This includes a change from Thomas Gleixner to make the sp_nodes
FIFO ordered, plus some other small code changes and some small
documentation cleanup.
I fixed plist_entry() to work more like list_entry() , and made
the proper update to kernel/rt.c .
Oleg, do you have any correctness concerns with this patch?
Daniel
Index: linux-2.6.11/include/linux/plist.h
===================================================================
--- linux-2.6.11.orig/include/linux/plist.h 2005-06-05 01:32:38.000000000 +0000
+++ linux-2.6.11/include/linux/plist.h 2005-06-05 01:44:50.000000000 +0000
@@ -7,6 +7,8 @@
* 2001-2005 (c) MontaVista Software, Inc.
* Daniel Walker <[email protected]>
*
+ * (C) 2005 Thomas Gleixner <[email protected]>
+ *
* Licensed under the FSF's GNU Public License v2 or later.
*
* Based on simple lists (include/linux/list.h).
@@ -28,11 +30,14 @@
*
* - The tier 1 list is the dp list (Different Priority)
*
- * - The tier 2 list is the sp list (Same Priority)
+ * - The tier 2 list is the sp list (Serialized Priority)
+ *
+ * The nodes on the sp list are ordered by priority and can contain
+ * entries which have the same priority. Those entries are ordered
+ * FIFO.
*
- * All the nodes in a SP list have the same priority, and all the DP
- * lists have different priorities (and are sorted by priority, of
- * course).
+ * The DP lists have different priorities (and are sorted by priority,
+ * of course).
*
* Addition means: look for the DP node in the DP list for the
* priority of the node and append to the SP list corresponding to
@@ -83,7 +88,7 @@ struct plist {
* @member: the name of the list_struct within the struct.
*/
#define plist_entry(ptr, type, member) \
- container_of(plist_first(ptr), type, member)
+ container_of(ptr, type, member)
/**
* plist_for_each - iterate over the plist
* @pos1: the type * to use as a loop counter.
Index: linux-2.6.11/kernel/rt.c
===================================================================
--- linux-2.6.11.orig/kernel/rt.c 2005-06-05 01:32:38.000000000 +0000
+++ linux-2.6.11/kernel/rt.c 2005-06-05 01:33:20.000000000 +0000
@@ -773,7 +773,7 @@ static inline struct task_struct * pick_
*
* (same-prio RT tasks go FIFO)
*/
- waiter = plist_entry(&lock->wait_list, struct rt_mutex_waiter, list);
+ waiter = plist_entry(plist_first(&lock->wait_list), struct rt_mutex_waiter, list);
trace_special_pid(waiter->task->pid, waiter->task->prio, 0);
@@ -1351,7 +1351,7 @@ static void __up_mutex(struct rt_mutex *
*/
prio = mutex_getprio(old_owner);
if (!plist_empty(&old_owner->pi_waiters)) {
- w = plist_entry(&old_owner->pi_waiters, struct rt_mutex_waiter, pi_list);
+ w = plist_entry(plist_first(&old_owner->pi_waiters), struct rt_mutex_waiter, pi_list);
if (w->task->prio < prio)
prio = w->task->prio;
}
Index: linux-2.6.11/lib/plist.c
===================================================================
--- linux-2.6.11.orig/lib/plist.c 2005-06-05 01:33:15.000000000 +0000
+++ linux-2.6.11/lib/plist.c 2005-06-05 01:33:34.000000000 +0000
@@ -9,6 +9,8 @@
* 2001-2005 (c) MontaVista Software, Inc.
* Daniel Walker <[email protected]>
*
+ * (C) 2005 Thomas Gleixner <[email protected]>
+ *
* Licensed under the FSF's GNU Public License v2 or later.
*
* Based on simple lists (include/linux/list.h).
@@ -80,13 +82,12 @@ static inline void __plist_add_sorted(st
itr_pl = plist;
new_sp_head:
- itr_pl2 = container_of(itr_pl->dp_node.prev, struct plist, dp_node);
list_add_tail(&pl->dp_node, &itr_pl->dp_node);
- list_add(&pl->sp_node, &itr_pl2->sp_node);
+ list_add_tail(&pl->sp_node, &itr_pl->sp_node);
return;
existing_sp_head:
- itr_pl2 = container_of(itr_pl->dp_node.prev, struct plist, dp_node);
- list_add(&pl->sp_node, &itr_pl2->sp_node);
+ itr_pl2 = container_of(itr_pl->dp_node.next, struct plist, dp_node);
+ list_add_tail(&pl->sp_node, &itr_pl2->sp_node);
return;
}
@@ -110,16 +111,17 @@ unsigned plist_add(struct plist *pl, str
static inline
void __plist_del(struct plist *pl)
{
- if (!list_empty(&pl->sp_node) && !list_empty(&pl->dp_node)) {
+ if (!list_empty(&pl->sp_node)) {
/* SP list head, not empty */
- struct plist *pl_new = container_of(pl->sp_node.prev,
+ struct plist *pl_new = container_of(pl->sp_node.next,
struct plist, sp_node);
- if (pl->dp_node.prev == &pl_new->dp_node) {
+ if (pl->dp_node.next == &pl_new->dp_node) {
/* end of this priorities list */
list_del_init(&pl->dp_node);
- } else if (pl->prio == pl_new->prio) {
+ } else {
list_replace_rcu(&pl->dp_node, &pl_new->dp_node);
+ INIT_LIST_HEAD(&pl->dp_node);
}
}
list_del_init(&pl->sp_node);
@@ -160,7 +162,7 @@ void __plist_chprio(struct plist *pl, in
*/
unsigned plist_chprio(struct plist *plist, struct plist *pl, int new_prio)
{
- if (new_prio == plist->prio)
+ if (new_prio == pl->prio)
return 0;
__plist_chprio(pl, new_prio);
-
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