Re: Containers: css_put() dilemma

["Paul (宝瑠) Menage" <menage@google.com>]

On 7/17/07, Paul Jackson <pj@sgi.com> wrote:
>
> At least for cpusets (the mother of all containers), notify on release
> is part of the user visible API of cpusets.  The kernel does not remove
> cpusets; it runs a user program, /sbin/cpuset_release_agent.  That
> program might choose to rmdir the cpuset directory, and/or do other
> actions, like notify a batch scheduler that one of its cpusets was
> released.

Right, that's what the release agent patch for process containers does
- there's a file in the hierarchy root called "release_agent" that
contains the path to the program to run if a notify_on_release
container goes idle. When you mount the "cpuset" filesystem, it
automatically populates that file with "/sbin/cpuset_release_agent". A
workqueue task is used to actually do the notifications so that
references can be dropped without having to potentially run a
userspace helper.

Paul