Re: mm/Kconfig: warning: (COMPACTION && EXPERIMENTAL && HUGETLB_PAGE&& MMU) selects MIGRATION which has unmet direct dependencies (NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE)

[Sedat Dilek]

On Thu, Sep 9, 2010 at 5:23 PM, Randy Dunlap <randy.dunlap@xxxxxxxxxx> wrote:
> On Thu, 9 Sep 2010 17:10:34 +0200 Sedat Dilek wrote:
>
>> Hi,
>>
>> while build latest 2.6.36-rc3 I get this warning:
>>
>> [ build.log]
>> ...
>> warning: (COMPACTION && EXPERIMENTAL && HUGETLB_PAGE && MMU) selects
>> MIGRATION which has unmet direct dependencies (NUMA ||
>> ARCH_ENABLE_MEMORY_HOTREMOVE)
>> ...
>>
>> Here the excerpt of...
>>
>> [ mm/Kconfig ]
>> ...
>> # support for memory compaction
>> config COMPACTION
>> Â Â Â Â bool "Allow for memory compaction"
>> Â Â Â Â select MIGRATION
>> Â Â Â Â depends on EXPERIMENTAL && HUGETLB_PAGE && MMU
>> Â Â Â Â help
>> Â Â Â Â Â Allows the compaction of memory for the allocation of huge pages.
>> ...
>>
>> I have set the following kernel-config parameters:
>>
>> $ egrep 'COMPACTION|HUGETLB_PAGE|MMU|MIGRATION|NUMA|ARCH_ENABLE_MEMORY_HOTREMOVE'
>> linux-2.6.36-rc3/debian/build/build_i386_none_686/.config
>> CONFIG_MMU=y
>> # CONFIG_IOMMU_HELPER is not set
>> CONFIG_IOMMU_API=y
>> CONFIG_COMPACTION=y
>> CONFIG_MIGRATION=y
>> CONFIG_MMU_NOTIFIER=y
>> CONFIG_HUGETLB_PAGE=y
>> # CONFIG_IOMMU_STRESS is not set
>>
>> Looks like I have no NUMA or ARCH_ENABLE_MEMORY_HOTREMOVE set.
>>
>> Ok, it is a *warning*...
>
>
> Andrea Arcangeli posted a patch for this on linux-mm on 2010-SEP-03.
> (below)
>
> ---
> From: Andrea Arcangeli <aarcange@xxxxxxxxxx>
>
> COMPACTION enables MIGRATION, but MIGRATION spawns a warning if numa
> or memhotplug aren't selected. However MIGRATION doesn't depend on
> them. I guess it's just trying to be strict doing a double check on
> who's enabling it, but it doesn't know that compaction also enables
> MIGRATION.
>
> Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
> ---
>
> diff --git a/mm/Kconfig b/mm/Kconfig
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -189,7 +189,7 @@ config COMPACTION
> Âconfig MIGRATION
> Â Â Â Âbool "Page migration"
> Â Â Â Âdef_bool y
> - Â Â Â depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE
> + Â Â Â depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE || COMPACTION
> Â Â Â Âhelp
> Â Â Â Â ÂAllows the migration of the physical location of pages of processes
> Â Â Â Â Âwhile the virtual addresses are not changed. This is useful in
>

Below is the URL for...

"[PATCH] avoid warning when COMPACTION is selected"

- Sedat -

[1] http://marc.info/?l=linux-mm&m=128352833826498&w=2
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