From: Christoph Lameter <clameter@sgi.com>
To: linux-ia64@vger.kernel.org
Subject: RE: [RFC] Variable Kernel Page size support
Date: Fri, 13 Oct 2006 01:12:21 +0000 [thread overview]
Message-ID: <Pine.LNX.4.64.0610121810160.23030@schroedinger.engr.sgi.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0610121730050.22778@schroedinger.engr.sgi.com>
On Thu, 12 Oct 2006, Chen, Kenneth W wrote:
> > If set then a lookup is performed using the region7_pgdir table.
> > That table is segmented into 8 section for the varying page
> > sizes supported.
>
> What is the reason to anchor these 8 sections with pgdir? Can't we just
> extract page size directly from the virtual address? Chop off bit 54 - 60,
> that's the physical address, whola. I don't see why it can't be done.
Yes we are chopping off the page size from the virtual address. But we
need a page table to get to the physical address. That is what
region7_pgdir is for. And it has different sections because that enables
concurrent use of various page sizes in region 7. If pages with multiple
page sizes would be in the same page table then we would have strange
page number overlap scenarios to deal with.
next prev parent reply other threads:[~2006-10-13 1:12 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-13 0:32 [RFC] Variable Kernel Page size support Christoph Lameter
2006-10-13 0:50 ` Chen, Kenneth W
2006-10-13 0:55 ` Chen, Kenneth W
2006-10-13 1:12 ` Christoph Lameter [this message]
2006-10-13 1:28 ` Chen, Kenneth W
2006-10-13 1:38 ` Christoph Lameter
2006-10-13 9:21 ` Robin Holt
2006-10-13 18:03 ` Christoph Lameter
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