From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753729AbeDPM1v (ORCPT ); Mon, 16 Apr 2018 08:27:51 -0400 Received: from mx2.suse.de ([195.135.220.15]:41424 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752496AbeDPM1u (ORCPT ); Mon, 16 Apr 2018 08:27:50 -0400 Date: Mon, 16 Apr 2018 14:27:47 +0200 From: Michal Hocko To: Vlastimil Babka Cc: Johannes Weiner , Minchan Kim , Roman Gushchin , linux-mm@kvack.org, Andrew Morton , Alexander Viro , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 3/3] dcache: account external names as indirectly reclaimable memory Message-ID: <20180416122747.GM17484@dhcp22.suse.cz> References: <20180305133743.12746-1-guro@fb.com> <20180305133743.12746-5-guro@fb.com> <20180413133519.GA213834@rodete-laptop-imager.corp.google.com> <20180413135923.GT17484@dhcp22.suse.cz> <13f1f5b5-f3f8-956c-145a-4641fb996048@suse.cz> <20180413142821.GW17484@dhcp22.suse.cz> <20180413143716.GA5378@cmpxchg.org> <20180416114144.GK17484@dhcp22.suse.cz> <1475594b-c1ad-9625-7aeb-ad8ad385b793@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1475594b-c1ad-9625-7aeb-ad8ad385b793@suse.cz> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 16-04-18 14:06:21, Vlastimil Babka wrote: > On 04/16/2018 01:41 PM, Michal Hocko wrote: > > On Fri 13-04-18 10:37:16, Johannes Weiner wrote: > >> On Fri, Apr 13, 2018 at 04:28:21PM +0200, Michal Hocko wrote: > >>> On Fri 13-04-18 16:20:00, Vlastimil Babka wrote: > >>>> We would need kmalloc-reclaimable-X variants. It could be worth it, > >>>> especially if we find more similar usages. I suspect they would be more > >>>> useful than the existing dma-kmalloc-X :) > >>> > >>> I am still not sure why __GFP_RECLAIMABLE cannot be made work as > >>> expected and account slab pages as SLAB_RECLAIMABLE > >> > >> Can you outline how this would work without separate caches? > > > > I thought that the cache would only maintain two sets of slab pages > > depending on the allocation reuquests. I am pretty sure there will be > > other details to iron out and > > For example the percpu (and other) array caches... > > > maybe it will turn out that such a large > > portion of the chache would need to duplicate the state that a > > completely new cache would be more reasonable. > > I'm afraid that's the case, yes. > > > Is this worth exploring > > at least? I mean something like this should help with the fragmentation > > already AFAIU. Accounting would be just free on top. > > Yep. It could be also CONFIG_urable so smaller systems don't need to > deal with the memory overhead of this. > > So do we put it on LSF/MM agenda? If you volunteer to lead the discussion, then I do not have any objections. -- Michal Hocko SUSE Labs