From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933212AbeEWOGK (ORCPT ); Wed, 23 May 2018 10:06:10 -0400 Received: from mx2.suse.de ([195.135.220.15]:60404 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932942AbeEWOGH (ORCPT ); Wed, 23 May 2018 10:06:07 -0400 Date: Wed, 23 May 2018 16:06:02 +0200 From: Michal Hocko To: Anshuman Khandual Cc: Andrew Morton , Oscar Salvador , Vlastimil Babka , Pavel Tatashin , Reza Arbab , Igor Mammedov , Vitaly Kuznetsov , LKML , linux-mm@kvack.org Subject: Re: [PATCH 2/2] mm: do not warn on offline nodes unless the specific node is explicitly requested Message-ID: <20180523140601.GQ20441@dhcp22.suse.cz> References: <20180523125555.30039-1-mhocko@kernel.org> <20180523125555.30039-3-mhocko@kernel.org> <11e26a4e-552e-b1dc-316e-ce3e92973556@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <11e26a4e-552e-b1dc-316e-ce3e92973556@linux.vnet.ibm.com> User-Agent: Mutt/1.9.5 (2018-04-13) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 23-05-18 19:15:51, Anshuman Khandual wrote: > On 05/23/2018 06:25 PM, Michal Hocko wrote: > > when adding memory to a node that is currently offline. > > > > The VM_WARN_ON is just too loud without a good reason. In this > > particular case we are doing > > alloc_pages_node(node, GFP_KERNEL|__GFP_RETRY_MAYFAIL|__GFP_NOWARN, order) > > > > so we do not insist on allocating from the given node (it is more a > > hint) so we can fall back to any other populated node and moreover we > > explicitly ask to not warn for the allocation failure. > > > > Soften the warning only to cases when somebody asks for the given node > > explicitly by __GFP_THISNODE. > > node hint passed here eventually goes into __alloc_pages_nodemask() > function which then picks up the applicable zonelist irrespective of > the GFP flag __GFP_THISNODE. __GFP_THISNODE should enforce the given node without any fallbacks unless something has changed recently. > Though we can go into zones of other > nodes if the present node (whose zonelist got picked up) does not > have any memory in it's zones. So warning here might not be without > any reason. I am not sure I follow. Are you suggesting a different VM_WARN_ON? -- Michal Hocko SUSE Labs