From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Fri, 6 Jul 2018 18:06:17 +0100 Subject: [PATCH v2] arm64: add ARM64-specific support for flatmem In-Reply-To: <20180706170215.56116-1-nkela@cisco.com> References: <20180706170215.56116-1-nkela@cisco.com> Message-ID: <20180706170617.GB4961@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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-kernel at external.cisco.com > Cc: Nikunj Kela > Signed-off-by: Nikunj Kela > --- > 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