[RFC][PATCH 6/7] rbtree, rtmutex: Use rb_add_cached()

From: Peter Zijlstra
Date: Wed Apr 29 2020 - 11:38:03 EST



Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
kernel/locking/rtmutex.c | 54 +++++++++++++++--------------------------------
1 file changed, 18 insertions(+), 36 deletions(-)

--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -267,27 +267,18 @@ rt_mutex_waiter_equal(struct rt_mutex_wa
return 1;
}

+#define __node_2_waiter(node) \
+ rb_entry((node), struct rt_mutex_waiter, tree_entry)
+
+static inline bool __waiter_less(struct rb_node *a, const struct rb_node *b)
+{
+ return rt_mutex_waiter_less(__node_2_waiter(a), __node_2_waiter(b));
+}
+
static void
rt_mutex_enqueue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter)
{
- struct rb_node **link = &lock->waiters.rb_root.rb_node;
- struct rb_node *parent = NULL;
- struct rt_mutex_waiter *entry;
- bool leftmost = true;
-
- while (*link) {
- parent = *link;
- entry = rb_entry(parent, struct rt_mutex_waiter, tree_entry);
- if (rt_mutex_waiter_less(waiter, entry)) {
- link = &parent->rb_left;
- } else {
- link = &parent->rb_right;
- leftmost = false;
- }
- }
-
- rb_link_node(&waiter->tree_entry, parent, link);
- rb_insert_color_cached(&waiter->tree_entry, &lock->waiters, leftmost);
+ rb_add_cached(&lock->waiters, &waiter->tree_entry, __waiter_less);
}

static void
@@ -300,27 +291,18 @@ rt_mutex_dequeue(struct rt_mutex *lock,
RB_CLEAR_NODE(&waiter->tree_entry);
}

+#define __node_2_pi_waiter(node) \
+ rb_entry((node), struct rt_mutex_waiter, pi_tree_entry)
+
+static inline bool __pi_waiter_less(struct rb_node *a, const struct rb_node *b)
+{
+ return rt_mutex_waiter_less(__node_2_pi_waiter(a), __node_2_pi_waiter(b));
+}
+
static void
rt_mutex_enqueue_pi(struct task_struct *task, struct rt_mutex_waiter *waiter)
{
- struct rb_node **link = &task->pi_waiters.rb_root.rb_node;
- struct rb_node *parent = NULL;
- struct rt_mutex_waiter *entry;
- bool leftmost = true;
-
- while (*link) {
- parent = *link;
- entry = rb_entry(parent, struct rt_mutex_waiter, pi_tree_entry);
- if (rt_mutex_waiter_less(waiter, entry)) {
- link = &parent->rb_left;
- } else {
- link = &parent->rb_right;
- leftmost = false;
- }
- }
-
- rb_link_node(&waiter->pi_tree_entry, parent, link);
- rb_insert_color_cached(&waiter->pi_tree_entry, &task->pi_waiters, leftmost);
+ rb_add_cached(&task->pi_waiters, &waiter->pi_tree_entry, __pi_waiter_less);
}

static void