Re: [PATCH 3/3] cgroup: remove CGRP_RELEASABLE flag

[Tejun Heo <tj@kernel.org>]

On Fri, Sep 19, 2014 at 04:51:00PM +0800, Zefan Li wrote:
> We call put_css_set() after setting CGRP_RELEASABLE flag in
> cgroup_task_migrate(), but in other places we call it without setting
> the flag. I don't see the necessity of this flag.
> 
> Moreover once the flag is set, it will never be cleared, unless writing
> to the notify_on_release control file, so it can be quite confusing
> if we look at the output of debug.releasable.
> 
>   # mount -t cgroup -o debug xxx /cgroup
>   # mkdir /cgroup/child
>   # cat /cgroup/child/debug.releasable
>   0   <-- shows 0 though the cgroup is empty
>   # echo $$ > /cgroup/child/tasks
>   # cat /cgroup/child/debug.releasable
>   0
>   # echo $$ > /cgroup/tasks && echo $$ > /cgroup/child/tasks
>   # cat /proc/child/debug.releasable
>   1   <-- shows 1 though the cgroup is not empty
> 
> This patch removes the flag, and now debug.releasable shows if the
> cgroup is empty or not.
> 
> Signed-off-by: Zefan Li <lizefan@huawei.com>

Applied to cgroup/for-3.18.

Thanks.

-- 
tejun