* [PATCH v2] arm64: add ARM64-specific support for flatmem
@ 2018-07-06 17:02 ` Nikunj Kela
0 siblings, 0 replies; 6+ messages in thread
From: Nikunj Kela @ 2018-07-06 17:02 UTC (permalink / raw)
To: linux-arm-kernel
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 <nkela@cisco.com>
Signed-off-by: Nikunj Kela <nkela@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
+
config HAVE_ARCH_PFN_VALID
def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM
--
2.10.3.dirty
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2] arm64: add ARM64-specific support for flatmem
@ 2018-07-06 17:02 ` Nikunj Kela
0 siblings, 0 replies; 6+ messages in thread
From: Nikunj Kela @ 2018-07-06 17:02 UTC (permalink / raw)
To: Catalin Marinas, Will Deacon; +Cc: xe-kernel, linux-arm-kernel, linux-kernel
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@external.cisco.com
Cc: Nikunj Kela <nkela@cisco.com>
Signed-off-by: Nikunj Kela <nkela@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
+
config HAVE_ARCH_PFN_VALID
def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM
--
2.10.3.dirty
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2] arm64: add ARM64-specific support for flatmem
2018-07-06 17:02 ` Nikunj Kela
@ 2018-07-06 17:06 ` Will Deacon
-1 siblings, 0 replies; 6+ messages in thread
From: Will Deacon @ 2018-07-06 17:06 UTC (permalink / raw)
To: linux-arm-kernel
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 <nkela@cisco.com>
> Signed-off-by: Nikunj Kela <nkela@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
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] arm64: add ARM64-specific support for flatmem
@ 2018-07-06 17:06 ` Will Deacon
0 siblings, 0 replies; 6+ messages in thread
From: Will Deacon @ 2018-07-06 17:06 UTC (permalink / raw)
To: Nikunj Kela; +Cc: Catalin Marinas, xe-kernel, linux-arm-kernel, linux-kernel
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@external.cisco.com
> Cc: Nikunj Kela <nkela@cisco.com>
> Signed-off-by: Nikunj Kela <nkela@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
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v2] arm64: add ARM64-specific support for flatmem
2018-07-06 17:06 ` Will Deacon
@ 2018-07-06 17:16 ` Nikunj Kela (nkela)
-1 siblings, 0 replies; 6+ messages in thread
From: Nikunj Kela (nkela) @ 2018-07-06 17:16 UTC (permalink / raw)
To: linux-arm-kernel
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.deacon@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-kernel at external.cisco.com
> Cc: Nikunj Kela <nkela@cisco.com>
> Signed-off-by: Nikunj Kela <nkela@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
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] arm64: add ARM64-specific support for flatmem
@ 2018-07-06 17:16 ` Nikunj Kela (nkela)
0 siblings, 0 replies; 6+ messages in thread
From: Nikunj Kela (nkela) @ 2018-07-06 17:16 UTC (permalink / raw)
To: Will Deacon
Cc: Catalin Marinas, xe-kernel@external.cisco.com,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
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.deacon@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-kernel@external.cisco.com
> Cc: Nikunj Kela <nkela@cisco.com>
> Signed-off-by: Nikunj Kela <nkela@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
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2018-07-06 17:25 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2018-07-06 17:02 [PATCH v2] arm64: add ARM64-specific support for flatmem Nikunj Kela
2018-07-06 17:02 ` Nikunj Kela
2018-07-06 17:06 ` Will Deacon
2018-07-06 17:06 ` Will Deacon
2018-07-06 17:16 ` Nikunj Kela (nkela)
2018-07-06 17:16 ` Nikunj Kela (nkela)
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