From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f180.google.com (mail-wi0-f180.google.com [209.85.212.180]) by kanga.kvack.org (Postfix) with ESMTP id CD59E6B00B9 for ; Tue, 25 Feb 2014 15:36:55 -0500 (EST) Received: by mail-wi0-f180.google.com with SMTP id hm4so1298455wib.7 for ; Tue, 25 Feb 2014 12:36:55 -0800 (PST) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTP id v2si9028948wix.2.2014.02.25.12.36.53 for ; Tue, 25 Feb 2014 12:36:54 -0800 (PST) Message-ID: <530CFEDF.3060801@redhat.com> Date: Tue, 25 Feb 2014 15:36:47 -0500 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [patch 1/2] mm: page_alloc: reset aging cycle with GFP_THISNODE References: <1393360022-22566-1-git-send-email-hannes@cmpxchg.org> In-Reply-To: <1393360022-22566-1-git-send-email-hannes@cmpxchg.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner , Andrew Morton Cc: Jan Stancek , Mel Gorman , linux-mm@kvack.org, linux-kernel@vger.kernel.org On 02/25/2014 03:27 PM, Johannes Weiner wrote: > Jan Stancek reports manual page migration encountering allocation > failures after some pages when there is still plenty of memory free, > and bisected the problem down to 81c0a2bb515f ("mm: page_alloc: fair > zone allocator policy"). > > The problem is that page migration uses GFP_THISNODE and this makes > the page allocator bail out before entering the slowpath entirely, > without resetting the zone round-robin batches. A string of such > allocations will fail long before the node's free memory is exhausted. > > GFP_THISNODE is a special flag for callsites that implement their own > clever node fallback and so no direct reclaim should be invoked. But > if the allocations fail, the fair allocation batches should still be > reset, and if the node is full, it should be aged in the background. > > Make GFP_THISNODE wake up kswapd and reset the zone batches, but bail > out before entering direct reclaim to not stall the allocating task. > > Reported-by: Jan Stancek > Signed-off-by: Johannes Weiner > Cc: # 3.12+ Acked-by: Rik van Riel -- 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