Messages in this thread | | | Subject | Re: 2.6.13-rc6-rt9 | From | Thomas Gleixner <> | Date | Fri, 30 Sep 2005 03:07:29 +0200 |
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On Thu, 2005-09-29 at 18:00 -0700, Paul E. McKenney wrote: > > Even with a current -rt (2.6.14-rc2-rt5) UML does not run. The issue is > > indeed (as jeff pointed out) that VTALRM is never send. The small test > > programm below illustrates this. > > > > On a non-rt kernel it completed in 1 second. > > On a -rt kernel it waits at infinitum. > > Will play with it and see what I broke...
Paul,
you are not the culprit :)
The run_posix_cpu_timers(p) call is #ifdef'd out with PREEMPT_RT.
Thats a hard to fix issue.
It can not be run from hardirq context, as it takes a lot of locks (especially our favorites: tasklist_lock and sighand->siglock). :(
Maybe another playground for rcu, but it might also be solved by some other mechanism for accounting and delayed execution in the PREEMPT_RT case.
tglx
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