drm/i915: Add unit tests for the breadcrumb rbtree, completion

Second retroactive test, make sure that the waiters are removed from the
global wait-tree when their seqno completes.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170213171558.20942-4-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/selftests/intel_breadcrumbs.c

@@ -64,6 +64,27 @@ static int check_rbtree(struct intel_engine_cs *engine,
 	return 0;
 }
 
+static int check_completion(struct intel_engine_cs *engine,
+			    const unsigned long *bitmap,
+			    const struct intel_wait *waiters,
+			    const int count)
+{
+	int n;
+
+	for (n = 0; n < count; n++) {
+		if (intel_wait_complete(&waiters[n]) != !!test_bit(n, bitmap))
+			continue;
+
+		pr_err("waiter[%d, seqno=%d] is %s, but expected %s\n",
+		       n, waiters[n].seqno,
+		       intel_wait_complete(&waiters[n]) ? "complete" : "active",
+		       test_bit(n, bitmap) ? "active" : "complete");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int check_rbtree_empty(struct intel_engine_cs *engine)
 {
 	struct intel_breadcrumbs *b = &engine->breadcrumbs;
@@ -153,10 +174,96 @@ static int igt_random_insert_remove(void *arg)
 	return err;
 }
 
+static int igt_insert_complete(void *arg)
+{
+	const u32 seqno_bias = 0x1000;
+	struct intel_engine_cs *engine = arg;
+	struct intel_wait *waiters;
+	const int count = 4096;
+	unsigned long *bitmap;
+	int err = -ENOMEM;
+	int n, m;
+
+	mock_engine_reset(engine);
+
+	waiters = drm_malloc_gfp(count, sizeof(*waiters), GFP_TEMPORARY);
+	if (!waiters)
+		goto out_engines;
+
+	bitmap = kcalloc(DIV_ROUND_UP(count, BITS_PER_LONG), sizeof(*bitmap),
+			 GFP_TEMPORARY);
+	if (!bitmap)
+		goto out_waiters;
+
+	for (n = 0; n < count; n++) {
+		intel_wait_init(&waiters[n], n + seqno_bias);
+		intel_engine_add_wait(engine, &waiters[n]);
+		__set_bit(n, bitmap);
+	}
+	err = check_rbtree(engine, bitmap, waiters, count);
+	if (err)
+		goto out_bitmap;
+
+	/* On each step, we advance the seqno so that several waiters are then
+	 * complete (we increase the seqno by increasingly larger values to
+	 * retire more and more waiters at once). All retired waiters should
+	 * be woken and removed from the rbtree, and so that we check.
+	 */
+	for (n = 0; n < count; n = m) {
+		int seqno = 2 * n;
+
+		GEM_BUG_ON(find_first_bit(bitmap, count) != n);
+
+		if (intel_wait_complete(&waiters[n])) {
+			pr_err("waiter[%d, seqno=%d] completed too early\n",
+			       n, waiters[n].seqno);
+			err = -EINVAL;
+			goto out_bitmap;
+		}
+
+		/* complete the following waiters */
+		mock_seqno_advance(engine, seqno + seqno_bias);
+		for (m = n; m <= seqno; m++) {
+			if (m == count)
+				break;
+
+			GEM_BUG_ON(!test_bit(m, bitmap));
+			__clear_bit(m, bitmap);
+		}
+
+		intel_engine_remove_wait(engine, &waiters[n]);
+		RB_CLEAR_NODE(&waiters[n].node);
+
+		err = check_rbtree(engine, bitmap, waiters, count);
+		if (err) {
+			pr_err("rbtree corrupt after seqno advance to %d\n",
+			       seqno + seqno_bias);
+			goto out_bitmap;
+		}
+
+		err = check_completion(engine, bitmap, waiters, count);
+		if (err) {
+			pr_err("completions after seqno advance to %d failed\n",
+			       seqno + seqno_bias);
+			goto out_bitmap;
+		}
+	}
+
+	err = check_rbtree_empty(engine);
+out_bitmap:
+	kfree(bitmap);
+out_waiters:
+	drm_free_large(waiters);
+out_engines:
+	mock_engine_flush(engine);
+	return err;
+}
+
 int intel_breadcrumbs_mock_selftests(void)
 {
 	static const struct i915_subtest tests[] = {
 		SUBTEST(igt_random_insert_remove),
+		SUBTEST(igt_insert_complete),
 	};
 	struct intel_engine_cs *engine;
 	int err;

drivers/gpu/drm/i915/selftests/mock_engine.h

@@ -29,4 +29,10 @@ struct intel_engine_cs *mock_engine(const char *name);
 void mock_engine_flush(struct intel_engine_cs *engine);
 void mock_engine_reset(struct intel_engine_cs *engine);
 
+static inline void mock_seqno_advance(struct intel_engine_cs *engine, u32 seqno)
+{
+	intel_write_status_page(engine, I915_GEM_HWS_INDEX, seqno);
+	intel_engine_wakeup(engine);
+}
+
 #endif /* !__MOCK_ENGINE_H__ */