[PATCH V3 (RESEND) 3/3] arm64/mm: Enable vmem_altmap support for vmemmap mappings

[Catalin Marinas]

On Thu, Jun 18, 2020 at 06:45:30AM +0530, Anshuman Khandual wrote:
> Device memory ranges when getting hot added into ZONE_DEVICE, might require
> their vmemmap mapping's backing memory to be allocated from their own range
> instead of consuming system memory. This prevents large system memory usage
> for potentially large device memory ranges. Device driver communicates this
> request via vmem_altmap structure. Architecture needs to take this request
> into account while creating and tearing down vemmmap mappings.
> 
> This enables vmem_altmap support in vmemmap_populate() and vmemmap_free()
> which includes vmemmap_populate_basepages() used for ARM64_16K_PAGES and
> ARM64_64K_PAGES configs.
> 
> Cc: Catalin Marinas <catalin.marinas at arm.com>
> Cc: Will Deacon <will at kernel.org>
> Cc: Mark Rutland <mark.rutland at arm.com>
> Cc: Steve Capper <steve.capper at arm.com>
> Cc: David Hildenbrand <david at redhat.com>
> Cc: Yu Zhao <yuzhao at google.com>
> Cc: Hsin-Yi Wang <hsinyi at chromium.org>
> Cc: Thomas Gleixner <tglx at linutronix.de>
> Cc: Andrew Morton <akpm at linux-foundation.org>
> Cc: linux-arm-kernel at lists.infradead.org
> Cc: linux-kernel at vger.kernel.org
> Tested-by: Jia He <justin.he at arm.com>
> Signed-off-by: Anshuman Khandual <anshuman.khandual at arm.com>

This looks fine to me:

Reviewed-by: Catalin Marinas <catalin.marinas at arm.com>

I presume this series would go into mainline via the mm tree as it
touches several architectures.