From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760739Ab2CNKWN (ORCPT ); Wed, 14 Mar 2012 06:22:13 -0400 Received: from e28smtp08.in.ibm.com ([122.248.162.8]:59182 "EHLO e28smtp08.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760682Ab2CNKWK (ORCPT ); Wed, 14 Mar 2012 06:22:10 -0400 From: "Aneesh Kumar K.V" To: Andrew Morton Cc: linux-mm@kvack.org, mgorman@suse.de, kamezawa.hiroyu@jp.fujitsu.com, dhillf@gmail.com, aarcange@redhat.com, mhocko@suse.cz, hannes@cmpxchg.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org Subject: Re: [PATCH -V3 2/8] memcg: Add HugeTLB extension In-Reply-To: <20120313143316.0ef74d0e.akpm@linux-foundation.org> References: <1331622432-24683-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <1331622432-24683-3-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <20120313143316.0ef74d0e.akpm@linux-foundation.org> User-Agent: Notmuch/0.11.1+190~g31a336a (http://notmuchmail.org) Emacs/23.3.1 (x86_64-pc-linux-gnu) Date: Wed, 14 Mar 2012 15:51:50 +0530 Message-ID: <87zkbj8ou9.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii x-cbid: 12031410-2000-0000-0000-000006C2098E Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 13 Mar 2012 14:33:16 -0700, Andrew Morton wrote: > On Tue, 13 Mar 2012 12:37:06 +0530 > "Aneesh Kumar K.V" wrote: > > > +static int mem_cgroup_hugetlb_usage(struct mem_cgroup *memcg) > > +{ > > + int idx; > > + for (idx = 0; idx < hugetlb_max_hstate; idx++) { > > + if (memcg->hugepage[idx].usage > 0) > > + return memcg->hugepage[idx].usage; > > + } > > + return 0; > > +} > > Please document the function? Had you done this, I might have been > able to work out why the function bales out on the first used hugepage > size, but I can't :( I guess the function is named wrongly. I will rename it to mem_cgroup_have_hugetlb_usage() in the next iteration ? The function will return (bool) 1 if it has any hugetlb resource usage. > > This could have used for_each_hstate(), had that macro been better > designed (or updated). > Can you explain this ?. for_each_hstate allows to iterate over different hstates. But here we need to look at different hugepage rescounter in memcg. I can still use for_each_hstate() and find the hstate index (h - hstates) and use that to index memcg rescounter array. But that would make it more complex ? > Upon return this function coerces an unsigned long long into an "int". > We decided last week that more than 2^32 hugepages was not > inconceivable, so I guess that's a bug. > -aneesh