From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [PATCHSET] percpu: generalize first chunk allocators and improve lpage NUMA support Date: Fri, 26 Jun 2009 08:54:23 +0200 Message-ID: <20090626065423.GY6760@one.firstfloor.org> References: <1245850216-31653-1-git-send-email-tj@kernel.org> <20090624165508.30b88343.akpm@linux-foundation.org> <20090625000202.GR6760@one.firstfloor.org> <4A42C131.6040007@zytor.com> <20090625091939.GS6760@one.firstfloor.org> <4A43871F.9030507@zytor.com> <20090625195408.GW6760@one.firstfloor.org> <4A43DAFD.90409@zytor.com> <20090625202642.GX6760@one.firstfloor.org> <4A4418EA.9000705@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from one.firstfloor.org ([213.235.205.2]:43964 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750853AbZFZGyW (ORCPT ); Fri, 26 Jun 2009 02:54:22 -0400 Content-Disposition: inline In-Reply-To: <4A4418EA.9000705@kernel.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Tejun Heo Cc: Andi Kleen , "H. Peter Anvin" , Andrew Morton , linux-kernel@vger.kernel.org, x86@kernel.org, linux-arch@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de, cl@linux-foundation.org On Fri, Jun 26, 2009 at 09:40:10AM +0900, Tejun Heo wrote: > Andi Kleen wrote: > >> I don't know why, but in the configuration I saw each percpu area was > >> something like 1.8 MB. > > > > That sounds like something that needs to be investigated and fixed then. > > In a sense per cpu space is precious like stack space and shouldn't > > be wasted. > > The large percpu space is most likely from lockdep. It would be better then to fix lockdep then to add weird hacks for that elsewhere. e.g. it could just allocate buffers in a cpu up/down callback and only put a pointer to these buffers into percpu. -Andi -- ak@linux.intel.com -- Speaking for myself only.