From patchwork Wed Jul 31 11:27:17 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Wanpeng Li X-Patchwork-Id: 11067529 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5278F13AC for ; Wed, 31 Jul 2019 11:27:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3F40D205FC for ; Wed, 31 Jul 2019 11:27:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 33761288F4; Wed, 31 Jul 2019 11:27:30 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 73C83288EF for ; Wed, 31 Jul 2019 11:27:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387393AbfGaL12 (ORCPT ); Wed, 31 Jul 2019 07:27:28 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:36688 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725793AbfGaL1Z (ORCPT ); Wed, 31 Jul 2019 07:27:25 -0400 Received: by mail-pl1-f196.google.com with SMTP id k8so30376917plt.3; Wed, 31 Jul 2019 04:27:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=VHS57PmtuwPLtfBLBbltEv6DFT+0iXK6WiNzQSWrzrE=; b=dSzE4VGKLVc5cptEp5NMZBvonc0E/Mbzeb3v3kZ2sxvS3MocB+Ey4AdqyrtDCd6y9v DCf8ngnHUtuo4l20ghiUhdYu6+Q/lyQ8YQWECVv7FndGXX5UKvoZVCitKN+DrOyJQWm7 hgoAjRHZSDUtBTLnwIHv1IYkMXQylL7hCoaD0lRfZK7+eMPyoHp8kmoPJqKu0aVLbkCs /NrFg0TZLA5QR8NH12QCUVHuPdD+N3VDuDmGkAuwmA1WXBFBY/tacPzvhs0eoT2+l4I8 1YsCb9omqhQgf5Hp95OJNL2jHAtRHp6lVTj/EndYIFZ8Fle7RoKtMaVvt1Ky2kxVKzAS +eug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=VHS57PmtuwPLtfBLBbltEv6DFT+0iXK6WiNzQSWrzrE=; b=iEWWK25ljgyrrUkgef5PlzvgB8xX+Mur5wrq0dpoHxWY9Xtd0n0ZqqnAFzPvWVES71 ByYxRhfRftT0ZjM76RSneEfPVGPk3rMczt2cABuB6lYYO/EgsFhjK0viv1scMmmRdnBX Nb1BDZ1KiNuzTvu3F1+dQOp6BcoTW7W7r5lFfQS0D2bOdR+vvYnXHfs9/H8LGwb86x6/ DUT+zHU5dthM2nGCdXaoRi343MRywIIhD/nMBq1y2ZQ9aBZGY8egv2EqpHtvx8XAoFnZ fzKZVlokyGP5p0pjBN8F6QGnUc7ribH/2JaYCgTzXHBRgcRCCOVFkWVD/KKwFHNbOACM r3vw== X-Gm-Message-State: APjAAAVp6rN/3ATY58vUtSMnQww+pBNVqXhbNU9iaV6P4N/WbUly5rtQ dZI5VTkisq+du019wif7fFgBhMj2Y8Y= X-Google-Smtp-Source: APXvYqy2Umcofp2a7ba/gLc41pb58cmWuK120xoCrZgYeHsxJpEp44GERukISjQ4a835VZZtogc5YQ== X-Received: by 2002:a17:902:ba8b:: with SMTP id k11mr119794439pls.107.1564572444762; Wed, 31 Jul 2019 04:27:24 -0700 (PDT) Received: from localhost.localdomain ([203.205.141.123]) by smtp.googlemail.com with ESMTPSA id e3sm1211441pgm.64.2019.07.31.04.27.23 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 31 Jul 2019 04:27:24 -0700 (PDT) From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= Subject: [PATCH 2/3] KVM: Check preempted_in_kernel for involuntary preemption Date: Wed, 31 Jul 2019 19:27:17 +0800 Message-Id: <1564572438-15518-2-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1564572438-15518-1-git-send-email-wanpengli@tencent.com> References: <1564572438-15518-1-git-send-email-wanpengli@tencent.com> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Wanpeng Li preempted_in_kernel is updated in preempt_notifier when involuntary preemption ocurrs, it can be stale when the voluntarily preempted vCPUs are taken into account by kvm_vcpu_on_spin() loop. This patch lets it just check preempted_in_kernel for involuntary preemption. Cc: Paolo Bonzini Cc: Radim Krčmář Signed-off-by: Wanpeng Li --- virt/kvm/kvm_main.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 887f3b0..ed061d8 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2508,7 +2508,8 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode) continue; if (swait_active(&vcpu->wq) && !kvm_arch_vcpu_runnable(vcpu)) continue; - if (yield_to_kernel_mode && !kvm_arch_vcpu_in_kernel(vcpu)) + if (READ_ONCE(vcpu->preempted) && yield_to_kernel_mode && + !kvm_arch_vcpu_in_kernel(vcpu)) continue; if (!kvm_vcpu_eligible_for_directed_yield(vcpu)) continue; @@ -4205,7 +4206,7 @@ static void kvm_sched_in(struct preempt_notifier *pn, int cpu) { struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn); - vcpu->preempted = false; + WRITE_ONCE(vcpu->preempted, false); WRITE_ONCE(vcpu->ready, false); kvm_arch_sched_in(vcpu, cpu); @@ -4219,7 +4220,7 @@ static void kvm_sched_out(struct preempt_notifier *pn, struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn); if (current->state == TASK_RUNNING) { - vcpu->preempted = true; + WRITE_ONCE(vcpu->preempted, true); WRITE_ONCE(vcpu->ready, true); } kvm_arch_vcpu_put(vcpu);