From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755281AbeEAJMZ (ORCPT ); Tue, 1 May 2018 05:12:25 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:48443 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755012AbeEAJMU (ORCPT ); Tue, 1 May 2018 05:12:20 -0400 From: "Rafael J. Wysocki" To: Peter Zijlstra , tglx@linutronix.de Cc: linux-kernel@vger.kernel.org, diego.viola@gmail.com, len.brown@intel.com, rui.zhang@intel.com Subject: Re: [PATCH v2 0/7] Various tsc/clocksource fixes Date: Tue, 01 May 2018 11:12:03 +0200 Message-ID: <2748619.xuzImzcDij@aspire.rjw.lan> In-Reply-To: <20180430100008.503783478@infradead.org> References: <20180430100008.503783478@infradead.org> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday, April 30, 2018 12:00:08 PM CEST Peter Zijlstra wrote: > These patches are the result of the regression Diego reported against commit: > > aa83c45762a2 ("x86/tsc: Introduce early tsc clocksource") > > His Core2 triggers mark_tsc_unstable() while we're running with tsc-early, > which then results in us failing to unregister the clocksource. > > Furthermore, since mark_tsc_unstable() only looks at the regular tsc > clocksource, we don't even mark tsc_early UNSTABLE or de-rate it, resulting in > it actually staying a desirable clocksource. > > Fixing that is a little more tricky; albeit far less critical after we > guarantee to unregister tsc-early. > > Please consider these for /urgent. I've used both Fixes and stable tags > on a bunch of them because the above commit is already in v4.16 and > would need stable help. > > These patches have been tested on both a Core2 and an IVB. On IVB I've both > changed intel_idle to always report the TSC unstable and mucked about with the > TSC msr from userspace to tickle the watchdog paths. > > --- > Changes since v1 > > - fix __clocksource_change_rating() locking > - removed work->kthread->watchdog hoops > - fixed up comment > > I've had a deeper look at the patches and have not found anything of concern in them, so for the whole series: Reviewed-by: Rafael J. Wysocki