lkml.org 
[lkml]   [2016]   [Dec]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: drm/radeon spamming alloc_contig_range: [xxx, yyy) PFNs busy busy
Let's also CC Marek

On Thu 01-12-16 08:43:40, Vlastimil Babka wrote:
> On 12/01/2016 08:21 AM, Michal Hocko wrote:
> > Forgot to CC Joonsoo. The email thread starts more or less here
> > http://lkml.kernel.org/r/20161130092239.GD18437@dhcp22.suse.cz
> >
> > On Thu 01-12-16 08:15:07, Michal Hocko wrote:
> > > On Wed 30-11-16 20:19:03, Robin H. Johnson wrote:
> > > [...]
> > > > alloc_contig_range: [83f2a3, 83f2a4) PFNs busy
> > >
> > > Huh, do I get it right that the request was for a _single_ page? Why do
> > > we need CMA for that?
>
> Ugh, good point. I assumed that was just the PFNs that it failed to migrate
> away, but it seems that's indeed the whole requested range. Yeah sounds some
> part of the dma-cma chain could be smarter and attempt CMA only for e.g.
> costly orders.

Is there any reason why the DMA api doesn't try the page allocator first
before falling back to the CMA? I simply have a hard time to see why the
CMA should be used (and fragment) for small requests size.
--
Michal Hocko
SUSE Labs

\
 
 \ /
  Last update: 2016-12-01 15:11    [W:0.075 / U:0.056 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site