Re: [RFC][PATCH -mm] Freezer: Handle uninterruptible tasks

From: Oliver Neukum
Date: Fri Jul 06 2007 - 18:38:42 EST


Am Freitag, 6. Juli 2007 schrieb Oleg Nesterov:
> Rafael J. Wysocki wrote:
> >
> > This patch makes the freezer skip uninterruptible user space tasks (ie. such
> > that have an mm of their own) when counting the tasks to be frozen.  As a
> > result, these tasks have the TIF_FREEZE and TIF_SIGPENDING flags set, but the
> > freezer doesn't wait for them to enter the refrigerator.  Nevertheless, they
> > will enter the refrigerator as soon as they change their state.
>
> A small correction: they will enter the refrigerator on return to user-space.

That is too late. We would need them to go to sleep as soon as they are
woken up. This does not matter if they are in uninterruptible sleep due to
fuse deadlocking, as they won't be woken up, but it kills the other cases.

Regards
Oliver
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