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Date: Fri, 21 Feb 2003 11:15:38 -0800
From: William Lee Irwin III <wli@holomorphy.com>
To: Rik van Riel <riel@imladris.surriel.com>, Andrew Morton <akpm@digeo.com>,
       "Martin J. Bligh" <mbligh@aracnet.com>, linux-kernel@vger.kernel.org,
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Subject: Re: [Lse-tech] Re: Performance of partial object-based rmap
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On Fri, Feb 21, 2003 at 02:00:10AM -0800, William Lee Irwin III wrote:
> nr_page_table_pages                  689
> which amounts to 2756KB RAM used for PTE's, demonstrating large

Pagetables are also grossly fragmented. From the same sample:

nr_reverse_maps                   156027

To preempt the FAQ, this is the number of reverse mappings performed,
where one is done for every instantiated non-swap PTE.

$ echo $(( (689*1024)/156027.0 ))
4.5218840328917427

So the space flushed down the toilet there is also relatively large.
Approximately 4.5 PTE's per pagetable page, or a utilization of:

$ echo $(( (100*689)/156027.0 ))
0.44159023758708427

percent.

-- wli
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