Re: [PATCH v2 5/6] arch/*: increase lowmem size to avoid highmem use

[Mike Rapoport <rppt@kernel.org>]

On Thu, Nov 12, 2026 at 12:25:27PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> Most of the common 32-bit architectures (x86, arm, powerpc) all use the
> default virtual memory layout that was already in place for i386 systems
> in the 1990s, using exactly 3GiB of user TASK_SIZE, with the upper 1GiB
> of addresses split between (at most 896MiB) lowmem and vmalloc.

...

> Based on the above observations and the discussion at the kernel summit,
> change the defaults to the most appropriate values: use 1GiB of lowmem on
> non-highmem configurations, and either 2GiB or 1.75GiB of lowmem on highmem
> builds, depending on what is available on the architecture.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

> ---
>  arch/arm/Kconfig                            |  5 ++++-
>  arch/arm/configs/aspeed_g5_defconfig        |  1 -
>  arch/arm/configs/u8500_defconfig            |  1 -
>  arch/arm/configs/vt8500_v6_v7_defconfig     |  2 --
>  arch/arm/mach-omap2/Kconfig                 |  1 -
>  arch/microblaze/Kconfig                     |  9 ++++++---
>  arch/microblaze/configs/mmu_defconfig       |  1 -
>  arch/powerpc/Kconfig                        | 14 +++++++++-----
>  arch/powerpc/configs/44x/akebono_defconfig  |  1 -
>  arch/powerpc/configs/85xx/ksi8560_defconfig |  1 -
>  arch/powerpc/configs/85xx/stx_gp3_defconfig |  1 -
>  arch/x86/Kconfig                            |  4 +++-
>  12 files changed, 22 insertions(+), 19 deletions(-)

-- 
Sincerely yours,
Mike.