From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx176.postini.com [74.125.245.176]) by kanga.kvack.org (Postfix) with SMTP id E3B7D6B0032 for ; Mon, 22 Jul 2013 16:21:12 -0400 (EDT) Message-ID: <51ED9433.60707@redhat.com> Date: Mon, 22 Jul 2013 16:21:07 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [patch 3/3] mm: page_alloc: fair zone allocator policy References: <1374267325-22865-1-git-send-email-hannes@cmpxchg.org> <1374267325-22865-4-git-send-email-hannes@cmpxchg.org> In-Reply-To: <1374267325-22865-4-git-send-email-hannes@cmpxchg.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: Andrew Morton , Mel Gorman , Andrea Arcangeli , linux-mm@kvack.org, linux-kernel@vger.kernel.org On 07/19/2013 04:55 PM, Johannes Weiner wrote: > @@ -1984,7 +1992,8 @@ this_zone_full: > goto zonelist_scan; > } > > - if (page) > + if (page) { > + atomic_sub(1U << order, &zone->alloc_batch); > /* > * page->pfmemalloc is set when ALLOC_NO_WATERMARKS was > * necessary to allocate the page. The expectation is Could this be moved into the slow path in buffered_rmqueue and rmqueue_bulk, or would the effect of ignoring the pcp buffers be too detrimental to keeping the balance between zones? It would be kind of nice to not have this atomic operation on every page allocation... As a side benefit, higher-order buffered_rmqueue and rmqueue_bulk both happen under the zone->lock, so moving this accounting down to that layer might allow you to get rid of the atomics alltogether. I like the overall approach though. This is something Linux has needed for a long time, and could be extremely useful to automatic NUMA balancing as well... -- All rights reversed -- 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