# Re: \[RFC 0/7\] Support high-order page bulk allocation

- From: David Hildenbrand \<hidden\>
- Date: 2020-08-17 17:04:04 
- List: linux-mm
- Page: https://ratatoskr.run/linux-mm/2020/08/6502655
- Thread: https://ratatoskr.run/linux-mm/2020/08/6502583/t.md

```text
>>>> A usecase is device can set a exclusive CMA area up when system boots.
>>>> When device needs 4800 * order-4 pages, it could call this bulk against
>>>> of the area so that it could effectively be guaranteed to allocate
>>>> enough fast.
>>>
>>> Just wondering
>>>
>>> a) Why does it have to be fast?
>>
>> That's because it's related to application latency, which ends up
>> user feel bad.
> 
> Okay, but in theory, your device-needs are very similar to
> application-needs, besides you requiring order-4 pages, correct? Similar
> to an application that starts up and pins 300M (or more), just with
> ordr-4 pages.

Pinning was probably misleading.

I meant either actual pinning, like vfio pins all pages backing a VM
e.g., in QEMU, or mlocking+populating all memory.


-- 
Thanks,

David / dhildenb


```