From: Heiko Carstens

create_rt_workqueue will create a real time prioritized workqueue.
This is needed for the conversion of stop_machine to a workqueue based
implementation.
This patch adds yet another parameter to __create_workqueue_key to tell
it that we want an rt workqueue.
However it looks like we rather should have something like "int type"
instead of singlethread, freezable and rt.

Signed-off-by: Heiko Carstens
---
include/linux/workqueue.h | 18 ++++++++++--------
kernel/workqueue.c | 7 ++++++-
2 files changed, 16 insertions(+), 9 deletions(-)

Index: linux-2.6/include/linux/workqueue.h
================================================== =================
--- linux-2.6.orig/include/linux/workqueue.h
+++ linux-2.6/include/linux/workqueue.h
@@ -149,11 +149,11 @@ struct execute_work {

extern struct workqueue_struct *
__create_workqueue_key(const char *name, int singlethread,
- int freezeable, struct lock_class_key *key,
+ int freezeable, int rt, struct lock_class_key *key,
const char *lock_name);

#ifdef CONFIG_LOCKDEP
-#define __create_workqueue(name, singlethread, freezeable) \
+#define __create_workqueue(name, singlethread, freezeable, rt) \
({ \
static struct lock_class_key __key; \
const char *__lock_name; \
@@ -164,17 +164,19 @@ __create_workqueue_key(const char *name,
__lock_name = #name; \
\
__create_workqueue_key((name), (singlethread), \
- (freezeable), &__key, \
+ (freezeable), (rt), &__key, \
__lock_name); \
})
#else
-#define __create_workqueue(name, singlethread, freezeable) \
- __create_workqueue_key((name), (singlethread), (freezeable), NULL, NULL)
+#define __create_workqueue(name, singlethread, freezeable, rt) \
+ __create_workqueue_key((name), (singlethread), (freezeable), (rt), \
+ NULL, NULL)
#endif

-#define create_workqueue(name) __create_workqueue((name), 0, 0)
-#define create_freezeable_workqueue(name) __create_workqueue((name), 1, 1)
-#define create_singlethread_workqueue(name) __create_workqueue((name), 1, 0)
+#define create_workqueue(name) __create_workqueue((name), 0, 0, 0)
+#define create_rt_workqueue(name) __create_workqueue((name), 0, 0, 1)
+#define create_freezeable_workqueue(name) __create_workqueue((name), 1, 1, 0)
+#define create_singlethread_workqueue(name) __create_workqueue((name), 1, 0, 0)

extern void destroy_workqueue(struct workqueue_struct *wq);

Index: linux-2.6/kernel/workqueue.c
================================================== =================
--- linux-2.6.orig/kernel/workqueue.c
+++ linux-2.6/kernel/workqueue.c
@@ -62,6 +62,7 @@ struct workqueue_struct {
const char *name;
int singlethread;
int freezeable; /* Freeze threads during suspend */
+ int rt;
#ifdef CONFIG_LOCKDEP
struct lockdep_map lockdep_map;
#endif
@@ -766,6 +767,7 @@ init_cpu_workqueue(struct workqueue_stru

static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
{
+ struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
struct workqueue_struct *wq = cwq->wq;
const char *fmt = is_single_threaded(wq) ? "%s" : "%s/%d";
struct task_struct *p;
@@ -781,7 +783,8 @@ static int create_workqueue_thread(struc
*/
if (IS_ERR(p))
return PTR_ERR(p);
-
+ if (cwq->wq->rt)
+ sched_setscheduler_nocheck(p, SCHED_FIFO, &param);
cwq->thread = p;

return 0;
@@ -801,6 +804,7 @@ static void start_workqueue_thread(struc
struct workqueue_struct *__create_workqueue_key(const char *name,
int singlethread,
int freezeable,
+ int rt,
struct lock_class_key *key,
const char *lock_name)
{
@@ -822,6 +826,7 @@ struct workqueue_struct *__create_workqu
lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
wq->singlethread = singlethread;
wq->freezeable = freezeable;
+ wq->rt = rt;
INIT_LIST_HEAD(&wq->list);

if (singlethread) {

--
--
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