From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1755817Ab3IYPfy (ORCPT <rfc822;w@1wt.eu>);
	Wed, 25 Sep 2013 11:35:54 -0400
Received: from merlin.infradead.org ([205.233.59.134]:51362 "EHLO
	merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1753936Ab3IYPfv (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Wed, 25 Sep 2013 11:35:51 -0400
Date: Wed, 25 Sep 2013 17:35:33 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Steven Rostedt <rostedt@goodmis.org>, Mel Gorman <mgorman@suse.de>,
        Rik van Riel <riel@redhat.com>,
        Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
        Ingo Molnar <mingo@kernel.org>, Andrea Arcangeli <aarcange@redhat.com>,
        Johannes Weiner <hannes@cmpxchg.org>, Linux-MM <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] hotplug: Optimize {get,put}_online_cpus()
Message-ID: <20130925153533.GN3081@twins.programming.kicks-ass.net>
References: <20130919143241.GB26785@twins.programming.kicks-ass.net>
 <20130923175052.GA20991@redhat.com>
 <20130924123821.GT12926@twins.programming.kicks-ass.net>
 <20130924160359.GA2739@redhat.com>
 <20130924124341.64d57912@gandalf.local.home>
 <20130924170631.GB5059@redhat.com>
 <20130924174717.GH9093@linux.vnet.ibm.com>
 <20130924180005.GA7148@redhat.com>
 <20130924203512.GS9326@twins.programming.kicks-ass.net>
 <20130925151642.GA13244@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20130925151642.GA13244@redhat.com>
User-Agent: Mutt/1.5.21 (2012-12-30)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Wed, Sep 25, 2013 at 05:16:42PM +0200, Oleg Nesterov wrote:
> Yes, but my point was, this can only happen in recursive fast path.

Right, I understood.

> And in this case (I think) we do not care, we are already in the critical
> section.

I tend to agree, however paranoia..

> OK, please forget. I guess I will never understand this ;)

It might just be I'm less certain about there not being any avenue of
mischief.