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RE: [Xen-devel] One question on alloc_bitmap

To: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>, Daniel Magenheimer <dan.magenheimer@xxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, "Wang, Shane" <shane.wang@xxxxxxxxx>
Subject: RE: [Xen-devel] One question on alloc_bitmap
From: "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx>
Date: Mon, 22 Sep 2008 15:50:34 +0800
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Thread-topic: [Xen-devel] One question on alloc_bitmap
Keir Fraser <mailto:keir.fraser@xxxxxxxxxxxxx> wrote:
> Um, I was suggesting we *don't* use an explicit radix tree in
> this case (I
> assume Dan has a diffeent scenario where he actually requires
> an explicit
> radix tree structure). For alloc_bitmap[] we can stitch
> together a linear
> virtual address space using page tables, just as we do for frame_table[].

We were working on using the virtual address method like frame_table. I asked 
patch from Dan just because I thought he already implemented patch for this and 
want to avoid conflct. If he is using radix tree for other purpose, that's ok.

Yunhong Jiang

> -- Keir
> On 22/9/08 06:35, "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx> wrote:
>> Sure, can you please share the patch to avoid duplicate patch?
>> Thanks
>> Yunhong Jiang
>> Daniel Magenheimer <mailto:dan.magenheimer@xxxxxxxxxx> wrote:
>>> FYI, I'm working on a patch that requires radix trees and
>>> have borrowed a bunch of code from Linux for it.  I had
>>> to make a few changes to generalize the code (e.g.
>>> callouts for node alloc/free); if it would be useful,
>>> please let me know and I will post it.
>>>> -----Original Message-----
>>>> From: Keir Fraser [mailto:keir.fraser@xxxxxxxxxxxxx]
>>>> Sent: Friday, September 19, 2008 3:32 AM
>>>> To: Jiang, Yunhong; xen-devel@xxxxxxxxxxxxxxxxxxx; Wang, Shane
>>>> Subject: Re: [Xen-devel] One question on alloc_bitmap
>>>> 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
>>>> _______________________________________________
>>>> Xen-devel mailing list
>>>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>>>> http://lists.xensource.com/xen-devel

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