From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ingo Molnar <mingo@elte.hu>
Subject: Re: suspend blockers & Android integration
Date: Fri, 4 Jun 2010 12:03:06 +0200
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To: Peter Zijlstra <peterz@infradead.org>
Cc: tytso@mit.edu, Brian Swetland <swetland@google.com>, Neil Brown <neilb@suse.de>, Arve Hj?nnev?g <arve@android.com>, Thomas Gleixner <tglx@linutronix.de>, "Rafael J. Wysocki" <rjw@sisk.pl>, Alan Stern <stern@rowland.harvard.edu>, Felipe Balbi <felipe.balbi@nokia.com>, LKML <linux-kernel@vger.kernel.org>, Florian Mickler <florian@mickler.org>, Linux OMAP Mailing List <linux-omap@vger.kernel.org>, Linux PM <linux-pm@lists.linux-foundation.org>, Alan Cox <alan@lxorguk.ukuu.org.uk>, James Bottomley <James.Bottomley@suse.de>, Linus Torvalds <torvalds@linux-foundation.org>, Kevin Hilman <khilman@deeprootsystems.com>, "H. Peter Anvin" <hpa@zytor.com>, Arjan van de Ven <arjan@infradead.org>


* Peter Zijlstra <peterz@infradead.org> wrote:

> On Fri, 2010-06-04 at 11:43 +0200, Peter Zijlstra wrote:
> > I still believe containment is a cgroup problem. The freeze/snapshot/resume
> > container folks seem to face many of the same problems. Including the
> > pending timer one I suspect. Lets solve it there. 
> 
> While talking to Thomas about this, we'd probably need a CLOCK_MONOTONIC 
> namespace to pull this off, so that resumed apps don't see the jump in 
> absolute time.
> 
> This would also help with locating the relevant timers, since they'd be on 
> the related timer base.

Ok - this looks workable, and looks technically isolated that can be pursued 
as a separate module of this whole topic.

> The only 'interesting' issue I can see here is that if you create 1000 
> CLOCK_MONOTONIC namepaces, we'd need to have a tree of trees in order to 
> efficiently find the leftmost timer.

Realistically Android userspace would create just a single such namespace for 
all the untrusted/unknown/uncontrolled apps, right?

	Ingo