From patchwork Mon Sep 28 12:59:58 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zhijian Li \(Fujitsu\)\" via" X-Patchwork-Id: 272586 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5FD61C2D0A8 for ; Mon, 28 Sep 2020 13:48:20 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id E0D1F208FE for ; Mon, 28 Sep 2020 13:48:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E0D1F208FE Authentication-Results: mail.kernel.org; dmarc=pass (p=none dis=none) header.from=nongnu.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:34542 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kMtVo-0004vr-Lw for qemu-devel@archiver.kernel.org; Mon, 28 Sep 2020 09:48:16 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56094) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kMsnv-0006F0-P3; Mon, 28 Sep 2020 09:03:00 -0400 Received: from relay.sw.ru ([185.231.240.75]:59132 helo=relay3.sw.ru) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kMsns-0000bG-CG; Mon, 28 Sep 2020 09:02:55 -0400 Received: from [172.16.25.136] (helo=localhost.sw.ru) by relay3.sw.ru with esmtp (Exim 4.94) (envelope-from ) id 1kMsnK-001tba-GQ; Mon, 28 Sep 2020 16:02:18 +0300 To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, kwolf@redhat.com, mreitz@redhat.com, stefanha@redhat.com, fam@euphon.net, jsnow@redhat.com, armbru@redhat.com, eblake@redhat.com, den@openvz.org, vsementsov@virtuozzo.com, andrey.shinkevich@virtuozzo.com Subject: [PATCH v9 6/9] copy-on-read: skip non-guest reads if no copy needed Date: Mon, 28 Sep 2020 15:59:58 +0300 Message-Id: <1601298001-774096-7-git-send-email-andrey.shinkevich@virtuozzo.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1601298001-774096-1-git-send-email-andrey.shinkevich@virtuozzo.com> References: <1601298001-774096-1-git-send-email-andrey.shinkevich@virtuozzo.com> Received-SPF: pass client-ip=185.231.240.75; envelope-from=andrey.shinkevich@virtuozzo.com; helo=relay3.sw.ru X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/28 09:00:28 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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=ham autolearn_force=no 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Reply-to: Andrey Shinkevich X-Patchwork-Original-From: Andrey Shinkevich via From: "Zhijian Li \(Fujitsu\)\" via" If the flag BDRV_REQ_PREFETCH was set, pass it further to the COR-driver to skip unneeded reading. It can be taken into account for the COR-algorithms optimization. That check is being made during the block stream job by the moment. Signed-off-by: Andrey Shinkevich --- block/copy-on-read.c | 14 ++++++++++---- block/io.c | 2 +- 2 files changed, 11 insertions(+), 5 deletions(-) diff --git a/block/copy-on-read.c b/block/copy-on-read.c index f53f7e0..5389dca 100644 --- a/block/copy-on-read.c +++ b/block/copy-on-read.c @@ -145,10 +145,16 @@ static int coroutine_fn cor_co_preadv_part(BlockDriverState *bs, } } - ret = bdrv_co_preadv_part(bs->file, offset, n, qiov, qiov_offset, - local_flags); - if (ret < 0) { - return ret; + if ((flags & BDRV_REQ_PREFETCH) & + !(local_flags & BDRV_REQ_COPY_ON_READ)) { + /* Skip non-guest reads if no copy needed */ + } else { + + ret = bdrv_co_preadv_part(bs->file, offset, n, qiov, qiov_offset, + local_flags); + if (ret < 0) { + return ret; + } } offset += n; diff --git a/block/io.c b/block/io.c index 11df188..62b75a5 100644 --- a/block/io.c +++ b/block/io.c @@ -1388,7 +1388,7 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child, qemu_iovec_init_buf(&local_qiov, bounce_buffer, pnum); ret = bdrv_driver_preadv(bs, cluster_offset, pnum, - &local_qiov, 0, 0); + &local_qiov, 0, flags & BDRV_REQ_PREFETCH); if (ret < 0) { goto err; }