On Mon, May 16, 2011 at 11:13:07PM +0000, tip-bot for David Rientjes wrote:
> Commit-ID: dc382fd5bcca7098a984705ed6ac880f539d068e
> Gitweb: http://git.kernel.org/tip/dc382fd5bcca7098a984705ed6ac880f539d068e
> Author: David Rientjes <rientjes@xxxxxxxxxx>
> AuthorDate: Mon, 16 May 2011 13:54:10 -0700
> Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
> CommitDate: Mon, 16 May 2011 14:03:28 -0700
>
> x86, mm: Allow ZONE_DMA to be configurable
>
> ZONE_DMA is unnecessary for a large number of machines that do not
> require less than 32-bit DMA addressing, e.g. ISA legacy DMA or PCI
> cards with a restricted DMA address mask.
>
> This patch allows users to disable ZONE_DMA for x86 if they know they
> will not be using such devices with their kernel.
>
> This prevents the VM from unnecessarily reserving a ratio of memory
> (defaulting to 1/256th of system capacity) with lowmem_reserve_ratio
> for such allocations when it will never be used.
>
> Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
> Link: http://lkml.kernel.org/r/alpine.DEB.2.00.1105161353560.4353@xxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
This causes the ZONE_DMA menu option to appear in the toplevel menu of
the kernel configurator instead of under EXPERT, where it should belong
IMO.
> ---
> arch/x86/Kconfig | 9 ++++++++-
> arch/x86/mm/init_32.c | 2 ++
> arch/x86/mm/init_64.c | 2 ++
> 3 files changed, 12 insertions(+), 1 deletions(-)
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 648fca4..0eb801a 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -112,7 +112,14 @@ config MMU
> def_bool y
>
> config ZONE_DMA
> - def_bool y
> + bool "DMA memory allocation support" if EXPERT
> + default y
> + help
> + DMA memory allocation support allows devices with less than 32-bit
> + addressing to allocate within the first 16MB of address space.
> + Disable if no such devices will be used.
> +
> + If unsure, say Y.
maybe this should go into init/Kconfig ?
Thanks.
--
Regards/Gruss,
Boris.
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