Re: AGP PAT issue.

["Thomas Hellström" <thomas@tungstengraphics.com>]

Pallipadi, Venkatesh wrote:
>   
>> -----Original Message-----
>> From: Thomas Hellstrom [mailto:thomas@tungstengraphics.com]
>> Sent: Thursday, October 09, 2008 8:53 AM
>> To: Rene Herman
>> Cc: Pallipadi, Venkatesh; Ingo Molnar; Dave Airlie; Li,
>> Shaohua; Yinghai Lu; Andreas Herrmann; Arjan van de Ven; Linux
>> Kernel; Siddha, Suresh B; Thomas Gleixner; H. Peter Anvin;
>> Dave Jones; Alan Hourihane
>> Subject: Re: AGP PAT issue.
>>
>> Rene Herman wrote:
>>     
>>> On 13-09-08 02:26, Pallipadi, Venkatesh wrote:
>>>
>>>       
>>>>>>> Haven't been subcribed to any lists recently and someone was
>>>>>>> talking about "the other thread" before but just noticed that
>>>>>>> an-rc6 was cut.
>>>>>>>
>>>>>>> Please note that the shutdown issue remains unfixed in it (I'm
>>>>>>> doing my coalescing changes locally).
>>>>>>>
>>>>>>>               
>>>>>> here's what is pending in tip/x86/pat for v2.6.28:
>>>>>>
>>>>>>             
>>>>> Only talking about .27 and just making sure again the
>>>>>           
>> issue is known.
>>     
>>>>> The above mentioned subject for the entry cache one ("fix Xorg
>>>>> startup/shutdown slowdown with PAT") after all mistakingly says it
>>>>> does something for shutdown.
>>>>>
>>>>>           
>>>> Can you try the patch here
>>>> http://www.ussg.iu.edu/hypermail/linux/kernel/0809.1/2074.html
>>>>
>>>> That should resolve both reserve and free issues..
>>>>         
>>> Not for .27 though.
>>>
>>> Rene.
>>>       
>> Hi!
>> What's the status on this?
>>     
>
> This patch is now in upstream git and well on its way to .28
>
>   
>> There are graphics devices we're working with that require large
>> (non-AGP) write-combined memory buffers at any time.
>> We can solve the tlb- and cache flush latencies by using pools of these
>> pages to allocate from and free to, but sooner or later we'll probably
>> end up with _huge_ memtype lists. In the (very unlikely) worst case I
>> guess they'd contain every other lowmem page in they system.
>>
>> If I understand things correctly the patch above will fix this issue?
>> Will it be considered for future kernel inclusion.
>>     
>
> Yes this patch will help the above case.
>
> Thanks,
> Venki
>   
Thanks, Venki.
Much appreciated.

/Thomas