From f808c13fd3738948e10196496959871130612b61 Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Fri, 8 Sep 2017 16:15:08 -0700 Subject: lib/interval_tree: fast overlap detection MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Allow interval trees to quickly check for overlaps to avoid unnecesary tree lookups in interval_tree_iter_first(). As of this patch, all interval tree flavors will require using a 'rb_root_cached' such that we can have the leftmost node easily available. While most users will make use of this feature, those with special functions (in addition to the generic insert, delete, search calls) will avoid using the cached option as they can do funky things with insertions -- for example, vma_interval_tree_insert_after(). [jglisse@redhat.com: fix deadlock from typo vm_lock_anon_vma()] Link: http://lkml.kernel.org/r/20170808225719.20723-1-jglisse@redhat.com Link: http://lkml.kernel.org/r/20170719014603.19029-12-dave@stgolabs.net Signed-off-by: Davidlohr Bueso Signed-off-by: Jérôme Glisse Acked-by: Christian König Acked-by: Peter Zijlstra (Intel) Acked-by: Doug Ledford Acked-by: Michael S. Tsirkin Cc: David Airlie Cc: Jason Wang Cc: Christian Benvenuti Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/gpu/drm/drm_mm.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) (limited to 'drivers/gpu/drm/drm_mm.c') diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c index f794089d30ac..61a1c8ea74bc 100644 --- a/drivers/gpu/drm/drm_mm.c +++ b/drivers/gpu/drm/drm_mm.c @@ -169,7 +169,7 @@ INTERVAL_TREE_DEFINE(struct drm_mm_node, rb, struct drm_mm_node * __drm_mm_interval_first(const struct drm_mm *mm, u64 start, u64 last) { - return drm_mm_interval_tree_iter_first((struct rb_root *)&mm->interval_tree, + return drm_mm_interval_tree_iter_first((struct rb_root_cached *)&mm->interval_tree, start, last) ?: (struct drm_mm_node *)&mm->head_node; } EXPORT_SYMBOL(__drm_mm_interval_first); @@ -180,6 +180,7 @@ static void drm_mm_interval_tree_add_node(struct drm_mm_node *hole_node, struct drm_mm *mm = hole_node->mm; struct rb_node **link, *rb; struct drm_mm_node *parent; + bool leftmost = true; node->__subtree_last = LAST(node); @@ -196,9 +197,10 @@ static void drm_mm_interval_tree_add_node(struct drm_mm_node *hole_node, rb = &hole_node->rb; link = &hole_node->rb.rb_right; + leftmost = false; } else { rb = NULL; - link = &mm->interval_tree.rb_node; + link = &mm->interval_tree.rb_root.rb_node; } while (*link) { @@ -208,14 +210,15 @@ static void drm_mm_interval_tree_add_node(struct drm_mm_node *hole_node, parent->__subtree_last = node->__subtree_last; if (node->start < parent->start) link = &parent->rb.rb_left; - else + else { link = &parent->rb.rb_right; + leftmost = true; + } } rb_link_node(&node->rb, rb, link); - rb_insert_augmented(&node->rb, - &mm->interval_tree, - &drm_mm_interval_tree_augment); + rb_insert_augmented_cached(&node->rb, &mm->interval_tree, leftmost, + &drm_mm_interval_tree_augment); } #define RB_INSERT(root, member, expr) do { \ @@ -577,7 +580,7 @@ void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new) *new = *old; list_replace(&old->node_list, &new->node_list); - rb_replace_node(&old->rb, &new->rb, &old->mm->interval_tree); + rb_replace_node(&old->rb, &new->rb, &old->mm->interval_tree.rb_root); if (drm_mm_hole_follows(old)) { list_replace(&old->hole_stack, &new->hole_stack); @@ -863,7 +866,7 @@ void drm_mm_init(struct drm_mm *mm, u64 start, u64 size) mm->color_adjust = NULL; INIT_LIST_HEAD(&mm->hole_stack); - mm->interval_tree = RB_ROOT; + mm->interval_tree = RB_ROOT_CACHED; mm->holes_size = RB_ROOT; mm->holes_addr = RB_ROOT; -- cgit