Re: [PATCH 11/24] drm: Introduce an iterator over holes in the drm_mm range manager

[Daniel Vetter <daniel@ffwll.ch>]

On Thu, Aug 30, 2012 at 04:31:06PM +0100, Chris Wilson wrote:
> This will be used i915 in forthcoming patches in order to measure the
> largest contiguous chunk of memory available for enabling chipset
> features.
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Dave Airlie <airlied@redhat.com>

While discussing the iterator in private a bit with Ben I've noticed that
you've ignore my bikeshed! tsk ... ;-)

http://lists.freedesktop.org/archives/intel-gfx/2012-September/020436.html

-Daniel

> ---
>  drivers/gpu/drm/drm_mm.c |   55 +++++++++++++++-------------------------------
>  include/drm/drm_mm.h     |   26 ++++++++++++++++++++++
>  2 files changed, 44 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
> index 5db8c20..c3d11ec 100644
> --- a/drivers/gpu/drm/drm_mm.c
> +++ b/drivers/gpu/drm/drm_mm.c
> @@ -102,20 +102,6 @@ int drm_mm_pre_get(struct drm_mm *mm)
>  }
>  EXPORT_SYMBOL(drm_mm_pre_get);
>  
> -static inline unsigned long drm_mm_hole_node_start(struct drm_mm_node *hole_node)
> -{
> -	return hole_node->start + hole_node->size;
> -}
> -
> -static inline unsigned long drm_mm_hole_node_end(struct drm_mm_node *hole_node)
> -{
> -	struct drm_mm_node *next_node =
> -		list_entry(hole_node->node_list.next, struct drm_mm_node,
> -			   node_list);
> -
> -	return next_node->start;
> -}
> -
>  static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
>  				 struct drm_mm_node *node,
>  				 unsigned long size, unsigned alignment,
> @@ -127,7 +113,7 @@ static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
>  	unsigned long adj_start = hole_start;
>  	unsigned long adj_end = hole_end;
>  
> -	BUG_ON(!hole_node->hole_follows || node->allocated);
> +	BUG_ON(node->allocated);
>  
>  	if (mm->color_adjust)
>  		mm->color_adjust(hole_node, color, &adj_start, &adj_end);
> @@ -168,15 +154,10 @@ struct drm_mm_node *drm_mm_create_block(struct drm_mm *mm,
>  {
>  	struct drm_mm_node *hole, *node;
>  	unsigned long end = start + size;
> +	unsigned long hole_start;
> +	unsigned long hole_end;
>  
> -	list_for_each_entry(hole, &mm->hole_stack, hole_stack) {
> -		unsigned long hole_start;
> -		unsigned long hole_end;
> -
> -		BUG_ON(!hole->hole_follows);
> -		hole_start = drm_mm_hole_node_start(hole);
> -		hole_end = drm_mm_hole_node_end(hole);
> -
> +	drm_mm_for_each_hole(hole, mm, hole_start, hole_end) {
>  		if (hole_start > start || hole_end < end)
>  			continue;
>  
> @@ -361,8 +342,10 @@ void drm_mm_remove_node(struct drm_mm_node *node)
>  				== drm_mm_hole_node_end(node));
>  		list_del(&node->hole_stack);
>  	} else
> -		BUG_ON(drm_mm_hole_node_start(node)
> -				!= drm_mm_hole_node_end(node));
> +		BUG_ON(node->start + node->size !=
> +		       list_entry(node->node_list.next,
> +				  struct drm_mm_node, node_list)->start);
> +
>  
>  	if (!prev_node->hole_follows) {
>  		prev_node->hole_follows = 1;
> @@ -420,6 +403,8 @@ struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
>  {
>  	struct drm_mm_node *entry;
>  	struct drm_mm_node *best;
> +	unsigned long adj_start;
> +	unsigned long adj_end;
>  	unsigned long best_size;
>  
>  	BUG_ON(mm->scanned_blocks);
> @@ -427,17 +412,13 @@ struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
