Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757869AbbLCHtJ (ORCPT ); Thu, 3 Dec 2015 02:49:09 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:40854 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751446AbbLCHtH (ORCPT ); Thu, 3 Dec 2015 02:49:07 -0500 Date: Thu, 3 Dec 2015 08:49:02 +0100 From: Pavel Machek To: Chris Snook Cc: David Miller , mhocko@kernel.org, akpm@osdl.org, linux-kernel@vger.kernel.org, jcliburn@gmail.com, netdev@vger.kernel.org, rjw@rjwysocki.net, linux-mm@kvack.org, nic-devel@qualcomm.com, ronangeles@gmail.com, ebiederm@xmission.com Subject: Re: [PATCH] Improve Atheros ethernet driver not to do order 4 GFP_ATOMIC allocation Message-ID: <20151203074902.GB4139@amd> References: <20151127082010.GA2500@dhcp22.suse.cz> <20151128145113.GB4135@amd> <20151130132129.GB21950@dhcp22.suse.cz> <20151201.153517.224543138214404348.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: 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: 1825 Lines: 47 On Wed 2015-12-02 22:43:31, Chris Snook wrote: > On Tue, Dec 1, 2015 at 12:35 PM David Miller wrote: > > > From: Michal Hocko > > Date: Mon, 30 Nov 2015 14:21:29 +0100 > > > > > On Sat 28-11-15 15:51:13, Pavel Machek wrote: > > >> > > >> atl1c driver is doing order-4 allocation with GFP_ATOMIC > > >> priority. That often breaks networking after resume. Switch to > > >> GFP_KERNEL. Still not ideal, but should be significantly better. > > > > > > It is not clear why GFP_KERNEL can replace GFP_ATOMIC safely neither > > > from the changelog nor from the patch context. > > > > Earlier in the function we do a GFP_KERNEL kmalloc so: > > > > ¯\_(ツ)_/¯ > > > > It should be fine. > > > > AFAICT, the people who benefit from GFP_ATOMIC are the people running all > their storage over NFS/iSCSI who are suspending their machines while > they're so busy they don't have any clean order 4 pagecache to drop, and > want the machine to panic rather than hang. The people who benefit >from iSCSI on machine that suspends... is that a joke or complicated way of saying that noone benefits? And code uses... both GFP_ATOMIC and GFP_KERNEL so that both sides are equally unhappy? :-). Do you want to test the patch, update the subject line and send it to Davem, or should I do it? Do you see a way to split the allocation? Not even order 4 GFP_KERNEL allocation is a nice thing to do... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/