Re: [PATCH 2/4] mm: slub: Do not wake kswapd for SLUBs speculativehigh-order allocations

[Pekka Enberg]

On 5/17/11 12:10 AM, David Rientjes wrote:
> On Fri, 13 May 2011, Mel Gorman wrote:
>
> > To avoid locking and per-cpu overhead, SLUB optimisically uses
> > high-order allocations and falls back to lower allocations if they
> > fail.  However, by simply trying to allocate, kswapd is woken up to
> > start reclaiming at that order. On a desktop system, two users report
> > that the system is getting locked up with kswapd using large amounts
> > of CPU.  Using SLAB instead of SLUB made this problem go away.
> >
> > This patch prevents kswapd being woken up for high-order allocations.
> > Testing indicated that with this patch applied, the system was much
> > harder to hang and even when it did, it eventually recovered.
> >
> > Signed-off-by: Mel Gorman<mgorman@xxxxxxx>
> Acked-by: David Rientjes<rientjes@xxxxxxxxxx>

Christoph? I think this patch is sane although the original rationale 
was to workaround kswapd problems.

                Pekka
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