From f42240d729b97a01e863b8c24177ec4e54885357 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Fri, 23 Mar 2012 15:02:14 -0700 Subject: prio_tree: remove unnecessary code in prio_tree_replace Remove the code since 'node' has already been initialized in the begin of the function Signed-off-by: Xiao Guangrong Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/prio_tree.c | 1 - 1 file changed, 1 deletion(-) (limited to 'lib/prio_tree.c') diff --git a/lib/prio_tree.c b/lib/prio_tree.c index ccfd850b0de..423eba80478 100644 --- a/lib/prio_tree.c +++ b/lib/prio_tree.c @@ -151,7 +151,6 @@ struct prio_tree_node *prio_tree_replace(struct prio_tree_root *root, * We can reduce root->index_bits here. However, it is complex * and does not help much to improve performance (IMO). */ - node->parent = node; root->prio_tree_node = node; } else { node->parent = old->parent; -- cgit v1.2.3-70-g09d2 From f35368dd1cef11cdd310b07c74d74f45e3469c64 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Fri, 23 Mar 2012 15:02:15 -0700 Subject: prio_tree: cleanup prio_tree_left()/prio_tree_right() Introduce iter_walk_down()/iter_walk_up() to remove the common code between prio_tree_left() and prio_tree_right(). Signed-off-by: Xiao Guangrong Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/prio_tree.c | 78 +++++++++++++++++++++++++++------------------------------ 1 file changed, 37 insertions(+), 41 deletions(-) (limited to 'lib/prio_tree.c') diff --git a/lib/prio_tree.c b/lib/prio_tree.c index 423eba80478..888e8b3a97e 100644 --- a/lib/prio_tree.c +++ b/lib/prio_tree.c @@ -304,6 +304,40 @@ void prio_tree_remove(struct prio_tree_root *root, struct prio_tree_node *node) cur = prio_tree_replace(root, cur->parent, cur); } +static void iter_walk_down(struct prio_tree_iter *iter) +{ + iter->mask >>= 1; + if (iter->mask) { + if (iter->size_level) + iter->size_level++; + return; + } + + if (iter->size_level) { + BUG_ON(!prio_tree_left_empty(iter->cur)); + BUG_ON(!prio_tree_right_empty(iter->cur)); + iter->size_level++; + iter->mask = ULONG_MAX; + } else { + iter->size_level = 1; + iter->mask = 1UL << (BITS_PER_LONG - 1); + } +} + +static void iter_walk_up(struct prio_tree_iter *iter) +{ + if (iter->mask == ULONG_MAX) + iter->mask = 1UL; + else if (iter->size_level == 1) + iter->mask = 1UL; + else + iter->mask <<= 1; + if (iter->size_level) + iter->size_level--; + if (!iter->size_level && (iter->value & iter->mask)) + iter->value ^= iter->mask; +} + /* * Following functions help to enumerate all prio_tree_nodes in the tree that * overlap with the input interval X [radix_index, heap_index]. The enumeration @@ -322,21 +356,7 @@ static struct prio_tree_node *prio_tree_left(struct prio_tree_iter *iter, if (iter->r_index <= *h_index) { iter->cur = iter->cur->left; - iter->mask >>= 1; - if (iter->mask) { - if (iter->size_level) - iter->size_level++; - } else { - if (iter->size_level) { - BUG_ON(!prio_tree_left_empty(iter->cur)); - BUG_ON(!prio_tree_right_empty(iter->cur)); - iter->size_level++; - iter->mask = ULONG_MAX; - } else { - iter->size_level = 1; - iter->mask = 1UL << (BITS_PER_LONG - 1); - } - } + iter_walk_down(iter); return iter->cur; } @@ -363,22 +383,7 @@ static struct prio_tree_node *prio_tree_right(struct prio_tree_iter *iter, if (iter->r_index <= *h_index) { iter->cur = iter->cur->right; - iter->mask >>= 1; - iter->value = value; - if (iter->mask) { - if (iter->size_level) - iter->size_level++; - } else { - if (iter->size_level) { - BUG_ON(!prio_tree_left_empty(iter->cur)); - BUG_ON(!prio_tree_right_empty(iter->cur)); - iter->size_level++; - iter->mask = ULONG_MAX; - } else { - iter->size_level = 1; - iter->mask = 1UL << (BITS_PER_LONG - 1); - } - } + iter_walk_down(iter); return iter->cur; } @@ -388,16 +393,7 @@ static struct prio_tree_node *prio_tree_right(struct prio_tree_iter *iter, static struct prio_tree_node *prio_tree_parent(struct prio_tree_iter *iter) { iter->cur = iter->cur->parent; - if (iter->mask == ULONG_MAX) - iter->mask = 1UL; - else if (iter->size_level == 1) - iter->mask = 1UL; - else - iter->mask <<= 1; - if (iter->size_level) - iter->size_level--; - if (!iter->size_level && (iter->value & iter->mask)) - iter->value ^= iter->mask; + iter_walk_up(iter); return iter->cur; } -- cgit v1.2.3-70-g09d2 From 742245d5c2ebd75c2a002f8fc2afbdc5c26edd8c Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Fri, 23 Mar 2012 15:02:15 -0700 Subject: prio_tree: simplify prio_tree_expand() In current code, the deleted-node is recorded from first to last, actually, we can directly attach these node on 'node' we will insert as the left child, it can let the code more