Date: Tue, 30 Nov 2010 13:13:46 -0600 (CST)
From: Christoph Lameter <cl@linux.com>
To: Simon Kirby <sim@hostway.ca>
cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
        Mel Gorman <mel@csn.ul.ie>, Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel <linux-kernel@vger.kernel.org>, linux-mm@kvack.org
Subject: Re: Free memory never fully used, swapping
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On Tue, 30 Nov 2010, Simon Kirby wrote:

> Can we also mess with these /sys files on the fly?

Sure. Go ahead. These are runtime configurable.

> I'm not familiar with how slub works, but I assume there's some overhead
> or some reason not to just use order 0 for <= kmalloc-4096?  Or is it
> purely just trying to reduce cpu by calling alloc_pages less often?

Using higher order pages reduces the memory overhead for objects (that
after all need to be packed into an order N page), decreases the amount
of metadata that needs to be managed and decreases the use of the
slowpaths. That implies also a reduction in the locking overhead.


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