Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754763AbaAMRRh (ORCPT ); Mon, 13 Jan 2014 12:17:37 -0500 Received: from www.sr71.net ([198.145.64.142]:42506 "EHLO blackbird.sr71.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752513AbaAMRRd (ORCPT ); Mon, 13 Jan 2014 12:17:33 -0500 Message-ID: <52D41F52.5020805@sr71.net> Date: Mon, 13 Jan 2014 09:16:02 -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: Joonsoo Kim , Christoph Lameter CC: 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> In-Reply-To: <20140113014408.GA25900@lge.com> 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 01/12/2014 05:44 PM, Joonsoo Kim wrote: > We only touch one struct page on small allocation. > In 64-byte case, we always use one cacheline for touching struct page, since > it is aligned to cacheline size. However, in 56-byte case, we possibly use > two cachelines because struct page isn't aligned to cacheline size. I think you're completely correct that this can _happen_, but I'm a bit unconvinced that what you're talking about is the thing which dominates the results. I'm sure it plays a role, but the tests I was doing were doing tens of millions of allocations and touching a _lot_ of 'struct pages'. I would not expect these effects to be observable across such a large sample of pages. -- 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/