diff options
Diffstat (limited to 'lib/plist.c')
| -rw-r--r-- | lib/plist.c | 191 |
1 files changed, 167 insertions, 24 deletions
diff --git a/lib/plist.c b/lib/plist.c index 1471988d919..d408e774b74 100644 --- a/lib/plist.c +++ b/lib/plist.c @@ -23,11 +23,14 @@ * information. */ +#include <linux/bug.h> #include <linux/plist.h> #include <linux/spinlock.h> #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 +57,8 @@ static void plist_check_list(struct list_head *top) static void plist_check_head(struct plist_head *head) { - WARN_ON(!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 +74,33 @@ 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)); + + if (plist_head_empty(head)) + goto ins_node; + + first = iter = plist_first(head); - 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; + 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 +115,150 @@ 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; - list_move_tail(&next->plist.prio_list, &node->plist.prio_list); - list_del_init(&node->plist.prio_list); + next = list_entry(node->node_list.next, + struct plist_node, node_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); +} + +/** + * plist_requeue - Requeue @node at end of same-prio entries. + * + * This is essentially an optimized plist_del() followed by + * plist_add(). It moves an entry already in the plist to + * after any other same-priority entries. + * + * @node: &struct plist_node pointer - entry to be moved + * @head: &struct plist_head pointer - list head + */ +void plist_requeue(struct plist_node *node, struct plist_head *head) +{ + struct plist_node *iter; + struct list_head *node_next = &head->node_list; + + plist_check_head(head); + BUG_ON(plist_head_empty(head)); + BUG_ON(plist_node_empty(node)); + + if (node == plist_last(head)) + return; + + iter = plist_next(node); + + if (node->prio != iter->prio) + return; + + plist_del(node, head); + + plist_for_each_continue(iter, head) { + if (node->prio != iter->prio) { + node_next = &iter->node_list; + break; + } + } + list_add_tail(&node->node_list, node_next); 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 void __init plist_test_requeue(struct plist_node *node) +{ + plist_requeue(node, &test_head); + + if (node != plist_last(&test_head)) + BUG_ON(node->prio == plist_next(node)->prio); +} + +static int __init plist_test(void) +{ + int nr_expect = 0, i, loop; + unsigned int r = local_clock(); + + printk(KERN_DEBUG "start plist test\n"); + plist_head_init(&test_head); + 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); + if (!plist_node_empty(test_node + i)) { + plist_test_requeue(test_node + i); + 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_DEBUG "end plist test\n"); + return 0; +} + +module_init(plist_test); + +#endif |