Re: [PATCH 3/9] PM: suspend_block: Abort task freezing if a suspend_blocker is active.

Rafael J. Wysocki
2009-05-08T23:01:01Z

On Saturday 09 May 2009, Nigel Cunningham wrote:
> Hi.
>
> On Fri, 2009-05-08 at 16:40 +0200, Rafael J. Wysocki wrote:
> > The timeout is actually a workaround for the problem that we don't
> > really
> > know if tasks are going to react to our freeze requests and how much time it is
> > going to take. The current value of 20 s was chosen after a number of
> > experiments showing that in some cases the freezing _was_ going to take so
> > much time. Of course the question is whether it makes sense to give up earlier
> > even if tasks would eventually freeze, but that's a different issue.
>
> What were the circumstances in which freezing could take 20s?

Compiling the kernel with "make -j " on a dual core system IIRC.

Generally, the situation in which there are many runnable tasks and new tasks
come and go etc. I haven't repeated this benchmark recently, though, so it's
probably worth doing again.

Which has a little to do with the $subject patch IMO, because I think that
it's reasonable to stop freezing tasks as soon as we know that it won't be
necessary anyway.

Thanks,
Rafael