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Date: Fri, 16 Mar 2007 16:14:48 +1100
From: Paul Mackerras <paulus@samba.org>
To: Stefan Roese <sr@denx.de>
Subject: Re: [PATCH] ppc: Add support for bigger page sizes than 4KB on PPC44x
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Stefan Roese writes:

> This patch adds support for the PAGE_SIZE set equal to 64 KB on
> PPC32 platforms.

If I'm reading the patch right, with 64k pages you're using 8kB pgd
arrays and 256-byte pte arrays, so you're only using 1/256th of each
PTE page.  In fact each PTE page could map 512MB (assuming 8 byte
ptes), and the pgd array could be a tiny 8-entry thing, which we could
kmalloc.  I think that would use memory more efficiently.

Paul.