On 24/02/2020 09:59, Chris Wilson wrote:
If we do find ourselves with an idle barrier inside our active while
waiting, attempt to flush it by emitting a pulse using the kernel
context.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Steve Carbonari <steven.carbonari@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_active.c | 42 ++++++++++++++----
drivers/gpu/drm/i915/selftests/i915_active.c | 46 ++++++++++++++++++++
2 files changed, 79 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c
index 9ccb931a733e..fae7e3820592 100644
--- a/drivers/gpu/drm/i915/i915_active.c
+++ b/drivers/gpu/drm/i915/i915_active.c
@@ -7,6 +7,7 @@
#include <linux/debugobjects.h>
#include "gt/intel_context.h"
+#include "gt/intel_engine_heartbeat.h"
#include "gt/intel_engine_pm.h"
#include "gt/intel_ring.h"
@@ -460,26 +461,49 @@ static void enable_signaling(struct i915_active_fence *active)
dma_fence_put(fence);
}
-int i915_active_wait(struct i915_active *ref)
+static int flush_barrier(struct active_node *it)
{
- struct active_node *it, *n;
- int err = 0;
+ struct intel_engine_cs *engine;
- might_sleep();
+ if (!is_barrier(&it->base))
+ return 0;
- if (!i915_active_acquire_if_busy(ref))
+ engine = __barrier_to_engine(it);
+ smp_rmb(); /* serialise with add_active_barriers */
+ if (!is_barrier(&it->base))
return 0;
What is the purpose of the first !is_barrier check? Just to kind of look
better by not calling __bariier_to_engine on the wrong thing?
- /* Flush lazy signals */
+ return intel_engine_flush_barriers(engine);
+}
+
+static int flush_lazy_signals(struct i915_active *ref)
+{
+ struct active_node *it, *n;
+ int err = 0;
+
enable_signaling(&ref->excl);
rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
- if (is_barrier(&it->base)) /* unconnected idle barrier */
- continue;
+ err = flush_barrier(it); /* unconnected idle barrier? */
+ if (err)
+ break;
enable_signaling(&it->base);
}
- /* Any fence added after the wait begins will not be auto-signaled */
+ return err;
+}
+
+int i915_active_wait(struct i915_active *ref)
+{
+ int err;
+
+ might_sleep();
+
+ if (!i915_active_acquire_if_busy(ref))
+ return 0;
+
+ /* Any fence added after the wait begins will not be auto-signaled */
+ err = flush_lazy_signals(ref);
i915_active_release(ref);
if (err)
return err;
diff --git a/drivers/gpu/drm/i915/selftests/i915_active.c b/drivers/gpu/drm/i915/selftests/i915_active.c
index ef572a0c2566..067e30b8927f 100644
--- a/drivers/gpu/drm/i915/selftests/i915_active.c
+++ b/drivers/gpu/drm/i915/selftests/i915_active.c
@@ -201,11 +201,57 @@ static int live_active_retire(void *arg)
return err;
}
+static int live_active_barrier(void *arg)
+{
+ struct drm_i915_private *i915 = arg;
+ struct intel_engine_cs *engine;
+ struct live_active *active;
+ int err = 0;
+
+ /* Check that we get a callback when requests retire upon waiting */
+
+ active = __live_alloc(i915);
+ if (!active)
+ return -ENOMEM;
+
+ err = i915_active_acquire(&active->base);
+ if (err)
+ goto out;
+
+ for_each_uabi_engine(engine, i915) {
+ err = i915_active_acquire_preallocate_barrier(&active->base,
+ engine);
+ if (err)
+ break;
+
+ i915_active_acquire_barrier(&active->base);
+ }
+
+ i915_active_release(&active->base);
+
+ if (err == 0)
+ err = i915_active_wait(&active->base);
+
+ if (err == 0 && !READ_ONCE(active->retired)) {
+ pr_err("i915_active not retired after flushing barriers!\n");
+ err = -EINVAL;
+ }
+
+out:
+ __live_put(active);
+
+ if (igt_flush_test(i915))
+ err = -EIO;
+
+ return err;
+}
+
int i915_active_live_selftests(struct drm_i915_private *i915)
{
static const struct i915_subtest tests[] = {
SUBTEST(live_active_wait),
SUBTEST(live_active_retire),
+ SUBTEST(live_active_barrier),
};
if (intel_gt_is_wedged(&i915->gt))
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Regards,
Tvrtko
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