Use atomic operations in task pool

This ensures proper values of currently running tasks in the pool
(previously difference between mutex locks when acquiring new job
and releasing it might in theory give wrong values).

1 files changed, 7 insertions, 5 deletions

diff --git a/source/blender/blenlib/intern/task.c b/source/blender/blenlib/intern/task.c
index e4cded18b76..d187a8d1968 100644
--- a/source/blender/blenlib/intern/task.c
+++ b/source/blender/blenlib/intern/task.c
@@ -33,6 +33,8 @@
 #include "BLI_task.h"
 #include "BLI_threads.h"
 
+#include "atomic_ops.h"
+
 /* Types */
 
 typedef struct Task {
@@ -49,8 +51,8 @@ struct TaskPool {
 
 	volatile size_t num;
 	volatile size_t done;
-	volatile int num_threads;
-	volatile int currently_running_tasks;
+	size_t num_threads;
+	size_t currently_running_tasks;
 	ThreadMutex num_mutex;
 	ThreadCondition num_cond;
 
@@ -86,7 +88,7 @@ static void task_pool_num_decrease(TaskPool *pool, size_t done)
 	BLI_assert(pool->num >= done);
 
 	pool->num -= done;
-	pool->currently_running_tasks -= done;
+	atomic_sub_z(&pool->currently_running_tasks, done);
 	pool->done += done;
 
 	if (pool->num == 0)
@@ -130,7 +132,7 @@ static bool task_scheduler_thread_wait_pop(TaskScheduler *scheduler, Task **task
 			{
 				*task = current_task;
 				found_task = true;
-				pool->currently_running_tasks++;
+				atomic_add_z(&pool->currently_running_tasks, 1);
 				BLI_remlink(&scheduler->queue, *task);
 				break;
 			}
@@ -392,7 +394,7 @@ void BLI_task_pool_work_and_wait(TaskPool *pool)
 		/* if found task, do it, otherwise wait until other tasks are done */
 		if (found_task) {
 			/* run task */
-			pool->currently_running_tasks++;
+			atomic_add_z(&pool->currently_running_tasks, 1);
 			work_task->run(pool, work_task->taskdata, 0);
 
 			/* delete task */