On Mon, Apr 16, 2012 at 01:28:55PM +0300, Gleb Natapov wrote:
> On Sat, Apr 14, 2012 at 11:44:53AM +0200, Peter Zijlstra wrote:
> > On Wed, 2012-04-04 at 15:30 +0300, Gleb Natapov wrote:
> > >
> > > @@ -253,7 +254,10 @@ do_async_page_fault(struct pt_regs *regs, unsigned
> > > long error_code)
> > > kvm_async_pf_task_wait((u32)read_cr2());
> > > break;
> > > case KVM_PV_REASON_PAGE_READY:
> > > + rcu_irq_enter();
> > > + exit_idle();
> > > kvm_async_pf_task_wake((u32)read_cr2());
> > > + rcu_irq_exit();
> > > break;
> > > }
> > > }
> >
> > Wouldn't irq_enter() / irq_exit() be more appropriate? You're basically
> > taking an interrupt/exception from idle, irq_enter() will fix up
> > everything that needs fixing up, including time sources (which the
> > scheduler expects to be up-to-date).
> >
> You are right. Will send a patch.
>
KVM: Call irq_enter() instead of rcu_irq_enter() during async PF.
As Peter noted there are more things that should be done when leaving
idle state. irq_(enter|exit)() does them and also call rcu functions.
Signed-off-by: Gleb Natapov <g...@redhat.com>
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index b8ba6e4..83a48f6 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -254,10 +254,10 @@ do_async_page_fault(struct pt_regs *regs, unsigned long
error_code)
kvm_async_pf_task_wait((u32)read_cr2());
break;
case KVM_PV_REASON_PAGE_READY:
- rcu_irq_enter();
+ irq_enter();
exit_idle();
kvm_async_pf_task_wake((u32)read_cr2());
- rcu_irq_exit();
+ irq_exit();
break;
}
}
--
Gleb.
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