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

From: David Rientjes
Date: Mon May 16 2011 - 17:10:34 EST

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>
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