drm/i915: Only queue requests during execlists submission

Leave the more complicated request dequeueing to the tasklet and instead
just kick start the tasklet if we detect we are adding the first
request.

v2: Play around with list operators until we agree upon something

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160909131201.16673-2-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 92bfe47ad33cc7f0aaf428d648e2824f83f3044e..9bfe304c5256da4191b9ff470852c955d1c7e761 100644 (file)
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -609,35 +609,15 @@ static void intel_lrc_irq_handler(unsigned long data)
 static void execlists_submit_request(struct drm_i915_gem_request *request)
 {
        struct intel_engine_cs *engine = request->engine;
-       struct drm_i915_gem_request *cursor;
-       int num_elements = 0;
 
        spin_lock_bh(&engine->execlist_lock);
 
-       list_for_each_entry(cursor, &engine->execlist_queue, execlist_link)
-               if (++num_elements > 2)
-                       break;
-
-       if (num_elements > 2) {
-               struct drm_i915_gem_request *tail_req;
-
-               tail_req = list_last_entry(&engine->execlist_queue,
-                                          struct drm_i915_gem_request,
-                                          execlist_link);
-
-               if (request->ctx == tail_req->ctx) {
-                       WARN(tail_req->elsp_submitted != 0,
-                               "More than 2 already-submitted reqs queued\n");
-                       list_del(&tail_req->execlist_link);
-                       i915_gem_request_put(tail_req);
-               }
-       }
-
        i915_gem_request_get(request);
-       list_add_tail(&request->execlist_link, &engine->execlist_queue);
        request->ctx_hw_id = request->ctx->hw_id;
-       if (num_elements == 0)
-               execlists_unqueue(engine);
+
+       if (list_empty(&engine->execlist_queue))
+               tasklet_hi_schedule(&engine->irq_tasklet);
+       list_add_tail(&request->execlist_link, &engine->execlist_queue);
 
        spin_unlock_bh(&engine->execlist_lock);
 }