bf6a9b8336
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>
138 lines
3.2 KiB
C
138 lines
3.2 KiB
C
/*
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* lib/plist.c
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*
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* Descending-priority-sorted double-linked list
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*
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* (C) 2002-2003 Intel Corp
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* Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>.
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*
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* 2001-2005 (c) MontaVista Software, Inc.
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* Daniel Walker <dwalker@mvista.com>
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*
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* (C) 2005 Thomas Gleixner <tglx@linutronix.de>
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*
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* Simplifications of the original code by
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* Oleg Nesterov <oleg@tv-sign.ru>
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*
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* Licensed under the FSF's GNU Public License v2 or later.
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*
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* Based on simple lists (include/linux/list.h).
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*
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* This file contains the add / del functions which are considered to
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* be too large to inline. See include/linux/plist.h for further
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* information.
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*/
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#include <linux/plist.h>
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#include <linux/spinlock.h>
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#ifdef CONFIG_DEBUG_PI_LIST
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static void plist_check_prev_next(struct list_head *t, struct list_head *p,
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struct list_head *n)
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{
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WARN(n->prev != p || p->next != n,
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"top: %p, n: %p, p: %p\n"
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"prev: %p, n: %p, p: %p\n"
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"next: %p, n: %p, p: %p\n",
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t, t->next, t->prev,
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p, p->next, p->prev,
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n, n->next, n->prev);
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}
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static void plist_check_list(struct list_head *top)
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{
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struct list_head *prev = top, *next = top->next;
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plist_check_prev_next(top, prev, next);
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while (next != top) {
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prev = next;
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next = prev->next;
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plist_check_prev_next(top, prev, next);
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}
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}
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static void plist_check_head(struct plist_head *head)
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{
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WARN_ON(!head->rawlock && !head->spinlock);
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if (head->rawlock)
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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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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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#else
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# define plist_check_head(h) do { } while (0)
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#endif
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/**
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* plist_add - add @node to @head
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*
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* @node: &struct plist_node pointer
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* @head: &struct plist_head pointer
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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 *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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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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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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/**
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* plist_del - Remove a @node from plist.
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*
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* @node: &struct plist_node pointer - entry to be removed
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* @head: &struct plist_head pointer - list head
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*/
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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->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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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->node_list);
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plist_check_head(head);
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}
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