From patchwork Thu Jun 11 17:11:42 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Denis V. Lunev" X-Patchwork-Id: 1307663 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=openvz.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 49jVqB4HGkz9sR4 for ; Fri, 12 Jun 2020 03:15:18 +1000 (AEST) Received: from localhost ([::1]:42702 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jjQnL-0002ni-98 for incoming@patchwork.ozlabs.org; Thu, 11 Jun 2020 13:15:15 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34044) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jjQk8-0005XS-2t; Thu, 11 Jun 2020 13:11:56 -0400 Received: from relay.sw.ru ([185.231.240.75]:35188 helo=relay3.sw.ru) by eggs.gnu.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jjQk2-0000qi-OE; Thu, 11 Jun 2020 13:11:55 -0400 Received: from [192.168.15.81] (helo=iris.sw.ru) by relay3.sw.ru with esmtp (Exim 4.93) (envelope-from ) id 1jjQjt-0000BN-0n; Thu, 11 Jun 2020 20:11:41 +0300 From: "Denis V. Lunev" To: qemu-block@nongnu.org, qemu-devel@nongnu.org Subject: [PATCH 3/4] block, migration: add bdrv_flush_vmstate helper Date: Thu, 11 Jun 2020 20:11:42 +0300 Message-Id: <20200611171143.21589-4-den@openvz.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200611171143.21589-1-den@openvz.org> References: <20200611171143.21589-1-den@openvz.org> Received-SPF: pass client-ip=185.231.240.75; envelope-from=den@openvz.org; helo=relay3.sw.ru X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/11 13:11:47 X-ACL-Warn: Detected OS = Linux 3.11 and newer X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-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 , Vladimir Sementsov-Ogievskiy , Juan Quintela , "Dr. David Alan Gilbert" , Max Reitz , Denis Plotnikov , Stefan Hajnoczi , "Denis V. Lunev" Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" 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; +} + /**************************************************************/ /* 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); }