From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qe0-f52.google.com (mail-qe0-f52.google.com [209.85.128.52]) by kanga.kvack.org (Postfix) with ESMTP id 07A996B0031 for ; Thu, 19 Dec 2013 10:21:20 -0500 (EST) Received: by mail-qe0-f52.google.com with SMTP id ne12so1104069qeb.11 for ; Thu, 19 Dec 2013 07:21:20 -0800 (PST) Received: from qmta07.emeryville.ca.mail.comcast.net (qmta07.emeryville.ca.mail.comcast.net. [2001:558:fe2d:43:76:96:30:64]) by mx.google.com with ESMTP id h17si2974980qej.41.2013.12.19.07.21.18 for ; Thu, 19 Dec 2013 07:21:19 -0800 (PST) Date: Thu, 19 Dec 2013 09:21:15 -0600 (CST) From: Christoph Lameter Subject: Re: [RFC][PATCH 0/7] re-shrink 'struct page' when SLUB is on. In-Reply-To: <52B2424F.7050406@sr71.net> Message-ID: References: <20131213235903.8236C539@viggo.jf.intel.com> <20131216160128.aa1f1eb8039f5eee578cf560@linux-foundation.org> <52AF9EB9.7080606@sr71.net> <0000014301223b3e-a73f3d59-8234-48f1-9888-9af32709a879-000000@email.amazonses.com> <52B23CAF.809@sr71.net> <20131218164109.5e169e258378fac44ec5212d@linux-foundation.org> <52B2424F.7050406@sr71.net> Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Pravin B Shelar , "Kirill A. Shutemov" , Andi Kleen , Pekka Enberg On Wed, 18 Dec 2013, Dave Hansen wrote: > On 12/18/2013 04:41 PM, Andrew Morton wrote: > >> > Unless somebody can find some holes in this, I think we have no choice > >> > but to unset the HAVE_ALIGNED_STRUCT_PAGE config option and revert using > >> > the cmpxchg, at least for now. > > > > So your scary patch series which shrinks struct page while retaining > > the cmpxchg_double() might reclaim most of this loss? > > That's what I'll test next, but I hope so. > > The config tweak is important because it shows a low-risk way to get a > small 'struct page', plus get back some performance that we lost and > evidently never noticed. A distro that was nearing a release might want > to go with this, for instance. Ok then lets just drop the cmpxchg updates to the page struct. The spinlock code is already in there so just removing the __CMPXCHG flag related processing should do the trick. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org