Report: Performance regression from ib_umem_get on zone device pages

[Jason Gunthorpe]

On Mon, Apr 28, 2025 at 12:11:40PM -0700, jane.chu at oracle.com wrote:

> 6.15-rc3 is orders of magnitude better.
> Agreed that device-dax's using folio are likely the heros. I've yet to check
> the code and bisect, maybe pin_user_page_fast() adds folios to page_list[]
> instead of 4K pages?

It does not.

I think a bisection would be interesting information

Jason