Re: [PATCH 1/3] mm/page_alloc: don't break highest order freepage if steal

From: Mel Gorman
Date: Mon Apr 27 2015 - 04:09:02 EST


On Mon, Apr 27, 2015 at 04:23:39PM +0900, Joonsoo Kim wrote:
> When we steal whole pageblock, we don't need to break highest order
> freepage. Perhaps, there is small order freepage so we can use it.
>

The reason why the largest block is taken is to reduce the probability
there will be another fallback event in the near future. Early on, there
were a lot of tests conducted to measure the number of external fragmenting
events and take steps to reduce them. Stealing the largest highest order
freepage was one of those steps.

--
Mel Gorman
SUSE Labs
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