thread: add methods to get rt priority range

pipewire-jack/src/pipewire-jack.c

@@ -56,7 +56,6 @@
 
 #define JACK_DEFAULT_VIDEO_TYPE	"32 bit float RGBA video"
 
-#define JACK_SCHED_POLICY SCHED_FIFO
 /* use 512KB stack per thread - the default is way too high to be feasible
  * with mlockall() on many systems */
 #define THREAD_STACK 524288
@@ -5437,11 +5436,11 @@ SPA_EXPORT
 int jack_client_max_real_time_priority (jack_client_t *client)
 {
 	struct client *c = (struct client *) client;
-	int max;
+	int min, max;
 
 	spa_return_val_if_fail(c != NULL, -1);
 
-	max = sched_get_priority_max(JACK_SCHED_POLICY);
+	pw_thread_utils_get_rt_range(NULL, &min, &max);
 	return SPA_MIN(max, c->rt_max) - 1;
 }
 

src/modules/module-rt.c

@@ -45,6 +45,8 @@
 /** \page page_module_rt PipeWire Module: RT
  */
 
+#define DEFAULT_POLICY	SCHED_FIFO
+
 #define DEFAULT_NICE_LEVEL -11
 #define DEFAULT_RT_PRIO 88
 #define DEFAULT_RT_TIME_SOFT 2000000
@@ -178,9 +180,20 @@ static int impl_join(void *data, struct pw_thread *thread, void **retval)
 	return pthread_join(pt, retval);
 }
 
+static int impl_get_rt_range(void *data, const struct spa_dict *props,
+		int *min, int *max)
+{
+	int policy = DEFAULT_POLICY;
+	if (min)
+		*min = sched_get_priority_min(policy);
+	if (max)
+		*max = sched_get_priority_max(policy);
+	return 0;
+}
+
 static int impl_acquire_rt(void *data, struct pw_thread *thread, int priority)
 {
-	int err, policy = SCHED_FIFO;
+	int err, policy = DEFAULT_POLICY;
 	int rtprio = priority;
 	struct sched_param sp;
 	pthread_t pt = (pthread_t)thread;
@@ -222,6 +235,7 @@ static const struct pw_thread_utils_methods impl_thread_utils = {
 	PW_VERSION_THREAD_UTILS_METHODS,
 	.create = impl_create,
 	.join = impl_join,
+	.get_rt_range = impl_get_rt_range,
 	.acquire_rt = impl_acquire_rt,
 	.drop_rt = impl_drop_rt,
 };

src/modules/module-rtkit.c

@@ -572,6 +572,17 @@ static int impl_join(void *data, struct pw_thread *thread, void **retval)
 	return pthread_join(pt, retval);
 }
 
+static int impl_get_rt_range(void *data, const struct spa_dict *props,
+		int *min, int *max)
+{
+	struct impl *impl = data;
+	if (min)
+		*min = 1;
+	if (max)
+		*max = pw_rtkit_get_max_realtime_priority(impl->system_bus);
+	return 0;
+}
+
 static pid_t impl_gettid(struct impl *impl, pthread_t pt)
 {
 	struct thread *thr;
@@ -645,6 +656,7 @@ static const struct pw_thread_utils_methods impl_thread_utils = {
 	PW_VERSION_THREAD_UTILS_METHODS,
 	.create = impl_create,
 	.join = impl_join,
+	.get_rt_range = impl_get_rt_range,
 	.acquire_rt = impl_acquire_rt,
 	.drop_rt = impl_drop_rt,
 };

src/pipewire/thread.c

@@ -54,6 +54,16 @@ static int impl_join(void *data, struct pw_thread *thread, void **retval)
 	return pthread_join(pt, retval);
 }
 
+static int impl_get_rt_range(void *data, const struct spa_dict *props,
+		int *min, int *max)
+{
+	if (min)
+		*min = sched_get_priority_min(SCHED_OTHER);
+	if (max)
+		*max = sched_get_priority_max(SCHED_OTHER);
+	return 0;
+}
+
 static struct {
 	struct pw_thread_utils utils;
 	struct pw_thread_utils_methods methods;
@@ -63,8 +73,10 @@ static struct {
 		 SPA_CALLBACKS_INIT(&default_impl.methods,
 				 &default_impl) } },
 	{ PW_VERSION_THREAD_UTILS_METHODS,
-            .create = impl_create,
+		.create = impl_create,
-	    .join = impl_join, }
+		.join = impl_join,
+		.get_rt_range = impl_get_rt_range
+	}
 };
 
 static struct pw_thread_utils *global_impl = &default_impl.utils;
@@ -78,41 +90,7 @@ void pw_thread_utils_set_impl(struct pw_thread_utils *impl)
 }
 
