On Thu, Jun 18, 2020 at 06:45:28AM +0530, Anshuman Khandual wrote: > vmemmap_populate_basepages() is used across platforms to allocate backing > memory for vmemmap mapping. This is used as a standard default choice or > as a fallback when intended huge pages allocation fails. This just creates > entire vmemmap mapping with base pages (PAGE_SIZE). > > On arm64 platforms, vmemmap_populate_basepages() is called instead of the > platform specific vmemmap_populate() when ARM64_SWAPPER_USES_SECTION_MAPS > is not enabled as in case for ARM64_16K_PAGES and ARM64_64K_PAGES configs. > > At present vmemmap_populate_basepages() does not support allocating from > driver defined struct vmem_altmap while trying to create vmemmap mapping > for a device memory range. It prevents ARM64_16K_PAGES and ARM64_64K_PAGES > configs on arm64 from supporting device memory with vmemap_altmap request. > > This enables vmem_altmap support in vmemmap_populate_basepages() unlocking > device memory allocation for vmemap mapping on arm64 platforms with 16K or > 64K base page configs. > > Each architecture should evaluate and decide on subscribing device memory > based base page allocation through vmemmap_populate_basepages(). Hence lets > keep it disabled on all archs in order to preserve the existing semantics. > A subsequent patch enables it on arm64. > > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > Cc: Will Deacon <will@xxxxxxxxxx> > Cc: Mark Rutland <mark.rutland@xxxxxxx> > Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx> > Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx> > Cc: Tony Luck <tony.luck@xxxxxxxxx> > Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx> > Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> > Cc: Andy Lutomirski <luto@xxxxxxxxxx> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > Cc: David Hildenbrand <david@xxxxxxxxxx> > Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx> > Cc: Michal Hocko <mhocko@xxxxxxxx> > Cc: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> > Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: Dan Williams <dan.j.williams@xxxxxxxxx> > Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > Cc: linux-ia64@xxxxxxxxxxxxxxx > Cc: linux-riscv@xxxxxxxxxxxxxxxxxxx > Cc: x86@xxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx > Tested-by: Jia He <justin.he@xxxxxxx> > Acked-by: Will Deacon <will@xxxxxxxxxx> > Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> For arm64: Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
