Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751963AbZIYFy5 (ORCPT ); Fri, 25 Sep 2009 01:54:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751128AbZIYFyz (ORCPT ); Fri, 25 Sep 2009 01:54:55 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:56589 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751076AbZIYFyz (ORCPT ); Fri, 25 Sep 2009 01:54:55 -0400 Message-ID: <4ABC5AF9.6060808@cn.fujitsu.com> Date: Fri, 25 Sep 2009 13:54:01 +0800 From: Xiao Guangrong User-Agent: Thunderbird 2.0.0.6 (Windows/20070728) MIME-Version: 1.0 To: Ingo Molnar CC: Peter Zijlstra , Paul Mackerras , LKML Subject: [PATCH 2/2 v2] optimize for perf_event_init_task() References: <4AB88F06.10900@cn.fujitsu.com> <19128.39768.149110.673711@cargo.ozlabs.ibm.com> <4AB98BB0.6020202@cn.fujitsu.com> <19129.38627.94363.857137@cargo.ozlabs.ibm.com> <4AB9D7FA.5040707@cn.fujitsu.com> <1253695230.7695.122.camel@twins> <4ABC5A55.7000208@cn.fujitsu.com> In-Reply-To: <4ABC5A55.7000208@cn.fujitsu.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1143 Lines: 35 We can traverse ctx->group_list to get all group leader, it should be safe since we hold ctx->mutex Changlog v1->v2: - remove WARN_ON_ONCE() as Peter Zijlstra's suggestion Signed-off-by: Xiao Guangrong --- kernel/perf_event.c | 4 +--- 1 files changed, 1 insertions(+), 3 deletions(-) diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 2a15cd6..0276fb4 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -4767,9 +4767,7 @@ int perf_event_init_task(struct task_struct *child) * We dont have to disable NMIs - we are only looking at * the list, not manipulating it: */ - list_for_each_entry_rcu(event, &parent_ctx->event_list, event_entry) { - if (event != event->group_leader) - continue; + list_for_each_entry(event, &parent_ctx->group_list, group_entry) { if (!event->attr.inherit) { inherited_all = 0; -- 1.6.1.2 -- 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/