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-rw-r--r--drivers/gpu/drm/i915/gt/intel_lrc.c22
-rw-r--r--drivers/gpu/drm/i915/gt/selftest_lrc.c168
-rw-r--r--drivers/gpu/drm/i915/i915_scheduler.c17
-rw-r--r--drivers/gpu/drm/i915/i915_scheduler.h18
4 files changed, 196 insertions, 29 deletions
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index e9fe9f79cedd..d0088d020220 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -352,10 +352,15 @@ static inline bool need_preempt(const struct intel_engine_cs *engine,
* However, the priority hint is a mere hint that we may need to
* preempt. If that hint is stale or we may be trying to preempt
* ourselves, ignore the request.
+ *
+ * More naturally we would write
+ * prio >= max(0, last);
+ * except that we wish to prevent triggering preemption at the same
+ * priority level: the task that is running should remain running
+ * to preserve FIFO ordering of dependencies.
*/
- last_prio = effective_prio(rq);
- if (!i915_scheduler_need_preempt(engine->execlists.queue_priority_hint,
- last_prio))
+ last_prio = max(effective_prio(rq), I915_PRIORITY_NORMAL - 1);
+ if (engine->execlists.queue_priority_hint <= last_prio)
return false;
/*
@@ -1509,8 +1514,17 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
* submission.
*/
if (!list_is_last(&last->sched.link,
- &engine->active.requests))
+ &engine->active.requests)) {
+ /*
+ * Even if ELSP[1] is occupied and not worthy
+ * of timeslices, our queue might be.
+ */
+ if (!execlists->timer.expires &&
+ need_timeslice(engine, last))
+ mod_timer(&execlists->timer,
+ jiffies + 1);
return;
+ }
/*
* WaIdleLiteRestore:bdw,skl
diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c
index 007d6203fe0e..5dc679781a08 100644
--- a/drivers/gpu/drm/i915/gt/selftest_lrc.c
+++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c
@@ -325,7 +325,13 @@ semaphore_queue(struct intel_engine_cs *engine, struct i915_vma *vma, int idx)
if (IS_ERR(rq))
goto out_ctx;
- err = emit_semaphore_chain(rq, vma, idx);
+ err = 0;
+ if (rq->engine->emit_init_breadcrumb)
+ err = rq->engine->emit_init_breadcrumb(rq);
+ if (err == 0)
+ err = emit_semaphore_chain(rq, vma, idx);
+ if (err == 0)
+ i915_request_get(rq);
i915_request_add(rq);
if (err)
rq = ERR_PTR(err);
@@ -338,10 +344,10 @@ out_ctx:
static int
release_queue(struct intel_engine_cs *engine,
struct i915_vma *vma,
- int idx)
+ int idx, int prio)
{
struct i915_sched_attr attr = {
- .priority = I915_USER_PRIORITY(I915_PRIORITY_MAX),
+ .priority = prio,
};
struct i915_request *rq;
u32 *cs;
@@ -362,9 +368,15 @@ release_queue(struct intel_engine_cs *engine,
*cs++ = 1;
intel_ring_advance(rq, cs);
+
+ i915_request_get(rq);
i915_request_add(rq);
+ local_bh_disable();
engine->schedule(rq, &attr);
+ local_bh_enable(); /* kick tasklet */
+
+ i915_request_put(rq);
return 0;
}
@@ -383,7 +395,6 @@ slice_semaphore_queue(struct intel_engine_cs *outer,
if (IS_ERR(head))
return PTR_ERR(head);
- i915_request_get(head);
for_each_engine(engine, outer->gt, id) {
for (i = 0; i < count; i++) {
struct i915_request *rq;
@@ -393,10 +404,12 @@ slice_semaphore_queue(struct intel_engine_cs *outer,
err = PTR_ERR(rq);
