Re: [PATCH 2/7] freezer: add missing mb's to freezer_count() andfreezer_should_skip()

From: Tejun Heo
Date: Wed Oct 24 2012 - 14:57:09 EST


Hello, Oleg.

On Tue, Oct 23, 2012 at 05:39:19PM +0200, Oleg Nesterov wrote:
> > Hmm.... Guess we should drop __ from set_current_state.
>
> Yes.
>
> Or we can change ptrace_stop() and do_signal_stop() to use freezer_do_not_count/
> freezer_count and remove task_is_stopped_or_traced() from update_if_frozen()
> and try_to_freeze_tasks(). But this means that do_signal_stop() will call
> try_to_freeze() twice, unless we add __freezer_count() which only clears
> PF_FREEZER_SKIP.

Ooh, I like this idea. If we have a mechanism to mark a task "frozen
enough", it makes sense to use it universally. As long as
try_to_freeze() invocation stays outside fast path, I don't think
invoking it twice really matters. Can you please cook up a patch for
it?

Thanks.

--
tejun
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/