Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752332AbdFVN5l (ORCPT ); Thu, 22 Jun 2017 09:57:41 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:55777 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750812AbdFVN5k (ORCPT ); Thu, 22 Jun 2017 09:57:40 -0400 Date: Thu, 22 Jun 2017 15:56:39 +0200 (CEST) From: Thomas Gleixner To: Zhenzhong Duan cc: mingo@redhat.com, hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RESEND] Calling check_system_tsc_reliable() before unsynchronized_tsc() In-Reply-To: Message-ID: References: User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1369 Lines: 41 Zhenzhong, On Wed, 21 Jun 2017, Zhenzhong Duan wrote: So the patch format is now correct, but the subject line is missing a proper subsystem prefix. Please use 'git log 'path/to/patched/file' next time to see what the usually used prefix for a file is. In this case it's: x86/tsc Also please do not use [PATCH RESEND] when your patch is different from the version you sent before. Please use [PATCH v2] instead. > unsynchronized_tsc() checks value of tsc_clocksource_reliable which is set by > check_system_tsc_reliable(). It's better to move check_system_tsc_reliable() at > front. Please make your statements affirmative. 'It's better' is a weak expression. > Though X86_FEATURE_CONSTANT_TSC is usually set for TSC reliable system, just in > case. So what you wanted to say here is: tsc_clocksource_reliable is initialized in check_system_tsc_reliable(), but it is checked in unsynchronized_tsc() which is called before the initialization. In practice that's not an issue because systems which mark the TSC reliable have X86_FEATURE_CONSTANT_TSC set as well, which is evaluated in unsynchronized_tsc() before tsc_clocksource_reliable. Reorder the calls so initialization happens before usage. All this information is also documented in Documentation/process/. No need to resend. I'll fix it up for you this time. Thanks, tglx