readable. Signed-off-by: Xiao Guangrong Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/prio_tree.c | 38 ++++++++++++++------------------------ 1 file changed, 14 insertions(+), 24 deletions(-) (limited to 'lib/prio_tree.c') diff --git a/lib/prio_tree.c b/lib/prio_tree.c index 888e8b3a97e..928482bb838 100644 --- a/lib/prio_tree.c +++ b/lib/prio_tree.c @@ -94,43 +94,33 @@ static inline unsigned long prio_tree_maxindex(unsigned int bits) static struct prio_tree_node *prio_tree_expand(struct prio_tree_root *root, struct prio_tree_node *node, unsigned long max_heap_index) { - struct prio_tree_node *first = NULL, *prev, *last = NULL; + struct prio_tree_node *prev; if (max_heap_index > prio_tree_maxindex(root->index_bits)) root->index_bits++; + prev = node; + INIT_PRIO_TREE_NODE(node); + while (max_heap_index > prio_tree_maxindex(root->index_bits)) { + struct prio_tree_node *tmp = root->prio_tree_node; + root->index_bits++; if (prio_tree_empty(root)) continue; - if (first == NULL) { - first = root->prio_tree_node; - prio_tree_remove(root, root->prio_tree_node); - INIT_PRIO_TREE_NODE(first); - last = first; - } else { - prev = last; - last = root->prio_tree_node; - prio_tree_remove(root, root->prio_tree_node); - INIT_PRIO_TREE_NODE(last); - prev->left = last; - last->parent = prev; - } - } - - INIT_PRIO_TREE_NODE(node); + prio_tree_remove(root, root->prio_tree_node); + INIT_PRIO_TREE_NODE(tmp); - if (first) { - node->left = first; - first->parent = node; - } else - last = node; + prev->left = tmp; + tmp->parent = prev; + prev = tmp; + } if (!prio_tree_empty(root)) { - last->left = root->prio_tree_node; - last->left->parent = last; + prev->left = root->prio_tree_node; + prev->left->parent = prev; } root->prio_tree_node = node; -- cgit v1.2.3-70-g09d2 From 97e834c5040b85e133d8d922111a62b2b853a406 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Fri, 23 Mar 2012 15:02:15 -0700 Subject: prio_tree: introduce prio_set_parent() Introduce prio_set_parent() to abstract the operation which is used to attach the node to its parent. Signed-off-by: Xiao Guangrong Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/prio_tree.c | 47 ++++++++++++++++++++++------------------------- 1 file changed, 22 insertions(+), 25 deletions(-) (limited to 'lib/prio_tree.c') diff --git a/lib/prio_tree.c b/lib/prio_tree.c index 928482bb838..8d443af03b4 100644 --- a/lib/prio_tree.c +++ b/lib/prio_tree.c @@ -85,6 +85,17 @@ static inline unsigned long prio_tree_maxindex(unsigned int bits) return index_bits_to_maxindex[bits - 1]; } +static void prio_set_parent(struct prio_tree_node *parent, + struct prio_tree_node *child, bool left) +{ + if (left) + parent->left = child; + else + parent->right = child; + + child->parent = parent; +} + /* * Extend a priority search tree so that it can store a node with heap_index * max_heap_index. In the worst case, this algorithm takes O((log n)^2). @@ -113,15 +124,12 @@ static struct prio_tree_node *prio_tree_expand(struct prio_tree_root *root, prio_tree_remove(root, root->prio_tree_node); INIT_PRIO_TREE_NODE(tmp); - prev->left = tmp; - tmp->parent = prev; + prio_set_parent(prev, tmp, true); prev = tmp; } - if (!prio_tree_empty(root)) { - prev->left = root->prio_tree_node; - prev->left->parent = prev; - } + if (!prio_tree_empty(root)) + prio_set_parent(prev, root->prio_tree_node, true); root->prio_tree_node = node; return node; @@ -142,23 +150,14 @@ struct prio_tree_node *prio_tree_replace(struct prio_tree_root *root, * and does not help much to improve performance (IMO). */ root->prio_tree_node = node; - } else { - node->parent = old->parent; - if (old->parent->left == old) - old->parent->left = node; - else - old->parent->right = node; - } + } else + prio_set_parent(old->parent, node, old->parent->left == old); - if (!prio_tree_left_empty(old)) { - node->left = old->left; - old->left->parent = node; - } + if (!prio_tree_left_empty(old)) + prio_set_parent(node, old->left, true); - if (!prio_tree_right_empty(old)) { - node->right = old->right; - old->right->parent = node; - } + if (!prio_tree_right_empty(old)) + prio_set_parent(node, old->right, false); return old; } @@ -218,16 +217,14 @@ struct prio_tree_node *prio_tree_insert(struct prio_tree_root *root, if (index & mask) { if (prio_tree_right_empty(cur)) { INIT_PRIO_TREE_NODE(node); - cur->right = node; - node->parent = cur; + prio_set_parent(cur, node, false); return res; } else cur = cur->right; } else { if (prio_tree_left_empty(cur)) { INIT_PRIO_TREE_NODE(node); - cur->left = node; - node->parent = cur; + prio_set_parent(cur, node, true); return res; } else cur = cur->left; -- cgit v1.2.3-70-g09d2