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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: Michal Hocko <mhocko@suse.cz>
Cc: linux-mm@kvack.org, kamezawa.hiroyu@jp.fujitsu.com,
	dhillf@gmail.com, rientjes@google.com, 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
Date: Mon, 11 Jun 2012 21:05:30 +0530	[thread overview]
Message-ID: <878vftvp31.fsf@skywalker.in.ibm.com> (raw)
In-Reply-To: <20120611125952.GM12402@tiehlicka.suse.cz>

Michal Hocko <mhocko@suse.cz> writes:

> On Mon 11-06-12 14:58:45, Aneesh Kumar K.V wrote:
>> Michal Hocko <mhocko@suse.cz> writes:
>> 
>> > On Sat 09-06-12 14:29:56, Aneesh Kumar K.V wrote:
>> >> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
>> >> 
>> >> This patchset add the charge and uncharge routines for hugetlb cgroup.
>> >> This will be used in later patches when we allocate/free HugeTLB
>> >> pages.
>> >
>> > Please describe the locking rules.
>> 
>> All the update happen within hugetlb_lock.
>
> Yes, I figured but it is definitely worth mentioning in the patch
> description.

Done.

>
> [...]
>> >> +void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
>> >> +				  struct hugetlb_cgroup *h_cg,
>> >> +				  struct page *page)
>> >> +{
>> >> +	if (hugetlb_cgroup_disabled() || !h_cg)
>> >> +		return;
>> >> +
>> >> +	spin_lock(&hugetlb_lock);
>> >> +	if (hugetlb_cgroup_from_page(page)) {
>> >
>> > How can this happen? Is it possible that two CPUs are trying to charge
>> > one page?
>> 
>> That is why I added that. I looked at the alloc_huge_page, and I
>> don't see we would end with same page from different CPUs but then
>> we have similar checks in memcg, where we drop the charge if we find
>> the page cgroup already used.
>
> Yes but memcg is little bit more complicated than hugetlb which has
> which doesn't have to cope with async charges. Hugetlb allocation is
> serialized by hugetlb_lock so only one caller gets the page.
> I do not think the check is required here or add a comment explaining
> how it can happen.
>

updated.

-aneesh

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  reply	other threads:[~2012-06-11 15:35 UTC|newest]

