drm/i915: Slaughter the thundering i915_wait_request herd

[deliverable/linux.git] / drivers / gpu / drm / i915 / i915_drv.h

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 0d0e4ac4dadba2e2c77f20fd0f822da3cc79de71..1fefa8c495f2001789ff7ce3cae9303895702ff7 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -506,6 +506,7 @@ struct drm_i915_error_state {
                bool valid;
                /* Software tracked state */
                bool waiting;
+               int num_waiters;
                int hangcheck_score;
                enum intel_ring_hangcheck_action hangcheck_action;
                int num_requests;
@@ -551,6 +552,12 @@ struct drm_i915_error_state {
                        u32 tail;
                } *requests;
 
+               struct drm_i915_error_waiter {
+                       char comm[TASK_COMM_LEN];
+                       pid_t pid;
+                       u32 seqno;
+               } *waiters;
+
                struct {
                        u32 gfx_mode;
                        union {
@@ -1429,7 +1436,7 @@ struct i915_gpu_error {
 #define I915_STOP_RING_ALLOW_WARN      (1 << 30)
 
        /* For missed irq/seqno simulation. */
-       unsigned int test_irq_rings;
+       unsigned long test_irq_rings;
 };
 
 enum modeset_restore {
@@ -3064,7 +3071,6 @@ ibx_disable_display_interrupt(struct drm_i915_private *dev_priv, uint32_t bits)
        ibx_display_interrupt_update(dev_priv, bits, 0);
 }
 
-
 /* i915_gem.c */
 int i915_gem_create_ioctl(struct drm_device *dev, void *data,
                          struct drm_file *file_priv);
@@ -3975,4 +3981,34 @@ static inline void i915_trace_irq_get(struct intel_engine_cs *engine,
                i915_gem_request_assign(&engine->trace_irq_req, req);
 }
 
+static inline bool __i915_request_irq_complete(struct drm_i915_gem_request *req)
+{
+       /* Ensure our read of the seqno is coherent so that we
+        * do not "miss an interrupt" (i.e. if this is the last
+        * request and the seqno write from the GPU is not visible
+        * by the time the interrupt fires, we will see that the
+        * request is incomplete and go back to sleep awaiting
+        * another interrupt that will never come.)
+        *
+        * Strictly, we only need to do this once after an interrupt,
+        * but it is easier and safer to do it every time the waiter
+        * is woken.
+        */
+       if (i915_gem_request_completed(req, false))
+               return true;
+
+       /* We need to check whether any gpu reset happened in between
+        * the request being submitted and now. If a reset has occurred,
+        * the seqno will have been advance past ours and our request
+        * is complete. If we are in the process of handling a reset,
+        * the request is effectively complete as the rendering will
+        * be discarded, but we need to return in order to drop the
+        * struct_mutex.
+        */
+       if (i915_reset_in_progress(&req->i915->gpu_error))
+               return true;
+
+       return false;
+}
+
 #endif