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From: Akinobu Mita <amgta@yacht.ocn.ne.jp>
To: Christoph Lameter <clameter@sgi.com>
Subject: Re: Anticipatory prefaulting in the page fault handler V1
Date: Tue, 14 Dec 2004 21:24:11 +0900
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On Tuesday 14 December 2004 02:10, Christoph Lameter wrote:
> On Mon, 13 Dec 2004, Akinobu Mita wrote:

> > 3) don't set_pte() for the entry which already have been set
>
> Not sure how this could have happened in the patch.

This is why I inserted pte_none() for each page_table in case of
read fault too.

If read access fault occured for the address "addr".
It is completely unnecessary to check by pte_none() to the page_table
for "addr". Because page_table_lock has never been released until
do_anonymous_page returns (in case of read access fault)

But there is not any guarantee that the page_tables for addr+PAGE_SIZE,
addr+2*PAGE_SIZE, ...  have not been mapped yet.

Anyway, I will try your V2 patch.