From: Ingo Molnar Add the priority-sorted list (plist) implementation. Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Signed-off-by: Arjan van de Ven Signed-off-by: Andrew Morton --- include/linux/plist.h | 226 ++++++++++++++++++++++++++++++++++++++++ lib/Kconfig | 6 + lib/Makefile | 1 lib/plist.c | 72 ++++++++++++ 4 files changed, 305 insertions(+) diff -puN /dev/null include/linux/plist.h --- /dev/null 2003-09-15 06:40:47.000000000 -0700 +++ devel-akpm/include/linux/plist.h 2006-03-25 19:04:59.000000000 -0800 @@ -0,0 +1,226 @@ +/* + * Descending-priority-sorted double-linked list + * + * (C) 2002-2003 Intel Corp + * Inaky Perez-Gonzalez . + * + * 2001-2005 (c) MontaVista Software, Inc. + * Daniel Walker + * + * (C) 2005 Thomas Gleixner + * + * Simplifications of the original code by + * Oleg Nesterov + * + * Licensed under the FSF's GNU Public License v2 or later. + * + * Based on simple lists (include/linux/list.h). + * + * This is a priority-sorted list of nodes; each node has a + * priority from INT_MIN (highest) to INT_MAX (lowest). + * + * Addition is O(K), removal is O(1), change of priority of a node is + * O(K) and K is the number of RT priority levels used in the system. + * (1 <= K <= 99) + * + * This list is really a list of lists: + * + * - The tier 1 list is the prio_list, different priority nodes. + * + * - The tier 2 list is the node_list, serialized nodes. + * + * Simple ASCII art explanation: + * + * |HEAD | + * | | + * |prio_list.prev|<------------------------------------| + * |prio_list.next|<->|pl|<->|pl|<--------------->|pl|<-| + * |10 | |10| |21| |21| |21| |40| (prio) + * | | | | | | | | | | | | + * | | | | | | | | | | | | + * |node_list.next|<->|nl|<->|nl|<->|nl|<->|nl|<->|nl|<-| + * |node_list.prev|<------------------------------------| + * + * The nodes on the prio_list list are sorted by priority to simplify + * the insertion of new nodes. There are no nodes with duplicate + * priorites on the list. + * + * The nodes on the node_list is ordered by priority and can contain + * entries which have the same priority. Those entries are ordered + * FIFO + * + * Addition means: look for the prio_list node in the prio_list + * for the priority of the node and insert it before the node_list + * entry of the next prio_list node. If it is the first node of + * that priority, add it to the prio_list in the right position and + * insert it into the serialized node_list list + * + * Removal means remove it from the node_list and remove it from + * the prio_list if the node_list list_head is non empty. In case + * of removal from the prio_list it must be checked whether other + * entries of the same priority are on the list or not. If there + * is another entry of the same priority then this entry has to + * replace the removed entry on the prio_list. If the entry which + * is removed is the only entry of this priority then a simple + * remove from both list is sufficient. + * + * INT_MIN is the highest priority, 0 is the medium highest, INT_MAX + * is lowest priority. + * + * No locking is done, up to the caller. + * + */ +#ifndef _LINUX_PLIST_H_ +#define _LINUX_PLIST_H_ + +#include +#include + +struct plist_head { + struct list_head prio_list; + struct list_head node_list; +}; + +struct plist_node { + int prio; + struct plist_head plist; +}; + +/** + * #PLIST_HEAD_INIT - static struct plist_head initializer + * + * @head: struct plist_head variable name + */ +#define PLIST_HEAD_INIT(head) \ +{ \ + .prio_list = LIST_HEAD_INIT((head).prio_list), \ + .node_list = LIST_HEAD_INIT((head).node_list), \ +} + +/** + * #PLIST_NODE_INIT - static struct plist_node initializer + * + * @node: struct plist_node variable name + * @__prio: initial node priority + */ +#define PLIST_NODE_INIT(node, __prio) \ +{ \ + .prio = (__prio), \ + .plist = PLIST_HEAD_INIT((node).plist, NULL), \ +} + +/** + * plist_head_init - dynamic struct plist_head initializer + * + * @head: &struct plist_head pointer + */ +static inline void +plist_head_init(struct plist_head *head) +{ + INIT_LIST_HEAD(&head->prio_list); + INIT_LIST_HEAD(&head->node_list); +} + +/** + * plist_node_init - Dynamic struct plist_node initializer + * + * @node: &struct plist_node pointer + * @prio: initial node priority + */ +static inline void plist_node_init(struct plist_node *node, int prio) +{ + node->prio = prio; + plist_head_init(&node->plist); +} + +extern void plist_add(struct plist_node *node, struct plist_head *head); +extern void plist_del(struct plist_node *node, struct plist_head *head); + +/** + * plist_for_each - iterate over the plist + * + * @pos1: the type * to use as a loop counter. + * @head: the head for your list. + */ +#define plist_for_each(pos, head) \ + list_for_each_entry(pos, &(head)->node_list, plist.node_list) + +/** + * plist_for_each_entry_safe - iterate over a plist of given