From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754266Ab1EJKkc (ORCPT ); Tue, 10 May 2011 06:40:32 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:35234 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753739Ab1EJKkb (ORCPT ); Tue, 10 May 2011 06:40:31 -0400 Date: Tue, 10 May 2011 12:40:19 +0200 From: Ingo Molnar To: Jiri Olsa Cc: masami.hiramatsu.pt@hitachi.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] kprobes,x86: disable irq durinr optimized callback Message-ID: <20110510104019.GF2400@elte.hu> References: <1303822891-8450-1-git-send-email-jolsa@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1303822891-8450-1-git-send-email-jolsa@redhat.com> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.3.1 -2.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jiri Olsa wrote: > + local_irq_save(flags); > preempt_disable(); > if (kprobe_running()) { > kprobes_inc_nmissed_count(&op->kp); > @@ -1208,6 +1210,7 @@ static void __kprobes optimized_callback(struct optimized_kprobe *op, > __this_cpu_write(current_kprobe, NULL); > } > preempt_enable_no_resched(); > + local_irq_restore(flags); irq-disable is synonymous to preempt disable so the preempt_disable()/enable() pair looks like superfluous overhead. Thanks, Ingo