From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f173.google.com (mail-wi0-f173.google.com [209.85.212.173]) by kanga.kvack.org (Postfix) with ESMTP id D6875280309 for ; Thu, 16 Jul 2015 18:57:14 -0400 (EDT) Received: by wibud3 with SMTP id ud3so28742294wib.0 for ; Thu, 16 Jul 2015 15:57:14 -0700 (PDT) Received: from gum.cmpxchg.org (gum.cmpxchg.org. [85.214.110.215]) by mx.google.com with ESMTPS id mn10si16246382wjc.72.2015.07.16.15.57.12 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 16 Jul 2015 15:57:13 -0700 (PDT) Date: Thu, 16 Jul 2015 18:56:39 -0400 From: Johannes Weiner Subject: Re: [PATCH 1/5] memcg: export struct mem_cgroup Message-ID: <20150716225639.GA11131@cmpxchg.org> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150716143433.e43554a19b1c89a8524020cb@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Michal Hocko , Vladimir Davydov , Tejun Heo , linux-mm@kvack.org, LKML 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. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org