Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751974AbdF1Rja (ORCPT ); Wed, 28 Jun 2017 13:39:30 -0400 Received: from mail-qt0-f171.google.com ([209.85.216.171]:34956 "EHLO mail-qt0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751528AbdF1RjX (ORCPT ); Wed, 28 Jun 2017 13:39:23 -0400 MIME-Version: 1.0 In-Reply-To: <20170628132135.13622-1-shorne@gmail.com> References: <20170628132135.13622-1-shorne@gmail.com> From: John Stultz Date: Wed, 28 Jun 2017 10:39:21 -0700 Message-ID: Subject: Re: [PATCH] timekeeping: Use proper timekeeper for debug code To: Stafford Horne Cc: LKML , Thomas Gleixner , Stephen Boyd Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 934 Lines: 24 On Wed, Jun 28, 2017 at 6:21 AM, Stafford Horne wrote: > When CONFIG_DEBUG_TIMEKEEPING is enabled the timekeeping_check_update() > function will update status like last_warning and underflow_seen on the > timekeeper. > > If there are issues found this state is used to rate limit the warnings > that get printed. > > This rate limiting doesn't really really work if stored in real_tk as > the shadow timekeeper is overwritten onto real_tk at the end of every > update_wall_time() call, resetting last_warning and other statuses. > > Fix rate limiting by using the shadow_timekeeper for > timekeeping_check_update(). > > Fixes: commit 57d05a93ada7 ("time: Rework debugging variables so they aren't global") > Signed-off-by: Stafford Horne Interesting! Thanks for submitting this! Out of curiosity, can you also talk about the underlying issue that made you come across this issue? thanks -john