Re: page allocator bug in 3.16?

From: Chuck Ebbert
Date: Thu Sep 25 2014 - 15:36:05 EST

On Thu, 25 Sep 2014 14:55:02 -0400
Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> wrote:

> After several days uptime with a 3.16 kernel (generally running
> Thunderbird, emacs, kernel builds, several Chrome tabs on multiple
> desktop workspaces) I've been seeing some really extreme slowdowns.
> Mostly the slowdowns are associated with gpu-related tasks, like
> opening new emacs windows, switching workspaces, laughing at internet
> gifs, etc. Because this x86_64 desktop is nouveau-based, I didn't pursue
> it right away -- 3.15 is the first time suspend has worked reliably.
> This week I started looking into what the slowdown was and discovered
> it's happening during dma allocation through swiotlb (the cpus can do
> intel iommu but I don't use it because it's not the default for most users).
> I'm still working on a bisection but each step takes 8+ hours to
> validate and even then I'm no longer sure I still have the 'bad'
> commit in the bisection. [edit: yup, I started over]

There are six ttm patches queued for 3.16.4:

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at