[Mesa-dev] [PATCH 01/11] util/u_queue: add a way to remove a job when we just want to destroy it

[Marek Olšák]

From: Marek Olšák <marek.olsak at amd.com>

---
 src/util/u_queue.c | 50 ++++++++++++++++++++++++++++++++++++++++++++------
 src/util/u_queue.h |  2 ++
 2 files changed, 46 insertions(+), 6 deletions(-)

diff --git a/src/util/u_queue.c b/src/util/u_queue.c
index 8db09b0..3834b6f 100644
--- a/src/util/u_queue.c
+++ b/src/util/u_queue.c
@@ -173,27 +173,29 @@ util_queue_thread_func(void *input)
       if (job.job) {
          job.execute(job.job, thread_index);
          util_queue_fence_signal(job.fence);
          if (job.cleanup)
             job.cleanup(job.job, thread_index);
       }
    }
 
    /* signal remaining jobs before terminating */
    mtx_lock(&queue->lock);
-   while (queue->jobs[queue->read_idx].job) {
-      util_queue_fence_signal(queue->jobs[queue->read_idx].fence);
-
-      queue->jobs[queue->read_idx].job = NULL;
-      queue->read_idx = (queue->read_idx + 1) % queue->max_jobs;
+   for (unsigned i = queue->read_idx; i != queue->write_idx;
+        i = (i + 1) % queue->max_jobs) {
+      if (queue->jobs[i].job) {
+         util_queue_fence_signal(queue->jobs[i].fence);
+         queue->jobs[i].job = NULL;
+      }
    }
-   queue->num_queued = 0; /* reset this when exiting the thread */
+   queue->read_idx = (queue->read_idx + queue->num_queued) % queue->max_jobs;
+   queue->num_queued = 0;
    mtx_unlock(&queue->lock);
    return 0;
 }
 
 bool
 util_queue_init(struct util_queue *queue,
                 const char *name,
                 unsigned max_jobs,
                 unsigned num_threads)
 {
@@ -322,19 +324,55 @@ util_queue_add_job(struct util_queue *queue,
    ptr->fence = fence;
    ptr->execute = execute;
    ptr->cleanup = cleanup;
    queue->write_idx = (queue->write_idx + 1) % queue->max_jobs;
 
    queue->num_queued++;
    cnd_signal(&queue->has_queued_cond);
    mtx_unlock(&queue->lock);
 }
 
+/**
+ * Remove a queued job. If the job hasn't started execution, it's removed from
+ * the queue. If the job has started execution, the function waits for it to
+ * complete.
+ *
+ * In all cases, the fence is signalled when the function returns.
+ *
+ * The function can be used when destroying an object associated with the job
+ * when you don't care about the job completion state.
+ */
+void
+util_queue_drop_job(struct util_queue *queue, struct util_queue_fence *fence)
+{
+   bool removed = false;
+
+   if (util_queue_fence_is_signalled(fence))
+      return;
+
+   mtx_lock(&queue->lock);
+   for (unsigned i = queue->read_idx; i != queue->write_idx;
+        i = (i + 1) % queue->max_jobs) {
+      if (queue->jobs[i].fence == fence) {
+         /* Just clear it. The threads will drop it. */
+         memset(&queue->jobs[i], 0, sizeof(queue->jobs[i]));
+         removed = true;
+         break;
+      }
+   }
+   mtx_unlock(&queue->lock);
+
+   if (removed)
+      util_queue_fence_signal(fence);
+   else
+      util_queue_fence_wait(fence);
+}
+
 int64_t
 util_queue_get_thread_time_nano(struct util_queue *queue, unsigned thread_index)
 {
    /* Allow some flexibility by not raising an error. */
    if (thread_index >= queue->num_threads)
       return 0;
 
    return u_thread_get_time_nano(queue->threads[thread_index]);
 }
diff --git a/src/util/u_queue.h b/src/util/u_queue.h
index 4aec1f2..9876865 100644
--- a/src/util/u_queue.h
+++ b/src/util/u_queue.h
@@ -85,20 +85,22 @@ bool util_queue_init(struct util_queue *queue,
 void util_queue_destroy(struct util_queue *queue);
 void util_queue_fence_init(struct util_queue_fence *fence);
 void util_queue_fence_destroy(struct util_queue_fence *fence);
 
 /* optional cleanup callback is called after fence is signaled: */
 void util_queue_add_job(struct util_queue *queue,
                         void *job,
                         struct util_queue_fence *fence,
                         util_queue_execute_func execute,
                         util_queue_execute_func cleanup);
+void util_queue_drop_job(struct util_queue *queue,
+                         struct util_queue_fence *fence);
 
 void util_queue_fence_wait(struct util_queue_fence *fence);
 int64_t util_queue_get_thread_time_nano(struct util_queue *queue,
                                         unsigned thread_index);
 
 /* util_queue needs to be cleared to zeroes for this to work */
 static inline bool
 util_queue_is_initialized(struct util_queue *queue)
 {
    return queue->threads != NULL;
-- 
2.7.4