Re: suspend blockers & Android integration

From: Arve Hjønnevåg
Date: Mon Jun 07 2010 - 20:45:10 EST


On Sun, Jun 6, 2010 at 7:43 AM, Matt Helsley <matthltc@xxxxxxxxxx> wrote:
> On Sun, Jun 06, 2010 at 12:36:21PM +0200, Thomas Gleixner wrote:
>> On Sat, 5 Jun 2010, Arve Hjønnevåg wrote:
>
> <snip>
>
>> > events like input event go though a single thread in our system
>> > process, while other events like network packets (which are also
>> > wakeup events) goes directly to the app.
>
> If you want to wake up cgroup-frozen tasks for these fds perhaps your
> framework can fcnt(fd, F_SETOWN, <p[g]id>) to send SIGIO to a

How does the framework get all the fds that are used by the apps for
wakeup events?

> userspace-suspend-blocker thread/process/process group. When IO comes in, the
> suspend blocker is signalled which then unfreezes the cgroup of the frozen
> untrusted task. SIGIO works on pipes, fifos, sockets, ttys, and ptys --
> many of which are precisely the kinds of things that would connect [trusted
> and untrusted] apps. Notably absent (last I checked): inotify fds, signalfd,
> timerfd, eventfd, filesystem fds and likely more.
>
> Incidentally, this is just to show that it's not impossible to implement
> "wakeups" for cgroup-frozen tasks in userspace.
>
> Cheers,
>        -Matt Helsley
>



--
Arve Hjønnevåg
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