Re: [Xen-devel] One question on alloc_bitmap

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

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[].

 -- 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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