Re: [PATCH 2/2] mm: Consolidate page table accounting

From: Anshuman Khandual
Date: Thu Oct 05 2017 - 01:08:47 EST

On 10/04/2017 10:06 PM, Kirill A. Shutemov wrote:
> This patch switches page table accounting to single counter from
> three -- nr_ptes, nr_pmds and nr_puds.
> mm->pgtables_bytes is now used to account page table levels. We use
> bytes, because page table size for different levels of page table tree
> may be different.
> The change has user-visible effect: we don't have VmPMD and VmPUD
> reported in /proc/[pid]/status. Not sure if anybody uses them.
> (As alternative, we can always report 0 kB for them.)
> OOM-killer report is also slightly changed: we now report pgtables_bytes
> instead of nr_ptes, nr_pmd, nr_puds.

Could you please mention the motivation of doing this ? Why we are
consolidating the counters which also changes /proc/ interface as
well as OOM report ? What is the benefit ?