From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner+w=401wt.eu-S1756005Ab0AMWu3@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1756005Ab0AMWu3 (ORCPT <rfc822;w@1wt.eu>);
	Wed, 13 Jan 2010 17:50:29 -0500
Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755886Ab0AMWu2
	(ORCPT <rfc822;linux-kernel-outgoing>);
	Wed, 13 Jan 2010 17:50:28 -0500
Received: from mga14.intel.com ([143.182.124.37]:18498 "EHLO mga14.intel.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1755814Ab0AMWu2 (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Wed, 13 Jan 2010 17:50:28 -0500
X-ExtLoop1: 1
X-IronPort-AV: E=Sophos;i="4.47,316,1257148800"; 
   d="scan'208";a="232464205"
Subject: Re: [PATCH -v2 5/5] x86: use dmi check to treat disabled cpus as
 hotplug cpus.
From: Suresh Siddha <suresh.b.siddha@intel.com>
Reply-To: Suresh Siddha <suresh.b.siddha@intel.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>, Yinghai Lu <yinghai@kernel.org>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       "ananth@in.ibm.com" <ananth@in.ibm.com>, Ingo Molnar <mingo@elte.hu>,
       Thomas Gleixner <tglx@linutronix.de>,
       Andrew Morton <akpm@linux-foundation.org>,
       "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
In-Reply-To: <4B4E4AE3.1030608@zytor.com>
References: <1263338274-6485-1-git-send-email-yinghai@kernel.org>
	 <1263338274-6485-5-git-send-email-yinghai@kernel.org>
	 <1263340563.2854.1011.camel@sbs-t61.sc.intel.com>
	 <4B4D0E39.10200@kernel.org> <87tyupfzk8.fsf@basil.nowhere.org>
	 <4B4E427D.9090207@zytor.com> <20100113222348.GE24818@basil.fritz.box>
	 <4B4E48BB.5030902@zytor.com>
	 <1263421753.2865.103.camel@sbs-t61.sc.intel.com>
	 <4B4E4AE3.1030608@zytor.com>
Content-Type: text/plain
Organization: Intel Corp
Date: Wed, 13 Jan 2010 14:49:18 -0800
Message-Id: <1263422958.2865.107.camel@sbs-t61.sc.intel.com>
Mime-Version: 1.0
X-Mailer: Evolution 2.26.3 (2.26.3-1.fc11) 
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Wed, 2010-01-13 at 14:36 -0800, H. Peter Anvin wrote:
> On 01/13/2010 02:29 PM, Suresh Siddha wrote:
> >>
> >> Well, that *is* working around broken code, in this case the broken code
> >> is the percpu allocation strategy.
> > 
> > Andi, Recently percpu folks changed the per-cpu static first chunk to
> > PMD SIZE right. I think that is what causing all this issue.
> > 
> 
> Please don't tell me we're allocating 2 MB per CPU and throwing away
> most of it...

Looking at the percpu code, they do seem to free the unused memory in
that hole.

Yinghai, what are the configurations that need MB's of per cpu area?

thanks,
suresh