Re: Regression from "mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy()" in stable kernels

On Thu, Dec 12, 2019 at 12:19:11PM +0100, Joerg Roedel wrote:

Hi,

On Thu, Dec 12, 2019 at 06:54:12PM +0800, Chen-Yu Tsai wrote:

...

I'd like to report a very severe performance regression due to

mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy() in stable kernels

Yes, that is a known problem, with a couple of reports already in the past months. And I posted a fix from which I thought it is on its way upstream, but apparently its not:

https://lore.kernel.org/lkml/20191009124418.8286-1-joro@8bytes.org/

Ah, I missed that it is in linux-next already. Sorry for the noise.

Joerg