[PATCH 21/23] drm/i915/preemption: Select timeout when scheduling
Chris Wilson
chris at chris-wilson.co.uk
Tue Apr 3 14:14:09 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 | 106 ++++++++++++++++++++++++++++-
5 files changed, 114 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 6bd3119a3df6..2b1eeb1d46d7 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -482,7 +482,7 @@ static void __fence_set_priority(struct dma_fence *fence, int prio)
rcu_read_lock();
if (engine->schedule)
- engine->schedule(rq, prio);
+ engine->schedule(rq, prio, 0);
rcu_read_unlock();
}
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 585242831974..cdda3ebd51e2 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -1108,7 +1108,7 @@ void __i915_request_add(struct i915_request *request, bool flush_caches)
*/
rcu_read_lock();
if (engine->schedule)
- engine->schedule(request, request->ctx->priority);
+ engine->schedule(request, request->ctx->priority, 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 3df115422d34..a8aae4d220ca 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1265,7 +1265,8 @@ pt_lock_engine(struct i915_priotree *pt, struct intel_engine_cs *locked)
return engine;
}
-static void execlists_schedule(struct i915_request *request, int prio)
+static void execlists_schedule(struct i915_request *request,
+ int prio, unsigned int timeout)
{
struct intel_engine_cs *engine;
struct i915_dependency *dep, *p;
@@ -1361,7 +1362,7 @@ static void execlists_schedule(struct i915_request *request, int prio)
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 dab1b5d30cf7..500cc4ffa52c 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -463,13 +463,15 @@ 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, int priority);
+ void (*schedule)(struct i915_request *request,
+ int priority, 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 66aa6e22ff5b..4224e2e8b356 100644
--- a/drivers/gpu/drm/i915/selftests/intel_lrc.c
+++ b/drivers/gpu/drm/i915/selftests/intel_lrc.c
@@ -457,7 +457,7 @@ static int live_late_preempt(void *arg)
goto err_wedged;
}
- engine->schedule(rq, I915_PRIORITY_MAX);
+ engine->schedule(rq, I915_PRIORITY_MAX, 0);
if (!wait_for_spinner(&spin_hi, rq)) {
pr_err("High priority context failed to preempt the low priority context\n");
@@ -689,6 +689,109 @@ 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, 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, 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[] = {
@@ -697,6 +800,7 @@ 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);
}
--
2.16.3
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