Re: [PATCH -V8 10/16] hugetlb/cgroup: Add the cgroup pointer to page lru

[Aneesh Kumar K.V]

Michal Hocko <mhocko@xxxxxxx> writes:

> On Mon 11-06-12 14:33:52, Aneesh Kumar K.V wrote:
>> Michal Hocko <mhocko@xxxxxxx> writes:
>> 
>> > On Sat 09-06-12 14:29:55, Aneesh Kumar K.V wrote:
>> >> From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
>> >> 
>> >> Add the hugetlb cgroup pointer to 3rd page lru.next.
>> >
>> > Interesting and I really like the idea much more than tracking by
>> > page_cgroup.
>> >
>> >> This limit the usage to hugetlb cgroup to only hugepages with 3 or
>> >> more normal pages. I guess that is an acceptable limitation.
>> >
>> > Agreed.
>> >
>> >> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
>> >
>> > Other than some nits I like this.
>> > Thanks!
>> >
>> >> ---
>> >>  include/linux/hugetlb_cgroup.h |   31 +++++++++++++++++++++++++++++++
>> >>  mm/hugetlb.c                   |    4 ++++
>> >>  2 files changed, 35 insertions(+)
>> >> 
>> >> diff --git a/include/linux/hugetlb_cgroup.h b/include/linux/hugetlb_cgroup.h
>> >> index 5794be4..ceff1d5 100644
>> >> --- a/include/linux/hugetlb_cgroup.h
>> >> +++ b/include/linux/hugetlb_cgroup.h
>> >> @@ -26,6 +26,26 @@ struct hugetlb_cgroup {
>> >>  };
>> >>  
>> >>  #ifdef CONFIG_CGROUP_HUGETLB_RES_CTLR
>> >> +static inline struct hugetlb_cgroup *hugetlb_cgroup_from_page(struct page *page)
>> >> +{
>> >> +	if (!PageHuge(page))
>> >> +		return NULL;
>> >> +	if (compound_order(page) < 3)
>> >
>> > Why 3? I think you wanted 2 here, right?
>> 
>> Yes that should be 2. I updated that in an earlier. Already in v9
>> version I have locally.
>
> ohh, I should have read replies to the patch first where you already
> mentioned that you are aware of that.
> Maybe it would be worth something like:
> /* Minimum page order trackable by hugetlb cgroup.
>  * At least 3 pages are necessary for all the tracking information.
>  */
> #define HUGETLB_CGROUP_MIN_ORDER	2

Excellent will do that.

-aneesh

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