Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753484Ab1BBL2Z (ORCPT ); Wed, 2 Feb 2011 06:28:25 -0500 Received: from casper.infradead.org ([85.118.1.10]:40800 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753069Ab1BBL2Y (ORCPT ); Wed, 2 Feb 2011 06:28:24 -0500 Subject: Re: [PATCH 1/2] perf_events: add cgroup support (v8) From: Peter Zijlstra To: eranian@google.com Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, paulus@samba.org, davem@davemloft.net, fweisbec@gmail.com, perfmon2-devel@lists.sf.net, eranian@gmail.com, robert.richter@amd.com, acme@redhat.com, lizf@cn.fujitsu.com, Paul Menage , Balbir Singh In-Reply-To: <1295534345.28776.175.camel@laptop> References: <4d384700.2308e30a.70bc.ffffd532@mx.google.com> <1295534345.28776.175.camel@laptop> Content-Type: text/plain; charset="UTF-8" Date: Wed, 02 Feb 2011 12:29:20 +0100 Message-ID: <1296646160.26581.315.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1723 Lines: 43 On Thu, 2011-01-20 at 15:39 +0100, Peter Zijlstra wrote: > On Thu, 2011-01-20 at 15:30 +0200, Stephane Eranian wrote: > > @@ -4259,8 +4261,20 @@ void cgroup_exit(struct task_struct *tsk, int run_callbacks) > > > > /* Reassign the task to the init_css_set. */ > > task_lock(tsk); > > + /* > > + * we mask interrupts to prevent: > > + * - timer tick to cause event rotation which > > + * could schedule back in cgroup events after > > + * they were switched out by perf_cgroup_sched_out() > > + * > > + * - preemption which could schedule back in cgroup events > > + */ > > + local_irq_save(flags); > > + perf_cgroup_sched_out(tsk); > > cg = tsk->cgroups; > > tsk->cgroups = &init_css_set; > > + perf_cgroup_sched_in(tsk); > > + local_irq_restore(flags); > > task_unlock(tsk); > > if (cg) > > put_css_set_taskexit(cg); > > So you too need a callback on cgroup change there.. Li, Paul, any chance > we can fix this cgroup_subsys::exit callback? The scheduler code needs > to do funny thing because its in the wrong place as well. cgroup guys? Shall I just fix this exit thing since the only user seems to be the scheduler and now perf for both of which its unfortunate at best? Balbir, memcontrol.c uses pre_destroy(), I pose that using this method is broken per definition since it makes the cgroup empty notification void. -- 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/