>  	best = NULL;
>  	best_size = ~0UL;
>  
> -	list_for_each_entry(entry, &mm->hole_stack, hole_stack) {
> -		unsigned long adj_start = drm_mm_hole_node_start(entry);
> -		unsigned long adj_end = drm_mm_hole_node_end(entry);
> -
> +	drm_mm_for_each_hole(entry, mm, adj_start, adj_end) {
>  		if (mm->color_adjust) {
>  			mm->color_adjust(entry, color, &adj_start, &adj_end);
>  			if (adj_end <= adj_start)
>  				continue;
>  		}
>  
> -		BUG_ON(!entry->hole_follows);
>  		if (!check_free_hole(adj_start, adj_end, size, alignment))
>  			continue;
>  
> @@ -464,6 +445,8 @@ struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
>  {
>  	struct drm_mm_node *entry;
>  	struct drm_mm_node *best;
> +	unsigned long adj_start;
> +	unsigned long adj_end;
>  	unsigned long best_size;
>  
>  	BUG_ON(mm->scanned_blocks);
> @@ -471,13 +454,11 @@ struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
>  	best = NULL;
>  	best_size = ~0UL;
>  
> -	list_for_each_entry(entry, &mm->hole_stack, hole_stack) {
> -		unsigned long adj_start = drm_mm_hole_node_start(entry) < start ?
> -			start : drm_mm_hole_node_start(entry);
> -		unsigned long adj_end = drm_mm_hole_node_end(entry) > end ?
> -			end : drm_mm_hole_node_end(entry);
> -
> -		BUG_ON(!entry->hole_follows);
> +	drm_mm_for_each_hole(entry, mm, adj_start, adj_end) {
> +		if (adj_start < start)
> +			adj_start = start;
> +		if (adj_end > end)
> +			adj_end = end;
>  
>  		if (mm->color_adjust) {
>  			mm->color_adjust(entry, color, &adj_start, &adj_end);
> diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h
> index 4020f96..d710a10 100644
> --- a/include/drm/drm_mm.h
> +++ b/include/drm/drm_mm.h
> @@ -89,6 +89,19 @@ static inline bool drm_mm_initialized(struct drm_mm *mm)
>  {
>  	return mm->hole_stack.next;
>  }
> +
> +static inline unsigned long drm_mm_hole_node_start(struct drm_mm_node *hole_node)
> +{
> +	BUG_ON(!hole_node->hole_follows);
> +	return hole_node->start + hole_node->size;
> +}
> +
> +static inline unsigned long drm_mm_hole_node_end(struct drm_mm_node *hole_node)
> +{
> +	return list_entry(hole_node->node_list.next,
> +			  struct drm_mm_node, node_list)->start;
> +}
> +
>  #define drm_mm_for_each_node(entry, mm) list_for_each_entry(entry, \
>  						&(mm)->head_node.node_list, \
>  						node_list)
> @@ -99,6 +112,19 @@ static inline bool drm_mm_initialized(struct drm_mm *mm)
>  	     entry != NULL; entry = next, \
>  		next = entry ? list_entry(entry->node_list.next, \
>  			struct drm_mm_node, node_list) : NULL) \
> +
> +/* Note that we need to unroll list_for_each_entry in order to inline
> + * setting hole_start and hole_end on each iteration and keep the
> + * macro sane.
> + */
> +#define drm_mm_for_each_hole(entry, mm, hole_start, hole_end) \
> +	for (entry = list_entry((mm)->hole_stack.next, typeof(struct drm_mm_node), hole_stack); \
> +	     &entry->hole_stack != &(mm)->hole_stack ? \
> +	     hole_start = drm_mm_hole_node_start(entry), \
> +	     hole_end = drm_mm_hole_node_end(entry) : \
> +	     0; \
> +	     entry = list_entry(entry->hole_stack.next, typeof(struct drm_mm_node), hole_stack))
> +
>  /*
>   * Basic range manager support (drm_mm.c)
>   */
> -- 
> 1.7.10.4
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch