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Subject[PATCH 2.5.59] prioarray-1.0: Priority arrays as a separate data structure


This patch extracts some of the stuff that Ingo uses for the O(1)
scheduler and makes it avalable in linux/prioarray.h, so that it
can be used by other parts of the kernel.

It's main use right now is by the pfutex patch, that implements
priority based futexes.

Caveats:

- Ugly kludge in sched.h to include prioarray.h ...

Enjoy

This patch requires linux-2.5.59

diff -u /dev/null linux/include/linux/prioarray.h:1.1.2.1
--- /dev/null Tue Jan 28 17:37:07 2003
+++ linux/include/linux/prioarray.h Wed Dec 11 12:44:33 2002
@@ -0,0 +1,57 @@
+/*
+ * O(1) priority arrays
+ *
+ * Modified from code (C) 2002 Ingo Molnar <mingo@redhat.com> in
+ * sched.c by Iñaky Pérez-González <inaky.perez-gonzalez@intel.com> so
+ * that other parts of the kernel can use the same constructs.
+ */
+
+#ifndef _LINUX_PRIOARRAY_
+#define _LINUX_PRIOARRAY_
+
+ /* This inclusion is kind of recursive ... hmmm */
+
+#include <linux/sched.h>
+
+struct prio_array {
+ int nr_active;
+ unsigned long bitmap[BITMAP_SIZE];
+ struct list_head queue[MAX_PRIO];
+};
+
+typedef struct prio_array prio_array_t;
+
+static inline
+void pa_init (prio_array_t *array)
+{
+ unsigned cnt;
+ array->nr_active = 0;
+ memset (array->bitmap, 0, sizeof (array->bitmap));
+ for (cnt = 0; cnt < MAX_PRIO; cnt++)
+ INIT_LIST_HEAD (&array->queue[cnt]);
+}
+
+/*
+ * Adding/removing a node to/from a priority array:
+ */
+
+static inline
+void pa_dequeue (struct list_head *p, unsigned prio, prio_array_t *array)
+{
+ array->nr_active--;
+ list_del(p);
+ if (list_empty(array->queue + prio))
+ __clear_bit(prio, array->bitmap);
+}
+
+static inline
+void pa_enqueue (struct list_head *p, unsigned prio, prio_array_t *array)
+{
+ list_add_tail(p, array->queue + prio);
+ __set_bit(prio, array->bitmap);
+ array->nr_active++;
+}
+
+
+
+#endif /* #ifndef _LINUX_PRIOARRAY_ */
diff -u linux/include/linux/sched.h:1.1.1.13 linux/include/linux/sched.h:1.1.1.1.2.7
--- linux/include/linux/sched.h:1.1.1.13 Thu Jan 16 18:56:22 2003
+++ linux/include/linux/sched.h Fri Jan 24 20:00:58 2003
@@ -252,6 +252,9 @@
#define MAX_RT_PRIO MAX_USER_RT_PRIO

#define MAX_PRIO (MAX_RT_PRIO + 40)
+#define BITMAP_SIZE ((((MAX_PRIO+1+7)/8)+sizeof(long)-1)/sizeof(long))
+
+#include <linux/prioarray.h> /* Okay, this is ugly, but needs MAX_PRIO */

/*
* Some day this will be a full-fledged user tracking system..
@@ -276,7 +279,6 @@
extern struct user_struct root_user;
#define INIT_USER (&root_user)

-typedef struct prio_array prio_array_t;
struct backing_dev_info;

struct task_struct {
diff -u linux/kernel/sched.c:1.1.1.10 linux/kernel/sched.c:1.1.1.1.2.5
--- linux/kernel/sched.c:1.1.1.10 Thu Jan 16 18:56:23 2003
+++ linux/kernel/sched.c Fri Jan 24 20:00:58 2003
@@ -130,15 +130,8 @@
* These are the runqueue data structures:
*/

-#define BITMAP_SIZE ((((MAX_PRIO+1+7)/8)+sizeof(long)-1)/sizeof(long))
-
typedef struct runqueue runqueue_t;

-struct prio_array {
- int nr_active;
- unsigned long bitmap[BITMAP_SIZE];
- struct list_head queue[MAX_PRIO];
-};

/*
* This is the main, per-CPU runqueue data structure.
@@ -273,17 +266,12 @@
*/
static inline void dequeue_task(struct task_struct *p, prio_array_t *array)
{
- array->nr_active--;
- list_del(&p->run_list);
- if (list_empty(array->queue + p->prio))
- __clear_bit(p->prio, array->bitmap);
+ pa_dequeue (&p->run_list, p->prio, array);
}

static inline void enqueue_task(struct task_struct *p, prio_array_t *array)
{
- list_add_tail(&p->run_list, array->queue + p->prio);
- __set_bit(p->prio, array->bitmap);
- array->nr_active++;
+ pa_enqueue (&p->run_list, p->prio, array);
p->array = array;
}

--

Inaky Perez-Gonzalez -- Not speaking for Intel - opinions are my own [or my fault]
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