type safe + * against removal of list entry + * + * @pos1: the type * to use as a loop counter. + * @n1: another type * to use as temporary storage + * @head: the head for your list. + */ +#define plist_for_each_safe(pos, n, head) \ + list_for_each_entry_safe(pos, n, &(head)->node_list, plist.node_list) + +/** + * plist_for_each_entry - iterate over list of given type + * + * @pos: the type * to use as a loop counter. + * @head: the head for your list. + * @member: the name of the list_struct within the struct. + */ +#define plist_for_each_entry(pos, head, mem) \ + list_for_each_entry(pos, &(head)->node_list, mem.plist.node_list) + +/** + * plist_for_each_entry_safe - iterate over list of given type safe against + * removal of list entry + * + * @pos: the type * to use as a loop counter. + * @n: another type * to use as temporary storage + * @head: the head for your list. + * @m: the name of the list_struct within the struct. + */ +#define plist_for_each_entry_safe(pos, n, head, m) \ + list_for_each_entry_safe(pos, n, &(head)->node_list, m.plist.node_list) + +/** + * plist_head_empty - return !0 if a plist_head is empty + * + * @head: &struct plist_head pointer + */ +static inline int plist_head_empty(const struct plist_head *head) +{ + return list_empty(&head->node_list); +} + +/** + * plist_node_empty - return !0 if plist_node is not on a list + * + * @node: &struct plist_node pointer + */ +static inline int plist_node_empty(const struct plist_node *node) +{ + return plist_head_empty(&node->plist); +} + +/* All functions below assume the plist_head is not empty. */ + +/** + * plist_first_entry - get the struct for the first entry + * + * @ptr: the &struct plist_head pointer. + * @type: the type of the struct this is embedded in. + * @member: the name of the list_struct within the struct. + */ +#define plist_first_entry(head, type, member) \ + container_of(plist_first(head), type, member) + +/** + * plist_first - return the first node (and thus, highest priority) + * + * @head: the &struct plist_head pointer + * + * Assumes the plist is _not_ empty. + */ +static inline struct plist_node* plist_first(const struct plist_head *head) +{ + return list_entry(head->node_list.next, + struct plist_node, plist.node_list); +} + +#endif diff -puN lib/Kconfig~pi-futex-add-plist-implementation lib/Kconfig --- devel/lib/Kconfig~pi-futex-add-plist-implementation 2006-03-25 19:04:59.000000000 -0800 +++ devel-akpm/lib/Kconfig 2006-03-25 19:04:59.000000000 -0800 @@ -86,4 +86,10 @@ config TEXTSEARCH_BM config TEXTSEARCH_FSM tristate +# +# plist support is select#ed if needed +# +config PLIST + boolean + endmenu diff -puN lib/Makefile~pi-futex-add-plist-implementation lib/Makefile --- devel/lib/Makefile~pi-futex-add-plist-implementation 2006-03-25 19:04:59.000000000 -0800 +++ devel-akpm/lib/Makefile 2006-03-25 19:04:59.000000000 -0800 @@ -25,6 +25,7 @@ lib-$(CONFIG_SEMAPHORE_SLEEPERS) += sema lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o lib-$(CONFIG_GENERIC_HWEIGHT) += hweight.o obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o +obj-$(CONFIG_PLIST) += plist.o obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o ifneq ($(CONFIG_HAVE_DEC_LOCK),y) diff -puN /dev/null lib/plist.c --- /dev/null 2003-09-15 06:40:47.000000000 -0700 +++ devel-akpm/lib/plist.c 2006-03-25 19:04:59.000000000 -0800 @@ -0,0 +1,72 @@ +/* + * lib/plist.c + * + * Descending-priority-sorted double-linked list + * + * (C) 2002-2003 Intel Corp + * Inaky Perez-Gonzalez . + * + * 2001-2005 (c) MontaVista Software, Inc. + * Daniel Walker + * + * (C) 2005 Thomas Gleixner + * + * Simplifications of the original code by + * Oleg Nesterov + * + * Licensed under the FSF's GNU Public License v2 or later. + * + * Based on simple lists (include/linux/list.h). + * + * This file contains the add / del functions which are considered to + * be too large to inline. See include/linux/plist.h for further + * information. + */ + +#include +#include + +/** + * plist_add - add @node to @head + * + * @node: &struct plist_node pointer + * @head: &struct plist_head pointer + */ +void plist_add(struct plist_node *node, struct plist_head *head) +{ + struct plist_node *iter; + + WARN_ON(!plist_node_empty(node)); + + 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; + } + +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); +} + +/** + * plist_del - Remove a @node from plist. + * + * @node: &struct plist_node pointer - entry to be removed + * @head: &struct plist_head pointer - list head + */ +void plist_del(struct plist_node *node, struct plist_head *head) +{ + if (!list_empty(&node->plist.prio_list)) { + struct plist_node *next = plist_first(&node->plist); + + list_move_tail(&next->plist.prio_list, &node->plist.prio_list); + list_del_init(&node->plist.prio_list); + } + + list_del_init(&node->plist.node_list); +} _