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>
This commit is contained in:
Lai Jiangshan
Steven Rostedt
Родитель
017f2b239d
Коммит
bf6a9b8336
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@ -31,15 +31,17 @@
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*
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* Simple ASCII art explanation:
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*
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* |HEAD |
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* | |
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* |prio_list.prev|<------------------------------------|
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* |prio_list.next|<->|pl|<->|pl|<--------------->|pl|<-|
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* |10 | |10| |21| |21| |21| |40| (prio)
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* | | | | | | | | | | | |
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* | | | | | | | | | | | |
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* |node_list.next|<->|nl|<->|nl|<->|nl|<->|nl|<->|nl|<-|
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* |node_list.prev|<------------------------------------|
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* pl:prio_list (only for plist_node)
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* nl:node_list
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* HEAD| NODE(S)
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* |
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* ||------------------------------------|
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* ||->|pl|<->|pl|<--------------->|pl|<-|
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* | |10| |21| |21| |21| |40| (prio)
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* | | | | | | | | | | |
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* | | | | | | | | | | |
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* |->|nl|<->|nl|<->|nl|<->|nl|<->|nl|<->|nl|<-|
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* |-------------------------------------------|
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*
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* The nodes on the prio_list list are sorted by priority to simplify
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* the insertion of new nodes. There are no nodes with duplicate
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@ -78,7 +80,6 @@
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#include <linux/spinlock_types.h>
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struct plist_head {
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struct list_head prio_list;
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struct list_head node_list;
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#ifdef CONFIG_DEBUG_PI_LIST
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raw_spinlock_t *rawlock;
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@ -88,7 +89,8 @@ struct plist_head {
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struct plist_node {
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int prio;
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struct plist_head plist;
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struct list_head prio_list;
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struct list_head node_list;
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};
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#ifdef CONFIG_DEBUG_PI_LIST
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@ -100,7 +102,6 @@ struct plist_node {
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#endif
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#define _PLIST_HEAD_INIT(head) \
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.prio_list = LIST_HEAD_INIT((head).prio_list), \
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.node_list = LIST_HEAD_INIT((head).node_list)
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/**
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@ -133,7 +134,8 @@ struct plist_node {
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#define PLIST_NODE_INIT(node, __prio) \
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{ \
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.prio = (__prio), \
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.plist = { _PLIST_HEAD_INIT((node).plist) }, \
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.prio_list = LIST_HEAD_INIT((node).prio_list), \
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.node_list = LIST_HEAD_INIT((node).node_list), \
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}
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/**
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@ -144,7 +146,6 @@ struct plist_node {
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static inline void
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plist_head_init(struct plist_head *head, spinlock_t *lock)
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{
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INIT_LIST_HEAD(&head->prio_list);
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INIT_LIST_HEAD(&head->node_list);
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#ifdef CONFIG_DEBUG_PI_LIST
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head->spinlock = lock;
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@ -160,7 +161,6 @@ plist_head_init(struct plist_head *head, spinlock_t *lock)
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static inline void
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plist_head_init_raw(struct plist_head *head, raw_spinlock_t *lock)
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{
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INIT_LIST_HEAD(&head->prio_list);
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INIT_LIST_HEAD(&head->node_list);
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#ifdef CONFIG_DEBUG_PI_LIST
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head->rawlock = lock;
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@ -176,7 +176,8 @@ plist_head_init_raw(struct plist_head *head, raw_spinlock_t *lock)
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static inline void plist_node_init(struct plist_node *node, int prio)
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{
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node->prio = prio;
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plist_head_init(&node->plist, NULL);
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INIT_LIST_HEAD(&node->prio_list);
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INIT_LIST_HEAD(&node->node_list);
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}
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extern void plist_add(struct plist_node *node, struct plist_head *head);
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@ -188,7 +189,7 @@ extern void plist_del(struct plist_node *node, struct plist_head *head);
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* @head: the head for your list
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*/
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#define plist_for_each(pos, head) \
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list_for_each_entry(pos, &(head)->node_list, plist.node_list)
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list_for_each_entry(pos, &(head)->node_list, node_list)
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/**
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* plist_for_each_safe - iterate safely over a plist of given type
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@ -199,7 +200,7 @@ extern void plist_del(struct plist_node *node, struct plist_head *head);
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* Iterate over a plist of given type, safe against removal of list entry.
