Re: [PATCH resend 0/3] mm: allow arch to override lowmem_page_address

[Andrew Morton]

On Mon, 18 Apr 2016 18:04:54 +0200 Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote:

> These patches allow the arch to define the page_to_virt() conversion that
> is used in lowmem_page_address(). This is desirable for arm64, where this
> conversion is trivial when CONFIG_SPARSEMEM_VMEMMAP is enabled, while
> breaking it up into __va(PFN_PHYS(page_to_pfn(page))), as is done currently
> in lowmem_page_address(), will force the use of a virt-to-phys() conversion
> and back again, which always involves a memory access on arm64, since the
> start of physical memory is not a compile time constant.
> 
> I have split off these patches from my series 'arm64: optimize virt_to_page
> and page_address' which I sent out 3 weeks ago, and resending them in the
> hope that they can be picked up (with Will's ack on #3) to be merged via
> the mm tree.
> 
> I have cc'ed the nios2 and openrisc maintainers on previous versions, and
> cc'ing them again now. I have dropped both of the arch specific mailing
> lists, since one is defunct and the other is subscriber only.
> 
> Andrew, is this something you would be pulling to pick up (assuming that you
> agree with the contents)? Thanks.

Looks OK to me and apart from the trivial openrisc/nios2 changes it's
obviously a no-op for all-but-arm.  So I suggest you include these
patches in the appropriate arm tree.

Acked-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>