I might be wrong but I was under the impression that Sparse memory is only of
use on NUMA systems or systems supporting hot pluggable memory. the NODE_DATA()
macro needs to be switched on NUMA, but not on FLATMEM. I borrowed this
dependency from x86 Kconfig. If this is not needed, I will remove it.
Thanks,
-Nikunj
On 7/6/18, 10:05 AM, "Will Deacon" <will.dea...@arm.com> wrote:
On Fri, Jul 06, 2018 at 10:02:15AM -0700, Nikunj Kela wrote:
> Flatmem is useful in reducing kernel memory usage.
> One usecase is in kdump kernel. We are able to save
> ~14M by moving to flatmem scheme.
>
> Cc: xe-ker...@external.cisco.com
> Cc: Nikunj Kela <nk...@cisco.com>
> Signed-off-by: Nikunj Kela <nk...@cisco.com>
> ---
> arch/arm64/Kconfig | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 42c090c..96ab9a7 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -775,6 +775,10 @@ config ARCH_SPARSEMEM_DEFAULT
> config ARCH_SELECT_MEMORY_MODEL
> def_bool ARCH_SPARSEMEM_ENABLE
>
> +config ARCH_FLATMEM_ENABLE
> + def_bool y
> + depends on !NUMA
I still don't understand what this has to do with NUMA. SPARSEMEM is still
going to be what you want on a non-NUMA system with large holes in the
physical memory map, no?
Will
