From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755901AbbCBVpv (ORCPT ); Mon, 2 Mar 2015 16:45:51 -0500 Received: from shards.monkeyblade.net ([149.20.54.216]:54194 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755754AbbCBVpt (ORCPT ); Mon, 2 Mar 2015 16:45:49 -0500 Date: Mon, 02 Mar 2015 16:45:45 -0500 (EST) Message-Id: <20150302.164545.1603268042858889224.davem@davemloft.net> To: mhocko@suse.cz Cc: linux-mm@kvack.org, akpm@linux-foundation.org, hannes@cmpxchg.org, rientjes@google.com, david@fromorbit.com, tytso@mit.edu, mgorman@suse.de, penguin-kernel@I-love.SAKURA.ne.jp, sparclinux@vger.kernel.org, vipul@chelsio.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] sparc: clarify __GFP_NOFAIL allocation From: David Miller In-Reply-To: <20150302213610.GA31974@dhcp22.suse.cz> References: <20150302203304.GA20513@dhcp22.suse.cz> <20150302.154424.30182050492471222.davem@davemloft.net> <20150302213610.GA31974@dhcp22.suse.cz> X-Mailer: Mew version 6.5 on Emacs 24.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.7 (shards.monkeyblade.net [149.20.54.216]); Mon, 02 Mar 2015 13:45:49 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Michal Hocko Date: Mon, 2 Mar 2015 22:36:10 +0100 > 920c3ed74134 ([SPARC64]: Add basic infrastructure for MD add/remove > notification.) has added __GFP_NOFAIL for the allocation request but > it hasn't mentioned why is this strict requirement really needed. > The code was handling an allocation failure and propagated it properly > up the callchain so it is not clear why it is needed. > > Dave has clarified the intention when I tried to remove the flag as not > being necessary: > " > It is a serious failure. > > If we miss an MDESC update due to this allocation failure, the update > is not an event which gets retransmitted so we will lose the updated > machine description forever. > > We really need this allocation to succeed. > " > > So add a comment to clarify the nofail flag and get rid of the failure > check because __GFP_NOFAIL allocation doesn't fail. > > Signed-off-by: Michal Hocko Acked-by: David S. Miller