Messages in this thread | | | Date | Wed, 28 May 2014 13:33:28 +0200 | From | Michal Hocko <> | Subject | Re: [patch 7/9] mm: memcontrol: do not acquire page_cgroup lock for kmem pages |
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On Tue 27-05-14 15:53:42, Johannes Weiner wrote: > On Fri, May 23, 2014 at 03:39:38PM +0200, Michal Hocko wrote: [...] > > > if (!PageCgroupUsed(pc)) > > > return; > > > > > > - lock_page_cgroup(pc); > > > - if (PageCgroupUsed(pc)) { > > > - memcg = pc->mem_cgroup; > > > - ClearPageCgroupUsed(pc); > > > - } > > > - unlock_page_cgroup(pc); > > > > maybe add > > WARN_ON_ONCE(pc->flags != PCG_USED); > > > > to check for an unexpected flags usage in the kmem path? > > There is no overlap between page types that use PCG_USED and those > that don't. What would be the value of adding this?
I meant it as an early warning that something bad is going on.
-- Michal Hocko SUSE Labs
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