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-09  8:59 [PATCH -V8 00/16] hugetlb: Add HugeTLB controller to control HugeTLB allocation Aneesh Kumar K.V
2012-06-09  8:59 ` [PATCH -V8 01/16] hugetlb: rename max_hstate to hugetlb_max_hstate Aneesh Kumar K.V
2012-06-09  8:59 ` [PATCH -V8 02/16] hugetlb: don't use ERR_PTR with VM_FAULT* values Aneesh Kumar K.V
2012-06-09 11:10   ` Konrad Rzeszutek Wilk
2012-06-09 13:17     ` Aneesh Kumar K.V
2012-06-09 19:28   ` KOSAKI Motohiro
2012-06-10  1:59   ` Hillf Danton
2012-06-09  8:59 ` [PATCH -V8 03/16] hugetlb: add an inline helper for finding hstate index Aneesh Kumar K.V
2012-06-09  8:59 ` [PATCH -V8 04/16] hugetlb: use mmu_gather instead of a temporary linked list for accumulating pages Aneesh Kumar K.V
2012-06-09  8:59 ` [PATCH -V8 05/16] hugetlb: avoid taking i_mmap_mutex in unmap_single_vma() for hugetlb Aneesh Kumar K.V
2012-06-09  9:44   ` Johannes Weiner
2012-06-09 13:03     ` Aneesh Kumar K.V
2012-06-09 14:49       ` Johannes Weiner
2012-06-09  8:59 ` [PATCH -V8 06/16] hugetlb: simplify migrate_huge_page() Aneesh Kumar K.V
2012-06-12  7:31   ` Kamezawa Hiroyuki
2012-06-09  8:59 ` [PATCH -V8 07/16] hugetlb: add a list for tracking in-use HugeTLB pages Aneesh Kumar K.V
2012-06-09  8:59 ` [PATCH -V8 08/16] hugetlb: Make some static variables global Aneesh Kumar K.V
2012-06-12  7:35   ` Kamezawa Hiroyuki
2012-06-09  8:59 ` [PATCH -V8 09/16] mm/hugetlb: Add new HugeTLB cgroup Aneesh Kumar K.V
2012-06-12  7:46   ` Kamezawa Hiroyuki
2012-06-12  9:37     ` Aneesh Kumar K.V
2012-06-09  8:59 ` [PATCH -V8 10/16] hugetlb/cgroup: Add the cgroup pointer to page lru Aneesh Kumar K.V
2012-06-09 11:14   ` Konrad Rzeszutek Wilk
2012-06-09 17:04   ` Aneesh Kumar K.V
2012-06-11  8:16   ` Michal Hocko
2012-06-11  9:03     ` Aneesh Kumar K.V
2012-06-11  9:16       ` Michal Hocko
2012-06-11  9:33         ` Aneesh Kumar K.V
2012-06-11  8:41   ` Kamezawa Hiroyuki
2012-06-12  7:52   ` Kamezawa Hiroyuki
2012-06-12  9:40     ` Aneesh Kumar K.V
2012-06-09  8:59 ` [PATCH -V8 11/16] hugetlb/cgroup: Add charge/uncharge routines for hugetlb cgroup Aneesh Kumar K.V
2012-06-11  8:38   ` Michal Hocko
2012-06-11  9:10     ` Michal Hocko
2012-06-11  9:28     ` Aneesh Kumar K.V
2012-06-11 12:59       ` Michal Hocko
2012-06-11 15:35         ` Aneesh Kumar K.V [this message]
2012-06-12  8:08   ` Kamezawa Hiroyuki
2012-06-12 10:50     ` Aneesh Kumar K.V
2012-06-13 11:02       ` Kamezawa Hiroyuki
2012-06-09  8:59 ` [PATCH -V8 12/16] hugetlb/cgroup: Add support for cgroup removal Aneesh Kumar K.V
2012-06-11  8:52   ` Michal Hocko
2012-06-11  9:40     ` Aneesh Kumar K.V
2012-06-11 13:14       ` Michal Hocko
2012-06-11 15:34         ` Aneesh Kumar K.V
2012-06-12  8:23   ` Kamezawa Hiroyuki
2012-06-12 10:52     ` Aneesh Kumar K.V
2012-06-09  8:59 ` [PATCH -V8 13/16] hugetlb/cgroup: add hugetlb cgroup control files Aneesh Kumar K.V
2012-06-09 11:19   ` Konrad Rzeszutek Wilk
2012-06-11  9:02   ` Michal Hocko
2012-06-11  9:43     ` Aneesh Kumar K.V
2012-06-11 13:15       ` Michal Hocko
2012-06-12  8:35   ` Kamezawa Hiroyuki
2012-06-12 10:58     ` Aneesh Kumar K.V
2012-06-13  0:16       ` Kamezawa Hiroyuki
2012-06-09  8:59 ` [PATCH -V8 14/16] hugetlb/cgroup: add charge/uncharge calls for HugeTLB alloc/free Aneesh Kumar K.V
2012-06-09  9:23   ` Johannes Weiner
2012-06-09 13:09     ` Aneesh Kumar K.V
2012-06-09 14:30       ` Johannes Weiner
2012-06-09 15:55         ` Aneesh Kumar K.V
2012-06-11  9:19         ` Michal Hocko
2012-06-11  9:21   ` Michal Hocko
2012-06-11 10:29     ` Aneesh Kumar K.V
2012-06-09  9:00 ` [PATCH -V8 15/16] hugetlb/cgroup: migrate hugetlb cgroup info from oldpage to new page during migration Aneesh Kumar K.V
2012-06-11  9:24   ` Michal Hocko
2012-06-11 10:17     ` Aneesh Kumar K.V
2012-06-12  8:51   ` Kamezawa Hiroyuki
2012-06-12 11:00     ` Aneesh Kumar K.V
2012-06-13 11:15       ` Kamezawa Hiroyuki
2012-06-09  9:00 ` [PATCH -V8 16/16] hugetlb/cgroup: add HugeTLB controller documentation Aneesh Kumar K.V
2012-06-12  8:57   ` Kamezawa Hiroyuki

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