From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Morton <akpm@osdl.org>
Date: Thu, 03 Mar 2005 06:20:08 +0000
Subject: Re: Page fault scalability patch V18: Drop first acquisition of ptl
Message-Id: <20050302222008.4910eb7b.akpm@osdl.org>
List-Id: <linux-ia64.vger.kernel.org>
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To: Christoph Lameter <clameter@sgi.com>
Cc: linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org

Christoph Lameter <clameter@sgi.com> wrote:
>
> On Wed, 2 Mar 2005, Andrew Morton wrote:
> 
>  > > Any mmap changes requires the mmapsem.
>  >
>  > sys_remap_file_pages() will call install_page() under down_read(mmap_sem).
>  > It relies upon page_table_lock for pte atomicity.
> 
>  This is not relevant since it only deals with file pages.

OK.   And CONFIG_DEBUG_PAGEALLOC?

> ptes are only
>  installed atomically for anonymous memory (if CONFIG_ATOMIC_OPS
>  is defined).

It's a shame.  A *nice* solution to this problem would address all pte ops
and wouldn't have such special cases...