Messages in this thread Patch in this message | | | Date | Mon, 11 Jun 2012 11:16:58 +0200 | From | Michal Hocko <> | Subject | Re: [PATCH -V8 10/16] hugetlb/cgroup: Add the cgroup pointer to page lru |
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On Mon 11-06-12 14:33:52, Aneesh Kumar K.V wrote: > Michal Hocko <mhocko@suse.cz> writes: > > > On Sat 09-06-12 14:29:55, Aneesh Kumar K.V wrote: > >> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> > >> > >> 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@linux.vnet.ibm.com> > > > > 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
> >> @@ -591,6 +592,7 @@ static void update_and_free_page(struct hstate *h, struct page *page) > >> 1 << PG_active | 1 << PG_reserved | > >> 1 << PG_private | 1 << PG_writeback); > >> } > >> + BUG_ON(hugetlb_cgroup_from_page(page)); > > > > What about VM_BUG_ON? > > Will do, So when do one decide to choose VM_BUG_ON against BUG_ON ?
I think that VM_ variant is more approapriate here because it is more a debugging thing rather than a hard failure invariant.
-- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic
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