Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751303AbbEFMYp (ORCPT ); Wed, 6 May 2015 08:24:45 -0400 Received: from mx2.parallels.com ([199.115.105.18]:42766 "EHLO mx2.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750770AbbEFMYn (ORCPT ); Wed, 6 May 2015 08:24:43 -0400 Date: Wed, 6 May 2015 15:24:31 +0300 From: Vladimir Davydov To: Michal Hocko CC: Andrew Morton , Johannes Weiner , Tejun Heo , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Greg Thelen , , , Subject: Re: [PATCH 1/2] gfp: add __GFP_NOACCOUNT Message-ID: <20150506122431.GA29387@esperanza> References: <20150506115941.GH14550@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20150506115941.GH14550@dhcp22.suse.cz> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1925 Lines: 43 On Wed, May 06, 2015 at 01:59:41PM +0200, Michal Hocko wrote: > On Tue 05-05-15 12:45:42, Vladimir Davydov wrote: > > Not all kmem allocations should be accounted to memcg. The following > > patch gives an example when accounting of a certain type of allocations > > to memcg can effectively result in a memory leak. > > > This patch adds the __GFP_NOACCOUNT flag which if passed to kmalloc > > and friends will force the allocation to go through the root > > cgroup. It will be used by the next patch. > > The name of the flag is way too generic. It is not clear that the > accounting is KMEMCG related. __GFP_NO_KMEMCG sounds better? > > I was going to suggest doing per-cache rather than gfp flag and that > would actually work just fine for the kmemleak as it uses its own cache > already. But the ida_simple_get would be trickier because it doesn't use > any special cache and more over only one user seem to have a problem so > this doesn't sound like a good fit. I don't think making this flag per-cache is an option either, but for another reason - it would not be possible to merge such a kmem cache with caches without this flag set. As a result, total memory pressure would increase, even for setups without kmem-active memory cgroups, which does not sound acceptable to me. > > So I do not object to opt-out for kmemcg accounting but I really think > the name should be changed. I named it __GFP_NOACCOUNT to match with __GFP_NOTRACK, which is a very specific flag too (kmemcheck), nevertheless it has a rather generic name. Anyways, what else apart from memcg can account kmem so that we have to mention KMEMCG in the flag name explicitly? Thanks, Vladimir -- 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/