Date: Thu, 8 Nov 2007 11:25:48 -0600
From: Matt Mackall <mpm@selenic.com>
To: Mel Gorman <mel@skynet.ie>
Cc: Christoph Lameter <clameter@sgi.com>, akpm@linux-foundatin.org,
       linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [patch 02/23] SLUB: Rename NUMA defrag_ratio to remote_node_defrag_ratio
Message-ID: <20071108172548.GW17536@waste.org>
References: <20071107011130.382244340@sgi.com> <20071107011226.844437184@sgi.com> <20071108145044.GB2591@skynet.ie>
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On Thu, Nov 08, 2007 at 02:50:44PM +0000, Mel Gorman wrote:
> > -	if (!s->defrag_ratio || get_cycles() % 1024 > s->defrag_ratio)
> > +	if (!s->remote_node_defrag_ratio ||
> > +			get_cycles() % 1024 > s->remote_node_defrag_ratio)
> 
> I cannot figure out what the number of cycles currently showing on the TSC
> have to do with a ratio :(. I could semi-understand if we were counting up
> how many cycles were being spent trying to pack objects but that does not
> appear to be the case. The comment didn't help a whole lot either. It felt
> like a cost for packing, not a ratio

It's just a random number generator. And a bad one: lots of arches
return 0. And I believe at least one of them has some NUMA support.

-- 
Mathematics is the supreme nostalgia of our time.
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