On Sat, 21 May 2022 21:29:38 +0100,
Shivam Kumar <shivam.kumar1@xxxxxxxxxxx> wrote:
>
> Exit to userspace whenever the dirty quota is exhausted (i.e. dirty count
> equals/exceeds dirty quota) to request more dirty quota.
>
> Suggested-by: Shaju Abraham <shaju.abraham@xxxxxxxxxxx>
> Suggested-by: Manish Mishra <manish.mishra@xxxxxxxxxxx>
> Co-developed-by: Anurag Madnawat <anurag.madnawat@xxxxxxxxxxx>
> Signed-off-by: Anurag Madnawat <anurag.madnawat@xxxxxxxxxxx>
> Signed-off-by: Shivam Kumar <shivam.kumar1@xxxxxxxxxxx>
> ---
> arch/arm64/kvm/arm.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index ecc5958e27fe..5b6a239b83a5 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -848,6 +848,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
> ret = 1;
> run->exit_reason = KVM_EXIT_UNKNOWN;
> while (ret > 0) {
> + ret = kvm_vcpu_check_dirty_quota(vcpu);
> + if (!ret)
> + break;
> /*
> * Check conditions before entering the guest
> */
Why do we need yet another check on the fast path? It seems to me that
this is what requests are for, so I'm definitely not keen on this
approach. I certainly do not want any extra overhead for something
that is only used on migration. If anything, it is the migration path
that should incur the overhead.
M.
--
Without deviation from the norm, progress is not possible.
