From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f42.google.com (mail-pa0-f42.google.com [209.85.220.42]) by kanga.kvack.org (Postfix) with ESMTP id ED4E66B0031 for ; Wed, 18 Dec 2013 19:47:57 -0500 (EST) Received: by mail-pa0-f42.google.com with SMTP id lj1so413044pab.1 for ; Wed, 18 Dec 2013 16:47:57 -0800 (PST) Received: from blackbird.sr71.net (www.sr71.net. [198.145.64.142]) by mx.google.com with ESMTP id wm3si1257236pab.107.2013.12.18.16.47.54 for ; Wed, 18 Dec 2013 16:47:55 -0800 (PST) Message-ID: <52B2424F.7050406@sr71.net> Date: Wed, 18 Dec 2013 16:48:15 -0800 From: Dave Hansen MIME-Version: 1.0 Subject: Re: [RFC][PATCH 0/7] re-shrink 'struct page' when SLUB is on. 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> In-Reply-To: <20131218164109.5e169e258378fac44ec5212d@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Christoph Lameter , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Pravin B Shelar , "Kirill A. Shutemov" , Andi Kleen , Pekka Enberg 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. -- 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