Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752465Ab2FLKuY (ORCPT ); Tue, 12 Jun 2012 06:50:24 -0400 Received: from e23smtp08.au.ibm.com ([202.81.31.141]:49462 "EHLO e23smtp08.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752170Ab2FLKuT (ORCPT ); Tue, 12 Jun 2012 06:50:19 -0400 From: "Aneesh Kumar K.V" To: Kamezawa Hiroyuki Cc: linux-mm@kvack.org, dhillf@gmail.com, rientjes@google.com, mhocko@suse.cz, akpm@linux-foundation.org, hannes@cmpxchg.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org Subject: Re: [PATCH -V8 11/16] hugetlb/cgroup: Add charge/uncharge routines for hugetlb cgroup In-Reply-To: <4FD6F8F9.2040901@jp.fujitsu.com> References: <1339232401-14392-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <1339232401-14392-12-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <4FD6F8F9.2040901@jp.fujitsu.com> User-Agent: Notmuch/0.13.2+35~g0ff57e7 (http://notmuchmail.org) Emacs/24.1.50.1 (x86_64-unknown-linux-gnu) Date: Tue, 12 Jun 2012 16:20:03 +0530 Message-ID: <87ipewold0.fsf@skywalker.in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain x-cbid: 12061200-5140-0000-0000-0000019047FB Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2661 Lines: 90 Kamezawa Hiroyuki writes: > (2012/06/09 17:59), Aneesh Kumar K.V wrote: >> From: "Aneesh Kumar K.V" >> >> This patchset add the charge and uncharge routines for hugetlb cgroup. >> This will be used in later patches when we allocate/free HugeTLB >> pages. >> >> Signed-off-by: Aneesh Kumar K.V > > > I'm sorry if following has been already pointed out. > >> --- >> mm/hugetlb_cgroup.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 87 insertions(+) >> >> diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c >> index 20a32c5..48efd5a 100644 >> --- a/mm/hugetlb_cgroup.c >> +++ b/mm/hugetlb_cgroup.c >> @@ -105,6 +105,93 @@ static int hugetlb_cgroup_pre_destroy(struct cgroup *cgroup) >> return -EBUSY; >> } >> >> +int hugetlb_cgroup_charge_page(int idx, unsigned long nr_pages, >> + struct hugetlb_cgroup **ptr) >> +{ >> + int ret = 0; >> + struct res_counter *fail_res; >> + struct hugetlb_cgroup *h_cg = NULL; >> + unsigned long csize = nr_pages * PAGE_SIZE; >> + >> + if (hugetlb_cgroup_disabled()) >> + goto done; >> + /* >> + * We don't charge any cgroup if the compound page have less >> + * than 3 pages. >> + */ >> + if (hstates[idx].order< 2) >> + goto done; >> +again: >> + rcu_read_lock(); >> + h_cg = hugetlb_cgroup_from_task(current); >> + if (!h_cg) >> + h_cg = root_h_cgroup; >> + >> + if (!css_tryget(&h_cg->css)) { >> + rcu_read_unlock(); >> + goto again; >> + } >> + rcu_read_unlock(); >> + >> + ret = res_counter_charge(&h_cg->hugepage[idx], csize,&fail_res); >> + css_put(&h_cg->css); >> +done: >> + *ptr = h_cg; >> + return ret; >> +} >> + > > Memory cgroup uses very complicated 'charge' routine for handling pageout... > which gets sleep. > > For hugetlbfs, it has not sleep routine, you can do charge in simple way. > I guess...get/put here is overkill. > > For example, h_cg cannot be freed while it has tasks. So, if 'current' is > belongs to the cgroup, it cannot be disappear. Then, you don't need get/put, > additional atomic ops for holding cgroup. > > rcu_read_lock(); > h_cg = hugetlb_cgroup_from_task(current); > ret = res_counter_charge(&h_cg->hugetpage[idx], csize, &fail_res); > rcu_read_unlock(); > > return ret; > What if the task got moved ot of the cgroup and cgroup got deleted by an rmdir ? -aneesh -- 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/