Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755817AbZIVJjj (ORCPT ); Tue, 22 Sep 2009 05:39:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755554AbZIVJji (ORCPT ); Tue, 22 Sep 2009 05:39:38 -0400 Received: from ozlabs.org ([203.10.76.45]:34125 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755523AbZIVJji (ORCPT ); Tue, 22 Sep 2009 05:39:38 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <19128.39768.149110.673711@cargo.ozlabs.ibm.com> Date: Tue, 22 Sep 2009 19:39:36 +1000 From: Paul Mackerras To: Xiao Guangrong Cc: Ingo Molnar , Peter Zijlstra , LKML Subject: Re: [PATCH] perf_counter: cleanup for __perf_event_sched_in() In-Reply-To: <4AB88F06.10900@cn.fujitsu.com> References: <4AB88F06.10900@cn.fujitsu.com> X-Mailer: VM 8.0.12 under 22.2.1 (i486-pc-linux-gnu) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 959 Lines: 26 Xiao Guangrong writes: > It must be a group leader if event->attr.pinned is "1" Actually, looking at this more closely, it has to be a group leader anyway since it's at the top level of ctx->group_list. In fact I see four places where we do: list_for_each_entry(event, &ctx->group_list, group_entry) { if (event == event->group_leader) ... or the equivalent, three of which appear to have been introduced by afedadf2 ("perf_counter: Optimize sched in/out of counters") back in May by Peter Z. As far as I can see the if () is superfluous in each case (a singleton event will be a group of 1 and will have its group_leader pointing to itself). Peter, do you agree or have I missed something? Paul. -- 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/