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=-15.7 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,URIBL_BLOCKED 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 8E4BBC433ED for ; Fri, 30 Apr 2021 05:54:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 744ED61460 for ; Fri, 30 Apr 2021 05:54:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230315AbhD3FzJ (ORCPT ); Fri, 30 Apr 2021 01:55:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:46576 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229508AbhD3FzI (ORCPT ); Fri, 30 Apr 2021 01:55:08 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1356B6145A; Fri, 30 Apr 2021 05:54:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1619762061; bh=7UGIUayN1M2SixLFHqHPfEpQOm20pD1xyaZE+c71+vA=; h=Date:From:To:Subject:In-Reply-To:From; b=CTO01XDgCnR2+R+t9ihZ5hHyKjVyuL7CP92zUFlL9930ZqP2efZ3iLckmKxuIUHzo nWAiTTl2mMmsTgPloGEPxXK+4rL2Rk0ceeQMUr6DA9aR8Z5+L/JJh5JCP99UZzGqog TNzB/xTjQ128Mz68ZwyGwW/9nToe4XQiGxL3qCiU= Date: Thu, 29 Apr 2021 22:54:20 -0700 From: Andrew Morton To: akpm@linux-foundation.org, linux-mm@kvack.org, loberman@redhat.com, mhocko@suse.com, mingo@kernel.org, mm-commits@vger.kernel.org, peterz@infradead.org, pmladek@suse.com, tglx@linutronix.de, torvalds@linux-foundation.org, vincent.whitchurch@axis.com Subject: [patch 022/178] watchdog: rename __touch_watchdog() to a better descriptive name Message-ID: <20210430055420.QpghpVUZ-%akpm@linux-foundation.org> In-Reply-To: <20210429225251.02b6386d21b69255b4f6c163@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Petr Mladek Subject: watchdog: rename __touch_watchdog() to a better descriptive name Patch series "watchdog/softlockup: Report overall time and some cleanup", v2. I dug deep into the softlockup watchdog history when time permitted this year. And reworked the patchset that fixed timestamps and cleaned up the code[2]. I split it into very small steps and did even more code clean up. The result looks quite strightforward and I am pretty confident with the changes. [1] v2: https://lore.kernel.org/r/20201210160038.31441-1-pmladek@suse.com [2] v1: https://lore.kernel.org/r/20191024114928.15377-1-pmladek@suse.com This patch (of 6): There are many touch_*watchdog() functions. They are called in situations where the watchdog could report false positives or create unnecessary noise. For example, when CPU is entering idle mode, a virtual machine is stopped, or a lot of messages are printed in the atomic context. These functions set SOFTLOCKUP_RESET instead of a real timestamp. It allows to call them even in a context where jiffies might be outdated. For example, in an atomic context. The real timestamp is set by __touch_watchdog() that is called from the watchdog timer callback. Rename this callback to update_touch_ts(). It better describes the effect and clearly distinguish is from the other touch_*watchdog() functions. Another motivation is that two timestamps are going to be used. One will be used for the total softlockup time. The other will be used to measure time since the last report. The new function name will help to distinguish which timestamp is being updated. Link: https://lkml.kernel.org/r/20210311122130.6788-1-pmladek@suse.com Link: https://lkml.kernel.org/r/20210311122130.6788-2-pmladek@suse.com Signed-off-by: Petr Mladek Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Laurence Oberman Cc: Vincent Whitchurch Cc: Michal Hocko Signed-off-by: Andrew Morton --- kernel/watchdog.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/kernel/watchdog.c~watchdog-rename-__touch_watchdog-to-a-better-descriptive-name +++ a/kernel/watchdog.c @@ -236,7 +236,7 @@ static void set_sample_period(void) } /* Commands for resetting the watchdog */ -static void __touch_watchdog(void) +static void update_touch_ts(void) { __this_cpu_write(watchdog_touch_ts, get_timestamp()); } @@ -332,7 +332,7 @@ static DEFINE_PER_CPU(struct cpu_stop_wo */ static int softlockup_fn(void *data) { - __touch_watchdog(); + update_touch_ts(); complete(this_cpu_ptr(&softlockup_completion)); return 0; @@ -375,7 +375,7 @@ static enum hrtimer_restart watchdog_tim /* Clear the guest paused flag on watchdog reset */ kvm_check_and_clear_guest_paused(); - __touch_watchdog(); + update_touch_ts(); return HRTIMER_RESTART; } @@ -461,7 +461,7 @@ static void watchdog_enable(unsigned int HRTIMER_MODE_REL_PINNED_HARD); /* Initialize timestamp */ - __touch_watchdog(); + update_touch_ts(); /* Enable the perf event */ if (watchdog_enabled & NMI_WATCHDOG_ENABLED) watchdog_nmi_enable(cpu); _