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,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 A8162C3A589 for ; Fri, 16 Aug 2019 02:53:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 79B172089E for ; Fri, 16 Aug 2019 02:53:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="kueoEIA1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726656AbfHPCxn (ORCPT ); Thu, 15 Aug 2019 22:53:43 -0400 Received: from mail-pg1-f193.google.com ([209.85.215.193]:45620 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726555AbfHPCxk (ORCPT ); Thu, 15 Aug 2019 22:53:40 -0400 Received: by mail-pg1-f193.google.com with SMTP id o13so2181057pgp.12 for ; Thu, 15 Aug 2019 19:53:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=PV4Y2GS/UKkV9mmp2RyNU73hYsBVNlUw9/FLpkqOMOc=; b=kueoEIA1lOTWWLvj3OCilRsnT688/xt7NAqY5O3GcwDZ8WCJ9Dv5orDKZmoxrX7SKV CTqc5I1HVuTd5nfvowZLldeSDuBYC+cy5YFTfk69iJoNeQb7tmwcNN320cwyIu8qIvAb m3wgEFyC1as8OV7qgt+dYqSwQTGdjSYx42mPg= 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=PV4Y2GS/UKkV9mmp2RyNU73hYsBVNlUw9/FLpkqOMOc=; b=WcrMjenIJjBEkveOL+cqUSQwGhwFagv0RfhIB/+FyxFnM7xBCnoKvG2YtMwpWHJEqj uPMgl6Tm8NvNI97sbHPPrTUg2YILzHgmv2G1KuAUSfip5lJP0kVXIW+yFYGLVBjp9HCA l2VRC/vygbIIaD5kwqKxw7XlqTSjsFBpGZ2mZ1nNJAYlTXChimSHQWrTnVp6lUBopnzN g1yF61KzVmRcLbWn2IW2ltWGWPAPwe91BMfjysM75yNf2Wsvbxd/NjE5h/sGL0SALHWO SuVxXJeR1+sjRLURyiXVDlybadVkTmROHB1z9S42WauRRm4VybcVF5+M4iIq15b2z7Ip uxCQ== X-Gm-Message-State: APjAAAWmDFugLgJ5/2X6CiPxrkPI8/VmCLSptSg6FR9nFiqkkvAotvip jGO44WzN/g8AZIwzSOTfcuA8xtP2/XU= X-Google-Smtp-Source: APXvYqwZiZUHFMwCP5u7bsPOAFqQNVPhbXQFQMl/+8LdbccYtvysuawnk3kH1VC++pxK267JDyiYRA== X-Received: by 2002:a62:fb15:: with SMTP id x21mr8828810pfm.233.1565924019251; Thu, 15 Aug 2019 19:53:39 -0700 (PDT) Received: from joelaf.cam.corp.google.com ([172.19.216.18]) by smtp.gmail.com with ESMTPSA id v14sm4181258pfm.164.2019.08.15.19.53.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 15 Aug 2019 19:53:38 -0700 (PDT) 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 -rcu dev 2/3] rcu/tree: Fix issue where sometimes rcu_urgent_qs is not set on IPI Date: Thu, 15 Aug 2019 22:53:10 -0400 Message-Id: <20190816025311.241257-2-joel@joelfernandes.org> X-Mailer: git-send-email 2.23.0.rc1.153.gdeed80330f-goog In-Reply-To: <20190816025311.241257-1-joel@joelfernandes.org> References: <20190816025311.241257-1-joel@joelfernandes.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 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