Re: [linux-pm] [PATCH 0/8] Suspend block api (version 6)

From: Pavel Machek
Date: Tue May 25 2010 - 03:52:17 EST


Hi!

> > There are several general problems with the design of opportunistic
> > suspend and suspend-blocks.
> >
> > 1. The opportunistic suspend code bypasses existing Linux kernel code,
> > such as timers and the scheduler, that indicates when code
> > needs to run, and when the system is idle.
>
> Whoa! That's not my understanding at all.
>
> As I see it, opportunistic suspend doesn't bypass any code that isn't
> already bypassed by the existing suspend code. Users can do
>
> echo mem >/sys/power/state
>
> whenever they want, without regard to kernel timers and the scheduler
> (other than the fact that the user's thread must be running in order to
> carry out the write, of course).

Yep. And while I'm co-responsible for that interface, I would not
call it exactly nice. Yes, it does the job.

But imagine horrors atd/cron would have to do to work properly with
that interface... setting rtc wakeups etc.

So yes, mem > state already breaks promises, but lets not extend that.

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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