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Thu, 1 Aug 2019 11:38:02 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-204-187.brq.redhat.com [10.40.204.187]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A5B8560A9F; Thu, 1 Aug 2019 11:37:57 +0000 (UTC) To: Vladimir Sementsov-Ogievskiy , John Snow , "qemu-block@nongnu.org" References: <20190730163251.755248-1-vsementsov@virtuozzo.com> <20190730163251.755248-4-vsementsov@virtuozzo.com> <2b034619-ab55-a5f1-a1f4-ea14c4c5c18c@redhat.com> <12efde81-7a17-56c0-e50d-080574faa9f9@redhat.com> <29be5652-33d3-216c-a377-ed7d76c23c1b@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: Date: Thu, 1 Aug 2019 13:37:55 +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: <29be5652-33d3-216c-a377-ed7d76c23c1b@virtuozzo.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="q6RyEYM2ChhaUH8HFtFGTK6Fw0HG9nWoW" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Thu, 01 Aug 2019 11:38:02 +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 3/3] block/backup: refactor write_flags 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" , Denis Lunev , "armbru@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) --q6RyEYM2ChhaUH8HFtFGTK6Fw0HG9nWoW Content-Type: multipart/mixed; boundary="R9N77uutsdIoxkoNdtrhrNwj4x8pZhNb5"; protected-headers="v1" From: Max Reitz To: Vladimir Sementsov-Ogievskiy , John Snow , "qemu-block@nongnu.org" Cc: "kwolf@redhat.com" , "armbru@redhat.com" , "qemu-devel@nongnu.org" , Denis Lunev Message-ID: Subject: Re: [Qemu-devel] [PATCH 3/3] block/backup: refactor write_flags References: <20190730163251.755248-1-vsementsov@virtuozzo.com> <20190730163251.755248-4-vsementsov@virtuozzo.com> <2b034619-ab55-a5f1-a1f4-ea14c4c5c18c@redhat.com> <12efde81-7a17-56c0-e50d-080574faa9f9@redhat.com> <29be5652-33d3-216c-a377-ed7d76c23c1b@virtuozzo.com> In-Reply-To: <29be5652-33d3-216c-a377-ed7d76c23c1b@virtuozzo.com> --R9N77uutsdIoxkoNdtrhrNwj4x8pZhNb5 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 01.08.19 13:32, Vladimir Sementsov-Ogievskiy wrote: > 01.08.2019 14:28, Max Reitz wrote: >> On 31.07.19 18:01, Vladimir Sementsov-Ogievskiy wrote: >>> 30.07.2019 21:28, John Snow wrote: >>>> >>>> >>>> On 7/30/19 12:32 PM, Vladimir Sementsov-Ogievskiy wrote: >>>>> write flags are constant, let's store it in BackupBlockJob instead = of >>>>> recalculating. It also makes two boolean fields to be unused, so, >>>>> drop them. >>>>> >>>>> Signed-off-by: Vladimir Sementsov-Ogievskiy >>>>> --- >>>>> block/backup.c | 24 ++++++++++++------------ >>>>> 1 file changed, 12 insertions(+), 12 deletions(-) >>>>> >>>>> diff --git a/block/backup.c b/block/backup.c >>>>> index c5f941101a..4651649e9d 100644 >>>>> --- a/block/backup.c >>>>> +++ b/block/backup.c >>>>> @@ -47,7 +47,6 @@ typedef struct BackupBlockJob { >>>>> uint64_t len; >>>>> uint64_t bytes_read; >>>>> int64_t cluster_size; >>>>> - bool compress; >>>>> NotifierWithReturn before_write; >>>>> QLIST_HEAD(, CowRequest) inflight_reqs; >>>>> =20 >>>>> @@ -55,7 +54,7 @@ typedef struct BackupBlockJob { >>>>> bool use_copy_range; >>>>> int64_t copy_range_size; >>>>> =20 >>>>> - bool serialize_target_writes; >>>>> + BdrvRequestFlags write_flags; >>>>> } BackupBlockJob; >>>>> =20 >>>>> static const BlockJobDriver backup_job_driver; >>>>> @@ -110,10 +109,6 @@ static int coroutine_fn backup_cow_with_bounce= _buffer(BackupBlockJob *job, >>>>> BlockBackend *blk =3D job->common.blk; >>>>> int nbytes; >>>>> int read_flags =3D is_write_notifier ? BDRV_REQ_NO_SERIALISI= NG : 0; >>>>> - int write_flags =3D >>>>> - (job->serialize_target_writes ? BDRV_REQ_SERIALISING := 0) | >>>>> - (job->compress ? BDRV_REQ_WRITE_COMPRESSED : 0); >>>>> - >>>>> =20 >>>>> assert(QEMU_IS_ALIGNED(start, job->cluster_size)); >>>>> hbitmap_reset(job->copy_bitmap, start, job->cluster_size); >>>>> @@ -132,7 +127,7 @@ static int coroutine_fn backup_cow_with_bounce_= buffer(BackupBlockJob *job, >>>>> } >>>>> =20 >>>>> ret =3D blk_co_pwrite(job->target, start, nbytes, *bounce_bu= ffer, >>>>> - write_flags); >>>>> + job->write_flags); >>>>> if (ret < 0) { >>>>> trace_backup_do_cow_write_fail(job, start, ret); >>>>> if (error_is_read) { >>>>> @@ -160,7 +155,6 @@ static int coroutine_fn backup_cow_with_offload= (BackupBlockJob *job, >>>>> BlockBackend *blk =3D job->common.blk; >>>>> int nbytes; >>>>> int read_flags =3D is_write_notifier ? BDRV_REQ_NO_SERIALISI= NG : 0; >>>>> - int write_flags =3D job->serialize_target_writes ? BDRV_REQ_SE= RIALISING : 0; >>>>> =20 >>>>> assert(QEMU_IS_ALIGNED(job->copy_range_size, job->cluster_si= ze)); >>>>> assert(QEMU_IS_ALIGNED(start, job->cluster_size)); >>>>> @@ -168,7 +162,7 @@ static int coroutine_fn backup_cow_with_offload= (BackupBlockJob *job, >>>>> nr_clusters =3D DIV_ROUND_UP(nbytes, job->cluster_size); >>>>> hbitmap_reset(job->copy_bitmap, start, job->cluster_size * n= r_clusters); >>>>> ret =3D blk_co_copy_range(blk, start, job->target, start, nb= ytes, >>>>> - read_flags, write_flags); >>>>> + read_flags, job->write_flags); >>>>> if (ret < 0) { >>>>> trace_backup_do_cow_copy_range_fail(job, start, ret); >>>>> hbitmap_set(job->copy_bitmap, start, job->cluster_size *= nr_clusters); >>>>> @@ -638,10 +632,16 @@ BlockJob *backup_job_create(const char *job_i= d, BlockDriverState *bs, >>>>> job->sync_mode =3D sync_mode; >>>>> job->sync_bitmap =3D sync_mode =3D=3D MIRROR_SYNC_MODE_INCRE= MENTAL ? >>>>> sync_bitmap : NULL; >>>>> - job->compress =3D compress; >>>>> =20 >>>>> - /* Detect image-fleecing (and similar) schemes */ >>>>> - job->serialize_target_writes =3D bdrv_chain_contains(target, b= s); >>>>> + /* >>>>> + * Set write flags: >>>>> + * 1. Detect image-fleecing (and similar) schemes >>>>> + * 2. Handle compression >>>>> + */ >>>>> + job->write_flags =3D >>>>> + (bdrv_chain_contains(target, bs) ? BDRV_REQ_SERIALISIN= G : 0) | >>>>> + (compress ? BDRV_REQ_WRITE_COMPRESSED : 0); >>>>> + >>>>> job->cluster_size =3D cluster_size; >>>>> job->copy_bitmap =3D copy_bitmap; >>>>> copy_bitmap =3D NULL; >>>>> >>>> >>>> What happens if you did pass BDRV_REQ_WRITE_COMPRESSED to >>>> blk_co_copy_range? Is that rejected somewhere in the stack? >>> >>> >>> Hmm, I'm afraid that it will be silently ignored. >>> >>> And I have one question related to copy offload too. >>> >>> Do we really need to handle max_transfer in backup code for copy offl= oad? >>> Is max_transfer related to it really? >>> >>> Anyway, bl.max_transfer should be handled in generic copy_range code = in block/io.c >>> (if it should at all), I'm going to fix it, but may be, I can just dr= op this limitation >>> from backup? >> >> On a quick glance, it doesn=E2=80=99t look like a limitation to me but= actually >> like the opposite. backup_cow_with_bounce_buffer() only copies up to >> cluster_size, whereas backup_cow_with_offload() will copy up to the >> maximum transfer size permitted by both source and target for copy >> offloading. >> >=20 > I mean, why not to just copy the whole chunk comes in notifier and don'= t care about > max_transfer? Backup loop copies cluster by cluster anyway, so only not= ifier may copy > larger chunk. One thing that comes to mind is the hbitmap_get() check in backup_do_cow(). You don=E2=80=99t want to copy everything just because = the first cluster needs to be copied. Max --R9N77uutsdIoxkoNdtrhrNwj4x8pZhNb5-- --q6RyEYM2ChhaUH8HFtFGTK6Fw0HG9nWoW Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl1CzxQACgkQ9AfbAGHV z0DOdQgAiXT5+42goawYJh8YlwFH9fJuIjDw6qJPYp06dOomaBUdfdKWYq5v+9ZB S2pJUFBS4ahX2o+HyyYlgkqzIrOgsw4hWj0/ELiQ2UnZp1luLCTurpmGT5QBBFMT 9M9Z857BwJmZAtenkUon43x3sH6r1w6TON4tFjxedPnYwQJ73JI+NyDhd+rkqtoa Qi8Qzo+m2Ty8kCKKFRrHvPtWgP1Yejblhhac8bco0Yg0ozFIgK9my9VetfpbkH3M jw1KG5ufQWQUEShpKtAKCP/JQGaBv3iGNTpnLGl4fJvxzlX7yuGUryvkrfJ2Xxjz S9leGDSveKFU1j1k/IJ6nXk9Dy63Xw== =/NAr -----END PGP SIGNATURE----- --q6RyEYM2ChhaUH8HFtFGTK6Fw0HG9nWoW--