Messages in this thread | | | Date | Tue, 13 Aug 2013 11:05:49 -0400 | From | Tejun Heo <> | Subject | Re: [PATCH 2/2] cpuset: remove redundant checks in file write functions |
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On Tue, Aug 13, 2013 at 09:17:53AM +0800, Li Zefan wrote: > Now cgroup core gets a reference to the css when a cgroup file is > opened(), and the reference is dropped at file release. so it's > guaranteed the cpuset is online during the write function.
Hmmm... it doesn't really guarantee that as css's can be offlined with residual css refcnts, os the css may well be offlined by the time it reaches the rw functions. What's guaranteed is that their refcnts wouldn't be zero. Eventually we need to implement proper sever semantics (probably by replacing the custom fs implementation with sysfs) but right now controllers still need to deal with offline css's.
Thanks.
-- tejun
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