Re: [PATCH 1/3] cpuset: clean up cpuset hierarchy traversal code

[Paul Jackson <pj@sgi.com>]

Li Zefan wrote:
> +	list_add(&top_cpuset.stack_list, &q);

Can you figure out if we are holding any system wide lock, such as
cgroup_mutex, at this point?  There is only one top_cpuset.stack_list
in the system, so I would think that we need to single thread its usage
somehow.

The hotplug hooks, such as common_cpu_mem_hotplug_unplug() that were
added sometime in the last few months (while the so called maintainer,
who's initials seem to be 'pj', was asleep ;) don't describe what
locking applies to them very well, and they call rebuild_sched_domains(),
where the above line of code lives.

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                  Paul Jackson <pj@sgi.com> 1.940.382.4214