Re: [PATCH 1/8] PM: Add suspend block api.

Matthew Garrett
2010-05-07T17:12:18Z

On Thu, May 06, 2010 at 07:05:41PM -0700, Tony Lindgren wrote:
> * Matthew Garrett <mjg@redhat.com> [100506 11:39]:
> > And the untrusted userspace code that's waiting for a network packet?
> > Adding a few seconds of latency isn't an option here.
>
> Hmm well hitting retention and wake you can basically do between
> jiffies. Hitting off mode in idle has way longer latencies,
> but still in few hundred milliseconds or so, not seconds.

The situation is this. You've frozen most of your userspace because you
don't trust the applications. One of those applications has an open
network socket, and policy indicates that receiving a network packet
should generate a wakeup, allow the userspace application to handle the
packet and then return to sleep. What mechanism do you use to do that?

--
Matthew Garrett | mjg59@srcf.ucam.org