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authorIngo Molnar <mingo@elte.hu>2006-06-27 05:54:51 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-27 20:32:46 -0400
commit77ba89c5cf28d5d98a3cae17f67a3e42b102cc25 (patch)
treed487b536522574ab183cc600b62008c60db85b59 /include/linux/plist.h
parent8eb94f80dd2da5977c35cd094f0802c1501a12cd (diff)
[PATCH] pi-futex: add plist implementation
Add the priority-sorted list (plist) implementation. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux/plist.h')
-rw-r--r--include/linux/plist.h247
1 files changed, 247 insertions, 0 deletions
diff --git a/include/linux/plist.h b/include/linux/plist.h
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+++ b/include/linux/plist.h
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1/*
2 * Descending-priority-sorted double-linked list
3 *
4 * (C) 2002-2003 Intel Corp
5 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>.
6 *
7 * 2001-2005 (c) MontaVista Software, Inc.
8 * Daniel Walker <dwalker@mvista.com>
9 *
10 * (C) 2005 Thomas Gleixner <tglx@linutronix.de>
11 *
12 * Simplifications of the original code by
13 * Oleg Nesterov <oleg@tv-sign.ru>
14 *
15 * Licensed under the FSF's GNU Public License v2 or later.
16 *
17 * Based on simple lists (include/linux/list.h).
18 *
19 * This is a priority-sorted list of nodes; each node has a
20 * priority from INT_MIN (highest) to INT_MAX (lowest).
21 *
22 * Addition is O(K), removal is O(1), change of priority of a node is
23 * O(K) and K is the number of RT priority levels used in the system.
24 * (1 <= K <= 99)
25 *
26 * This list is really a list of lists:
27 *
28 * - The tier 1 list is the prio_list, different priority nodes.
29 *
30 * - The tier 2 list is the node_list, serialized nodes.
31 *
32 * Simple ASCII art explanation:
33 *
34 * |HEAD |
35 * | |
36 * |prio_list.prev|<------------------------------------|
37 * |prio_list.next|<->|pl|<->|pl|<--------------->|pl|<-|
38 * |10 | |10| |21| |21| |21| |40| (prio)
39 * | | | | | | | | | | | |
40 * | | | | | | | | | | | |
41 * |node_list.next|<->|nl|<->|nl|<->|nl|<->|nl|<->|nl|<-|
42 * |node_list.prev|<------------------------------------|
43 *
44 * The nodes on the prio_list list are sorted by priority to simplify
45 * the insertion of new nodes. There are no nodes with duplicate
46 * priorites on the list.
47 *
48 * The nodes on the node_list is ordered by priority and can contain
49 * entries which have the same priority. Those entries are ordered
50 * FIFO
51 *
52 * Addition means: look for the prio_list node in the prio_list
53 * for the priority of the node and insert it before the node_list
54 * entry of the next prio_list node. If it is the first node of
55 * that priority, add it to the prio_list in the right position and
56 * insert it into the serialized node_list list
57 *
58 * Removal means remove it from the node_list and remove it from
59 * the prio_list if the node_list list_head is non empty. In case
60 * of removal from the prio_list it must be checked whether other
61 * entries of the same priority are on the list or not. If there
62 * is another entry of the same priority then this entry has to
63 * replace the removed entry on the prio_list. If the entry which
64 * is removed is the only entry of this priority then a simple
65 * remove from both list is sufficient.
66 *
67 * INT_MIN is the highest priority, 0 is the medium highest, INT_MAX
68 * is lowest priority.
69 *
70 * No locking is done, up to the caller.
