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Commit 99561217 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

Merge branch 'tip/futex/devel' of... 

Merge branch 'tip/futex/devel' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-rt into core/futexes

 futex,plist: Pass the real head of the priority list to plist_del()
 futex,plist: Remove debug lock assignment from plist_node
 plist: Shrink struct plist_head
 plist: Add priority list test
parents 8d7718aa 6d55da53

include/linux/plist.h

+24 −23
Original line number Diff line number Diff line
@@ -31,15 +31,17 @@ 
 *

 * Simple ASCII art explanation:

 *

 * |HEAD          |

 * |              |

 * |prio_list.prev|<------------------------------------|

 * |prio_list.next|<->|pl|<->|pl|<--------------->|pl|<-|

 * |10            |   |10|   |21|   |21|   |21|   |40|   (prio)

 * |              |   |  |   |  |   |  |   |  |   |  |

 * |              |   |  |   |  |   |  |   |  |   |  |

 * |node_list.next|<->|nl|<->|nl|<->|nl|<->|nl|<->|nl|<-|

 * |node_list.prev|<------------------------------------|

 * pl:prio_list (only for plist_node)

 * nl:node_list

 *   HEAD|             NODE(S)

 *       |

 *       ||------------------------------------|

 *       ||->|pl|<->|pl|<--------------->|pl|<-|

 *       |   |10|   |21|   |21|   |21|   |40|   (prio)

 *       |   |  |   |  |   |  |   |  |   |  |

 *       |   |  |   |  |   |  |   |  |   |  |

 * |->|nl|<->|nl|<->|nl|<->|nl|<->|nl|<->|nl|<-|

 * |-------------------------------------------|

 *

 * The nodes on the prio_list list are sorted by priority to simplify

 * the insertion of new nodes. There are no nodes with duplicate
@@ -78,7 +80,6 @@ 
#include <linux/spinlock_types.h>



struct plist_head {

	struct list_head prio_list;

	struct list_head node_list;

#ifdef CONFIG_DEBUG_PI_LIST

	raw_spinlock_t *rawlock;
@@ -88,7 +89,8 @@ struct plist_head { 


struct plist_node {

	int			prio;

	struct plist_head	plist;

	struct list_head	prio_list;

	struct list_head	node_list;

};



#ifdef CONFIG_DEBUG_PI_LIST
@@ -100,7 +102,6 @@ struct plist_node { 
#endif



#define _PLIST_HEAD_INIT(head)				\

	.prio_list = LIST_HEAD_INIT((head).prio_list),	\

	.node_list = LIST_HEAD_INIT((head).node_list)



/**
@@ -133,7 +134,8 @@ struct plist_node { 
#define PLIST_NODE_INIT(node, __prio)			\

{							\

	.prio  = (__prio),				\

	.plist = { _PLIST_HEAD_INIT((node).plist) },	\

	.prio_list = LIST_HEAD_INIT((node).prio_list),	\

	.node_list = LIST_HEAD_INIT((node).node_list),	\

}



/**
@@ -144,7 +146,6 @@ struct plist_node { 
static inline void

plist_head_init(struct plist_head *head, spinlock_t *lock)

{

	INIT_LIST_HEAD(&head->prio_list);

	INIT_LIST_HEAD(&head->node_list);

#ifdef CONFIG_DEBUG_PI_LIST

	head->spinlock = lock;
@@ -160,7 +161,6 @@ plist_head_init(struct plist_head *head, spinlock_t *lock) 
static inline void

plist_head_init_raw(struct plist_head *head, raw_spinlock_t *lock)

{

	INIT_LIST_HEAD(&head->prio_list);

	INIT_LIST_HEAD(&head->node_list);

#ifdef CONFIG_DEBUG_PI_LIST

	head->rawlock = lock;
@@ -176,7 +176,8 @@ plist_head_init_raw(struct plist_head *head, raw_spinlock_t *lock) 
static inline void plist_node_init(struct plist_node *node, int prio)

{

	node->prio = prio;

	plist_head_init(&node->plist, NULL);

	INIT_LIST_HEAD(&node->prio_list);

	INIT_LIST_HEAD(&node->node_list);