goto out;
}
+
+ i915_request_put(rq);
}
}
- err = release_queue(outer, vma, n);
+ err = release_queue(outer, vma, n, INT_MAX);
if (err)
goto out;
@@ -482,6 +495,150 @@ err_obj:
return err;
}
+static struct i915_request *nop_request(struct intel_engine_cs *engine)
+{
+ struct i915_request *rq;
+
+ rq = i915_request_create(engine->kernel_context);
+ if (IS_ERR(rq))
+ return rq;
+
+ i915_request_get(rq);
+ i915_request_add(rq);
+
+ return rq;
+}
+
+static void wait_for_submit(struct intel_engine_cs *engine,
+ struct i915_request *rq)
+{
+ do {
+ cond_resched();
+ intel_engine_flush_submission(engine);
+ } while (!i915_request_is_active(rq));
+}
+
+static int live_timeslice_queue(void *arg)
+{
+ struct intel_gt *gt = arg;
+ struct drm_i915_gem_object *obj;
+ struct intel_engine_cs *engine;
+ enum intel_engine_id id;
+ struct i915_vma *vma;
+ void *vaddr;
+ int err = 0;
+
+ /*
+ * Make sure that even if ELSP[0] and ELSP[1] are filled with
+ * timeslicing between them disabled, we *do* enable timeslicing
+ * if the queue demands it. (Normally, we do not submit if
+ * ELSP[1] is already occupied, so must rely on timeslicing to
+ * eject ELSP[0] in favour of the queue.)
+ */
+
+ obj = i915_gem_object_create_internal(gt->i915, PAGE_SIZE);
+ if (IS_ERR(obj))
+ return PTR_ERR(obj);
+
+ vma = i915_vma_instance(obj, &gt->ggtt->vm, NULL);
+ if (IS_ERR(vma)) {
+ err = PTR_ERR(vma);
+ goto err_obj;
+ }
+
+ vaddr = i915_gem_object_pin_map(obj, I915_MAP_WC);
+ if (IS_ERR(vaddr)) {
+ err = PTR_ERR(vaddr);
+ goto err_obj;
+ }
+
+ err = i915_vma_pin(vma, 0, 0, PIN_GLOBAL);
+ if (err)
+ goto err_map;
+
+ for_each_engine(engine, gt, id) {
+ struct i915_sched_attr attr = {
+ .priority = I915_USER_PRIORITY(I915_PRIORITY_MAX),
+ };
+ struct i915_request *rq, *nop;
+
+ if (!intel_engine_has_preemption(engine))
+ continue;
+
+ memset(vaddr, 0, PAGE_SIZE);
+
+ /* ELSP[0]: semaphore wait */
+ rq = semaphore_queue(engine, vma, 0);
+ if (IS_ERR(rq)) {
+ err = PTR_ERR(rq);
+ goto err_pin;
+ }
+ engine->schedule(rq, &attr);
+ wait_for_submit(engine, rq);
+
+ /* ELSP[1]: nop request */
+ nop = nop_request(engine);
+ if (IS_ERR(nop)) {
+ err = PTR_ERR(nop);
+ i915_request_put(rq);
+ goto err_pin;
+ }
+ wait_for_submit(engine, nop);
+ i915_request_put(nop);
+
+ GEM_BUG_ON(i915_request_completed(rq));
+ GEM_BUG_ON(execlists_active(&engine->execlists) != rq);
+
+ /* Queue: semaphore signal, matching priority as semaphore */
+ err = release_queue(engine, vma, 1, effective_prio(rq));
+ if (err) {
+ i915_request_put(rq);
+ goto err_pin;
+ }
+
+ intel_engine_flush_submission(engine);
+ if (!READ_ONCE(engine->execlists.timer.expires) &&
+ !i915_request_completed(rq)) {
+ struct drm_printer p =
+ drm_info_printer(gt->i915->drm.dev);
+
+ GEM_TRACE_ERR("%s: Failed to enable timeslicing!\n",
+ engine->name);
+ intel_engine_dump(engine, &p,
+ "%s\n", engine->name);
+ GEM_TRACE_DUMP();
+
+ memset(vaddr, 0xff, PAGE_SIZE);
+ err = -EINVAL;
+ }
+
+ /* Timeslice every jiffie, so within 2 we should signal */
+ if (i915_request_wait(rq, 0, 3) < 0) {
+ struct drm_printer p =
+ drm_info_printer(gt->i915->drm.dev);
+
+ pr_err("%s: Failed to timeslice into queue\n",
