Messages in this thread | | | Date | Fri, 9 Jan 2009 13:47:36 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [RFC][PATCH 1/4] memcg: fix for mem_cgroup_get_reclaim_stat_from_page |
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On Fri, 9 Jan 2009 10:02:57 +0530 Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
> > pc = lookup_page_cgroup(page); > > + smp_rmb(); > > Do you really need the read memory barrier? > Necessary.
> > + if (!PageCgroupUsed(pc)) > > + return NULL; > > + > > In this case we've hit a case where the page is valid and the pc is > not. This does fix the problem, but won't this impact us getting > correct reclaim stats and thus indirectly impact the working of > pressure? > - If retruns NULL, only global LRU's status is updated.
Because this page is not belongs to any memcg, we cannot update any counters. But yes, your point is a concern.
Maybe moving acitvate_page() to == do_swap_page() { - activate_page() mem_cgroup_try_charge().. .... mem_cgroup_commit_charge().... .... + activate_page() } == is necessary. How do you think, kosaki ?
Thanks, -Kame
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