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Commit a23ba907 authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Linus Torvalds
Browse files

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: default avatarDavidlohr Bueso <dbueso@suse.de>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2161573e

include/linux/init_task.h

+2 −3
Original line number Diff line number Diff line
@@ -175,9 +175,8 @@ extern struct cred init_cred; 


#ifdef CONFIG_RT_MUTEXES

# define INIT_RT_MUTEXES(tsk)						\

	.pi_waiters = RB_ROOT,						\

	.pi_top_task = NULL,						\

	.pi_waiters_leftmost = NULL,

	.pi_waiters = RB_ROOT_CACHED,					\

	.pi_top_task = NULL,

#else

# define INIT_RT_MUTEXES(tsk)

#endif

include/linux/rtmutex.h

+5 −6
Original line number Diff line number Diff line
@@ -22,14 +22,13 @@ extern int max_lock_depth; /* for sysctl */ 
 * The rt_mutex structure

 *

 * @wait_lock:	spinlock to protect the structure

 * @waiters:	rbtree root to enqueue waiters in priority order

 * @waiters_leftmost: top waiter

 * @waiters:	rbtree root to enqueue waiters in priority order;

 *              caches top-waiter (leftmost node).

 * @owner:	the mutex owner

 */

struct rt_mutex {

	raw_spinlock_t		wait_lock;

	struct rb_root          waiters;

	struct rb_node          *waiters_leftmost;

	struct rb_root_cached   waiters;

	struct task_struct	*owner;

#ifdef CONFIG_DEBUG_RT_MUTEXES

	int			save_state;
@@ -84,7 +83,7 @@ do { \ 


#define __RT_MUTEX_INITIALIZER(mutexname) \

	{ .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \

	, .waiters = RB_ROOT \

	, .waiters = RB_ROOT_CACHED \

	, .owner = NULL \

	__DEBUG_RT_MUTEX_INITIALIZER(mutexname) \

	__DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)}

include/linux/sched.h

+1 −2
Original line number Diff line number Diff line
@@ -812,8 +812,7 @@ struct task_struct { 


#ifdef CONFIG_RT_MUTEXES

	/* PI waiters blocked on a rt_mutex held by this task: */

	struct rb_root			pi_waiters;

	struct rb_node			*pi_waiters_leftmost;

	struct rb_root_cached		pi_waiters;

	/* Updated under owner's pi_lock and rq lock */

	struct task_struct		*pi_top_task;

	/* Deadlock detection and priority inheritance handling: */

kernel/fork.c

+1 −2
Original line number Diff line number Diff line
@@ -1462,8 +1462,7 @@ static void rt_mutex_init_task(struct task_struct *p) 
{

	raw_spin_lock_init(&p->pi_lock);

#ifdef CONFIG_RT_MUTEXES

	p->pi_waiters = RB_ROOT;

	p->pi_waiters_leftmost = NULL;

	p->pi_waiters = RB_ROOT_CACHED;

	p->pi_top_task = NULL;

	p->pi_blocked_on = NULL;

#endif

kernel/locking/rtmutex-debug.c

+1 −1
Original line number Diff line number Diff line
@@ -58,7 +58,7 @@ static void printk_lock(struct rt_mutex *lock, int print_owner) 


void rt_mutex_debug_task_free(struct task_struct *task)

{

	DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters));

	DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root));

	DEBUG_LOCKS_WARN_ON(task->pi_blocked_on);

}