Re: [PATCH v2 0/5] KVM: mm: count KVM page table pages in pagetable stats

From: Sean Christopherson
Date: Tue Apr 05 2022 - 16:56:56 EST

On Mon, Apr 04, 2022, Yosry Ahmed wrote:
> We keep track of several kernel memory stats (total kernel memory, page
> tables, stack, vmalloc, etc) on multiple levels (global, per-node,
> per-memcg, etc). These stats give insights to users to how much memory
> is used by the kernel and for what purposes.
> Currently, memory used by kvm for its page tables is not accounted in
> the pagetable stats. This patch series accounts the memory pages used by
> KVM for page tables in those stats.

It's still not obvious to me that piggybacking NR_PAGETABLE is desirable, probably
because I am quite clueless as to how these stats are used on the backend. E.g.
why not have a NR_SECONDARY_PAGETABLE entry to track pages used for secondary MMU
page tables?