}



extern void plist_add(struct plist_node *node, struct plist_head *head);
@@ -188,7 +189,7 @@ extern void plist_del(struct plist_node *node, struct plist_head *head); 
 * @head:	the head for your list

 */

#define plist_for_each(pos, head)	\

	 list_for_each_entry(pos, &(head)->node_list, plist.node_list)

	 list_for_each_entry(pos, &(head)->node_list, node_list)



/**

 * plist_for_each_safe - iterate safely over a plist of given type
@@ -199,7 +200,7 @@ extern void plist_del(struct plist_node *node, struct plist_head *head); 
 * Iterate over a plist of given type, safe against removal of list entry.

 */

#define plist_for_each_safe(pos, n, head)	\

	 list_for_each_entry_safe(pos, n, &(head)->node_list, plist.node_list)

	 list_for_each_entry_safe(pos, n, &(head)->node_list, node_list)



/**

 * plist_for_each_entry	- iterate over list of given type
@@ -208,7 +209,7 @@ extern void plist_del(struct plist_node *node, struct plist_head *head); 
 * @mem:	the name of the list_struct within the struct

 */

#define plist_for_each_entry(pos, head, mem)	\

	 list_for_each_entry(pos, &(head)->node_list, mem.plist.node_list)

	 list_for_each_entry(pos, &(head)->node_list, mem.node_list)



/**

 * plist_for_each_entry_safe - iterate safely over list of given type
@@ -220,7 +221,7 @@ extern void plist_del(struct plist_node *node, struct plist_head *head); 
 * Iterate over list of given type, safe against removal of list entry.

 */

#define plist_for_each_entry_safe(pos, n, head, m)	\

	list_for_each_entry_safe(pos, n, &(head)->node_list, m.plist.node_list)

	list_for_each_entry_safe(pos, n, &(head)->node_list, m.node_list)



/**

 * plist_head_empty - return !0 if a plist_head is empty
@@ -237,7 +238,7 @@ static inline int plist_head_empty(const struct plist_head *head) 
 */

static inline int plist_node_empty(const struct plist_node *node)

{

	return plist_head_empty(&node->plist);

	return list_empty(&node->node_list);

}



/* All functions below assume the plist_head is not empty. */
@@ -285,7 +286,7 @@ static inline int plist_node_empty(const struct plist_node *node) 
static inline struct plist_node *plist_first(const struct plist_head *head)

{

	return list_entry(head->node_list.next,

			  struct plist_node, plist.node_list);

			  struct plist_node, node_list);

}



/**
@@ -297,7 +298,7 @@ static inline struct plist_node *plist_first(const struct plist_head *head) 
static inline struct plist_node *plist_last(const struct plist_head *head)

{

	return list_entry(head->node_list.prev,

			  struct plist_node, plist.node_list);

			  struct plist_node, node_list);

}



#endif

kernel/futex.c

+23 −17
Original line number Diff line number Diff line
@@ -772,6 +772,24 @@ static int futex_lock_pi_atomic(u32 __user *uaddr, struct futex_hash_bucket *hb, 
	return ret;

}



/**

 * __unqueue_futex() - Remove the futex_q from its futex_hash_bucket

 * @q:	The futex_q to unqueue

 *

 * The q->lock_ptr must not be NULL and must be held by the caller.

 */

static void __unqueue_futex(struct futex_q *q)

{

	struct futex_hash_bucket *hb;



	if (WARN_ON(!q->lock_ptr || !spin_is_locked(q->lock_ptr)

			|| plist_node_empty(&q->list)))

		return;



	hb = container_of(q->lock_ptr, struct futex_hash_bucket, lock);

	plist_del(&q->list, &hb->chain);

}



/*

 * The hash bucket lock must be held when this is called.

