Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754867AbbGTLYD (ORCPT ); Mon, 20 Jul 2015 07:24:03 -0400 Received: from mail-wi0-f172.google.com ([209.85.212.172]:36209 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752475AbbGTLYA (ORCPT ); Mon, 20 Jul 2015 07:24:00 -0400 Date: Mon, 20 Jul 2015 13:23:56 +0200 From: Michal Hocko To: Johannes Weiner Cc: Andrew Morton , Vladimir Davydov , Tejun Heo , linux-mm@kvack.org, LKML Subject: Re: [PATCH 1/5] memcg: export struct mem_cgroup Message-ID: <20150720112356.GF1211@dhcp22.suse.cz> References: <1436958885-18754-1-git-send-email-mhocko@kernel.org> <1436958885-18754-2-git-send-email-mhocko@kernel.org> <20150715135711.1778a8c08f2ea9560a7c1f6f@linux-foundation.org> <20150716071948.GC3077@dhcp22.suse.cz> <20150716143433.e43554a19b1c89a8524020cb@linux-foundation.org> <20150716225639.GA11131@cmpxchg.org> <20150716160358.de3404c44ba29dc132032bbc@linux-foundation.org> <20150717122819.GA14895@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150717122819.GA14895@cmpxchg.org> 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: 2392 Lines: 51 On Fri 17-07-15 08:28:19, Johannes Weiner wrote: > On Thu, Jul 16, 2015 at 04:03:58PM -0700, Andrew Morton wrote: > > On Thu, 16 Jul 2015 18:56:39 -0400 Johannes Weiner wrote: > > > > > On Thu, Jul 16, 2015 at 02:34:33PM -0700, Andrew Morton wrote: > > > > On Thu, 16 Jul 2015 09:19:49 +0200 Michal Hocko wrote: > > > > > I agree with Johannes who originally suggested to expose mem_cgroup that > > > > > it will allow for a better code later. > > > > > > > > Sure, but how *much* better? Are there a significant number of > > > > fastpath functions involved? > > > > > > > > From a maintainability/readability point of view, this is quite a bad > > > > patch. It exposes a *lot* of stuff to the whole world. We need to get > > > > a pretty good runtime benefit from doing this to ourselves. I don't > > > > think that saving 376 bytes on a fatconfig build is sufficient > > > > justification? > > > > > > It's not a performance issue for me. Some stuff is hard to read when > > > you have memcg functions with klunky names interrupting the code flow > > > to do something trivial to a struct mem_cgroup member, like > > > mem_cgroup_lruvec_online() and mem_cgroup_get_lru_size(). > > > > > > Maybe we can keep thresholds private and encapsulate the softlimit > > > tree stuff in mem_cgroup_per_zone into something private as well, as > > > this is not used - and unlikely to be used - outside of memcg proper. > > > > > > But otherwise, I think struct mem_cgroup should have mm-scope. > > > > Meaning a new mm/memcontrol.h? That's a bit better I suppose. > > I meant as opposed to being private to memcontrol.c. I'm not sure I > quite see the problem of having these definitions in include/linux, as > long as we keep the stuff that is genuinely only used in memcontrol.c > private to that file. Completely agreed > But mm/memcontrol.h would probably work too. I am not sure this is a good idea. There is a code outside of mm which is using memcg functionality. I do not think we want two sets of header files - one for mm and other for other external users. -- Michal Hocko SUSE Labs -- 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/