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Lunev" , qemu-block@nongnu.org, qemu-devel@nongnu.org References: <20200611171143.21589-1-den@openvz.org> <20200611171143.21589-4-den@openvz.org> From: Vladimir Sementsov-Ogievskiy Message-ID: Date: Mon, 15 Jun 2020 10:56:40 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.1 In-Reply-To: <20200611171143.21589-4-den@openvz.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: AM4PR05CA0022.eurprd05.prod.outlook.com (2603:10a6:205::35) To AM7PR08MB5494.eurprd08.prod.outlook.com (2603:10a6:20b:dc::15) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [192.168.100.2] (185.215.60.182) by AM4PR05CA0022.eurprd05.prod.outlook.com (2603:10a6:205::35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3088.19 via Frontend Transport; Mon, 15 Jun 2020 07:56:41 +0000 X-Originating-IP: [185.215.60.182] X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: f80e9ebd-63ef-4888-89d5-08d81101a46f X-MS-TrafficTypeDiagnostic: AM7PR08MB5333: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:9508; X-Forefront-PRVS: 04359FAD81 X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: Erq7RzESZgGD7GMw2LH+/ON4ttQU9vL8OZg+0ATuQfb14F6buXmWdYC5/pfgikZNBmDQxEd2BDd5i+Ggqwi37nODMFkVJDsp3VsC9EhFII+i00ZYTXK0K7JiRRaCf1eYI9TJ/AIx8YrWl1bryWX623/o4NyXQk1YEtaB2usq7hFk28D0Z6gpYv3O2DUNRLBCAGQ41DG5EUqQtVn1/PRm+tzgMR4uAnvgUf348u+/m5Cws6mww+0S9M27qhA+lgditAR56Uhjs80W/ONUCDmEP0162eadsYsS1ShDzgGw1jo9VYNwf6GL7xp/55BVKfPdRbrRQOiJCU3pq/5iYhtKIHLn+WiRj/Cct5Qc7OtIZZssDR59cqSxROooZgO3Ka3A X-Forefront-Antispam-Report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:AM7PR08MB5494.eurprd08.prod.outlook.com; PTR:; CAT:NONE; SFTY:; SFS:(4636009)(366004)(39830400003)(136003)(376002)(396003)(346002)(36756003)(478600001)(52116002)(956004)(31686004)(26005)(16526019)(186003)(16576012)(8676002)(107886003)(54906003)(316002)(2616005)(2906002)(8936002)(4326008)(5660300002)(83380400001)(6486002)(66476007)(66556008)(86362001)(31696002)(66946007)(43740500002); DIR:OUT; SFP:1102; X-MS-Exchange-AntiSpam-MessageData: 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 X-OriginatorOrg: virtuozzo.com X-MS-Exchange-CrossTenant-Network-Message-Id: f80e9ebd-63ef-4888-89d5-08d81101a46f X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Jun 2020 07:56:42.5632 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 0bc7f26d-0264-416e-a6fc-8352af79c58f X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: YdQ3UTTnnywOS2p7T7OsohtOLFNT2eU/AfE/fJnN54lUHKIjo32BysQfR3s04UjrKMT8P4+p5zvqq65QTj7ligxEt0AzB3I2wjuWwnh48T4= X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM7PR08MB5333 Received-SPF: pass client-ip=40.107.14.135; envelope-from=vsementsov@virtuozzo.com; helo=EUR01-VE1-obe.outbound.protection.outlook.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/15 03:56:43 X-ACL-Warn: Detected OS = Windows NT kernel [generic] [fuzzy] X-Spam_score_int: -37 X-Spam_score: -3.8 X-Spam_bar: --- X-Spam_report: (-3.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MSGID_FROM_MTA_HEADER=0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action 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: Kevin Wolf , Fam Zheng , Juan Quintela , "Dr. David Alan Gilbert" , Max Reitz , Denis Plotnikov , Stefan Hajnoczi Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 11.06.2020 20:11, Denis V. Lunev wrote: > Right now bdrv_fclose() is just calling bdrv_flush(). > > The problem is that migration code is working inefficently from black > layer terms and are frequently called for very small pieces of not > properly aligned data. Block layer is capable to work this way, but > this is very slow. > > This patch is a preparation for the introduction of the intermediate > buffer at block driver state. It would be beneficial to separate > conventional bdrv_flush() from closing QEMU file from migration code. > > The patch also forces