From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx186.postini.com [74.125.245.186]) by kanga.kvack.org (Postfix) with SMTP id 5C0C36B0032 for ; Mon, 22 Jul 2013 12:49:02 -0400 (EDT) Message-ID: <51ED6274.3000509@bitsync.net> Date: Mon, 22 Jul 2013 18:48:52 +0200 From: Zlatko Calusic MIME-Version: 1.0 Subject: Re: [patch 0/3] mm: improve page aging fairness between zones/nodes References: <1374267325-22865-1-git-send-email-hannes@cmpxchg.org> In-Reply-To: <1374267325-22865-1-git-send-email-hannes@cmpxchg.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: Andrew Morton , Mel Gorman , Rik van Riel , Andrea Arcangeli , linux-mm@kvack.org, linux-kernel@vger.kernel.org On 19.07.2013 22:55, Johannes Weiner wrote: > The way the page allocator interacts with kswapd creates aging > imbalances, where the amount of time a userspace page gets in memory > under reclaim pressure is dependent on which zone, which node the > allocator took the page frame from. > > #1 fixes missed kswapd wakeups on NUMA systems, which lead to some > nodes falling behind for a full reclaim cycle relative to the other > nodes in the system > > #3 fixes an interaction where kswapd and a continuous stream of page > allocations keep the preferred zone of a task between the high and > low watermark (allocations succeed + kswapd does not go to sleep) > indefinitely, completely underutilizing the lower zones and > thrashing on the preferred zone > > These patches are the aging fairness part of the thrash-detection > based file LRU balancing. Andrea recommended to submit them > separately as they are bugfixes in their own right. > I have the patch applied and under testing. So far, so good. It looks like it could finally fix the bug that I was chasing few months ago (nicely described in your bullet #3). But, few more days of testing will be needed before I can reach a quality verdict. Good job! -- Zlatko -- 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