIkuhncgDBvGbF3aBtjrJVP+5ABEBAAGJ ASUEGAEIAA8FAlXOJlcCGwwFCRLMAwAACgkQ9AfbAGHVz0CbFwf9F/PXxQR9i4N0iipISYjU sxVdjJOM2TMut+ZZcQ6NSMvhZ0ogQxJ+iEQ5OjnIputKvPVd5U7WRh+4lF1lB/NQGrGZQ1ic alkj6ocscQyFwfib+xIe9w8TG1CVGkII7+TbS5pXHRxZH1niaRpoi/hYtgzkuOPp35jJyqT/ /ELbqQTDAWcqtJhzxKLE/ugcOMK520dJDeb6x2xVES+S5LXby0D4juZlvUj+1fwZu+7Io5+B bkhSVPb/QdOVTpnz7zWNyNw+OONo1aBUKkhq2UIByYXgORPFnbfMY7QWHcjpBVw9MgC4tGeF R4bv+1nAMMxKmb5VvQCExr0eFhJUAHAhVg== Message-ID: <23fd227d-9074-3a9e-b6c7-09f4abadc021@redhat.com> Date: Wed, 7 Aug 2019 20:01:05 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190807080750.15950-5-vsementsov@virtuozzo.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="eY5UdLN4bLnK0UE2iRSemEcBU9aJbuTFJ" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Wed, 07 Aug 2019 18:01:13 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH 4/8] block/backup: improve unallocated clusters skipping X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: fam@euphon.net, kwolf@redhat.com, qemu-devel@nongnu.org, armbru@redhat.com, stefanha@redhat.com, den@openvz.org, jsnow@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --eY5UdLN4bLnK0UE2iRSemEcBU9aJbuTFJ Content-Type: multipart/mixed; boundary="g2szmPiiB0ykmyTTWHdjAI74Ls3aegkit"; protected-headers="v1" From: Max Reitz To: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, armbru@redhat.com, fam@euphon.net, stefanha@redhat.com, kwolf@redhat.com, jsnow@redhat.com, den@openvz.org Message-ID: <23fd227d-9074-3a9e-b6c7-09f4abadc021@redhat.com> Subject: Re: [PATCH 4/8] block/backup: improve unallocated clusters skipping References: <20190807080750.15950-1-vsementsov@virtuozzo.com> <20190807080750.15950-5-vsementsov@virtuozzo.com> In-Reply-To: <20190807080750.15950-5-vsementsov@virtuozzo.com> --g2szmPiiB0ykmyTTWHdjAI74Ls3aegkit Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 07.08.19 10:07, Vladimir Sementsov-Ogievskiy wrote: > Limit block_status querying to request bounds on write notifier to > avoid extra seeking. I don=E2=80=99t understand this reasoning. Checking whether something is= allocated for qcow2 should just mean an L2 cache lookup. Which we have to do anyway when we try to copy data off the source. I could understand saying this makes the code easier, but I actually don=E2=80=99t think it does. If you implemented checking the allocation = status only for areas where the bitmap is reset (which I think this patch should), then it=E2=80=99d just duplicate the existing loop. > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > block/backup.c | 38 +++++++++++++++++++++----------------- > 1 file changed, 21 insertions(+), 17 deletions(-) >=20 > diff --git a/block/backup.c b/block/backup.c > index 11e27c844d..a4d37d2d62 100644 > --- a/block/backup.c > +++ b/block/backup.c [...] > @@ -267,6 +267,18 @@ static int coroutine_fn backup_do_cow(BackupBlockJ= ob *job, > wait_for_overlapping_requests(job, start, end); > cow_request_begin(&cow_request, job, start, end); > =20 > + if (job->initializing_bitmap) { > + int64_t off, chunk; > + > + for (off =3D offset; offset < end; offset +=3D chunk) { This is what I=E2=80=99m referring to, I think this loop should skip area= s that are clean. > + ret =3D backup_bitmap_reset_unallocated(job, off, end - of= f, &chunk); > + if (ret < 0) { > + chunk =3D job->cluster_size; > + } > + } > + } > + ret =3D 0; > + > while (start < end) { > int64_t dirty_end; > =20 > @@ -276,15 +288,6 @@ static int coroutine_fn backup_do_cow(BackupBlockJ= ob *job, > continue; /* already copied */ > } > =20 > - if (job->initializing_bitmap) { > - ret =3D backup_bitmap_reset_unallocated(job, start, &skip_= bytes); > - if (ret =3D=3D 0) { > - trace_backup_do_cow_skip_range(job, start, skip_bytes)= ; > - start +=3D skip_bytes; > - continue; > - } > - } > - > dirty_end =3D bdrv_dirty_bitmap_next_zero(job->copy_bitmap, st= art, > end - start); > if (dirty_end < 0) { Hm, you resolved that conflict differently from me. I decided the bdrv_dirty_bitmap_next_zero() call should go before the backup_bitmap_reset_unallocated() call so that we can then do a dirty_end =3D MIN(dirty_end, start + skip_bytes); because we probably don=E2=80=99t want to copy anything past what backup_bitmap_reset_unallocated() has inquired. But then again this patch eliminates the difference anyway... Max > @@ -546,7 +549,8 @@ static int coroutine_fn backup_run(Job *job, Error = **errp) > goto out; > } > =20 > - ret =3D backup_bitmap_reset_unallocated(s, offset, &count)= ; > + ret =3D backup_bitmap_reset_unallocated(s, offset, s->len = - offset, > + &count); > if (ret < 0) { > goto out; > } >=20 --g2szmPiiB0ykmyTTWHdjAI74Ls3aegkit-- --eY5UdLN4bLnK0UE2iRSemEcBU9aJbuTFJ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl1LEeEACgkQ9AfbAGHV z0DFOQf/ZqlolhoQr9bg13lKH/idiVUVUF0wdEjb1aobuX6lnaRNgLtb+SYOmk/o /PoOBG/FsUgZRBc+/prcC3SEyskIjkmhyUiKIaI16DeXGNPstDTqhSQajIlqHxi1 37BE2d/EnayLkm0GeA2bGZZhE3MLgQhHJnrk5+hvYZ0/PGCV6Njz3CmDjSIne49a qCUXycUAxtb/SnveYc+j/rO4t6g4XiK8lStM+l25EZUGxURyrcl2mwWWqjtk++nS PcE7db1EXbz8L215anOvpwU1py20bbsn+vCl4i2iZb2B+vArB19x+6xD5+gzIWSh bENyE6Pw2EcxkLE95Yiaw2BwTLFkgw== =pI3O -----END PGP SIGNATURE----- --eY5UdLN4bLnK0UE2iRSemEcBU9aJbuTFJ--