Messages in this thread | | | Date | Thu, 18 Oct 2012 15:41:48 -0700 | From | Tejun Heo <> | Subject | Re: [PATCH 4/6] cgroups: forbid pre_destroy callback to fail |
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Hello, Michal.
On Wed, Oct 17, 2012 at 03:30:46PM +0200, Michal Hocko wrote: > Now that mem_cgroup_pre_destroy callback doesn't fail finally we can > safely move on and forbit all the callbacks to fail. The last missing > piece is moving cgroup_call_pre_destroy after cgroup_clear_css_refs so > that css_tryget fails so no new charges for the memcg can happen. > The callbacks are also called from within cgroup_lock to guarantee that > no new tasks show up. We could theoretically call them outside of the > lock but then we have to move after CGRP_REMOVED flag is set. > > Signed-off-by: Michal Hocko <mhocko@suse.cz>
So, the plan is to do something like the following once memcg is ready.
http://thread.gmane.org/gmane.linux.kernel.containers/22559/focus=75251
Note that the patch is broken in a couple places but it does show the general direction. I'd prefer if patch #3 simply makes pre_destroy() return 0 and drop __DEPRECATED_clear_css_refs from mem_cgroup_subsys. Then, I can pull the branch in and drop all the unnecessary cruft.
Thanks.
-- tejun
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