drm/msm: Signal fences sooner

Nothing we do to in update_fences() can't be done in an atomic context,
so move this into the GPU's irq context to reduce latency (and call
dma_fence_signal() so we aren't relying on dma_fence_is_signaled() which
would defeat the purpose).

Signed-off-by: Rob Clark <robdclark@chromium.org>
Link: https://lore.kernel.org/r/20210726144359.2179302-3-robdclark@gmail.com
Signed-off-by: Rob Clark <robdclark@chromium.org>

diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index 0ebf7bc..647af45 100644 (file)
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -278,16 +278,18 @@ static void update_fences(struct msm_gpu *gpu, struct msm_ringbuffer *ring,
                uint32_t fence)
 {
        struct msm_gem_submit *submit;
+       unsigned long flags;
 
-       spin_lock(&ring->submit_lock);
+       spin_lock_irqsave(&ring->submit_lock, flags);
        list_for_each_entry(submit, &ring->submits, node) {
                if (submit->seqno > fence)
                        break;
 
                msm_update_fence(submit->ring->fctx,
                        submit->fence->seqno);
+               dma_fence_signal(submit->fence);
        }
-       spin_unlock(&ring->submit_lock);
+       spin_unlock_irqrestore(&ring->submit_lock, flags);
 }
 
 #ifdef CONFIG_DEV_COREDUMP
@@ -443,15 +445,16 @@ static struct msm_gem_submit *
 find_submit(struct msm_ringbuffer *ring, uint32_t fence)
 {
        struct msm_gem_submit *submit;
+       unsigned long flags;
 
-       spin_lock(&ring->submit_lock);
+       spin_lock_irqsave(&ring->submit_lock, flags);
        list_for_each_entry(submit, &ring->submits, node) {
                if (submit->seqno == fence) {
-                       spin_unlock(&ring->submit_lock);
+                       spin_unlock_irqrestore(&ring->submit_lock, flags);
                        return submit;
                }
        }
-       spin_unlock(&ring->submit_lock);
+       spin_unlock_irqrestore(&ring->submit_lock, flags);
 
        return NULL;
 }
@@ -547,11 +550,12 @@ static void recover_worker(struct kthread_work *work)
                 */
                for (i = 0; i < gpu->nr_rings; i++) {
                        struct msm_ringbuffer *ring = gpu->rb[i];
+                       unsigned long flags;
 
-                       spin_lock(&ring->submit_lock);
+                       spin_lock_irqsave(&ring->submit_lock, flags);
                        list_for_each_entry(submit, &ring->submits, node)
                                gpu->funcs->submit(gpu, submit);
-                       spin_unlock(&ring->submit_lock);
+                       spin_unlock_irqrestore(&ring->submit_lock, flags);
                }
        }
 
@@ -641,7 +645,7 @@ static void hangcheck_handler(struct timer_list *t)
                hangcheck_timer_reset(gpu);
 
        /* workaround for missing irq: */
-       kthread_queue_work(gpu->worker, &gpu->retire_work);
+       msm_gpu_retire(gpu);
 }
 
 /*
@@ -752,6 +756,7 @@ static void retire_submit(struct msm_gpu *gpu, struct msm_ringbuffer *ring,
        int index = submit->seqno % MSM_GPU_SUBMIT_STATS_COUNT;
        volatile struct msm_gpu_submit_stats *stats;
        u64 elapsed, clock = 0;
+       unsigned long flags;
        int i;
 
        stats = &ring->memptrs->stats[index];
@@ -781,9 +786,9 @@ static void retire_submit(struct msm_gpu *gpu, struct msm_ringbuffer *ring,
        pm_runtime_mark_last_busy(&gpu->pdev->dev);
        pm_runtime_put_autosuspend(&gpu->pdev->dev);
 
-       spin_lock(&ring->submit_lock);
+       spin_lock_irqsave(&ring->submit_lock, flags);
        list_del(&submit->node);
-       spin_unlock(&ring->submit_lock);
+       spin_unlock_irqrestore(&ring->submit_lock, flags);
 
        msm_gem_submit_put(submit);
 }
@@ -798,11 +803,12 @@ static void retire_submits(struct msm_gpu *gpu)
 
                while (true) {
                        struct msm_gem_submit *submit = NULL;
+                       unsigned long flags;
 
-                       spin_lock(&ring->submit_lock);
+                       spin_lock_irqsave(&ring->submit_lock, flags);
                        submit = list_first_entry_or_null(&ring->submits,
                                        struct msm_gem_submit, node);
-                       spin_unlock(&ring->submit_lock);
+                       spin_unlock_irqrestore(&ring->submit_lock, flags);
 
                        /*
                         * If no submit, we are done.  If submit->fence hasn't
@@ -821,10 +827,6 @@ static void retire_submits(struct msm_gpu *gpu)
 static void retire_worker(struct kthread_work *work)
 {
        struct msm_gpu *gpu = container_of(work, struct msm_gpu, retire_work);
-       int i;
-
-       for (i = 0; i < gpu->nr_rings; i++)
-               update_fences(gpu, gpu->rb[i], gpu->rb[i]->memptrs->fence);
 
        retire_submits(gpu);
 }
@@ -832,6 +834,11 @@ static void retire_worker(struct kthread_work *work)
 /* call from irq handler to schedule work to retire bo's */
 void msm_gpu_retire(struct msm_gpu *gpu)
 {
+       int i;
+
+       for (i = 0; i < gpu->nr_rings; i++)
+               update_fences(gpu, gpu->rb[i], gpu->rb[i]->memptrs->fence);
+
        kthread_queue_work(gpu->worker, &gpu->retire_work);
        update_sw_cntrs(gpu);
 }
@@ -842,6 +849,7 @@ void msm_gpu_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
        struct drm_device *dev = gpu->dev;
        struct msm_drm_private *priv = dev->dev_private;
        struct msm_ringbuffer *ring = submit->ring;
+       unsigned long flags;
        int i;
 
        WARN_ON(!mutex_is_locked(&dev->struct_mutex));
@@ -879,9 +887,9 @@ void msm_gpu_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
         */
        msm_gem_submit_get(submit);
 
-       spin_lock(&ring->submit_lock);
+       spin_lock_irqsave(&ring->submit_lock, flags);
        list_add_tail(&submit->node, &ring->submits);
-       spin_unlock(&ring->submit_lock);
+       spin_unlock_irqrestore(&ring->submit_lock, flags);
 
        gpu->funcs->submit(gpu, submit);
        priv->lastctx = submit->queue->ctx;