 * Afterwards, the futex_q must not be accessed.
@@ -789,7 +807,7 @@ static void wake_futex(struct futex_q *q) 
	 */

	get_task_struct(p);



	plist_del(&q->list, &q->list.plist);

	__unqueue_futex(q);

	/*

	 * The waiting task can free the futex_q as soon as

	 * q->lock_ptr = NULL is written, without taking any locks. A
@@ -1064,9 +1082,6 @@ void requeue_futex(struct futex_q *q, struct futex_hash_bucket *hb1, 
		plist_del(&q->list, &hb1->chain);

		plist_add(&q->list, &hb2->chain);

		q->lock_ptr = &hb2->lock;

#ifdef CONFIG_DEBUG_PI_LIST

		q->list.plist.spinlock = &hb2->lock;

#endif

	}

	get_futex_key_refs(key2);

	q->key = *key2;
@@ -1093,16 +1108,12 @@ void requeue_pi_wake_futex(struct futex_q *q, union futex_key *key, 
	get_futex_key_refs(key);

	q->key = *key;



	WARN_ON(plist_node_empty(&q->list));

	plist_del(&q->list, &q->list.plist);

	__unqueue_futex(q);



	WARN_ON(!q->rt_waiter);

	q->rt_waiter = NULL;



	q->lock_ptr = &hb->lock;

#ifdef CONFIG_DEBUG_PI_LIST

	q->list.plist.spinlock = &hb->lock;

#endif



	wake_up_state(q->task, TASK_NORMAL);

}
@@ -1450,9 +1461,6 @@ static inline void queue_me(struct futex_q *q, struct futex_hash_bucket *hb) 
	prio = min(current->normal_prio, MAX_RT_PRIO);



	plist_node_init(&q->list, prio);

#ifdef CONFIG_DEBUG_PI_LIST

	q->list.plist.spinlock = &hb->lock;

#endif

	plist_add(&q->list, &hb->chain);

	q->task = current;

	spin_unlock(&hb->lock);
@@ -1497,8 +1505,7 @@ static int unqueue_me(struct futex_q *q) 
			spin_unlock(lock_ptr);

			goto retry;

		}

		WARN_ON(plist_node_empty(&q->list));

		plist_del(&q->list, &q->list.plist);

		__unqueue_futex(q);



		BUG_ON(q->pi_state);
@@ -1518,8 +1525,7 @@ static int unqueue_me(struct futex_q *q) 
static void unqueue_me_pi(struct futex_q *q)

	__releases(q->lock_ptr)

{

	WARN_ON(plist_node_empty(&q->list));

	plist_del(&q->list, &q->list.plist);

	__unqueue_futex(q);



	BUG_ON(!q->pi_state);

	free_pi_state(q->pi_state);
@@ -2156,7 +2162,7 @@ int handle_early_requeue_pi_wakeup(struct futex_hash_bucket *hb, 
		 * We were woken prior to requeue by a timeout or a signal.

		 * Unqueue the futex_q and determine which it was.

		 */

		plist_del(&q->list, &q->list.plist);

		plist_del(&q->list, &hb->chain);



		/* Handle spurious wakeups gracefully */

		ret = -EWOULDBLOCK;

lib/plist.c

+115 −20
Original line number Diff line number Diff line
@@ -28,6 +28,8 @@ 


#ifdef CONFIG_DEBUG_PI_LIST



static struct plist_head test_head;



static void plist_check_prev_next(struct list_head *t, struct list_head *p,

				  struct list_head *n)

{
@@ -54,12 +56,13 @@ static void plist_check_list(struct list_head *top) 


static void plist_check_head(struct plist_head *head)

{

	WARN_ON(!head->rawlock && !head->spinlock);

	WARN_ON(head != &test_head && !head->rawlock && !head->spinlock);

	if (head->rawlock)

		WARN_ON_SMP(!raw_spin_is_locked(head->rawlock));

	if (head->spinlock)

		WARN_ON_SMP(!spin_is_locked(head->spinlock));

	plist_check_list(&head->prio_list);

	if (!plist_head_empty(head))

		plist_check_list(&plist_first(head)->prio_list);

	plist_check_list(&head->node_list);

}
@@ -75,25 +78,33 @@ static void plist_check_head(struct plist_head *head) 
 */

void plist_add(struct plist_node *node, struct plist_head *head)

{

	struct plist_node *iter;

	struct plist_node *first, *iter, *prev = NULL;

	struct list_head *node_next = &head->node_list;



	plist_check_head(head);

	WARN_ON(!plist_node_empty(node));