bdrv_flush_vmstate() operation inside > synchronous blk_save_vmstate() operation. This helper is used from > qemu-io only. > > Signed-off-by: Denis V. Lunev > CC: Kevin Wolf > CC: Max Reitz > CC: Stefan Hajnoczi > CC: Fam Zheng > CC: Juan Quintela > CC: "Dr. David Alan Gilbert" > CC: Vladimir Sementsov-Ogievskiy > CC: Denis Plotnikov > --- > block/block-backend.c | 6 +++++- > block/io.c | 39 +++++++++++++++++++++++++++++++++++++++ > include/block/block.h | 1 + > migration/savevm.c | 3 +++ > 4 files changed, 48 insertions(+), 1 deletion(-) > > diff --git a/block/block-backend.c b/block/block-backend.c > index 9342a475cb..2107ace699 100644 > --- a/block/block-backend.c > +++ b/block/block-backend.c > @@ -2177,7 +2177,7 @@ int blk_truncate(BlockBackend *blk, int64_t offset, bool exact, > int blk_save_vmstate(BlockBackend *blk, const uint8_t *buf, > int64_t pos, int size) > { > - int ret; > + int ret, ret2; > > if (!blk_is_available(blk)) { > return -ENOMEDIUM; > @@ -2187,6 +2187,10 @@ int blk_save_vmstate(BlockBackend *blk, const uint8_t *buf, > if (ret < 0) { > return ret; > } > + ret2 = bdrv_flush_vmstate(blk_bs(blk)); > + if (ret2 < 0) { > + return ret; > + } > > if (ret == size && !blk->enable_write_cache) { > ret = bdrv_flush(blk_bs(blk)); > diff --git a/block/io.c b/block/io.c > index 121ce17a49..fbf352f39d 100644 > --- a/block/io.c > +++ b/block/io.c > @@ -2725,6 +2725,45 @@ int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos) > return bdrv_rw_vmstate(bs, qiov, pos, true); > } > > + > +typedef struct FlushVMStateCo { > + BlockDriverState *bs; > + int ret; > +} FlushVMStateCo; > + > +static int coroutine_fn bdrv_co_flush_vmstate(BlockDriverState *bs) > +{ > + return 0; > +} > + > +static void coroutine_fn bdrv_flush_vmstate_co_entry(void *opaque) > +{ > + FlushVMStateCo *rwco = opaque; > + > + rwco->ret = bdrv_co_flush_vmstate(rwco->bs); > + aio_wait_kick(); > +} > + > +int bdrv_flush_vmstate(BlockDriverState *bs) > +{ > + Coroutine *co; > + FlushVMStateCo flush_co = { > + .bs = bs, > + .ret = NOT_DONE, > + }; > + > + if (qemu_in_coroutine()) { > + /* Fast-path if already in coroutine context */ > + bdrv_flush_vmstate_co_entry(&flush_co); > + } else { > + co = qemu_coroutine_create(bdrv_flush_vmstate_co_entry, &flush_co); > + bdrv_coroutine_enter(bs, co); > + BDRV_POLL_WHILE(bs, flush_co.ret == NOT_DONE); > + } > + > + return flush_co.ret; > +} In block/io.c, since 7d2410cea154bf, these coroutine wrappers are using bdrv_run_co() instead. I hope, it's an intermediate state, and my series with auto-generated wrappers will be applied, still, now we should use bdrv_run_co()-based approach for consistency. Otherwise, patch looks OK for me, just add a new interface, doing nothing for now. Still, would be good to add a comment in block.h, that bdrv_flush_vmsate is needed after bdrv_save_vmstate. > + > /**************************************************************/ > /* async I/Os */ > > diff --git a/include/block/block.h b/include/block/block.h > index 25e299605e..024525b87d 100644 > --- a/include/block/block.h > +++ b/include/block/block.h > @@ -572,6 +572,7 @@ int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf, > > int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf, > int64_t pos, int size); > +int bdrv_flush_vmstate(BlockDriverState *bs); > > void bdrv_img_create(const char *filename, const char *fmt, > const char *base_filename, const char *base_fmt, > diff --git a/migration/savevm.c b/migration/savevm.c > index 0ff5bb40ed..9698c909d7 100644 > --- a/migration/savevm.c > +++ b/migration/savevm.c > @@ -150,6 +150,9 @@ static ssize_t block_get_buffer(void *opaque, uint8_t *buf, int64_t pos, > > static int bdrv_fclose(void *opaque, Error **errp) > { > + int err = bdrv_flush_vmstate(opaque); > + if (err < 0) > + return err; > return bdrv_flush(opaque); > } > > -- Best regards, Vladimir