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 12/16] hugetlb/cgroup: Add support for cgroup removal
Date: Mon, 11 Jun 2012 21:04:43 +0530 [thread overview]
Message-ID: <87bokpvp4c.fsf@skywalker.in.ibm.com> (raw)
In-Reply-To: <20120611131411.GN12402@tiehlicka.suse.cz>
Michal Hocko <mhocko@suse.cz> writes:
> On Mon 11-06-12 15:10:20, Aneesh Kumar K.V wrote:
>> Michal Hocko <mhocko@suse.cz> writes:
> [...]
>> >> +static int hugetlb_cgroup_move_parent(int idx, struct cgroup *cgroup,
>> >> + struct page *page)
>> >
>> > deserves a comment about the locking (needs to be called with
>> > hugetlb_lock).
>>
>> will do
>>
>> >
>> >> +{
>> >> + int csize;
>> >> + struct res_counter *counter;
>> >> + struct res_counter *fail_res;
>> >> + struct hugetlb_cgroup *page_hcg;
>> >> + struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
>> >> + struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(cgroup);
>> >> +
>> >> + if (!get_page_unless_zero(page))
>> >> + goto out;
>> >> +
>> >> + page_hcg = hugetlb_cgroup_from_page(page);
>> >> + /*
>> >> + * We can have pages in active list without any cgroup
>> >> + * ie, hugepage with less than 3 pages. We can safely
>> >> + * ignore those pages.
>> >> + */
>> >> + if (!page_hcg || page_hcg != h_cg)
>> >> + goto err_out;
>> >
>> > How can we have page_hcg != NULL && page_hcg != h_cg?
>>
>> pages belonging to other cgroup ?
>
> OK, I've forgot that you are iterating over all active huge pages in
> hugetlb_cgroup_pre_destroy. What prevents you from doing the filtering
> in the caller?
> I am also wondering why you need to play with the page reference
> counting here. You are under hugetlb_lock so the page cannot disappear
> in the meantime or am I missing something?
That is correct. Updated the patch and also added the below comment to
the function.
+
+/*
+ * Should be called with hugetlb_lock held.
+ * Since we are holding hugetlb_lock, pages cannot get moved from
+ * active list or uncharged from the cgroup, So no need to get
+ * page reference and test for page active here.
+ */
-aneesh
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next prev parent 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
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 [this message]
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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