drm/i915/execlists: Cache the priolist when rescheduling

When rescheduling a change of dependencies, they all need to be added to
the same priolist (at least the ones on the same engine!). Since we
likely want to move a batch of requests, keep the priolist around.

v2: Throw in an assert to catch trivial errors quickly.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180508003046.2633-2-chris@chris-wilson.co.uk

1 files changed, 10 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index bf9a44dae558..046adf397a71 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -346,6 +346,7 @@ static void __unwind_incomplete_requests(struct intel_engine_cs *engine)
                         p = lookup_priolist(engine, last_prio);
                 }
 
+                GEM_BUG_ON(p->priority != rq_prio(rq));
                 list_add(&rq->sched.link, &p->requests);
         }
 }
@@ -1198,7 +1199,8 @@ sched_lock_engine(struct i915_sched_node *node, struct intel_engine_cs *locked)
 static void execlists_schedule(struct i915_request *request,
                                const struct i915_sched_attr *attr)
 {
-        struct intel_engine_cs *engine;
+        struct i915_priolist *uninitialized_var(pl);
+        struct intel_engine_cs *engine, *last;
         struct i915_dependency *dep, *p;
         struct i915_dependency stack;
         const int prio = attr->priority;
@@ -1271,6 +1273,7 @@ static void execlists_schedule(struct i915_request *request,
                 __list_del_entry(&stack.dfs_link);
         }
 
+        last = NULL;
         engine = request->engine;
         spin_lock_irq(&engine->timeline.lock);
 
@@ -1287,8 +1290,12 @@ static void execlists_schedule(struct i915_request *request,
 
                 node->attr.priority = prio;
                 if (!list_empty(&node->link)) {
-                        __list_del_entry(&node->link);
-                        queue_request(engine, node, prio);
+                        if (last != engine) {
+                                pl = lookup_priolist(engine, prio);
+                                last = engine;
+                        }
+                        GEM_BUG_ON(pl->priority != prio);
+                        list_move_tail(&node->link, &pl->requests);
                 }
 
                 if (prio > engine->execlists.queue_priority &&