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=-11.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT,USER_AGENT_SANE_1 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 9C80EC3A589 for ; Fri, 16 Aug 2019 02:59:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6C7122089E for ; Fri, 16 Aug 2019 02:59:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="gdQSJruo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726801AbfHPC7d (ORCPT ); Thu, 15 Aug 2019 22:59:33 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:40238 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726506AbfHPC7c (ORCPT ); Thu, 15 Aug 2019 22:59:32 -0400 Received: by mail-pl1-f196.google.com with SMTP id a93so1845310pla.7 for ; Thu, 15 Aug 2019 19:59:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=5TOZw4aX2ouYHWL3SPiBVA6qRZbVTxguU44+pODdzqI=; b=gdQSJruoAM1XM+3a/CIqDvm0o6MwERJuLTfpy9OI9EGyi8eqi1yTpNYOYc1pMFygim Mj0B864cQw1184rdHxkBe+b5EoTA7r8bRQv+vewlFkxnjYXVlvmIUEPqYeHeaxcuY2kj DZeEWsiHhMJMcd0pt4KxN4CQTl7VmYJBYI89Q= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=5TOZw4aX2ouYHWL3SPiBVA6qRZbVTxguU44+pODdzqI=; b=tWxGHQ6jP1282wWJ082sP5dSEW/OVOTdoD2XLHywd26yeuTnEJy8VQmmABipa063Yo Wu9eWvqI+DRW0fSGJkWK4jfm43W4Jbf1mSSlm+YkGtay3HpdV+z/DWnAzfpvNxHVE38r 5ehmcHZ4bUs7XVuKnFJuLpAnteCxlyqOlNu4niBQHVUNVx8f+xjuiKCYfoMVvyYPL9mG oz7TECt6PfVxDRydHXDRk8e5dYcii0q7LjD3wrXcmQfbpyG/IGpQmyoNuScrkP0bmmNj xeDVCT7Nw9LUG695smZVyclQqjOs7Of6MZJl9nMwzIintUvfbznwU3bwYkUIGpi+34iZ +NDQ== X-Gm-Message-State: APjAAAW11HCs9lsz7x+S9pU1fCG6+F/jM2PqV/IxqJ7u3YOfC71Pa4JQ U7K0OLcJCgbZCB1/VNg4W4CbHOIZmPo= X-Google-Smtp-Source: APXvYqzOsc28s9gVz0EkrhaSrs5/PUB6mUriwSSU1aeKlkoNXVLriuQGGqrLsSQSAAAn3wdPYB2XOg== X-Received: by 2002:a17:902:424:: with SMTP id 33mr7238481ple.34.1565924371577; Thu, 15 Aug 2019 19:59:31 -0700 (PDT) Received: from localhost ([172.19.216.18]) by smtp.gmail.com with ESMTPSA id v184sm3378377pgd.34.2019.08.15.19.59.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 15 Aug 2019 19:59:30 -0700 (PDT) Date: Thu, 15 Aug 2019 22:59:14 -0400 From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org Cc: "Joel Fernandes (Google)" , rcu@vger.kernel.org, "Paul E. McKenney" , frederic@kernel.org Subject: [PATCH v2 -rcu dev 2/3] rcu/tree: Fix issue where sometimes rcu_urgent_qs is not set on IPI Message-ID: <20190816025914.GB242309@google.com> References: <20190816025311.241257-1-joel@joelfernandes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190816025311.241257-1-joel@joelfernandes.org> X-Mailer: git-send-email 2.23.0.rc1.153.gdeed80330f-goog User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sometimes I see rcu_urgent_qs is not set. This could be when the last IPI was a long time ago, however, the grace period just started. Set rcu_urgent_qs so the tick can indeed not be stopped. Signed-off-by: Joel Fernandes (Google) --- kernel/rcu/tree.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 322b1b57967c..856d3c9f1955 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1091,6 +1091,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) if (tick_nohz_full_cpu(rdp->cpu) && time_after(jiffies, READ_ONCE(rdp->last_fqs_resched) + jtsq * 3)) { + WRITE_ONCE(*ruqp, true); resched_cpu(rdp->cpu); WRITE_ONCE(rdp->last_fqs_resched, jiffies); } -- 2.23.0.rc1.153.gdeed80330f-goog