Add back copyrights, documentation, and function descriptions.
Signed-Off-By: Daniel Walker <[email protected]>
Index: linux-2.6.14/include/linux/plist.h
===================================================================
--- linux-2.6.14.orig/include/linux/plist.h
+++ linux-2.6.14/include/linux/plist.h
@@ -1,3 +1,79 @@
+/*
+ * Descending-priority-sorted double-linked list
+ *
+ * (C) 2002-2003 Intel Corp
+ * Inaky Perez-Gonzalez <[email protected]>.
+ *
+ * 2001-2005 (c) MontaVista Software, Inc.
+ * Daniel Walker <[email protected]>
+ *
+ * (C) 2005 Thomas Gleixner <[email protected]>
+ * Tested and made it functional.
+ *
+ * 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 >= 0
+ * priority from 0 (highest) to INT_MAX (lowest). The list itself has
+ * a priority too (the highest of all the nodes), stored in the head
+ * of the list (that is a node itself).
+ *
+ * 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.
+ *
+ * NOTE: This implementation does not offer as many interfaces as
+ * linux/list.h does -- it is lazily minimal. You are welcome to
+ * add them.
+ */
#ifndef _LINUX_PLIST_H_
#define _LINUX_PLIST_H_
@@ -13,24 +89,46 @@ struct pl_node {
struct pl_head plist;
};
+/**
+ * #PL_HEAD_INIT - static struct pl_head initializer
+ *
+ * @head: struct pl_head variable name
+ */
#define PL_HEAD_INIT(head) \
{ \
.prio_list = LIST_HEAD_INIT((head).prio_list), \
.node_list = LIST_HEAD_INIT((head).node_list), \
}
+/**
+ * #PL_NODE_INIT - static struct pl_node initializer
+ *
+ * @node: struct pl_node variable name
+ * @__prio: initial node priority
+ */
#define PL_NODE_INIT(node, __prio) \
{ \
.prio = (__prio), \
.plist = PL_HEAD_INIT((node).plist), \
}
+/**
+ * pl_head_init - dynamic struct pl_head initializer
+ *
+ * @head: &struct pl_head pointer
+ */
static inline void pl_head_init(struct pl_head *head)
{
INIT_LIST_HEAD(&head->prio_list);
INIT_LIST_HEAD(&head->node_list);
}
+/**
+ * pl_node_init - Dynamic struct pl_node initializer
+ *
+ * @node: &struct pl_node pointer
+ * @prio: initial node priority
+ */
static inline void pl_node_init(struct pl_node *node, int prio)
{
node->prio = prio;
@@ -40,23 +138,63 @@ static inline void pl_node_init(struct p
extern void plist_add(struct pl_node *node, struct pl_head *head);
extern void plist_del(struct pl_node *node);
+/**
+ * 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.
+ * @member: the name of the list_struct within the struct.
+ */
#define plist_for_each_entry_safe(pos, n, head, mem) \
list_for_each_entry_safe(pos, n, &(head)->node_list, mem.plist.node_list)
+/**
+ * plist_empty - return !0 if plist is empty
+ *
+ * @head: &struct pl_head pointer
+ */
static inline int plist_empty(const struct pl_head *head)
{
return list_empty(&head->node_list);
}
+/**
+ * plist_unhashed - return !0 if plist node is not on a list
+ *
+ * @node: &struct pl_node pointer
+ */
static inline int plist_unhashed(const struct pl_node *node)
{
return list_empty(&node->plist.node_list);
@@ -64,9 +202,23 @@ static inline int plist_unhashed(const s
/* All functions below assume the pl_head is not empty. */
+/**
+ * plist_first_entry - get the struct for the first entry
+ *
+ * @ptr: the &struct pl_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 pl_head pointer
+ *
+ * Assumes the plist is _not_ empty.
+ */
static inline struct pl_node* plist_first(const struct pl_head *head)
{
return list_entry(head->node_list.next, struct pl_node, plist.node_list);
Index: linux-2.6.14/lib/plist.c
===================================================================
--- linux-2.6.14.orig/lib/plist.c
+++ linux-2.6.14/lib/plist.c
@@ -1,9 +1,32 @@
+
/*
- * lib/plist.c - Priority List implementation.
+ * lib/plist.c
+ *
+ * Descending-priority-sorted double-linked list
+ *
+ * (C) 2002-2003 Intel Corp
+ * Inaky Perez-Gonzalez <[email protected]>.
