From a23ba907d5e65d6aeea3e59c82fda9cd206a7aad Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Fri, 8 Sep 2017 16:15:01 -0700 Subject: locking/rtmutex: replace top-waiter and pi_waiters leftmost caching ... with the generic rbtree flavor instead. No changes in semantics whatsoever. Link: http://lkml.kernel.org/r/20170719014603.19029-10-dave@stgolabs.net Signed-off-by: Davidlohr Bueso Acked-by: Peter Zijlstra (Intel) Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/locking/rtmutex.c | 35 +++++++++++------------------------ 1 file changed, 11 insertions(+), 24 deletions(-) (limited to 'kernel/locking/rtmutex.c') diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 649dc9d3951a..6f3dba6e4e9e 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -271,10 +271,10 @@ rt_mutex_waiter_equal(struct rt_mutex_waiter *left, static void rt_mutex_enqueue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter) { - struct rb_node **link = &lock->waiters.rb_node; + struct rb_node **link = &lock->waiters.rb_root.rb_node; struct rb_node *parent = NULL; struct rt_mutex_waiter *entry; - int leftmost = 1; + bool leftmost = true; while (*link) { parent = *link; @@ -283,15 +283,12 @@ rt_mutex_enqueue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter) link = &parent->rb_left; } else { link = &parent->rb_right; - leftmost = 0; + leftmost = false; } } - if (leftmost) - lock->waiters_leftmost = &waiter->tree_entry; - rb_link_node(&waiter->tree_entry, parent, link); - rb_insert_color(&waiter->tree_entry, &lock->waiters); + rb_insert_color_cached(&waiter->tree_entry, &lock->waiters, leftmost); } static void @@ -300,20 +297,17 @@ rt_mutex_dequeue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter) if (RB_EMPTY_NODE(&waiter->tree_entry)) return; - if (lock->waiters_leftmost == &waiter->tree_entry) - lock->waiters_leftmost = rb_next(&waiter->tree_entry); - - rb_erase(&waiter->tree_entry, &lock->waiters); + rb_erase_cached(&waiter->tree_entry, &lock->waiters); RB_CLEAR_NODE(&waiter->tree_entry); } static void rt_mutex_enqueue_pi(struct task_struct *task, struct rt_mutex_waiter *waiter) { - struct rb_node **link = &task->pi_waiters.rb_node; + struct rb_node **link = &task->pi_waiters.rb_root.rb_node; struct rb_node *parent = NULL; struct rt_mutex_waiter *entry; - int leftmost = 1; + bool leftmost = true; while (*link) { parent = *link; @@ -322,15 +316,12 @@ rt_mutex_enqueue_pi(struct task_struct *task, struct rt_mutex_waiter *waiter) link = &parent->rb_left; } else { link = &parent->rb_right; - leftmost = 0; + leftmost = false; } } - if (leftmost) - task->pi_waiters_leftmost = &waiter->pi_tree_entry; - rb_link_node(&waiter->pi_tree_entry, parent, link); - rb_insert_color(&waiter->pi_tree_entry, &task->pi_waiters); + rb_insert_color_cached(&waiter->pi_tree_entry, &task->pi_waiters, leftmost); } static void @@ -339,10 +330,7 @@ rt_mutex_dequeue_pi(struct task_struct *task, struct rt_mutex_waiter *waiter) if (RB_EMPTY_NODE(&waiter->pi_tree_entry)) return; - if (task->pi_waiters_leftmost == &waiter->pi_tree_entry) - task->pi_waiters_leftmost = rb_next(&waiter->pi_tree_entry); - - rb_erase(&waiter->pi_tree_entry, &task->pi_waiters); + rb_erase_cached(&waiter->pi_tree_entry, &task->pi_waiters); RB_CLEAR_NODE(&waiter->pi_tree_entry); } @@ -1657,8 +1645,7 @@ void __rt_mutex_init(struct rt_mutex *lock, const char *name, { lock->owner = NULL; raw_spin_lock_init(&lock->wait_lock); - lock->waiters = RB_ROOT; - lock->waiters_leftmost = NULL; + lock->waiters = RB_ROOT_CACHED; if (name && key) debug_rt_mutex_init(lock, name, key); -- cgit v1.2.3