| Date | Mon, 28 Nov 2011 12:33:31 +0530 | Subject | Re: [patch 4/8] mm: memcg: lookup_page_cgroup (almost) never returns NULL | From | Balbir Singh <> |
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On Wed, Nov 23, 2011 at 9:12 PM, Johannes Weiner <hannes@cmpxchg.org> wrote: > From: Johannes Weiner <jweiner@redhat.com> > > Pages have their corresponding page_cgroup descriptors set up before > they are used in userspace, and thus managed by a memory cgroup. > > The only time where lookup_page_cgroup() can return NULL is in the > page sanity checking code that executes while feeding pages into the > page allocator for the first time. >
This is a legacy check from the days when we allocated PC during fault time on demand. It might make sense to assert on !pc in DEBUG_VM mode at some point in the future
Balbir
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