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Commit e6c03c5b authored by Chris Wilson's avatar Chris Wilson Committed by Dave Airlie
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drm: Memory fragmentation from lost alignment blocks 



If the block needs an alignment but otherwise fits exactly into the tail,
then the split-off block from the start would remain marked as non-free.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Acked-by: default avatarThomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 602c11a8

drivers/gpu/drm/drm_mm.c

+9 −11
Original line number Diff line number Diff line
@@ -188,36 +188,34 @@ static struct drm_mm_node *drm_mm_split_at_start(struct drm_mm_node *parent, 






struct drm_mm_node *drm_mm_get_block(struct drm_mm_node * parent,

struct drm_mm_node *drm_mm_get_block(struct drm_mm_node *node,

				     unsigned long size, unsigned alignment)

{



	struct drm_mm_node *align_splitoff = NULL;

	struct drm_mm_node *child;

	unsigned tmp = 0;



	if (alignment)

		tmp = parent->start % alignment;

		tmp = node->start % alignment;



	if (tmp) {

		align_splitoff =

		    drm_mm_split_at_start(parent, alignment - tmp, 0);

		    drm_mm_split_at_start(node, alignment - tmp, 0);

		if (unlikely(align_splitoff == NULL))

			return NULL;

	}



	if (parent->size == size) {

		list_del_init(&parent->fl_entry);

		parent->free = 0;

		return parent;

	if (node->size == size) {

		list_del_init(&node->fl_entry);

		node->free = 0;

	} else {

		child = drm_mm_split_at_start(parent, size, 0);

		node = drm_mm_split_at_start(node, size, 0);

	}



	if (align_splitoff)

		drm_mm_put_block(align_splitoff);



	return child;

	return node;

}



EXPORT_SYMBOL(drm_mm_get_block);