Messages in this thread Patch in this message | | | From | Xunlei Pang <> | Subject | [PATCH v4 1/3] lib/plist: Provide plist_add_head() for nodes with the same prio | Date | Mon, 16 Feb 2015 17:32:22 +0800 |
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From: Xunlei Pang <pang.xunlei@linaro.org>
If there're multiple nodes with the same prio as @node, currently plist_add() will add @node behind all of them. Now we need to add @node before all of these nodes for SMP RT scheduler.
This patch adds a common __plist_add() for adding @node before or behind existing nodes with the same prio, then adds plist_add_head() and plist_add_tail() inline wrapper functions for convenient uses.
Finally, define plist_add() with plist_add_tail() which has the same behaviour as before.
Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org> --- include/linux/plist.h | 30 +++++++++++++++++++++++++++++- lib/plist.c | 15 ++++++++++++--- 2 files changed, 41 insertions(+), 4 deletions(-)
diff --git a/include/linux/plist.h b/include/linux/plist.h index 9788360..e17bb96 100644 --- a/include/linux/plist.h +++ b/include/linux/plist.h @@ -138,7 +138,35 @@ static inline void plist_node_init(struct plist_node *node, int prio) INIT_LIST_HEAD(&node->node_list); } -extern void plist_add(struct plist_node *node, struct plist_head *head); +extern void __plist_add(struct plist_node *node, + struct plist_head *head, bool is_head); + +/** + * plist_add_head - add @node to @head, before all existing same-prio nodes + * + * @node: &struct plist_node pointer + * @head: &struct plist_head pointer + */ +static inline +void plist_add_head(struct plist_node *node, struct plist_head *head) +{ + __plist_add(node, head, 1); +} + +/** + * plist_add_tail - add @node to @head, after all existing same-prio nodes + * + * @node: &struct plist_node pointer + * @head: &struct plist_head pointer + */ +static inline +void plist_add_tail(struct plist_node *node, struct plist_head *head) +{ + __plist_add(node, head, 0); +} + +#define plist_add plist_add_tail + extern void plist_del(struct plist_node *node, struct plist_head *head); extern void plist_requeue(struct plist_node *node, struct plist_head *head); diff --git a/lib/plist.c b/lib/plist.c index d408e77..0e1f1b3 100644 --- a/lib/plist.c +++ b/lib/plist.c @@ -67,12 +67,16 @@ static void plist_check_head(struct plist_head *head) #endif /** - * plist_add - add @node to @head + * __plist_add - add @node to @head * * @node: &struct plist_node pointer * @head: &struct plist_head pointer + * @is_head: bool + * + * If there're any nodes with the same prio, add @node + * behind or before all of them according to @is_head. */ -void plist_add(struct plist_node *node, struct plist_head *head) +void __plist_add(struct plist_node *node, struct plist_head *head, bool is_head) { struct plist_node *first, *iter, *prev = NULL; struct list_head *node_next = &head->node_list; @@ -97,8 +101,13 @@ void plist_add(struct plist_node *node, struct plist_head *head) struct plist_node, prio_list); } while (iter != first); - if (!prev || prev->prio != node->prio) + if (!prev || prev->prio != node->prio) { list_add_tail(&node->prio_list, &iter->prio_list); + } else if (is_head) { + list_add(&node->prio_list, &prev->prio_list); + list_del_init(&prev->prio_list); + node_next = &prev->node_list; + } ins_node: list_add_tail(&node->node_list, node_next); -- 1.9.1
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