Re: [ckrm-tech] [PATCH 1/7] containers (V7): Generic container system abstracted from cpusets code

From: Paul Menage
Date: Thu Mar 08 2007 - 05:40:53 EST


On 3/8/07, Srivatsa Vaddagiri <vatsa@xxxxxxxxxx> wrote:
On Wed, Mar 07, 2007 at 12:50:03PM -0800, Paul Menage wrote:
> The callback mutex (which is what container_lock() actually locks) is
> also used to synchronize fork/exit against subsystem additions, in the
> event that some subsystem has registered fork or exit callbacks. We
> could probably have a separate subsystem_mutex for that instead.

Why can't manage_mutex itself be used there (to serialize fork/exit callbacks
against modification to hierarchy)?

Because manage_mutex can be held for very long periods of time. I
think that a combination of a new lock that's only taken by fork/exit
and register_subsys, plus task_lock (which prevents the current task
from being moved) would be more lightweight.

Paul
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