[dm-devel] remove dead bdi congestion leftovers

[Matthew Wilcox]

On Wed, Jul 01, 2020 at 06:57:47PM +0100, Matthew Wilcox wrote:
> On Wed, Jul 01, 2020 at 12:41:03PM -0400, Mike Snitzer wrote:
> > On Wed, Jul 01 2020 at  5:06am -0400,
> > Christoph Hellwig <hch at lst.de> wrote:
> > 
> > > Hi Jens,
> > > 
> > > we have a lot of bdi congestion related code that is left around without
> > > any use.  This series removes it in preparation of sorting out the bdi
> > > lifetime rules properly.
> > 
> > I could do some git archeology to see what the fs, mm and block core
> > changes were to stop using bdi congested but a pointer to associated
> > changes (or quick recap) would save me some time.
> > 
> > Also, curious to know how back-pressure should be felt back up the IO
> > stack now? (apologies if these are well worn topics, I haven't been
> > tracking this area of development).
> 
> It isn't.  Jens declared the implementation was broken, and broke it
> more.  So we're just living with stupid broken timeouts.

Here's a thread about it.  This would have been a discussion topic at
LSFMM2020, but COVID.

https://lore.kernel.org/linux-mm/20190917115824.16990-1-linf@wangsu.com/T/#u