Re: [PATCH 2/6] mm: vmscan: Scale number of pages reclaimed byreclaim/compaction based on failures

[Mel Gorman]

On Wed, Aug 08, 2012 at 10:48:24AM +0900, Minchan Kim wrote:
> Hi Mel,
> 
> Just out of curiosity.
> What's the problem did you see? (ie, What's the problem do this patch solve?)

Everythign in this series is related to the problem in the leader - high
order allocation success rates are lower. This patch increases the success
rates when allocating under load.

> AFAIUC, it seem to solve consecutive allocation success ratio through
> getting several free pageblocks all at once in a process/kswapd
> reclaim context. Right?

Only pageblocks if it is order-9 on x86, it reclaims an amount that depends
on an allocation size. This only happens during reclaim/compaction context
when we know that a high-order allocation has recently failed. The objective
is to reclaim enough order-0 pages so that compaction can succeed again.

-- 
Mel Gorman
SUSE Labs
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