From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753864Ab1I0VBd (ORCPT ); Tue, 27 Sep 2011 17:01:33 -0400 Received: from merlin.infradead.org ([205.233.59.134]:45651 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751446Ab1I0VBa convert rfc822-to-8bit (ORCPT ); Tue, 27 Sep 2011 17:01:30 -0400 Subject: Re: [RFD 1/9] Change cpustat fields to an array. From: Peter Zijlstra To: Glauber Costa Cc: linux-kernel@vger.kernel.org, paul@paulmenage.org, lizf@cn.fujitsu.com, daniel.lezcano@free.fr, jbottomley@parallels.com Date: Tue, 27 Sep 2011 23:00:52 +0200 In-Reply-To: <1316816432-9237-2-git-send-email-glommer@parallels.com> References: <1316816432-9237-1-git-send-email-glommer@parallels.com> <1316816432-9237-2-git-send-email-glommer@parallels.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Mailer: Evolution 3.0.3- Message-ID: <1317157252.21836.3.camel@twins> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2011-09-23 at 19:20 -0300, Glauber Costa wrote: > /* Must have preemption disabled for this to be meaningful. */ > -#define kstat_this_cpu __get_cpu_var(kstat) > +#define kstat_this_cpu this_cpu_ptr(task_group_kstat(current)) This just lost you a debug check, the former would whinge when called without preemption, the new one wont. Its part of the this_cpu feature set to make debugging impossible. > +#else > +#define kstat_cpu(cpu) per_cpu(kstat, cpu) > +#define kstat_this_cpu (&__get_cpu_var(kstat)) > +#endif > > extern unsigned long long nr_context_switches(void); > > @@ -52,8 +62,8 @@ struct irq_desc; > static inline void kstat_incr_irqs_this_cpu(unsigned int irq, > struct irq_desc *desc) > { > - __this_cpu_inc(kstat.irqs[irq]); > - __this_cpu_inc(kstat.irqs_sum); > + kstat_this_cpu->irqs[irq]++; > + kstat_this_cpu->irqs_sum++; It might be worth looking at the asm output of that, I think you made it worse, but I'm not quite sure how smart gcc is, it might just figure out what you meant. > }