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*/
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#define plist_for_each_safe(pos, n, head) \
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list_for_each_entry_safe(pos, n, &(head)->node_list, plist.node_list)
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list_for_each_entry_safe(pos, n, &(head)->node_list, node_list)
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/**
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* plist_for_each_entry - iterate over list of given type
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@ -208,7 +209,7 @@ extern void plist_del(struct plist_node *node, struct plist_head *head);
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* @mem: the name of the list_struct within the struct
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*/
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#define plist_for_each_entry(pos, head, mem) \
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list_for_each_entry(pos, &(head)->node_list, mem.plist.node_list)
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list_for_each_entry(pos, &(head)->node_list, mem.node_list)
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/**
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* plist_for_each_entry_safe - iterate safely over list of given type
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@ -220,7 +221,7 @@ extern void plist_del(struct plist_node *node, struct plist_head *head);
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* Iterate over list of given type, safe against removal of list entry.
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*/
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#define plist_for_each_entry_safe(pos, n, head, m) \
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list_for_each_entry_safe(pos, n, &(head)->node_list, m.plist.node_list)
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list_for_each_entry_safe(pos, n, &(head)->node_list, m.node_list)
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/**
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* plist_head_empty - return !0 if a plist_head is empty
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@ -237,7 +238,7 @@ static inline int plist_head_empty(const struct plist_head *head)
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*/
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static inline int plist_node_empty(const struct plist_node *node)
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{
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return plist_head_empty(&node->plist);
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return list_empty(&node->node_list);
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}
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/* All functions below assume the plist_head is not empty. */
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@ -285,7 +286,7 @@ static inline int plist_node_empty(const struct plist_node *node)
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static inline struct plist_node *plist_first(const struct plist_head *head)
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{
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return list_entry(head->node_list.next,
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struct plist_node, plist.node_list);
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struct plist_node, node_list);
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}
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/**
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@ -297,7 +298,7 @@ static inline struct plist_node *plist_first(const struct plist_head *head)
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static inline struct plist_node *plist_last(const struct plist_head *head)
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{
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return list_entry(head->node_list.prev,
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struct plist_node, plist.node_list);
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struct plist_node, node_list);
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}
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#endif
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54
lib/plist.c
54
lib/plist.c
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@ -59,7 +59,8 @@ static void plist_check_head(struct plist_head *head)
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WARN_ON_SMP(!raw_spin_is_locked(head->rawlock));
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if (head->spinlock)
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WARN_ON_SMP(!spin_is_locked(head->spinlock));
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plist_check_list(&head->prio_list);
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if (!plist_head_empty(head))
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plist_check_list(&plist_first(head)->prio_list);
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plist_check_list(&head->node_list);
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}
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@ -75,25 +76,33 @@ static void plist_check_head(struct plist_head *head)
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*/
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void plist_add(struct plist_node *node, struct plist_head *head)
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{
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struct plist_node *iter;
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struct plist_node *first, *iter, *prev = NULL;
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struct list_head *node_next = &head->node_list;
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plist_check_head(head);
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WARN_ON(!plist_node_empty(node));
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WARN_ON(!list_empty(&node->prio_list));
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list_for_each_entry(iter, &head->prio_list, plist.prio_list) {
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if (node->prio < iter->prio)
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goto lt_prio;
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else if (node->prio == iter->prio) {
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iter = list_entry(iter->plist.prio_list.next,
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struct plist_node, plist.prio_list);
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goto eq_prio;
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if (plist_head_empty(head))
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goto ins_node;
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first = iter = plist_first(head);
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do {
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if (node->prio < iter->prio) {
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node_next = &iter->node_list;
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break;
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}
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}
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lt_prio:
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list_add_tail(&node->plist.prio_list, &iter->plist.prio_list);
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eq_prio:
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list_add_tail(&node->plist.node_list, &iter->plist.node_list);
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prev = iter;
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iter = list_entry(iter->prio_list.next,
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struct plist_node, prio_list);
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} while (iter != first);
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if (!prev || prev->prio != node->prio)
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list_add_tail(&node->prio_list, &iter->prio_list);
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ins_node:
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list_add_tail(&node->node_list, node_next);
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plist_check_head(head);
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}
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@ -108,14 +117,21 @@ void plist_del(struct plist_node *node, struct plist_head *head)
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{
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plist_check_head(head);
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if (!list_empty(&node->plist.prio_list)) {
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struct plist_node *next = plist_first(&node->plist);
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if (!list_empty(&node->prio_list)) {
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if (node->node_list.next != &head->node_list) {
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struct plist_node *next;
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list_move_tail(&next->plist.prio_list, &node->plist.prio_list);
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list_del_init(&node->plist.prio_list);
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next = list_entry(node->node_list.next,
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struct plist_node, node_list);
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/* add the next plist_node into prio_list */
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if (list_empty(&next->prio_list))
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list_add(&next->prio_list, &node->prio_list);
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}
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list_del_init(&node->prio_list);
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}
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list_del_init(&node->plist.node_list);
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list_del_init(&node->node_list);
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plist_check_head(head);
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}
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