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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 D76BCC433FF for ; Mon, 5 Aug 2019 02:03:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B0CF020B1F for ; Mon, 5 Aug 2019 02:03:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="JRkjiLqh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727058AbfHECDk (ORCPT ); Sun, 4 Aug 2019 22:03:40 -0400 Received: from mail-pg1-f193.google.com ([209.85.215.193]:45417 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727023AbfHECDh (ORCPT ); Sun, 4 Aug 2019 22:03:37 -0400 Received: by mail-pg1-f193.google.com with SMTP id o13so38824266pgp.12; Sun, 04 Aug 2019 19:03:36 -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=8vRU7XOXMncH2HX3CBvpyWbhKeVRVshARm7btXYP42w=; b=JRkjiLqhPiQzvIKEiCqljsdkL9L0PLKJGD0M8FGiSEQyGD+ayKEZ1oT7QXiCZFYHee 11YGuCpYCC6khFTJMikwh8WVdxpDp8RPH3UCmQX5RNukpM62vOyZS/JlrSYBauHjkbI4 ThhsMYl3X2EeTzmjEVV1jbSEz/RGq1kvDR3IcbnbmhmzBYr4MlWfX8lMILYtL3urNZ6v 5T0IEg7vk3JVIckFDPvX1DR1i/ngxbrIKITnakd7yN0ctRDNZ/UXgiUaTgqQ0KemY0sI s/UgfztHXULBduVkloiO3K0ih2YFU/b8D8hrcWR9ZJdxdJJedNKudUKhkzSth7mLDLAF 4QQQ== 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=8vRU7XOXMncH2HX3CBvpyWbhKeVRVshARm7btXYP42w=; b=HYDXeY2IQHdkPCvCHQcws5ySpKdRohTsC3DPcYLtRo5rowoli++bH/73sK2kh49sTJ YUkEF6vxo6iePoaY28acGQNeGKY3ebBunqYIuz3ymaZC9O2pgKmQ12q31VD6zytnkL28 USmMPIWRDYXBxwTL1NV32j8rfwzGJ0iIcadjsjQZZCRNUmy2vvCgnIPTQHpMuhbwOF3p s4Dha3frmoNjR0fY/0H+y2dG5PQlTb0KM5G64n93hsTlaZJoSJ1Q9NZNZMf3aZgyanHU HHyC0cjycK/oHV2Ap5sMcsrxK/GWEKLvYRCVQmPlOMUcgQTN5rmfBHlR4cYDc571Qtf2 9mTg== X-Gm-Message-State: APjAAAUfsGrTn663v1ZHPfCpT4BzDCiN2//AW7kOM6W7iWa/RtZEfJtV ac/KrV60dOdTrMPIIPSe8vavHbc9 X-Google-Smtp-Source: APXvYqysH9UkVdeV7dX871CfGOlNrU5gaJfRp3C10inbQrUR5nPcAsJ8RE+ytIeCd/Eih61gHq03dQ== X-Received: by 2002:a17:90a:2ec1:: with SMTP id h1mr15787587pjs.119.1564970616325; Sun, 04 Aug 2019 19:03:36 -0700 (PDT) Received: from localhost.localdomain ([203.205.141.123]) by smtp.googlemail.com with ESMTPSA id o32sm14739365pje.9.2019.08.04.19.03.34 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sun, 04 Aug 2019 19:03:35 -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?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Subject: [PATCH v4 3/6] KVM: Check preempted_in_kernel for involuntary preemption Date: Mon, 5 Aug 2019 10:03:21 +0800 Message-Id: <1564970604-10044-3-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1564970604-10044-1-git-send-email-wanpengli@tencent.com> References: <1564970604-10044-1-git-send-email-wanpengli@tencent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 e121423..2ae9e84 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2522,7 +2522,8 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode) continue; if (swait_active(&vcpu->wq) && !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; @@ -4219,7 +4220,7 @@ 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); @@ -4233,7 +4234,7 @@ 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); -- 2.7.4