Subject: Re: [v3,1/3] powerpc/mm/book(e)(3s)/64: Add page table accounting

From: Michael Ellerman <[email-masked]>
Date: Thu, 8 Jun 2017 14:07:36 +1000 (AEST)

On Tue, 2017-05-02 at 05:17:04 UTC, Balbir Singh wrote:
> Introduce a helper pgtable_gfp_flags() which
> just returns the current gfp flags and adds
> __GFP_ACCOUNT to account for page table allocation.
> The generic helper is added to include/asm/pgalloc.h
> and has two variants - WARNING ugly bits ahead
> 
> 1. If the header is included from a module, no check
> for mm == &init_mm is done, since init_mm is not
> exported
> 2. For kernel includes, the check is done and required
> see (3e79ec7 arch: x86: charge page tables to kmemcg)
> 
> The fundamental assumption is that no module should be
> doing pgd/pud/pmd and pte alloc's on behalf of init_mm
> directly.
> 
> NOTE: This adds an overhead to pmd/pud/pgd allocations
> similar to x86.  The other alternative was to implement
> pmd_alloc_kernel/pud_alloc_kernel and pgd_alloc_kernel
> with their offset variants.
> 
> For 4k page size, pte_alloc_one no longer calls
> pte_alloc_one_kernel.
> 
> Signed-off-by: Balbir Singh <[email-masked]>

Series applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/de3b87611dd1f3c00f4e42fe298457

cheers