Messages in this thread | | | Date | Fri, 19 Oct 2012 17:33:18 +0800 | From | Li Zefan <> | Subject | Re: [PATCH 4/6] cgroups: forbid pre_destroy callback to fail |
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On 2012/10/17 21:30, 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.
I'm afraid this won't work. See commit 3fa59dfbc3b223f02c26593be69ce6fc9a940405 ("cgroup: fix potential deadlock in pre_destroy")
> 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> > --- > kernel/cgroup.c | 30 +++++++++--------------------- > 1 file changed, 9 insertions(+), 21 deletions(-)
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