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Re: [Xen-devel] One question on alloc_bitmap

To: "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, "Wang, Shane" <shane.wang@xxxxxxxxx>
Subject: Re: [Xen-devel] One question on alloc_bitmap
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Fri, 19 Sep 2008 10:32:07 +0100
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Thread-topic: [Xen-devel] One question on alloc_bitmap
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On 19/9/08 10:17, "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx> wrote:

>>> Any idea on it?
>> Yes, it could be sparsely allocated in future. No reason why not.
> Thanks for your clarification. We ask this because we are considering memory
> online.

I would suggest we allocate a virtual address range for the bitmap and then
demand-populate mappings in that area. Just as we do for the frame_table.

The alternative is an explicit radix tree data structure, but we may as well
make use of the page-table structures to do the lookup work for us.

 -- Keir

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