[PATCH 24/98] drm/i915/preemption: Select timeout when scheduling
Chris Wilson
chris at chris-wilson.co.uk
Fri Apr 27 11:10:07 UTC 2018
The choice of preemption timeout is determined by the context from which
we trigger the preemption, as such allow the caller to specify the
desired timeout.
Effectively the other choice would be to use the shortest timeout along
the dependency chain. However, given that we would have already
triggered preemption for the dependency chain, we can assume that no
preemption along that chain is more important than the current request,
ergo we need only consider the current timeout. Realising this, we can
then pass control of the preemption timeout to the caller for greater
flexibility.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_gem.c | 2 +-
drivers/gpu/drm/i915/i915_request.c | 2 +-
drivers/gpu/drm/i915/intel_lrc.c | 5 +-
drivers/gpu/drm/i915/intel_ringbuffer.h | 6 +-
drivers/gpu/drm/i915/selftests/intel_lrc.c | 110 ++++++++++++++++++++-
5 files changed, 118 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 7a515bd3bb11..86faa210eb15 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -580,7 +580,7 @@ static void __fence_set_priority(struct dma_fence *fence,
rcu_read_lock();
if (engine->schedule)
- engine->schedule(rq, attr);
+ engine->schedule(rq, attr, 0);
rcu_read_unlock();
}
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 26498ab14f53..b31ff4b2b596 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -1111,7 +1111,7 @@ void __i915_request_add(struct i915_request *request, bool flush_caches)
*/
rcu_read_lock();
if (engine->schedule)
- engine->schedule(request, &request->gem_context->sched);
+ engine->schedule(request, &request->gem_context->sched, 0);
rcu_read_unlock();
local_bh_disable();
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 2c7a995d0acc..876b58092439 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1332,7 +1332,8 @@ 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)
+ const struct i915_sched_attr *attr,
+ unsigned int timeout)
{
struct intel_engine_cs *engine;
struct i915_dependency *dep, *p;
@@ -1429,7 +1430,7 @@ static void execlists_schedule(struct i915_request *request,
if (prio > engine->execlists.queue_priority &&
i915_sw_fence_done(&sched_to_request(node)->submit))
- __submit_queue(engine, prio, 0);
+ __submit_queue(engine, prio, timeout);
}
spin_unlock_irq(&engine->timeline.lock);
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 8693d4d800ad..56be17df3c37 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -467,14 +467,16 @@ struct intel_engine_cs {
*/
void (*submit_request)(struct i915_request *rq);
- /* Call when the priority on a request has changed and it and its
+ /*
+ * Call when the priority on a request has changed and it and its
* dependencies may need rescheduling. Note the request itself may
* not be ready to run!
*
* Called under the struct_mutex.
*/
void (*schedule)(struct i915_request *request,
- const struct i915_sched_attr *attr);
+ const struct i915_sched_attr *attr,
+ unsigned int timeout);
/*
* Cancel all requests on the hardware, or queued for execution.