+ engine->name);
+ intel_engine_dump(engine, &p,
+ "%s\n", engine->name);
+
+ memset(vaddr, 0xff, PAGE_SIZE);
+ err = -EIO;
+ }
+ i915_request_put(rq);
+ if (err)
+ break;
+ }
+
+err_pin:
+ i915_vma_unpin(vma);
+err_map:
+ i915_gem_object_unpin_map(obj);
+err_obj:
+ i915_gem_object_put(obj);
+ return err;
+}
+
static int live_busywait_preempt(void *arg)
{
struct intel_gt *gt = arg;
@@ -2437,6 +2594,7 @@ int intel_execlists_live_selftests(struct drm_i915_private *i915)
SUBTEST(live_unlite_switch),
SUBTEST(live_unlite_preempt),
SUBTEST(live_timeslice_preempt),
+ SUBTEST(live_timeslice_queue),
SUBTEST(live_busywait_preempt),
SUBTEST(live_preempt),
SUBTEST(live_late_preempt),
diff --git a/drivers/gpu/drm/i915/i915_scheduler.c b/drivers/gpu/drm/i915/i915_scheduler.c
index 7b84ebca2901..0ca40f6bf08c 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.c
+++ b/drivers/gpu/drm/i915/i915_scheduler.c
@@ -177,9 +177,22 @@ static inline int rq_prio(const struct i915_request *rq)
return rq->sched.attr.priority | __NO_PREEMPTION;
}
+static inline bool need_preempt(int prio, int active)
+{
+ /*
+ * Allow preemption of low -> normal -> high, but we do
+ * not allow low priority tasks to preempt other low priority
+ * tasks under the impression that latency for low priority
+ * tasks does not matter (as much as background throughput),
+ * so kiss.
+ */
+ return prio >= max(I915_PRIORITY_NORMAL, active);
+}
+
static void kick_submission(struct intel_engine_cs *engine, int prio)
{
- const struct i915_request *inflight = *engine->execlists.active;
+ const struct i915_request *inflight =
+ execlists_active(&engine->execlists);
/*
* If we are already the currently executing context, don't
@@ -188,7 +201,7 @@ static void kick_submission(struct intel_engine_cs *engine, int prio)
* tasklet, i.e. we have not change the priority queue
* sufficiently to oust the running context.
*/
- if (!inflight || !i915_scheduler_need_preempt(prio, rq_prio(inflight)))
+ if (!inflight || !need_preempt(prio, rq_prio(inflight)))
return;
tasklet_hi_schedule(&engine->execlists.tasklet);
diff --git a/drivers/gpu/drm/i915/i915_scheduler.h b/drivers/gpu/drm/i915/i915_scheduler.h
index 7eefccff39bf..07d243acf553 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.h
+++ b/drivers/gpu/drm/i915/i915_scheduler.h
@@ -52,22 +52,4 @@ static inline void i915_priolist_free(struct i915_priolist *p)
__i915_priolist_free(p);
}
-static inline bool i915_scheduler_need_preempt(int prio, int active)
-{
- /*
- * Allow preemption of low -> normal -> high, but we do
- * not allow low priority tasks to preempt other low priority
- * tasks under the impression that latency for low priority
- * tasks does not matter (as much as background throughput),
- * so kiss.
- *
- * More naturally we would write
- * prio >= max(0, last);
- * except that we wish to prevent triggering preemption at the same
- * priority level: the task that is running should remain running
- * to preserve FIFO ordering of dependencies.
- */
- return prio > max(I915_PRIORITY_NORMAL - 1, active);
-}
-
#endif /* _I915_SCHEDULER_H_ */
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.