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Subject: Re: [PATCH 3/5] mm: powerpc ptlock comments
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Hugh Dickins <hugh@veritas.com>
Cc: Paul Mackerras <paulus@samba.org>, Andrew Morton <akpm@osdl.org>,
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Date: Tue, 22 Nov 2005 18:57:51 +1100
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On Tue, 2005-11-22 at 07:12 +0000, Hugh Dickins wrote:

> I'd appreciate something that updates the "because" part too, but don't
> know the answer.  That other patch will need to come from your end - Ben?

Hrm... same reason as __hash_page(), the code now locks the PTE using
the _PAGE_BUSY bit. The last store does the update and unlock and
doesn't need to be atomic. However, now that I look at it, it might need
an lwsync. Paul ?

Ben.