On Fri, Apr 30, 2021 at 4:52 AM Shahin, Md Shahadat Hossain
<shahinmd@xxxxxxxxx> wrote:
>
> Large pages not being created properly may result in increased memory
> access time. The 'lpages' kvm stat used to keep track of the current
> number of large pages in the system, but with TDP MMU enabled the stat
> is not showing the correct number.
>
> This patch extends the lpages counter to cover the TDP case.
>
> Signed-off-by: Md Shahadat Hossain Shahin <shahinmd@xxxxxxxxx>
> Cc: Bartosz Szczepanek <bsz@xxxxxxxxx>
Reviewed-by: Ben Gardon <bgardon@xxxxxxxxxx>
Thanks for fixing this!
> ---
> arch/x86/kvm/mmu/tdp_mmu.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
> index bc1283ed4db6..f89a140b8dea 100644
> --- a/arch/x86/kvm/mmu/tdp_mmu.c
> +++ b/arch/x86/kvm/mmu/tdp_mmu.c
> @@ -240,6 +240,13 @@ static void __handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
> if (old_spte == new_spte)
> return;
>
> + if (is_large_pte(old_spte) != is_large_pte(new_spte)) {
> + if (is_large_pte(old_spte))
> + atomic64_sub(1, (atomic64_t*)&kvm->stat.lpages);
> + else
> + atomic64_add(1, (atomic64_t*)&kvm->stat.lpages);
> + }
> +
> /*
> * The only times a SPTE should be changed from a non-present to
> * non-present state is when an MMIO entry is installed/modified/
> --
> 2.17.1
>
>
>
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