Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752208AbaANWGd (ORCPT ); Tue, 14 Jan 2014 17:06:33 -0500 Received: from www.sr71.net ([198.145.64.142]:54274 "EHLO blackbird.sr71.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751274AbaANWGc (ORCPT ); Tue, 14 Jan 2014 17:06:32 -0500 Message-ID: <52D5B48D.30006@sr71.net> Date: Tue, 14 Jan 2014 14:05:01 -0800 From: Dave Hansen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Christoph Lameter CC: Joonsoo Kim , Pekka Enberg , Andrew Morton , "linux-mm@kvack.org" , LKML Subject: Re: [PATCH 0/9] re-shrink 'struct page' when SLUB is on. References: <20140103180147.6566F7C1@viggo.jf.intel.com> <20140103141816.20ef2a24c8adffae040e53dc@linux-foundation.org> <20140106043237.GE696@lge.com> <52D05D90.3060809@sr71.net> <20140110153913.844e84755256afd271371493@linux-foundation.org> <52D0854F.5060102@sr71.net> <20140113014408.GA25900@lge.com> <52D41F52.5020805@sr71.net> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/14/2014 12:07 PM, Christoph Lameter wrote: > One easy way to shrink struct page is to simply remove the feature. The > patchset looked a bit complicated and does many other things. Sure. There's a clear path if you only care about 'struct page' size, or if you only care about making the slub fast path as fast as possible. We've got three variables, though: 1. slub fast path speed 2. space overhead from 'struct page' 3. code complexity. Arranged in three basic choices: 1. Big 'struct page', fast, medium complexity code 2. Small 'struct page', slow, lowest complexity 3. Small 'struct page', fast, highest complexity, risk of new code The question is what we should do by _default_, and what we should be recommending for our customers via the distros. Are you saying that you think we should completely rule out even having option 1 in mainline? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/