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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 70AB7C43142 for ; Tue, 31 Jul 2018 17:07:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3538C20844 for ; Tue, 31 Jul 2018 17:07:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3538C20844 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731427AbeGaStG (ORCPT ); Tue, 31 Jul 2018 14:49:06 -0400 Received: from mail-qt0-f195.google.com ([209.85.216.195]:42222 "EHLO mail-qt0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727269AbeGaStG (ORCPT ); Tue, 31 Jul 2018 14:49:06 -0400 Received: by mail-qt0-f195.google.com with SMTP id z8-v6so16727453qto.9 for ; Tue, 31 Jul 2018 10:07:51 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=WBgbT13wNojpZXbdhEfLoJAbFCIL7AQ9HO+enE/fwio=; b=jisKCkbjYKMG7JLbqRXWXnpTHjGfSuUgvhlNBNX3fxmdihi+KqAxS/G+BjDZoFegqK XGTU5D3rI7sip/EDOrH3joutcj7JljWZ/Stmez0kqEJ8sivuyer0VSY5YDTDW/WOp+Sc yU32kzdpe1aJ9WMbuADK3TPKY/Rwc6EngSOR3rz+bjEwU1bed+tui9ZvlcNclhpPodnN 2dEeqzrY42tEtHn3oBb6PYSOcMeCt4yQXc+PBv+Uqwy6aUT7jKYpaah4vzqL/odN/Aht JdEwew7RCNCo3faSzd+vHkBx6DX41khlZ4Asq85fVLweQRJLXftVlPd4ypP9ShhkK/5d qkmg== X-Gm-Message-State: AOUpUlFsTIu2yQ8JBMbHhmXQJSClT6gizjD405JonyS1nFtQ5PkWivsH tOvkc3e3DbGIS7bwRNRmYfFczw== X-Google-Smtp-Source: AAOMgpeJ7UHFmkGpYSeyL9erPMAZB2hKZb1WtLAszsnqplk19cGwyxk3nZASU/29g3vaXx16N7yWmA== X-Received: by 2002:ac8:218d:: with SMTP id 13-v6mr21911447qty.122.1533056870950; Tue, 31 Jul 2018 10:07:50 -0700 (PDT) Received: from t460s.bristot.redhat.com (host159-104-dynamic.182-80-r.retail.telecomitalia.it. [80.182.104.159]) by smtp.gmail.com with ESMTPSA id a144-v6sm9946350qkc.84.2018.07.31.10.07.48 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 31 Jul 2018 10:07:50 -0700 (PDT) Subject: Re: [PATCH] nohz: Fix local_timer_softirq_pending() To: Anna-Maria Gleixner , linux-kernel@vger.kernel.org Cc: bigeasy@linutronix.de, tglx@linutronix.de, frederic@kernel.org, paulmck@linux.vnet.ibm.com, peterz@infradead.org References: <20180731161358.29472-1-anna-maria@linutronix.de> From: Daniel Bristot de Oliveira Message-ID: <686f5d08-e910-9be1-6914-3164e723c16e@redhat.com> Date: Tue, 31 Jul 2018 19:07:45 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180731161358.29472-1-anna-maria@linutronix.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/31/2018 06:13 PM, Anna-Maria Gleixner wrote: > local_timer_softirq_pending() checks whether the timer softirq is > pending with: local_softirq_pending() & TIMER_SOFTIRQ. > > This is wrong because TIMER_SOFTIRQ is the softirq number and not a > bitmask. So the test checks for the wrong bit. > > Use BIT(TIMER_SOFTIRQ) instead. Reviewed-by: Daniel Bristot de Oliveira Thanks! -- Daniel > Fixes: 5d62c183f9e9 ("nohz: Prevent a timer interrupt storm in tick_nohz_stop_sched_tick()") > Signed-off-by: Anna-Maria Gleixner > --- > kernel/time/tick-sched.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c > index da9455a6b42b..5b33e2f5c0ed 100644 > --- a/kernel/time/tick-sched.c > +++ b/kernel/time/tick-sched.c > @@ -642,7 +642,7 @@ static void tick_nohz_restart(struct tick_sched *ts, ktime_t now) > > static inline bool local_timer_softirq_pending(void) > { > - return local_softirq_pending() & TIMER_SOFTIRQ; > + return local_softirq_pending() & BIT(TIMER_SOFTIRQ); > } > > static ktime_t tick_nohz_next_event(struct tick_sched *ts, int cpu) >