Subject: Re: [RFC] Replace the watermark-related union in struct zone with
	a watermark[] array
From: Dave Hansen <dave@linux.vnet.ibm.com>
To: Mel Gorman <mel@csn.ul.ie>
Cc: David Rientjes <rientjes@google.com>,
       Linux Memory Management List <linux-mm@kvack.org>,
       KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Date: Thu, 30 Apr 2009 06:48:20 -0700
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On Thu, 2009-04-30 at 14:35 +0100, Mel Gorman wrote:
> I think what you're saying that you'd be ok with
> 
> zone_wmark_min(z)
> zone_wmark_low(z)
> zone_wmark_high(z)
> 
> and z->pages_mark[WMARK_MIN] =
> and z->pages_mark[WMARK_LOW] =
> and z->pages_mark[WMARK_HIGH] =
> 
> ?
> 
> Is that a significant improvement over what the patch currently does? To
> me, it seems more verbose.

Either way, there are _relatively_ few users.  From a quick cscope, it
appears setup_per_zone_pages_min() is really the heaviest user assigning
them.

Personally, I do like having the 'wmark' or something similar in the
function or structure member names.  But, I also like having the units
in there as well.  There's probably not room for both, though.  I'm fine
with the naming you have above.  The only thing I might consider is
removing 'zone_' from the function names since it's implied from the
variable name:

	min_wmark_pages(z)

The 'z->pages_mark[WMARK_*]' form is ugly, but it should be basically
restricted to use in setup_per_zone_pages_min().  I think that means we
don't need set_foo() functions because of a lack of use sites.

-- Dave

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