[PATCH 18/54] drm/i915/preemption: Select timeout when scheduling
Chris Wilson
chris at chris-wilson.co.uk
Thu Apr 12 17:45:54 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 0536fa121976..7f10f7f78efd 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -578,7 +578,7 @@ 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 e1675d44ac92..0227c99eac1e 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -1062,7 +1062,7 @@ void __i915_request_add(struct i915_request *request, bool flush_caches)
*/
rcu_read_lock();
if (engine->schedule)
- engine->schedule(request, &request->ctx->sched);
+ engine->schedule(request, &request->ctx->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 5b32c60edc18..35953d1bd833 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1293,7 +1293,8 @@ pt_lock_engine(struct i915_priotree *pt, 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;
@@ -1390,7 +1391,7 @@ static void execlists_schedule(struct i915_request *request,
if (prio > engine->execlists.queue_priority &&
i915_sw_fence_done(&pt_to_request(pt)->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 6721984d25fa..0c5f31348b5b 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -464,14 +464,16 @@ 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 c8fbcff7148c..3cd45759ec57 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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