From mboxrd@z Thu Jan  1 00:00:00 1970
From: Huang Ying <ying.huang@intel.com>
Subject: Re: [PATCH 0/7] ACPI: Memory Mapped I/O (MMIO) pre-mapping
Date: Mon, 25 Oct 2010 16:43:55 +0800
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To: Andi Kleen <ak@linux.intel.com>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>, "Li, Shaohua" <shaohua.li@intel.com>, Myron Stowe <myron.stowe@hp.com>, "lenb@kernel.org" <lenb@kernel.org>, "linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>

On Mon, 2010-10-25 at 16:34 +0800, Andi Kleen wrote:
> > On ia64 (which also uses ACPI), kmap_atomic_pfn() also requires
> > a struct page.  An ia64-specific version that doesn't need a struct
> > page would be trivial, but I still don't know how to make it work on
> > x86_64.
> 
> Doing a struct page less kmap_atomic() shouldn't be too hard 
> on x86 either.
> 
> Just to avoid problems with concurrency you likely need per 
> CPU mappings.

One issue is PAT management, like in general ioremap implementation
(reserve_memtype).

Best Regards,
Huang Ying