Re: [PATCH] KVM: x86: Kick VCPU outside PIC lock again

[Avi Kivity]

On 02/24/2010 11:41 AM, Jan Kiszka wrote:
> Thomas Gleixner wrote:
>    
> > On Tue, 23 Feb 2010, Jan Kiszka wrote:
> >
> >      
> > > Thomas Gleixner wrote:
> > >        
> > > > The i8254/i8259 locks need to be real spinlocks on preempt-rt. Convert
> > > > them to raw_spinlock. No change for !RT kernels.
> > > >          
> > > Doesn't fly for -rt anymore: pic_irq_update runs under this raw lock and
> > > calls kvm_vcpu_kick which tries to wake_up some thread ->  scheduling
> > > while atomic.
> > >        
> > Hmm, a wakeup itself is fine. Is that code waking a wake queue ?
> >      
> Yes, it's a wake queue.
>    

So what's the core issue?  Is the lock_t in the wait_queue a sleeping mutex?

> This restores the deferred VCPU kicking before 956f97cf. We need this
> over -rt as wake_up* requires non-atomic context in this configuration.
>
>    

Seems sane, will apply once I understand why the current code fails.

--
error compiling committee.c: too many arguments to function

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/