	WARN_ON(!list_empty(&node->prio_list));



	list_for_each_entry(iter, &head->prio_list, plist.prio_list) {

		if (node->prio < iter->prio)

			goto lt_prio;

		else if (node->prio == iter->prio) {

			iter = list_entry(iter->plist.prio_list.next,

					struct plist_node, plist.prio_list);

			goto eq_prio;

		}

	if (plist_head_empty(head))

		goto ins_node;



	first = iter = plist_first(head);



	do {

		if (node->prio < iter->prio) {

			node_next = &iter->node_list;

			break;

		}



lt_prio:

	list_add_tail(&node->plist.prio_list, &iter->plist.prio_list);

eq_prio:

	list_add_tail(&node->plist.node_list, &iter->plist.node_list);

		prev = iter;

		iter = list_entry(iter->prio_list.next,

				struct plist_node, prio_list);

	} while (iter != first);



	if (!prev || prev->prio != node->prio)

		list_add_tail(&node->prio_list, &iter->prio_list);

ins_node:

	list_add_tail(&node->node_list, node_next);



	plist_check_head(head);

}
@@ -108,14 +119,98 @@ void plist_del(struct plist_node *node, struct plist_head *head) 
{

	plist_check_head(head);



	if (!list_empty(&node->plist.prio_list)) {

		struct plist_node *next = plist_first(&node->plist);

	if (!list_empty(&node->prio_list)) {

		if (node->node_list.next != &head->node_list) {

			struct plist_node *next;



			next = list_entry(node->node_list.next,

					struct plist_node, node_list);



		list_move_tail(&next->plist.prio_list, &node->plist.prio_list);

		list_del_init(&node->plist.prio_list);

			/* add the next plist_node into prio_list */

			if (list_empty(&next->prio_list))

				list_add(&next->prio_list, &node->prio_list);

		}

		list_del_init(&node->prio_list);

	}



	list_del_init(&node->plist.node_list);

	list_del_init(&node->node_list);



	plist_check_head(head);

}



#ifdef CONFIG_DEBUG_PI_LIST

#include <linux/sched.h>

#include <linux/module.h>

#include <linux/init.h>



static struct plist_node __initdata test_node[241];



static void __init plist_test_check(int nr_expect)

{

	struct plist_node *first, *prio_pos, *node_pos;



	if (plist_head_empty(&test_head)) {

		BUG_ON(nr_expect != 0);

		return;

	}



	prio_pos = first = plist_first(&test_head);

	plist_for_each(node_pos, &test_head) {

		if (nr_expect-- < 0)

			break;

		if (node_pos == first)

			continue;

		if (node_pos->prio == prio_pos->prio) {

			BUG_ON(!list_empty(&node_pos->prio_list));

			continue;

		}



		BUG_ON(prio_pos->prio > node_pos->prio);

		BUG_ON(prio_pos->prio_list.next != &node_pos->prio_list);

		prio_pos = node_pos;

	}



	BUG_ON(nr_expect != 0);

	BUG_ON(prio_pos->prio_list.next != &first->prio_list);

}



static int  __init plist_test(void)

{

	int nr_expect = 0, i, loop;

	unsigned int r = local_clock();



	printk(KERN_INFO "start plist test\n");

	plist_head_init(&test_head, NULL);

	for (i = 0; i < ARRAY_SIZE(test_node); i++)

		plist_node_init(test_node + i, 0);



	for (loop = 0; loop < 1000; loop++) {

		r = r * 193939 % 47629;

		i = r % ARRAY_SIZE(test_node);

		if (plist_node_empty(test_node + i)) {

			r = r * 193939 % 47629;

			test_node[i].prio = r % 99;

			plist_add(test_node + i, &test_head);

			nr_expect++;

		} else {

			plist_del(test_node + i, &test_head);

			nr_expect--;

		}

		plist_test_check(nr_expect);

	}



	for (i = 0; i < ARRAY_SIZE(test_node); i++) {

		if (plist_node_empty(test_node + i))

			continue;

		plist_del(test_node + i, &test_head);

		nr_expect--;

		plist_test_check(nr_expect);

	}



	printk(KERN_INFO "end plist test\n");

	return 0;

}



module_init(plist_test);



#endif