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author | Lai Jiangshan <laijs@cn.fujitsu.com> | 2010-12-21 12:55:14 +0300 |
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committer | Steven Rostedt <rostedt@goodmis.org> | 2011-03-11 23:13:26 +0300 |
commit | bf6a9b8336ba12672755c2ae898b0abe42c7a5ac (patch) | |
tree | c85f2b2acac9bf9b88e0c19d90d252b1780e0d35 /lib/plist.c | |
parent | 017f2b239dabb2740b91df162e004371b861f371 (diff) | |
download | linux-bf6a9b8336ba12672755c2ae898b0abe42c7a5ac.tar.xz |
plist: Shrink struct plist_head
struct plist_head is used in struct task_struct as well as struct
rtmutex. If we can make it smaller, it will also make these structures
smaller as well.
The field prio_list in struct plist_head is seldom used and we can get
its information from the plist_nodes. Removing this field will decrease
the size of plist_head by half.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4D107982.9090700@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'lib/plist.c')
-rw-r--r-- | lib/plist.c | 54 |
1 files changed, 35 insertions, 19 deletions
diff --git a/lib/plist.c b/lib/plist.c index 1471988d9190..8c614d0e6c35 100644 --- a/lib/plist.c +++ b/lib/plist.c @@ -59,7 +59,8 @@ static void plist_check_head(struct plist_head *head) 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 +76,33 @@ 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 +117,21 @@ 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); } |