Re: PATCH v4 0/6] mm, drm/ttm, drm/xe: Avoid reclaim/eviction loops under fragmentation

[Matthew Brost]

On Fri, May 01, 2026 at 02:10:07PM -0700, Matthew Brost wrote:
> On Fri, May 01, 2026 at 01:05:57PM -0700, Kenneth Crudup wrote:
> > 
> > On 5/1/26 13:00, Matthew Brost wrote:
> > 
> > > So is this 7.1-rc1? It looks like new feature to 7.1 added by Dave [1] and
> > > something look off here. Thanks for pointing this out.
> > 
> > Yeah. I grab his master branch daily (as of 6fe0be6dc7fa RN).
> > 
> > Is this a "shoot the messenger" thing? IOW, is the reporting off, or is the
> 
> I don't think I'm firing any shots.
> 
> > memory usage really that high?
> 
> I've been able to recreate this. It looks like accounting is correct
> until the Xe shrinker runs - every time it kicks in GPUActive grows and
> will not reduce past some new floor value. It looks like an accounting
> bug in TTM or Xe (?).
> 
> Here is my output on a 8G PTL where I have intentionally triggered
> shrinker to evict at least 23875 BOs (most likey quite few more but this
> what I easily see in dmesg) after closing everything on desktop.
> 
> cat /proc/meminfo | grep GPU; cat /proc/buddyinfo;
> GPUActive:      13100036 kB
> GPUReclaim:          152 kB
> Node 0, zone      DMA      0      1      0      0      0      0      0      0      1      1      3
> Node 0, zone    DMA32   2320   1882   1523   1238    980    740    482    275    114     88    205
> Node 0, zone   Normal   9751   9343   6466   4237   2703   1162    805    420    191    145    289
> 
> Let me spend a bit of time here to see if I figure out where the
> accounting goes wrong.
> 

Looks like a simple accounting error in the shrinking path. Here is a fix
[1] that seems to work for me.

If you want to give a it try, that would be helpful.

Matt
 
[1] https://patchwork.freedesktop.org/series/165862/

> Matt
> 
> > 
> > (BTW, those are in 30-second intervals)
> > 
> > > > ----
> > > > SwapTotal:      33554428 kB
> > > > MemTotal:       32345672 kB
> > > > GPUActive:        652640 kB
> > > > GPUReclaim:       403988 kB
> > > > 
> > > > SwapTotal:      33554428 kB
> > > > MemTotal:       32345672 kB
> > > > GPUActive:        651180 kB
> > > > GPUReclaim:       406812 kB
> > > > 
> > > > SwapTotal:      33554428 kB
> > > > MemTotal:       32345672 kB
> > > > GPUActive:        659004 kB
> > > > GPUReclaim:       399396 kB
> > > > 
> > > > SwapTotal:      33554428 kB
> > > > MemTotal:       32345672 kB
> > > > GPUActive:        666996 kB
> > > > GPUReclaim:       392764 kB
> > > > 
> > > > <some hours later>
> > > > GPUActive:      91832468 kB
> > > > SwapTotal:      33554428 kB
> > > > MemTotal:       32345672 kB
> > > > GPUReclaim:       488000 kB
> > > > 
> > > > GPUActive:      91832332 kB
> > > > SwapTotal:      33554428 kB
> > > > MemTotal:       32345672 kB
> > > > GPUReclaim:       487988 kB
> > > > 
> > > > GPUActive:      91869376 kB
> > > > SwapTotal:      33554428 kB
> > > > MemTotal:       32345672 kB
> > > > GPUReclaim:       486504 kB
> > > > ----
> > 
> > -K
> > 
> > -- 
> > Kenneth R. Crudup / Sr. SW Engineer, Scott County Consulting, Orange County
> > CA
> >