From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oleg Nesterov Subject: Re: [RFC PATCH v3 1/9] CPU hotplug: Provide APIs to prevent CPU offline from atomic context Date: Sun, 9 Dec 2012 21:22:34 +0100 Message-ID: <20121209202234.GA5793@redhat.com> References: <20121207173702.27305.1486.stgit@srivatsabhat.in.ibm.com> <20121207173759.27305.84316.stgit@srivatsabhat.in.ibm.com> <20121209191437.GA2816@redhat.com> <50C4EB79.5050203@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mx1.redhat.com ([209.132.183.28]:49277 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758925Ab2LIUWf (ORCPT ); Sun, 9 Dec 2012 15:22:35 -0500 Content-Disposition: inline In-Reply-To: <50C4EB79.5050203@linux.vnet.ibm.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Srivatsa S. Bhat" Cc: tglx@linutronix.de, peterz@infradead.org, paulmck@linux.vnet.ibm.com, rusty@rustcorp.com.au, mingo@kernel.org, akpm@linux-foundation.org, namhyung@kernel.org, vincent.guittot@linaro.org, tj@kernel.org, sbw@mit.edu, amit.kucheria@linaro.org, rostedt@goodmis.org, rjw@sisk.pl, wangyun@linux.vnet.ibm.com, xiaoguangrong@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org On 12/10, Srivatsa S. Bhat wrote: > > On 12/10/2012 12:44 AM, Oleg Nesterov wrote: > > > But yes, it is easy to blame somebody else's code ;) And I can't suggest > > something better at least right now. If I understand correctly, we can not > > use, say, synchronize_sched() in _cpu_down() path > > We can't sleep in that code.. so that's a no-go. But we can? Note that I meant _cpu_down(), not get_online_cpus_atomic() or take_cpu_down(). Oleg.