From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx183.postini.com [74.125.245.183]) by kanga.kvack.org (Postfix) with SMTP id 46E586B0031 for ; Fri, 7 Jun 2013 13:09:38 -0400 (EDT) Message-ID: <51B213CB.8070102@yandex-team.ru> Date: Fri, 07 Jun 2013 21:09:31 +0400 From: Roman Gushchin MIME-Version: 1.0 Subject: Re: slub: slab order on multi-processor machines References: <51B1A04B.7030003@yandex-team.ru> <0000013f1efbaa4f-6039ad3e-286e-4486-8b7e-7b0331edf990-000000@email.amazonses.com> In-Reply-To: <0000013f1efbaa4f-6039ad3e-286e-4486-8b7e-7b0331edf990-000000@email.amazonses.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: penberg@kernel.org, mpm@selenic.com, yanmin.zhang@intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org On 07.06.2013 18:12, Christoph Lameter wrote: > On Fri, 7 Jun 2013, Roman Gushchin wrote: > >> As I understand, the idea was to make kernel allocations cheaper by reducing >> the total >> number of page allocations (allocating 1 page with order 3 is cheaper than >> allocating >> 8 1-ordered pages). > > Its also affecting allocator speed. By having less page structures to > manage the metadata effort is reduced. By having more objects in a page > the fastpath of slub is more likely to be used (Visible in allocator > benchmarks). Slub can fall back dynamically to order 0 pages if necessary. > So it can take opportunistically take advantage of contiguous pages. Thank you for clarification! May be it's reasonable to fall back to order 0 pages if it's not possible to allocate new large page without direct compaction? I'll try to perform some tests here. Regards, Roman -- 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