Messages in this thread | | | Date | Tue, 17 Apr 2012 09:19:01 +0530 | From | Raghavendra K T <> | Subject | Re: [PATCH RFC V5 2/6] kvm hypervisor : Add a hypercall to KVM hypervisor to support pv-ticketlocks |
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Sorry for late reply, was on vacation for a week (without IMAP access :( )
On 04/12/2012 05:36 AM, Marcelo Tosatti wrote: > On Fri, Mar 23, 2012 at 01:37:04PM +0530, Raghavendra K T wrote: >> From: Srivatsa Vaddagiri<vatsa@linux.vnet.ibm.com> [snip] >> @@ -1567,6 +1568,9 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu) >> prepare_to_wait(&vcpu->wq,&wait, TASK_INTERRUPTIBLE); >> >> if (kvm_arch_vcpu_runnable(vcpu)) { >> + vcpu->pv_unhalted = 0; >> + /* preventing reordering should be enough here */ >> + barrier(); > > Is it always OK to erase the notification, even in case an unrelated > event such as interrupt was the source of wakeup?
Erasing notification is not good, But I think in this case,
kvm_make_request(KVM_REQ_UNHALT, vcpu);
below this would take care of the rest.
> > It would be easier to verify that notifications are not lost with atomic > > test_and_clear(pv_unhalted).
true, I 'll verify that (with pv_unhalt as atomic variable). my heart says current code is just fine, since we are about to unblock.
> > Also x86 specific code should remain in arch/x86/kvm/ >
I agree. 'll have clear function in arch/x86/kvm and add stub to rest of the archs
>
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