From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx110.postini.com [74.125.245.110]) by kanga.kvack.org (Postfix) with SMTP id DABC36B005C for ; Tue, 12 Jun 2012 06:50:22 -0400 (EDT) Received: from /spool/local by e23smtp08.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 12 Jun 2012 10:47:12 +1000 Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q5CAoC3t3998024 for ; Tue, 12 Jun 2012 20:50:13 +1000 Received: from d23av04.au.ibm.com (loopback [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q5CAoBMC013042 for ; Tue, 12 Jun 2012 20:50:12 +1000 From: "Aneesh Kumar K.V" 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> 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 Sender: owner-linux-mm@kvack.org List-ID: 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 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, 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