On Tue, 23 Mar 2021 11:52:38 +0000,
Keqian Zhu <zhukeqian1@xxxxxxxxxx> wrote:
>
> Hi Yoan,
>
> On 2021/3/20 0:17, Yoan Picchi wrote:
> > Add a counter for when a regular page is mapped, and another
> > for when a huge page is mapped.
> >
> > Signed-off-by: Yoan Picchi <yoan.picchi@xxxxxxx>
> > ---
> > arch/arm64/include/asm/kvm_host.h | 2 ++
> > arch/arm64/kvm/guest.c | 2 ++
> > arch/arm64/kvm/mmu.c | 7 +++++++
> > 3 files changed, 11 insertions(+)
> >
> > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> > index 3d10e6527..863603285 100644
> > --- a/arch/arm64/include/asm/kvm_host.h
> > +++ b/arch/arm64/include/asm/kvm_host.h
> > @@ -561,6 +561,8 @@ struct kvm_vcpu_stat {
> > u64 wfi_exit_stat;
> > u64 mmio_exit_user;
> > u64 mmio_exit_kernel;
> > + u64 regular_page_mapped;
> > + u64 huge_page_mapped;
> > u64 exits;
> > };
> >
> > diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
> > index 9bbd30e62..14b15fb8f 100644
> > --- a/arch/arm64/kvm/guest.c
> > +++ b/arch/arm64/kvm/guest.c
> > @@ -38,6 +38,8 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
> > VCPU_STAT("wfi_exit_stat", wfi_exit_stat),
> > VCPU_STAT("mmio_exit_user", mmio_exit_user),
> > VCPU_STAT("mmio_exit_kernel", mmio_exit_kernel),
> > + VCPU_STAT("regular_page_mapped", regular_page_mapped),
> > + VCPU_STAT("huge_page_mapped", huge_page_mapped),
> > VCPU_STAT("exits", exits),
> > VCPU_STAT("halt_poll_success_ns", halt_poll_success_ns),
> > VCPU_STAT("halt_poll_fail_ns", halt_poll_fail_ns),
> > diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> > index 77cb2d28f..3996b28da 100644
> > --- a/arch/arm64/kvm/mmu.c
> > +++ b/arch/arm64/kvm/mmu.c
> > @@ -914,6 +914,13 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
> > mark_page_dirty(kvm, gfn);
> > }
> >
> > + if (ret >= 0) {
> > + if (vma_pagesize == PAGE_SIZE) {
> > + vcpu->stat.regular_page_mapped++;
> > + } else {
> > + vcpu->stat.huge_page_mapped++;
> > + }
> > + }
> This looks too simple, as we don't always map a new regular_page or
> huge_page here. We may just relax permission or change mapping
> size, etc. If we mix these operations, the stat result seems not
> very valuable...
I can only agree. There is no such thing as a *huge page*. We have a
whole gamut of block mappings depending on the base granule size, and
we even have concatenation of pages/blocks (not yet implemented at S2,
but there is hope...).
What is this trying to express?
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
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