[PATCH] arm64: Force SPARSEMEM_VMEMMAP as the only memory management model

[Ard Biesheuvel]

On Tue, 20 Apr 2021 at 12:19, Will Deacon <will at kernel.org> wrote:
>
> On Tue, Apr 20, 2021 at 10:35:59AM +0100, Catalin Marinas wrote:
> > Currently arm64 allows a choice of FLATMEM, SPARSEMEM and
> > SPARSEMEM_VMEMMAP. However, only the latter is tested regularly. FLATMEM
> > does not seem to boot in certain configurations (guest under KVM with
> > Qemu as a VMM). Since the reduction of the SECTION_SIZE_BITS to 27 (4K
> > pages) or 29 (64K page), there's little argument against the memory
> > wasted by the mem_map array with SPARSEMEM.
> >
> > Make SPARSEMEM_VMEMMAP the only available option, non-selectable, and
> > remove the corresponding #ifdefs under arch/arm64/.
> >
> > Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
> > Cc: Will Deacon <will at kernel.org>
> > ---
> >
> > If there are any concerns, please shout (but show numbers as well to
> > back it up).
> >
> >  arch/arm64/Kconfig                      | 10 +---------
> >  arch/arm64/include/asm/kernel-pgtable.h |  2 +-
> >  arch/arm64/include/asm/memory.h         |  4 ++--
> >  arch/arm64/include/asm/sparsemem.h      |  3 ---
> >  arch/arm64/mm/init.c                    |  8 ++------
> >  arch/arm64/mm/mmu.c                     |  2 --
> >  arch/arm64/mm/ptdump.c                  |  2 --
> >  7 files changed, 6 insertions(+), 25 deletions(-)
>
> Acked-by: Will Deacon <will at kernel.org>
>

Acked-by: Ard Biesheuvel <ardb at kernel.org>