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Thu, 20 Feb 2020 09:10:54 +0000 (UTC) Received: from dresden.str.redhat.com (unknown [10.36.118.38]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C3A2619C4F; Thu, 20 Feb 2020 09:10:52 +0000 (UTC) Subject: Re: [PATCH v2 6/7] block/block-copy: reduce intersecting request lock To: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org References: <20191127180840.11937-1-vsementsov@virtuozzo.com> <20191127180840.11937-7-vsementsov@virtuozzo.com> <1ae71183-4732-fbe6-62d5-58252f01d2d6@redhat.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: <76ce73f2-fef9-27e6-4552-29e846fa313f@redhat.com> Date: Thu, 20 Feb 2020 10:10:50 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="t7U1zxQuxPWBtRnQpEvtfpd4683k5WZHB" X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 205.139.110.61 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) --t7U1zxQuxPWBtRnQpEvtfpd4683k5WZHB Content-Type: multipart/mixed; boundary="hmQlgePSpul5e8Q43gPgFCEWwoXbOLcd0" --hmQlgePSpul5e8Q43gPgFCEWwoXbOLcd0 Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 20.02.20 08:21, Vladimir Sementsov-Ogievskiy wrote: > 17.02.2020 16:38, Max Reitz wrote: >> On 27.11.19 19:08, Vladimir Sementsov-Ogievskiy wrote: [...] >>> +=A0=A0=A0=A0=A0=A0=A0 if (!block_copy_wait_one(s, start, bytes)) { >>> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 /* No dirty bits and nothing to wait= : the whole request >>> is done */ >> >> Wouldn=92t it make more sense to keep block_copy_wait_one() a loop (i.e.= , >> keep it as block_copy_wait_inflight_reqs()) that returns whether it >> waited or not?=A0 Because I suppose if we had to wait for anything, we >> might as well wait for everything in the range. >=20 > No, we don't need to wait all. If some dirty bits appeared we may start > copy them > immediately, not waiting for others. OK, especially considering you=92re aiming for block_copy(0, disk_size) eventually. Max --hmQlgePSpul5e8Q43gPgFCEWwoXbOLcd0-- --t7U1zxQuxPWBtRnQpEvtfpd4683k5WZHB Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl5OTRoACgkQ9AfbAGHV z0CTHwgAnqzetZhrJMis3HOJIvyMmrb7pm0Yp6dUrnFCuSyFHveOH6Gqnf7IPeuV Y+YpHJS4ZxOXMiIO0cqocZlsXjgbKgtBdzBoYI+3MyTQXcvqBOojFtylhu7F2iiF MP3sOD1krQXJ3bDGwPwwFQXmPGiwejmXy9GGO10IZKaeHF89lQsw87SDzr8mYdmN aGqgzFvUnKw1mQ00u5fY09l1ATFrHB2h1d9aCW+m3MdXcvahN50PY7mbxgsHv489 tfReB7gP92zzg/UFX2DV6j4hy8qOxPRy+FKmkMKqgDsqQWEZ1PIe3IVJJX+UC6LF 2Z/3SfmisH5INgGHB9AO62eW0lwLzg== =KvSY -----END PGP SIGNATURE----- --t7U1zxQuxPWBtRnQpEvtfpd4683k5WZHB--