From patchwork Mon Oct 12 17:43:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gonglei \(Arei\)\" via" X-Patchwork-Id: 303062 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, 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 2A3A0C433E7 for ; Mon, 12 Oct 2020 17:53:13 +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 BF28C2074F for ; Mon, 12 Oct 2020 17:53:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BF28C2074F 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]:49020 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kS20V-0000PH-TM for qemu-devel@archiver.kernel.org; Mon, 12 Oct 2020 13:53:11 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59858) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kS1yu-0006JI-D3; Mon, 12 Oct 2020 13:51:32 -0400 Received: from relay.sw.ru ([185.231.240.75]:34398 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 1kS1yq-00086o-5t; Mon, 12 Oct 2020 13:51:32 -0400 Received: from [172.16.25.136] (helo=localhost.sw.ru) by relay3.sw.ru with esmtp (Exim 4.94) (envelope-from ) id 1kS1xu-0047iC-3A; Mon, 12 Oct 2020 20:50:30 +0300 To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, kwolf@redhat.com, mreitz@redhat.com, fam@euphon.net, stefanha@redhat.com, armbru@redhat.com, jsnow@redhat.com, libvir-list@redhat.com, eblake@redhat.com, den@openvz.org, vsementsov@virtuozzo.com, andrey.shinkevich@virtuozzo.com Subject: [PATCH v11 09/13] copy-on-read: skip non-guest reads if no copy needed Date: Mon, 12 Oct 2020 20:43:21 +0300 Message-Id: <1602524605-481160-10-git-send-email-andrey.shinkevich@virtuozzo.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1602524605-481160-1-git-send-email-andrey.shinkevich@virtuozzo.com> References: <1602524605-481160-1-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 = 2020/10/12 13:44:17 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: "Gonglei \(Arei\)\" 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 | 13 +++++++++---- block/io.c | 3 ++- 2 files changed, 11 insertions(+), 5 deletions(-) diff --git a/block/copy-on-read.c b/block/copy-on-read.c index b136895..278a11a 100644 --- a/block/copy-on-read.c +++ b/block/copy-on-read.c @@ -148,10 +148,15 @@ 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..bff1808 100644 --- a/block/io.c +++ b/block/io.c @@ -1512,7 +1512,8 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child, max_bytes = ROUND_UP(MAX(0, total_bytes - offset), align); if (bytes <= max_bytes && bytes <= max_transfer) { - ret = bdrv_driver_preadv(bs, offset, bytes, qiov, qiov_offset, 0); + ret = bdrv_driver_preadv(bs, offset, bytes, qiov, qiov_offset, + flags & bs->supported_read_flags); goto out; }