Re: [PATCH] drm/i915: Fix type mismatch and accounting in i915_gem_shrink

[Daniel Vetter <daniel@ffwll.ch>]

On Tue, Sep 24, 2013 at 10:52:18AM +0100, Chris Wilson wrote:
> The interface uses an unsigned long, and we can use the unsigned counter
> throughout our code, so do so. In the process, we notice one instance
> where the shrink count is based on a heuristic rather than the result,
> and another where we ask for too many pages to be purged.
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 22 ++++++++++++----------
>  1 file changed, 12 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 1bfb792..af6ff15 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -64,8 +64,8 @@ static unsigned long i915_gem_inactive_count(struct shrinker *shrinker,
>  					     struct shrink_control *sc);
>  static unsigned long i915_gem_inactive_scan(struct shrinker *shrinker,
>  					    struct shrink_control *sc);
> -static long i915_gem_purge(struct drm_i915_private *dev_priv, long target);
> -static long i915_gem_shrink_all(struct drm_i915_private *dev_priv);
> +static unsigned long i915_gem_purge(struct drm_i915_private *dev_priv, long target);
> +static unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv);
>  static void i915_gem_object_truncate(struct drm_i915_gem_object *obj);
>  
>  static bool cpu_cache_is_coherent(struct drm_device *dev,
> @@ -1825,13 +1825,13 @@ i915_gem_object_put_pages(struct drm_i915_gem_object *obj)
>  	return 0;
>  }
>  
> -static long
> +static unsigned long
>  __i915_gem_shrink(struct drm_i915_private *dev_priv, long target,
>  		  bool purgeable_only)
>  {
>  	struct list_head still_bound_list;
>  	struct drm_i915_gem_object *obj, *next;
> -	long count = 0;
> +	unsigned long count = 0;
>  
>  	list_for_each_entry_safe(obj, next,
>  				 &dev_priv->mm.unbound_list,
> @@ -1897,13 +1897,13 @@ __i915_gem_shrink(struct drm_i915_private *dev_priv, long target,
>  	return count;
>  }
>  
> -static long
> +static unsigned long
>  i915_gem_purge(struct drm_i915_private *dev_priv, long target)
>  {
>  	return __i915_gem_shrink(dev_priv, target, true);
>  }
>  
> -static long
> +static unsigned long
>  i915_gem_shrink_all(struct drm_i915_private *dev_priv)
>  {
>  	struct drm_i915_gem_object *obj, *next;
> @@ -1913,9 +1913,8 @@ i915_gem_shrink_all(struct drm_i915_private *dev_priv)
>  
>  	list_for_each_entry_safe(obj, next, &dev_priv->mm.unbound_list,
>  				 global_list) {
> -		if (obj->pages_pin_count == 0)
> +		if (i915_gem_object_put_pages(obj) == 0)
>  			freed += obj->base.size >> PAGE_SHIFT;
> -		i915_gem_object_put_pages(obj);
>  	}
>  	return freed;
>  }
> @@ -5091,6 +5090,7 @@ i915_gem_inactive_count(struct shrinker *shrinker, struct shrink_control *sc)
>  
>  	if (unlock)
>  		mutex_unlock(&dev->struct_mutex);
> +
>  	return count;
>  }
>  
> @@ -5178,12 +5178,14 @@ i915_gem_inactive_scan(struct shrinker *shrinker, struct shrink_control *sc)

nr_to_scan here still seems to be an int. Otherwise looks good.
-Daniel

>  
>  	freed = i915_gem_purge(dev_priv, nr_to_scan);
>  	if (freed < nr_to_scan)
> -		freed += __i915_gem_shrink(dev_priv, nr_to_scan,
> -							false);
> +		freed += __i915_gem_shrink(dev_priv,
> +					   nr_to_scan - freed,
> +					   false);
>  	if (freed < nr_to_scan)
>  		freed += i915_gem_shrink_all(dev_priv);
>  
>  	if (unlock)
>  		mutex_unlock(&dev->struct_mutex);
> +
>  	return freed;
>  }
> -- 
> 1.8.4.rc3
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch