Re: [fuse-devel] Horrible mmap write performance (kernel writeback issue?)

[Ashish Sangwan]

On Tue, Apr 12, 2016 at 5:54 AM, Tejun Heo <tj@xxxxxxxxxx> wrote:
> Hello,
>
> On Mon, Apr 11, 2016 at 10:04:42AM +0200, Jakob Unterwurzacher wrote:
>> What seems to be happening in the kernel is that the estimated device bandwith
>> drops to zero. I'm not even sure how this works for FUSE, but that's what I
>> gathered from some printk debugging.
>
> Yeah, writeback bw getting messed up is the most likely cause.  Prolly
> some silly bug.  I can reproduce the problem.  Looking into it.

Probably you want to look into:
https://lkml.org/lkml/2016/3/10/21

The patch mentioned above solves the issue for me.

Thanks,
Ashish
>
> Thanks.
>
> --
> tejun