From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f170.google.com (mail-pd0-f170.google.com [209.85.192.170]) by kanga.kvack.org (Postfix) with ESMTP id 397B86B0038 for ; Mon, 13 Jan 2014 12:17:36 -0500 (EST) Received: by mail-pd0-f170.google.com with SMTP id z10so2301451pdj.15 for ; Mon, 13 Jan 2014 09:17:35 -0800 (PST) Received: from blackbird.sr71.net (www.sr71.net. [198.145.64.142]) by mx.google.com with ESMTP id dv5si16242648pbb.253.2014.01.13.09.17.33 for ; Mon, 13 Jan 2014 09:17:33 -0800 (PST) Message-ID: <52D41F52.5020805@sr71.net> Date: Mon, 13 Jan 2014 09:16:02 -0800 From: Dave Hansen MIME-Version: 1.0 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: owner-linux-mm@kvack.org List-ID: To: Joonsoo Kim , Christoph Lameter Cc: Pekka Enberg , Andrew Morton , "linux-mm@kvack.org" , LKML 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, 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