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SubjectRe: [PATCH 0/5] ia64 ski emulator patches
Mikael Pettersson writes:
> Mikulas Patocka writes:
> >
> >
> > On Sat, 25 Jan 2014, Mikael Pettersson wrote:
> >
> > > My ski patches are in <http://user.it.uu.se/~mikpe/linux/patches/ia64/ski-1.3.2/>
> > > for now. I'll post the kernel patches to linux-ia64 @ vger in a few minutes.
> > >
> > > /Mikael
> >
> > Thanks for the patches.
> >
> > Isn't this subject to races? - could it lock up if the signal happens just
> > before the pause syscall?
> >
> > + case SSC_HALT_LIGHT:
> > + /* Sleep until SIGIO or SIGALRM is received; this relies on
> > + keyboard/ethernet input being detected via SIGIO, and the
> > + ITC now being emulated via setitimer() and SIGALRM. */
> > + pause ();
> > + break;
> > +
>
> Thanks for the review. You're right, the pause mustn't happen if
> itc_itimer_fired == 1. Let me ponder this for a while...

Ok, I've fixed this in two different ways: one patch which uses pselect,
and one patch which uses plain select + the self-pipe trick. Both work
in limited testing, but the pselect one is much nicer and appears to have
a little less host CPU overhead, so that's the one I'm stress-testing now.

Both patches have been uploaded to the same place as before.

/Mikael


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