From mboxrd@z Thu Jan  1 00:00:00 1970
From: William Lee Irwin III <wli@holomorphy.com>
Date: Sun, 14 Mar 2004 09:07:24 +0000
Subject: Re: [Lse-tech] Re: Hugetlbpages in very large memory machines.......
Message-Id: <20040314090724.GR655@holomorphy.com>
List-Id: <linux-ia64.vger.kernel.org>
References: <40528383.10305@sgi.com> <20040313034840.GF4638@wotan.suse.de> <20040313184547.6e127b51.akpm@osdl.org> <40541A09.3050600@sgi.com> <20040314005737.7f57b8ad.akpm@osdl.org>
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To: Andrew Morton <akpm@osdl.org>
Cc: Ray Bryant <raybry@sgi.com>, ak@suse.de, lse-tech@lists.sourceforge.net, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org

On Sun, Mar 14, 2004 at 12:57:37AM -0800, Andrew Morton wrote:
> Well that's just a dumb implementation.  hugetlb_prefault() doesn't need
> page_table_lock while it is zeroing the page: just drop it, test for
> -EEXIST returned from add_to_page_cache().
> In fact we need to do that anyway: the current code is buggy if some other
> process with a different mm gets in there and instantiates the page in the
> pagecache before this process does: hugetlb_prefault() will return -EEXIST
> instead of simply accepting the race and using the page which someone else
> put there.

Don't blame me. I didn't write the expand-on-mmap() code.


-- wli