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Mon, 7 Oct 2019 14:17:39 +0000 (UTC) Received: from dresden.str.redhat.com (unknown [10.40.205.196]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B825E5EE1D; Mon, 7 Oct 2019 14:17:35 +0000 (UTC) Subject: Re: [PATCH 3/6] block/block-copy: refactor copying To: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org References: <20191003171539.12327-1-vsementsov@virtuozzo.com> <20191003171539.12327-4-vsementsov@virtuozzo.com> From: Max Reitz 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: Date: Mon, 7 Oct 2019 16:17:34 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.0 MIME-Version: 1.0 In-Reply-To: <20191003171539.12327-4-vsementsov@virtuozzo.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Y0hkN06j3Lvxs8jKc9qz1uf6YUCA7d4wP" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.48]); Mon, 07 Oct 2019 14:17:39 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 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: kwolf@redhat.com, den@openvz.org, jsnow@redhat.com, qemu-devel@nongnu.org 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) --Y0hkN06j3Lvxs8jKc9qz1uf6YUCA7d4wP Content-Type: multipart/mixed; boundary="grq8MN6miZ9EYQ8W7Jhwjsp4IKVobnKnC" --grq8MN6miZ9EYQ8W7Jhwjsp4IKVobnKnC Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 03.10.19 19:15, Vladimir Sementsov-Ogievskiy wrote: > Merge copying code into one function block_copy_do_copy, which only > calls bdrv_ io functions and don't do any synchronization (like dirty > bitmap set/reset). >=20 > Refactor block_copy() function so that it takes full decision about > size of chunk to be copied and does all the synchronization (checking > intersecting requests, set/reset dirty bitmaps). >=20 > It will help: > - introduce parallel processing of block_copy iterations: we need to > calculate chunk size, start async chunk copying and go to the next > iteration > - simplify synchronization improvement (like memory limiting in > further commit and reducing critical section (now we lock the whole > requested range, when actually we need to lock only dirty region > which we handle at the moment)) >=20 > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > block/block-copy.c | 113 ++++++++++++++++++++-------------------------= > block/trace-events | 6 +-- > 2 files changed, 53 insertions(+), 66 deletions(-) Looks good to me, just some clean-up path nit picks below. > diff --git a/block/block-copy.c b/block/block-copy.c > index 75287ce24d..cc49d2345d 100644 > --- a/block/block-copy.c > +++ b/block/block-copy.c > @@ -126,25 +126,43 @@ void block_copy_set_callbacks( > } > =20 > /* > - * Copy range to target with a bounce buffer and return the bytes copi= ed. If > - * error occurred, return a negative error number > + * block_copy_do_copy > + * > + * Do copy of cluser-aligned chunk. @end is allowed to exceed s->len o= nly to > + * cover last cluster when s->len is not aligned to clusters. > + * > + * No sync here: nor bitmap neighter intersecting requests handling, o= nly copy. > + * > + * Returns 0 on success. > */ > -static int coroutine_fn block_copy_with_bounce_buffer(BlockCopyState *= s, > - int64_t start, > - int64_t end, > - bool *error_is_r= ead) > +static int coroutine_fn block_copy_do_copy(BlockCopyState *s, > + int64_t start, int64_t end,= > + bool *error_is_read) > { > int ret; > - int nbytes; > - void *bounce_buffer =3D qemu_blockalign(s->source->bs, s->cluster_= size); > + int nbytes =3D MIN(end, s->len) - start; > + void *bounce_buffer =3D NULL; > =20 > assert(QEMU_IS_ALIGNED(start, s->cluster_size)); > - bdrv_reset_dirty_bitmap(s->copy_bitmap, start, s->cluster_size); > - nbytes =3D MIN(s->cluster_size, s->len - start); > + assert(QEMU_IS_ALIGNED(end, s->cluster_size)); > + assert(end < s->len || end =3D=3D QEMU_ALIGN_UP(s->len, s->cluster= _size)); > + > + if (s->use_copy_range) { > + ret =3D bdrv_co_copy_range(s->source, start, s->target, start,= nbytes, > + 0, s->write_flags); > + if (ret < 0) { > + trace_block_copy_copy_range_fail(s, start, ret); > + s->use_copy_range =3D false; > + } else { > + return ret; Maybe the =E2=80=9Cfail=E2=80=9D label should be called =E2=80=9Dout=E2=80= =9D and then we could go there from here. Doesn=E2=80=99t make much of a difference here (1 LoC either = way), but maybe it=E2=80=99s a bit cleaner to always use the clean-up path in t= his function (even when there=E2=80=99s nothing to clean up). *shrug* > + } > + } > + > + bounce_buffer =3D qemu_blockalign(s->source->bs, nbytes); > =20 > ret =3D bdrv_co_pread(s->source, start, nbytes, bounce_buffer, 0);= > if (ret < 0) { > - trace_block_copy_with_bounce_buffer_read_fail(s, start, ret); > + trace_block_copy_read_fail(s, start, ret); > if (error_is_read) { > *error_is_read =3D true; > } [...] > @@ -163,42 +181,12 @@ static int coroutine_fn block_copy_with_bounce_bu= ffer(BlockCopyState *s, > =20 > qemu_vfree(bounce_buffer); > =20 > - return nbytes; > + return 0; > + > fail: > qemu_vfree(bounce_buffer); > - bdrv_set_dirty_bitmap(s->copy_bitmap, start, s->cluster_size); > - return ret; > - > -} Wouldn=E2=80=99t it be simpler to drop the =E2=80=9Cqemu_vfree(bounce_buf= fer); return 0;=E2=80=9D above the fail label and just fall through? In any case: Reviewed-by: Max Reitz --grq8MN6miZ9EYQ8W7Jhwjsp4IKVobnKnC-- --Y0hkN06j3Lvxs8jKc9qz1uf6YUCA7d4wP Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl2bSP4ACgkQ9AfbAGHV z0BylQf9G0u+sKOASEl+ZCWljQ04VpOSDv7Dl5F+1LhNXP/S9UcHoDBTP7r51eUR Q98QppZRlOKYinfbbVq/XQuC69W4J5vO7TBq6EyodCdUqhPD80y3h0Zv3+8+Gzk3 masUp0TYjfj2WCjR01vDMugrd8LydxDJ0nCsyDQJKdmLpjm9tX62PX8tC3C+GL3u Y3fQ97EuqudcVSY6UOaLF4ytuPjZ4F7SQrqakrFreazoJNhwGuqLkd97EhJAwK68 If/oGDQYBfGlPFzesC2bZVJ0zvsGq5fMOp+4Z5EnjvDxeYjn6r0i8MEka/Em7fzf fwZiVLsYM64uR3dsuyL902aQIsSBew== =FhRE -----END PGP SIGNATURE----- --Y0hkN06j3Lvxs8jKc9qz1uf6YUCA7d4wP--