Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752762AbcD1Oz7 (ORCPT ); Thu, 28 Apr 2016 10:55:59 -0400 Received: from pandora.arm.linux.org.uk ([78.32.30.218]:56546 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751910AbcD1Oz6 (ORCPT ); Thu, 28 Apr 2016 10:55:58 -0400 Date: Thu, 28 Apr 2016 15:55:45 +0100 From: Russell King - ARM Linux To: Michal Hocko Cc: Andrew Morton , linux-mm@kvack.org, LKML , Michal Hocko , linux-arch@vger.kernel.org Subject: Re: [PATCH 04/20] arm: get rid of superfluous __GFP_REPEAT Message-ID: <20160428145545.GN19428@n2100.arm.linux.org.uk> References: <1461849846-27209-1-git-send-email-mhocko@kernel.org> <1461849846-27209-5-git-send-email-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1461849846-27209-5-git-send-email-mhocko@kernel.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1237 Lines: 32 On Thu, Apr 28, 2016 at 03:23:50PM +0200, Michal Hocko wrote: > From: Michal Hocko > > __GFP_REPEAT has a rather weak semantic but since it has been introduced > around 2.6.12 it has been ignored for low order allocations. > > PGALLOC_GFP uses __GFP_REPEAT but none of the allocation which uses > this flag is for more than order-2. This means that this flag has never > been actually useful here because it has always been used only for > PAGE_ALLOC_COSTLY requests. I'm unconvinced. Back in 2013, I was seeing a lot of failures, so: commit 8c65da6dc89ccb605d73773b1dd617e72982d971 Author: Russell King Date: Sat Nov 30 12:52:31 2013 +0000 ARM: pgd allocation: retry on failure Make pgd allocation retry on failure; we really need this to succeed otherwise fork() can trigger OOMs. Signed-off-by: Russell King Maybe something has changed again in the MM layer which makes this flag unnecessary again, and it was a temporary blip around that time, I don't know. -- RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.