[PATCH -mm] enable CONFIG_COMPACTION by default

Rik van Riel

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Sep 13, 2012, 4:30:02 PM9/13/12

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Now that lumpy reclaim has been removed, compaction is the
only way left to free up contiguous memory areas. It is time
to just enable CONFIG_COMPACTION by default.

Signed-off-by: Rik van Riel <ri...@redhat.com>

diff --git a/mm/Kconfig b/mm/Kconfig
index d5c8019..32ea0ef 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -191,6 +191,7 @@ config SPLIT_PTLOCK_CPUS
# support for memory compaction
config COMPACTION
bool "Allow for memory compaction"
+ def_bool y
select MIGRATION
depends on MMU
help
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Rafael Aquini

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Sep 13, 2012, 4:50:02 PM9/13/12

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On Thu, Sep 13, 2012 at 04:21:04PM -0400, Rik van Riel wrote:
> Now that lumpy reclaim has been removed, compaction is the
> only way left to free up contiguous memory areas. It is time
> to just enable CONFIG_COMPACTION by default.
>
> Signed-off-by: Rik van Riel <ri...@redhat.com>
>
> diff --git a/mm/Kconfig b/mm/Kconfig
> index d5c8019..32ea0ef 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -191,6 +191,7 @@ config SPLIT_PTLOCK_CPUS
> # support for memory compaction
> config COMPACTION
> bool "Allow for memory compaction"
> + def_bool y
> select MIGRATION
> depends on MMU
> help
>

Acked-by: Rafael Aquini <aqu...@redhat.com>

Johannes Weiner

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Sep 13, 2012, 7:20:01 PM9/13/12

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On Thu, Sep 13, 2012 at 04:21:04PM -0400, Rik van Riel wrote:

> Now that lumpy reclaim has been removed, compaction is the
> only way left to free up contiguous memory areas. It is time
> to just enable CONFIG_COMPACTION by default.
>
> Signed-off-by: Rik van Riel <ri...@redhat.com>

Acked-by: Johannes Weiner <han...@cmpxchg.org>

Minchan Kim

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Sep 13, 2012, 8:00:03 PM9/13/12

to

Hi Rik,

On Thu, Sep 13, 2012 at 04:21:04PM -0400, Rik van Riel wrote:

> Now that lumpy reclaim has been removed, compaction is the
> only way left to free up contiguous memory areas. It is time
> to just enable CONFIG_COMPACTION by default.
>
> Signed-off-by: Rik van Riel <ri...@redhat.com>

I tried this a few month ago and Mel had a concern on size
bloating (compaction.o + migration.o) where system doesn't
use higher order allocation.

Now that I think about it, admin should configure carefully
and manually if he has a size concern of vmlinux without
depending auto-generating config.
So I really want this.

Acked-by: Minchan Kim <min...@kernel.org>

--
Kind regards,
Minchan Kim