Re: [PATCH v4 1/2] USB: core: add a memory pool to urb caching host-controller private data

David Wang
2025-05-22T09:47:36Z

At 2025-05-22 16:33:42, "Greg KH" <gregkh@linuxfoundation.org> wrote:
>On Thu, May 22, 2025 at 03:09:43PM +0800, David Wang wrote:
>> From an end-user's perspective, the performance difference with this change
>> is insignificant when system is under no memory pressure, and when under
>> heavy memory pressure. When system is under heavy memory pressure,
>> everything is slow. There could be a point in-between no memory pressure
>> and heavy memory pressure where these 1k+/s memory allocations would
>> dominate the performance, but very hard to pinpoint it.
>
>For this reason alone I can't take this change, sorry.

Still, reasonable to me....
>
>Also, as others have stated, this could be done in the hcd drivers
>themselves if they want to, no need to push this into the usb core.

>
>thanks,
>
>greg k-h

Thanks all you guys for taking time reviewing/discussing this.

David