71 *
72 */
73#ifndef _LINUX_PLIST_H_
74#define _LINUX_PLIST_H_
75
76#include <linux/list.h>
77#include <linux/spinlock_types.h>
78
79struct plist_head {
80 struct list_head prio_list;
81 struct list_head node_list;
82#ifdef CONFIG_DEBUG_PI_LIST
83 spinlock_t *lock;
84#endif
85};
86
87struct plist_node {
88 int prio;
89 struct plist_head plist;
90};
91
92#ifdef CONFIG_DEBUG_PI_LIST
93# define PLIST_HEAD_LOCK_INIT(_lock) .lock = _lock
94#else
95# define PLIST_HEAD_LOCK_INIT(_lock)
96#endif
97
98/**
99 * #PLIST_HEAD_INIT - static struct plist_head initializer
100 *
101 * @head: struct plist_head variable name
102 */
103#define PLIST_HEAD_INIT(head, _lock) \
104{ \
105 .prio_list = LIST_HEAD_INIT((head).prio_list), \
106 .node_list = LIST_HEAD_INIT((head).node_list), \
107 PLIST_HEAD_LOCK_INIT(&(_lock)) \
108}
109
110/**
111 * #PLIST_NODE_INIT - static struct plist_node initializer
112 *
113 * @node: struct plist_node variable name
114 * @__prio: initial node priority
115 */
116#define PLIST_NODE_INIT(node, __prio) \
117{ \
118 .prio = (__prio), \
119 .plist = PLIST_HEAD_INIT((node).plist, NULL), \
120}
121
122/**
123 * plist_head_init - dynamic struct plist_head initializer
124 *
125 * @head: &struct plist_head pointer
126 */
127static inline void
128plist_head_init(struct plist_head *head, spinlock_t *lock)
129{
130 INIT_LIST_HEAD(&head->prio_list);
131 INIT_LIST_HEAD(&head->node_list);
132#ifdef CONFIG_DEBUG_PI_LIST
133 head->lock = lock;
134#endif
135}
136
137/**
138 * plist_node_init - Dynamic struct plist_node initializer
139 *
140 * @node: &struct plist_node pointer
141 * @prio: initial node priority
142 */
143static inline void plist_node_init(struct plist_node *node, int prio)
144{
145 node->prio = prio;
146 plist_head_init(&node->plist, NULL);
147}
148
149extern void plist_add(struct plist_node *node, struct plist_head *head);
150extern void plist_del(struct plist_node *node, struct plist_head *head);
151
152/**
153 * plist_for_each - iterate over the plist
154 *
155 * @pos1: the type * to use as a loop counter.
156 * @head: the head for your list.
157 */
158#define plist_for_each(pos, head) \
159 list_for_each_entry(pos, &(head)->node_list, plist.node_list)
160
161/**
162 * plist_for_each_entry_safe - iterate over a plist of given type safe
163 * against removal of list entry
164 *
165 * @pos1: the type * to use as a loop counter.
166 * @n1: another type * to use as temporary storage
167 * @head: the head for your list.
168 */
169#define plist_for_each_safe(pos, n, head) \
170 list_for_each_entry_safe(pos, n, &(head)->node_list, plist.node_list)
171
172/**
173 * plist_for_each_entry - iterate over list of given type
174 *
175 * @pos: the type * to use as a loop counter.
176 * @head: the head for your list.
177 * @member: the name of the list_struct within the struct.
178 */
179#define plist_for_each_entry(pos, head, mem) \
180 list_for_each_entry(pos, &(head)->node_list, mem.plist.node_list)
181
182/**
183 * plist_for_each_entry_safe - iterate over list of given type safe against
184 * removal of list entry
185 *
186 * @pos: the type * to use as a loop counter.
187 * @n: another type * to use as temporary storage
188 * @head: the head for your list.
189 * @m: the name of the list_struct within the struct.
190 */
191#define plist_for_each_entry_safe(pos, n, head, m) \
192 list_for_each_entry_safe(pos, n, &(head)->node_list, m.plist.node_list)
193
194/**
195 * plist_head_empty - return !0 if a plist_head is empty
196 *
197 * @head: &struct plist_head pointer
198 */
199static inline int plist_head_empty(const struct plist_head *head)
200{
201 return list_empty(&head->node_list);
202}
203
204/**
205 * plist_node_empty - return !0 if plist_node is not on a list
206 *
207 * @node: &struct plist_node pointer
208 */
209static inline int plist_node_empty(const struct plist_node *node)
210{
211 return plist_head_empty(&node->plist);
212}
213
214/* All functions below assume the plist_head is not empty. */
215
216/**
217 * plist_first_entry - get the struct for the first entry
218 *
219 * @ptr: the &struct plist_head pointer.
220 * @type: the type of the struct this is embedded in.
221 * @member: the name of the list_struct within the struct.
222 */
223#ifdef CONFIG_DEBUG_PI_LIST
224# define plist_first_entry(head, type, member) \
225({ \
226 WARN_ON(plist_head_empty(head)); \
227 container_of(plist_first(head), type, member); \
228})
229#else
230# define plist_first_entry(head, type, member) \
231 container_of(plist_first(head), type, member)
232#endif
233
234/**
235 * plist_first - return the first node (and thus, highest priority)
236 *
237 * @head: the &struct plist_head pointer
238 *
239 * Assumes the plist is _not_ empty.
240 */
241static inline struct plist_node* plist_first(const struct plist_head *head)
242{
243 return list_entry(head->node_list.next,
244 struct plist_node, plist.node_list);
245}
246
247#endif