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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 827AEC48BE5 for ; Fri, 11 Jun 2021 08:34:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6FC1461287 for ; Fri, 11 Jun 2021 08:34:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231535AbhFKIgo (ORCPT ); Fri, 11 Jun 2021 04:36:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231243AbhFKIgl (ORCPT ); Fri, 11 Jun 2021 04:36:41 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 69C5AC0617AF; Fri, 11 Jun 2021 01:34:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=RYBsgpQlclTJq0tXOTvuDyxVfi6BxJwFpXitPHLv2cs=; b=KgTNF15fR2piL1BInXLn6sjQ8/ Ky8E/1FCtGIH7g+kqs0m50FdhewSzNxG+MEUBI/nMAREHOX/Batchl8l8kMrd+vjR0+n1WzIcIGDU igZ/XC0p39apo0W7XUs6tMTYrKxjV4hLZRv41zzB1ccKdr/2xDRKpwOgeEuAqW3wn9RHdc5mdbAwj GeVHpegsdal2Dkh5o8RgXYAHXZ3BlyxIHV192yw/Npe0rEF+FzWhkaXboQgWAVa6mDdkQqJB+RD6w 6UIOmI42uQNKWVTDWnV6tqove80hSmq8WBfgZlcbho9B4jg5WH/L8/W8NOo7GOxDI+N80XQ8vnirk nKZQck7w==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1lrcY1-002ZW2-8Y; Fri, 11 Jun 2021 08:30:07 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 28385300577; Fri, 11 Jun 2021 10:29:43 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id E7D3A2BCF3931; Fri, 11 Jun 2021 10:29:42 +0200 (CEST) Message-ID: <20210611082838.285099381@infradead.org> User-Agent: quilt/0.66 Date: Fri, 11 Jun 2021 10:28:13 +0200 From: Peter Zijlstra To: Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira Cc: Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Jens Axboe , Alasdair Kergon , Mike Snitzer , "David S. Miller" , Jakub Kicinski , Felipe Balbi , Greg Kroah-Hartman , Alexander Viro , Tejun Heo , Zefan Li , Johannes Weiner , Jason Wessel , Daniel Thompson , Douglas Anderson , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , "Rafael J. Wysocki" , Pavel Machek , Will Deacon , Waiman Long , Boqun Feng , Oleg Nesterov , Davidlohr Bueso , "Paul E. McKenney" , Josh Triplett , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , John Stultz , Stephen Boyd , Andrew Morton , Paolo Bonzini , Stephen Rothwell , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org Subject: [PATCH v2 3/7] sched,perf,kvm: Fix preemption condition References: <20210611082810.970791107@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When ran from the sched-out path (preempt_notifier or perf_event), p->state is irrelevant to determine preemption. You can get preempted with !task_is_running() just fine. The right indicator for preemption is if the task is still on the runqueue in the sched-out path. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Mark Rutland --- kernel/events/core.c | 7 +++---- virt/kvm/kvm_main.c | 2 +- 2 files changed, 4 insertions(+), 5 deletions(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8568,13 +8568,12 @@ static void perf_event_switch(struct tas }, }; - if (!sched_in && task->state == TASK_RUNNING) + if (!sched_in && task->on_rq) { switch_event.event_id.header.misc |= PERF_RECORD_MISC_SWITCH_OUT_PREEMPT; + } - perf_iterate_sb(perf_event_switch_output, - &switch_event, - NULL); + perf_iterate_sb(perf_event_switch_output, &switch_event, NULL); } /* --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -4869,7 +4869,7 @@ static void kvm_sched_out(struct preempt { struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn); - if (current->state == TASK_RUNNING) { + if (current->on_rq) { WRITE_ONCE(vcpu->preempted, true); WRITE_ONCE(vcpu->ready, true); }