 SPA_EXPORT
-struct pw_thread *pw_thread_utils_create(const struct spa_dict *props,
+struct pw_thread_utils *pw_thread_utils_get_impl(void)
-		void *(*start_routine)(void*), void *arg)
 {
-	struct pw_thread *res = NULL;
+	return global_impl;
-	spa_interface_call_res(&global_impl->iface,
-			struct pw_thread_utils_methods, res, create, 0,
-			props, start_routine, arg);
-	return res;
-}
-
-SPA_EXPORT
-int pw_thread_utils_join(struct pw_thread *thread, void **retval)
-{
-	int res = -ENOTSUP;
-	spa_interface_call_res(&global_impl->iface,
-			struct pw_thread_utils_methods, res, join, 0,
-			thread, retval);
-	return res;
-}
-
-SPA_EXPORT
-int pw_thread_utils_acquire_rt(struct pw_thread *thread, int priority)
-{
-	int res = -ENOTSUP;
-	spa_interface_call_res(&global_impl->iface,
-			struct pw_thread_utils_methods, res, acquire_rt, 0,
-			thread, priority);
-	return res;
-}
-
-SPA_EXPORT
-int pw_thread_utils_drop_rt(struct pw_thread *thread)
-{
-	int res = -ENOTSUP;
-	spa_interface_call_res(&global_impl->iface,
-			struct pw_thread_utils_methods, res, drop_rt, 0, thread);
-	return res;
 }

src/pipewire/thread.h

@@ -42,6 +42,9 @@ extern "C" {
 
 #define PW_TYPE_INTERFACE_ThreadUtils	PW_TYPE_INFO_INTERFACE_BASE "ThreadUtils"
 
+/** a thread object.
+ * This can be cast to a platform native thread, like pthread on posix systems
+ */
 struct pw_thread;
 
 #define PW_VERSION_THREAD_UTILS		0
@@ -52,22 +55,67 @@ struct pw_thread_utils_methods {
 #define PW_VERSION_THREAD_UTILS_METHODS	0
 	uint32_t version;
 
+	/** create a new thread that runs \a start with \a arg */
 	struct pw_thread * (*create) (void *data, const struct spa_dict *props,
 			void *(*start)(void*), void *arg);
+	/** stop and join a thread */
 	int (*join)(void *data, struct pw_thread *thread, void **retval);
 
+	/** get realtime priority range for threads created with \a props */
+	int (*get_rt_range) (void *data, const struct spa_dict *props, int *min, int *max);
+	/** acquire realtime priority */
 	int (*acquire_rt) (void *data, struct pw_thread *thread, int priority);
+	/** drop realtime priority */
 	int (*drop_rt) (void *data, struct pw_thread *thread);
 };
 
 void pw_thread_utils_set_impl(struct pw_thread_utils *impl);
+struct pw_thread_utils *pw_thread_utils_get_impl(void);
 
-struct pw_thread *pw_thread_utils_create(const struct spa_dict *props,
+static inline struct pw_thread *pw_thread_utils_create(const struct spa_dict *props,
-		void *(*start)(void*), void *arg);
+		void *(*start_routine)(void*), void *arg)
-int pw_thread_utils_join(struct pw_thread *thread, void **retval);
+{
+	struct pw_thread *res = NULL;
+	spa_interface_call_res(&pw_thread_utils_get_impl()->iface,
+			struct pw_thread_utils_methods, res, create, 0,
+			props, start_routine, arg);
+	return res;
+}
 
-int pw_thread_utils_acquire_rt(struct pw_thread *thread, int priority);
+static inline int pw_thread_utils_join(struct pw_thread *thread, void **retval)
-int pw_thread_utils_drop_rt(struct pw_thread *thread);
+{
+	int res = -ENOTSUP;
+	spa_interface_call_res(&pw_thread_utils_get_impl()->iface,
+			struct pw_thread_utils_methods, res, join, 0,
+			thread, retval);
+	return res;
+}
+
+static inline int pw_thread_utils_get_rt_range(const struct spa_dict *props, int *min, int *max)
+{
+	int res = -ENOTSUP;
+	spa_interface_call_res(&pw_thread_utils_get_impl()->iface,
+			struct pw_thread_utils_methods, res, get_rt_range, 0,
+			props, min, max);
+	return res;
+}
+
+static inline int pw_thread_utils_acquire_rt(struct pw_thread *thread, int priority)
+{
+	int res = -ENOTSUP;
+	spa_interface_call_res(&pw_thread_utils_get_impl()->iface,
+			struct pw_thread_utils_methods, res, acquire_rt, 0,
+			thread, priority);
+	return res;
+}
+
+static inline int pw_thread_utils_drop_rt(struct pw_thread *thread)
+{
+	int res = -ENOTSUP;
+	spa_interface_call_res(&pw_thread_utils_get_impl()->iface,
+			struct pw_thread_utils_methods, res, drop_rt, 0, thread);
+	return res;
+}
 
 #ifdef __cplusplus
 }  /* extern "C" */