+ *
+ * 2001-2005 (c) MontaVista Software, Inc.
+ * Daniel Walker <[email protected]>
+ *
+ * (C) 2005 Thomas Gleixner <[email protected]>
+ * Tested and made it functional.
+ *
+ * Licensed under the FSF's GNU Public License v2 or later.
+ *
+ * Based on simple lists (include/linux/list.h).
*/
#include <linux/plist.h>
+/**
+ * plist_add - add @node to @head returns !0 if the plist prio changed, 0
+ * otherwise. XXX: Fix return code.
+ *
+ * @node: &struct pl_node pointer
+ * @head: &struct pl_head pointer
+ */
void plist_add(struct pl_node *node, struct pl_head *head)
{
struct pl_node *iter;
@@ -25,6 +48,12 @@ eq_prio:
list_add_tail(&node->plist.node_list, &iter->plist.node_list);
}
+/**
+ * plist_del - Remove a @node from plist. returns !0 if the plist prio
+ * changed, 0 otherwise. XXX: Fix return code.
+ *
+ * @node: &struct pl_node pointer
+ */
void plist_del(struct pl_node *node)
{
if (!list_empty(&node->plist.prio_list)) {
>From: Daniel Walker [mailto:[email protected]]
>...
>--- linux-2.6.14.orig/include/linux/plist.h
>+++ linux-2.6.14/include/linux/plist.h
>@@ -1,3 +1,79 @@
>+...
>+ * This is a priority-sorted list of nodes; each node has a >= 0
>+ * priority from 0 (highest) to INT_MAX (lowest). The list itself has
>+ * a priority too (the highest of all the nodes), stored in the head
>+ * of the list (that is a node itself).
I don't have access to the real source now, but if the prio
type is an int, we maybe should change that to 'INT_MIN(highest)
to INT_MAX(lowest)', or make the prio an unsigned and range it
0 to UINT_MAX.
>+ * 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 comment about K is kind of misleading; if I use the plist for
things other than scheduling chores, K changes. I'd cite that as an
example, something like:
...K is the number of priority levels used. For example, when
using this list type for real-time task queuing, 1 <= K <= 99.
Thanks,
-- Inaky
Daniel Walker wrote:
>
> Add back copyrights, documentation, and function descriptions.
Thank you for doing that!
> + * This is a priority-sorted list of nodes; each node has a >= 0
> + * priority from 0 (highest) to INT_MAX (lowest).
Why >= 0 ? ->prio is just integer, it can be < 0.
The list itself has
> + * a priority too (the highest of all the nodes), stored in the head
> + * of the list (that is a node itself).
No, the head is not a node, and does not have ->prio field. It is easy
to get plist's priority:
plist_empty(head) ? INT_MAX // or 0?
: plist_last(head)->prio
> + * INT_MIN is the highest priority, 0 is the medium highest, INT_MAX
> + * is lowest priority.
This is right, but contradicts with 'each node has a >= 0 priority' above.
Actually I don't understand why should we talk about min/max at all.
plist is sorted by ->prio which is integer. That's all.
> + * plist_add - add @node to @head returns !0 if the plist prio changed, 0
> + * otherwise. XXX: Fix return code.
> + *
> + * @node: &struct pl_node pointer
> + * @head: &struct pl_head pointer
> + */
> void plist_add(struct pl_node *node, struct pl_head *head)
> {
> struct pl_node *iter;
> @@ -25,6 +48,12 @@ eq_prio:
> list_add_tail(&node->plist.node_list, &iter->plist.node_list);
> }
> +/**
> + * plist_del - Remove a @node from plist. returns !0 if the plist prio
> + * changed, 0 otherwise. XXX: Fix return code.
> + *
> + * @node: &struct pl_node pointer
> + */
> void plist_del(struct pl_node *node)
> {
> if (!list_empty(&node->plist.prio_list)) {
Both of them have 'void' return type.
Oleg.
"Perez-Gonzalez, Inaky" wrote:
>
> I don't have access to the real source now, but if the prio
You can look at it here:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113509054523774
(the patch is against /dev/null).
Or get it along with user-space test:
http://www.tv-sign.ru/oleg/plist.tgz
The only change is s/plist_next_entry/plist_first_entry/.
Oleg.
On 12/22/05, Oleg Nesterov <[email protected]> wrote:
> Or get it along with user-space test:
> http://www.tv-sign.ru/oleg/plist.tgz
That doesn't seem like the right URL....
Pekka