On 2016.08.23 at 10:09 +0200, Michal Hocko wrote:
> From: Michal Hocko <mhocko@xxxxxxxx>
>
> The current wording of the COMPACTION Kconfig help text doesn't
> emphasise that disabling COMPACTION might cripple the page allocator
> which relies on the compaction quite heavily for high order requests and
> an unexpected OOM can happen with the lack of compaction. Make sure
> we are vocal about that.
Just a few nitpicks inline below:
> mm/Kconfig | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/mm/Kconfig b/mm/Kconfig
> index 78a23c5c302d..0dff2f05b6d1 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -262,7 +262,14 @@ config COMPACTION
> select MIGRATION
> depends on MMU
> help
> - Allows the compaction of memory for the allocation of huge pages.
> + Compaction is the only memory management component to form
> + high order (larger physically contiguous) memory blocks
> + reliably. Page allocator relies on the compaction heavily and
The page allo... on compaction
> + the lack of the feature can lead to unexpected OOM killer
> + invocation for high order memory requests. You shouldnm't
invocations shouldn't
> + disable this option unless there is really a strong reason for
really is
> + it and then we are really interested to hear about that at
would be
--
Markus
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