Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751156Ab2KSFVN (ORCPT ); Mon, 19 Nov 2012 00:21:13 -0500 Received: from mail-pb0-f46.google.com ([209.85.160.46]:54622 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750758Ab2KSFVM (ORCPT ); Mon, 19 Nov 2012 00:21:12 -0500 Message-ID: <50A9C1BD.1060308@gmail.com> Date: Mon, 19 Nov 2012 13:21:01 +0800 From: Shan Wei User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:16.0) Gecko/20121026 Thunderbird/16.0.2 MIME-Version: 1.0 To: rostedt@goodmis.org, fweisbec@gmail.com, mingo@redhat.com, Kernel-Maillist , Christoph Lameter Subject: [PATCH] trace: use __this_cpu_inc/dec operation instead of __get_cpu_var Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1319 Lines: 40 From: Shan Wei __this_cpu_inc_return() or __this_cpu_dec generates a single instruction, which is faster than __get_cpu_var operation. Signed-off-by: Shan Wei --- kernel/trace/trace.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 18c0aa8..3795694 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1313,7 +1313,7 @@ static void __ftrace_trace_stack(struct ring_buffer *buffer, */ preempt_disable_notrace(); - use_stack = ++__get_cpu_var(ftrace_stack_reserve); + use_stack = __this_cpu_inc_return(ftrace_stack_reserve); /* * We don't need any atomic variables, just a barrier. * If an interrupt comes in, we don't care, because it would @@ -1367,7 +1367,7 @@ static void __ftrace_trace_stack(struct ring_buffer *buffer, out: /* Again, don't let gcc optimize things here */ barrier(); - __get_cpu_var(ftrace_stack_reserve)--; + __this_cpu_dec(ftrace_stack_reserve); preempt_enable_notrace(); } -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/