linux-kernel - Re: Bad page state with x86

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Message-ID: <op.tgiz0y0t8n9ctc@pc-block.esd>
Date:	Wed, 27 Sep 2006 09:20:48 +0200
From:	"Andreas Block" <andreas.block@...-electronics.com>
To:	linux-kernel@...r.kernel.org
Subject: Re: Bad page state with x86_64

On Tue, 26 Sep 2006 14:41:46 +0200, Nick Piggin <nickpiggin@...oo.com.au>
wrote:

> It is freeing a PageReserved page. You should ensure to balance your
> reference counting on *each* page (or allocate a compound page and
> treat it as a single one). When you map pages into userspace via
> nopage or remap_pfn_range, you need to increment their count, which
> gets decremented by the VM when they are unmapped.

Thanks a lot for your time and help. Still there are a few things a
seemingly don't understand correctly.
Do I understand you right, I don't have to "put_page" after calling
"get_page" in my no-page handler?
Also I'm wondering, why this code works flawlessly on 2.6.10 32-Bit and
several 2.4.x kernels 32-Bit and PPC and is failing to work on x86_64,
only. Do I have to do the "get/put_page" mechanism differnetly on x86_64?
Another question:
In my no-page handler, I reserve the physical page. I do have to clear the
reserve bit of those page after unmap, right? Or is this done implicitly
as well?

Again, thanks for your effort.
-- 
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                             _/_/_/_/   Andreas Block
                            _/_/_/_/   Dipl.-Ing.
                           _/_/_/_/   andreas.block@...-electronics.com

       _/_/_/   _/_/_/_/_/_/_/      esd electronic system design gmbh
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    _/   _/    _/_/_/   _/   _/   D-30165 Hannover
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                               http://www.esd-electronics.com

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