Date: Wed, 30 Mar 2016 14:47:32 -0400
From: Tejun Heo <tj@kernel.org>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: Jakob Unterwurzacher <jakobunt@gmail.com>,
        fuse-devel <fuse-devel@lists.sourceforge.net>,
        Linux-Fsdevel <linux-fsdevel@vger.kernel.org>,
        Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [fuse-devel] Horrible mmap write performance (kernel writeback
 issue?)
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Hello,

On Mon, Mar 28, 2016 at 09:45:53PM +0200, Miklos Szeredi wrote:
> >> commit 947e9762a8ddefda38aa21e249e6a4fec215cd12
> >> Author: Tejun Heo <tj@kernel.org>
> >> Date:   Fri May 22 18:23:32 2015 -0400
> >>
> >>     writeback: update wb_over_bg_thresh() to use wb_domain aware operations
> >
> 
> Tejun,
> 
> Any idea why this commit stalls fuse mmap writes?
> 
> Here's the start of the this thread:
> 
>   http://marc.info/?l=fuse-devel&m=145008058603261&w=2

Hmmm... cgroup writeback support shouldn't affect fuse at all as the
backing device doesn't enable cgroup support.  I probably made some
silly mistake.  Is there a simple reproducer I can play with?

Thanks.

-- 
tejun