[PATCH] powerpc/mm: Allow ARCH_FORCE_MAX_ORDER up to 12

[PATCH] powerpc/mm: Allow ARCH_FORCE_MAX_ORDER up to 12

[Michael Ellerman]

Christophe reported that the change to ARCH_FORCE_MAX_ORDER to limit the
range to 10 had broken his ability to configure hugepages:

  # echo 1 > /sys/kernel/mm/hugepages/hugepages-8192kB/nr_hugepages
  sh: write error: Invalid argument

Several of the powerpc defconfigs previously set the
ARCH_FORCE_MAX_ORDER value to 12, via the definition in
arch/powerpc/configs/fsl-emb-nonhw.config, used by:

  mpc85xx_defconfig
  mpc85xx_smp_defconfig
  corenet32_smp_defconfig
  corenet64_smp_defconfig
  mpc86xx_defconfig
  mpc86xx_smp_defconfig

Fix it by increasing the allowed range to 12 to restore the previous
behaviour.

Fixes: 358e526a1648 ("powerpc/mm: Reinstate ARCH_FORCE_MAX_ORDER ranges")
Reported-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/id:8011d806-5b30-bf26-2bfe-a08c39d57e20@csgroup.eu
---
 arch/powerpc/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Christophe, can you confirm this fixes your system?

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c831e20cf40f..8977fa73c09e 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -928,7 +928,7 @@ config ARCH_FORCE_MAX_ORDER
 	default "6" if PPC32 && PPC_64K_PAGES
 	range 4 10 if PPC32 && PPC_256K_PAGES
 	default "4" if PPC32 && PPC_256K_PAGES
-	range 10 10
+	range 10 12
 	default "10"
 	help
 	  The kernel page allocator limits the size of maximal physically
-- 
2.41.0

Re: [PATCH] powerpc/mm: Allow ARCH_FORCE_MAX_ORDER up to 12

[Christophe Leroy]

Le 24/08/2023 à 14:28, Michael Ellerman a écrit :
> Christophe reported that the change to ARCH_FORCE_MAX_ORDER to limit the
> range to 10 had broken his ability to configure hugepages:
> 
>    # echo 1 > /sys/kernel/mm/hugepages/hugepages-8192kB/nr_hugepages
>    sh: write error: Invalid argument
> 
> Several of the powerpc defconfigs previously set the
> ARCH_FORCE_MAX_ORDER value to 12, via the definition in
> arch/powerpc/configs/fsl-emb-nonhw.config, used by:
> 
>    mpc85xx_defconfig
>    mpc85xx_smp_defconfig
>    corenet32_smp_defconfig
>    corenet64_smp_defconfig
>    mpc86xx_defconfig
>    mpc86xx_smp_defconfig
> 
> Fix it by increasing the allowed range to 12 to restore the previous
> behaviour.
> 
> Fixes: 358e526a1648 ("powerpc/mm: Reinstate ARCH_FORCE_MAX_ORDER ranges")
> Reported-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> Link: https://msgid.link/id:8011d806-5b30-bf26-2bfe-a08c39d57e20@csgroup.eu
> ---
>   arch/powerpc/Kconfig | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Christophe, can you confirm this fixes your system?

It works, thanks.

Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu>


> 
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index c831e20cf40f..8977fa73c09e 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -928,7 +928,7 @@ config ARCH_FORCE_MAX_ORDER
>   	default "6" if PPC32 && PPC_64K_PAGES
>   	range 4 10 if PPC32 && PPC_256K_PAGES
>   	default "4" if PPC32 && PPC_256K_PAGES
> -	range 10 10
> +	range 10 12
>   	default "10"
>   	help
>   	  The kernel page allocator limits the size of maximal physically

Re: [PATCH] powerpc/mm: Allow ARCH_FORCE_MAX_ORDER up to 12

[Michael Ellerman]

On Thu, 24 Aug 2023 22:28:49 +1000, Michael Ellerman wrote:
> Christophe reported that the change to ARCH_FORCE_MAX_ORDER to limit the
> range to 10 had broken his ability to configure hugepages:
> 
>   # echo 1 > /sys/kernel/mm/hugepages/hugepages-8192kB/nr_hugepages
>   sh: write error: Invalid argument
> 
> Several of the powerpc defconfigs previously set the
> ARCH_FORCE_MAX_ORDER value to 12, via the definition in
> arch/powerpc/configs/fsl-emb-nonhw.config, used by:
> 
> [...]

Applied to powerpc/fixes.

[1/1] powerpc/mm: Allow ARCH_FORCE_MAX_ORDER up to 12
      https://git.kernel.org/powerpc/c/ff9e8f41513669e290f6e1904e1bc75950584491

cheers