[PATCH] i915: slab shrinker have to return -1 if it cant shrink any objects

[Chris Wilson]

On Wed, 29 Jun 2011 20:53:54 -0700, Keith Packard <keithp at keithp.com> wrote:
> On Fri, 24 Jun 2011 17:03:22 +0900, KOSAKI Motohiro <kosaki.motohiro at jp.fujitsu.com> wrote:
> 
> > Now, i915_gem_inactive_shrink() should return -1 instead of 0 if it
> > can't take a lock. Otherwise, vmscan is getting a lot of confusing
> > because vmscan can't distinguish "can't take a lock temporary" and
> > "we've shrank all of i915 objects".
> 
> This doesn't look like the cleanest change possible. I think it would be
> better if the shrink function could uniformly return an error
> indication so that we wouldn't need the weird looking conditional return.

Unless I am mistaken, and there are more patches in flight, the return
code from i915_gem_inactive_shrink() is promoted to unsigned long and then
used in the calculation of how may objects to evict...
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre