From mboxrd@z Thu Jan 1 00:00:00 1970 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=-11.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, 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 523A7C433DB for ; Thu, 25 Mar 2021 11:31:37 +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 A49D26023F for ; Thu, 25 Mar 2021 11:31:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A49D26023F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:44084 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lPOD9-000554-LA for qemu-devel@archiver.kernel.org; Thu, 25 Mar 2021 07:31:35 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34034) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lPOBP-0003VP-1n for qemu-devel@nongnu.org; Thu, 25 Mar 2021 07:29:47 -0400 Received: from mail-wr1-x42c.google.com ([2a00:1450:4864:20::42c]:38434) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lPOBN-0006gA-7u for qemu-devel@nongnu.org; Thu, 25 Mar 2021 07:29:46 -0400 Received: by mail-wr1-x42c.google.com with SMTP id z2so1911285wrl.5 for ; Thu, 25 Mar 2021 04:29:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=LZBPq6Bnm1jLOGOoBjLvgoRlwGIANuyQGvrFCczpsn0=; b=Ldl4cnAQ356hdAw3LcDx8JcZ24r6IEqj/zpruZsLFxfBnen0T2y+y/+m6m1we1Um+T 69n4ObDgzyTWyQwIKBZuuqNRJSTdD0yaYyVvsSkburvDAZHhHdebnP8PHkHkmjNgepek HBoVBdLb9frCk3Ti9bujqPP98w2HY8DtcAX7+a3eUYM0X4BkqPKpdV93SrxO8nlnTSmx y4oEGdRsnZXdS+IjUh4DXnab5Nei+3Df5rMBioIxJj6KvgeJltNGhbyfjEPV+OLnEM0W jdmbFSnV6s/3w0HgJebc2cleZa0Er3BoAe5R7rBiqGNkj0G1ZXRGjEiTuybxtOnG/vD3 5Ijw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :mime-version:content-transfer-encoding; bh=LZBPq6Bnm1jLOGOoBjLvgoRlwGIANuyQGvrFCczpsn0=; b=CCi8hQEur8EnRI5Tx/KXK3UwZb+Kj0A69ePPq4oYqzmWzLZpR2r1OI+Ef+p4A1rwSj tx1N5cJWoALp6NYdxhuQqLO3Zmp0l7YPn8LaGEs/yx3byg8+evDB92eHlJiLDphLCsHX 59aHz5qv8ToZ3sRTX87vgbrIMnKB0W4KhCBirIySibFcaWstQx5+0IqUcOg2+kdOuZ62 H4vLidaoczvq2bULCz4xxjDLBVJf3FEGu2xk969ortn8L3gJyn+CjFuV6OzkHlbKXMCh LMD4pyvYvD4Rz975U9CojjU78OP2yLtZUB0zmEu1R9DL35UMMCYUnEJbHd0EpBYYVtYv ghWg== X-Gm-Message-State: AOAM530+oUVuN1kSHpcpNZDeNdNxg2UQi6IYyOLaXz1CiCEUXYZNq17W doX5FI3mkT1fOVuv/zzvzr+w66M2Ddg= X-Google-Smtp-Source: ABdhPJzlqhKYUsOIKQL8kPZS2ZXupuy6pQGEgxrYuPvJHMO8UluZ2nKRd/TPQmbGrmvg9Dt7pgEWcQ== X-Received: by 2002:a5d:6b50:: with SMTP id x16mr8224392wrw.379.1616671783003; Thu, 25 Mar 2021 04:29:43 -0700 (PDT) Received: from avogadro.lan ([2001:b07:6468:f312:5e2c:eb9a:a8b6:fd3e]) by smtp.gmail.com with ESMTPSA id g11sm7220118wrw.89.2021.03.25.04.29.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Mar 2021 04:29:42 -0700 (PDT) From: Paolo Bonzini To: qemu-devel@nongnu.org Subject: [PATCH v6 0/6] coroutine rwlock downgrade fix, minor VDI changes Date: Thu, 25 Mar 2021 12:29:35 +0100 Message-Id: <20210325112941.365238-1-pbonzini@redhat.com> X-Mailer: git-send-email 2.30.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2a00:1450:4864:20::42c; envelope-from=paolo.bonzini@gmail.com; helo=mail-wr1-x42c.google.com X-Spam_score_int: -14 X-Spam_score: -1.5 X-Spam_bar: - X-Spam_report: (-1.5 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FORGED_FROMDOMAIN=0.249, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=0.25, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no 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: , Cc: david.edmondson@oracle.com, stefanha@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is a resubmit of David Edmondson's series at https://patchew.org/QEMU/20210309144015.557477-1-david.edmondson@oracle.com/. After closer analysis on IRC, the CoRwlock's attempt to ensure fairness turned out to be flawed. Therefore, this series reimplements CoRwlock without using a CoQueue. Tracking whether each queued coroutine is a reader/writer makes it possible to never wake a writer when only readers should be allowed and vice versa. v2->v3: new CoRwlock implementation v3->v4: fix upgrade and add a test for that, too v4->v5: typo v5->v6: improve documentation, do not read lock->owners where neither wrlock nor lock->mutex exclude concurrent writes David Edmondson (4): block/vdi: When writing new bmap entry fails, don't leak the buffer block/vdi: Don't assume that blocks are larger than VdiHeader coroutine-lock: Store the coroutine in the CoWaitRecord only once test-coroutine: Add rwlock downgrade test Paolo Bonzini (2): coroutine-lock: Reimplement CoRwlock to fix downgrade bug test-coroutine: Add rwlock upgrade test block/vdi.c | 11 ++- include/qemu/coroutine.h | 17 ++-- tests/unit/test-coroutine.c | 161 ++++++++++++++++++++++++++++++++++++ util/qemu-coroutine-lock.c | 149 +++++++++++++++++++++------------ 4 files changed, 274 insertions(+), 64 deletions(-) -- 2.29.2