Re: linux-next: manual merge of the kvm-ppc tree with the tip tree

From: Paul Mackerras
Date: Wed Aug 26 2015 - 14:21:17 EST


Hi Stephen,

On Mon, Aug 24, 2015 at 03:59:54PM +1000, Stephen Rothwell wrote:
> Hi Alexander,
>
> Today's linux-next merge of the kvm-ppc tree got a conflict in:
>
> arch/powerpc/kvm/book3s_hv.c
>
> between commit:
>
> c56dadf39761 ("sched/preempt, powerpc, kvm: Use need_resched() instead of should_resched()")
>
> from the tip tree and commit:
>
> ec2571650826 ("KVM: PPC: Book3S HV: Make use of unused threads when running guests")
>
> from the kvm-ppc tree.
>
> I fixed it up (see below) and can carry the fix as necessary (no action
> is required).

The fix isn't quite correct (see below), but the error is benign.

> --
> Cheers,
> Stephen Rothwell sfr@xxxxxxxxxxxxxxxx
>
> diff --cc arch/powerpc/kvm/book3s_hv.c
> index a9f753fb73a8,fad52f226c12..000000000000
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@@ -2178,11 -2670,12 +2670,13 @@@ static int kvmppc_run_vcpu(struct kvm_r
> vc->runner = vcpu;
> if (n_ceded == vc->n_runnable) {
> kvmppc_vcore_blocked(vc);
> - } else if (should_resched()) {
> + } else if (need_resched()) {
> + vc->vcore_state = VCORE_PREEMPT;

This line is removed in the kvm-ppc tree because it is now in the new
kvmppc_vcore_preempt() function. Thus we don't need this line in the
merge result. However, having it here just means that we set
vc->vcore_state to VCORE_PREEMPT twice.

> + kvmppc_vcore_preempt(vc);
> /* Let something else run */
> cond_resched_lock(&vc->lock);
> - vc->vcore_state = VCORE_INACTIVE;
> + if (vc->vcore_state == VCORE_PREEMPT)
> + kvmppc_vcore_end_preempt(vc);
> } else {
> kvmppc_run_core(vc);
> }

Regards,
Paul.
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