diff --git a/drivers/gpu/drm/i915/selftests/intel_lrc.c b/drivers/gpu/drm/i915/selftests/intel_lrc.c
index 5ac4bf36aa84..ec906914bee2 100644
--- a/drivers/gpu/drm/i915/selftests/intel_lrc.c
+++ b/drivers/gpu/drm/i915/selftests/intel_lrc.c
@@ -460,7 +460,7 @@ static int live_late_preempt(void *arg)
}
attr.priority = I915_PRIORITY_MAX;
- engine->schedule(rq, &attr);
+ engine->schedule(rq, &attr, 0);
if (!wait_for_spinner(&spin_hi, rq)) {
pr_err("High priority context failed to preempt the low priority context\n");
@@ -683,6 +683,113 @@ static int live_preempt_reset(void *arg)
return err;
}
+static int live_late_preempt_timeout(void *arg)
+{
+ struct drm_i915_private *i915 = arg;
+ struct i915_gem_context *ctx_hi, *ctx_lo;
+ struct spinner spin_hi, spin_lo;
+ struct intel_engine_cs *engine;
+ enum intel_engine_id id;
+ int err = -ENOMEM;
+
+ if (!HAS_LOGICAL_RING_PREEMPTION(i915))
+ return 0;
+
+ mutex_lock(&i915->drm.struct_mutex);
+
+ if (spinner_init(&spin_hi, i915))
+ goto err_unlock;
+
+ if (spinner_init(&spin_lo, i915))
+ goto err_spin_hi;
+
+ ctx_hi = kernel_context(i915);
+ if (!ctx_hi)
+ goto err_spin_lo;
+
+ ctx_lo = kernel_context(i915);
+ if (!ctx_lo)
+ goto err_ctx_hi;
+
+ for_each_engine(engine, i915, id) {
+ struct i915_request *rq;
+
+ rq = spinner_create_request(&spin_lo, ctx_lo, engine, MI_NOOP);
+ if (IS_ERR(rq)) {
+ err = PTR_ERR(rq);
+ goto err_ctx_lo;
+ }
+
+ i915_request_add(rq);
+ if (!wait_for_spinner(&spin_lo, rq)) {
+ pr_err("First context failed to start\n");
+ goto err_wedged;
+ }
+
+ rq = spinner_create_request(&spin_hi, ctx_hi, engine, MI_NOOP);
+ if (IS_ERR(rq)) {
+ spinner_end(&spin_lo);
+ err = PTR_ERR(rq);
+ goto err_ctx_lo;
+ }
+
+ i915_request_add(rq);
+ if (wait_for_spinner(&spin_hi, rq)) {
+ pr_err("Second context overtook first?\n");
+ goto err_wedged;
+ }
+
+ GEM_TRACE("%s rescheduling (no timeout)\n", engine->name);
+ engine->schedule(rq, &(struct i915_sched_attr){
+ .priority = 1,
+ }, 0);
+
+ if (wait_for_spinner(&spin_hi, rq)) {
+ pr_err("High priority context overtook first without an arbitration point?\n");
+ goto err_wedged;
+ }
+
+ GEM_TRACE("%s rescheduling (with timeout)\n", engine->name);
+ engine->schedule(rq, &(struct i915_sched_attr){
+ .priority = 2,
+ }, 10 * 1000 /* 10us */);
+
+ if (!wait_for_spinner(&spin_hi, rq)) {
+ pr_err("High priority context failed to force itself in front of the low priority context\n");
+ GEM_TRACE_DUMP();
+ goto err_wedged;
+ }
+
+ spinner_end(&spin_hi);
+ spinner_end(&spin_lo);
+ if (flush_test(i915, I915_WAIT_LOCKED)) {
+ err = -EIO;
+ goto err_ctx_lo;
+ }
+ }
+
+ err = 0;
+err_ctx_lo:
+ kernel_context_close(ctx_lo);
+err_ctx_hi:
+ kernel_context_close(ctx_hi);
+err_spin_lo:
+ spinner_fini(&spin_lo);
+err_spin_hi:
+ spinner_fini(&spin_hi);
+err_unlock:
+ flush_test(i915, I915_WAIT_LOCKED);
+ mutex_unlock(&i915->drm.struct_mutex);
+ return err;
+
+err_wedged:
+ spinner_end(&spin_hi);
+ spinner_end(&spin_lo);
+ i915_gem_set_wedged(i915);
+ err = -EIO;
+ goto err_ctx_lo;
+}
+
int intel_execlists_live_selftests(struct drm_i915_private *i915)
{
static const struct i915_subtest tests[] = {
@@ -691,6 +798,7 @@ int intel_execlists_live_selftests(struct drm_i915_private *i915)
SUBTEST(live_late_preempt),
SUBTEST(live_preempt_timeout),
SUBTEST(live_preempt_reset),
+ SUBTEST(live_late_preempt_timeout),
};
return i915_subtests(tests, i915);
}
--
2.17.0
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