From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jacob Pan Subject: Re: [PATCH v2 2/2] powercap/rapl: reduce ipi calls Date: Wed, 13 Jan 2016 08:21:13 -0800 Message-ID: <20160113082113.3314fa92@icelake> References: <1452647483-14244-1-git-send-email-jacob.jun.pan@linux.intel.com> <1452647483-14244-3-git-send-email-jacob.jun.pan@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mga03.intel.com ([134.134.136.65]:59658 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752846AbcAMQW2 (ORCPT ); Wed, 13 Jan 2016 11:22:28 -0500 In-Reply-To: Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Thomas Gleixner Cc: LKML , Linux PM , Rafael Wysocki , "H. Peter Anvin" , Ingo Molnar , X86 Kernel , Srinivas Pandruvada , Peter Zijlstra , jacob.jun.pan@linux.intel.com, Borislav Petkov On Wed, 13 Jan 2016 10:47:26 +0100 (CET) Thomas Gleixner wrote: > So here you actually use that new (misnomed) function, but for > > > +static void power_limit_irq_save_cpu(void *info) > > and > > > +static void power_limit_irq_restore_cpu(void *info) > > you use a bog standard smp function call. What's the benefit of > adding that rmw function over a bog standard smp function call if you > can only use it for one instance of the same pattern? > > Boris asked you the same question here > > https://lkml.kernel.org/r/20151220152749.GA29805@pd.tnic > > but you decided to ignore it. +Borislav, Thanks for bring this out. I didn't mean to ignore. I thought my point was stated in the commit message there was no point of going back and forth. Read-Modify-Write is quite common, not just for RAPL could be used by future code. Sorry if I wasn't clear. Jacob