Re: [PATCH 01 of 66] disable lumpy when compaction is enabled

KOSAKI Motohiro
2010-11-09T03:18:54Z

> From: Andrea Arcangeli <aarcange@redhat.com>
>
> Compaction is more reliable than lumpy, and lumpy makes the system unusable
> when it runs.
>
> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
> ---
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -274,6 +274,7 @@ unsigned long shrink_slab(unsigned long
> static void set_lumpy_reclaim_mode(int priority, struct scan_control *sc,
> bool sync)
> {
> +#ifndef CONFIG_COMPACTION
> enum lumpy_mode mode = sync ? LUMPY_MODE_SYNC : LUMPY_MODE_ASYNC;
>
> /*
> @@ -294,11 +295,14 @@ static void set_lumpy_reclaim_mode(int p
> sc->lumpy_reclaim_mode = mode;
> else
> sc->lumpy_reclaim_mode = LUMPY_MODE_NONE;
> +#endif
> }

I'm talking very personal thing now. I'm usually testing both feature.
Then, runtime switching makes my happy :-)
However I don't know what are you and Mel talking and agree about this.
So, If many developer prefer this approach, I don't oppose anymore.

But, I bet almost all distro choose CONFIG_COMPACTION=y. then, lumpy code
will become nearly dead code. So, I like just kill than dead code. however
it is also only my preference. ;)