diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
index f451ef376548e19207233333d4231fcab2364624..06ff7695fa290b8ad68c4a9a7f2667eb41aed8a5 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -671,6 +671,7 @@ void
intel_engine_init_active(struct intel_engine_cs *engine, unsigned int subclass)
{
INIT_LIST_HEAD(&engine->active.requests);
+ INIT_LIST_HEAD(&engine->active.hold);
spin_lock_init(&engine->active.lock);
lockdep_set_subclass(&engine->active.lock, subclass);
@@ -1422,6 +1423,17 @@ static void print_request_ring(struct drm_printer *m, struct i915_request *rq)
}
}
+static unsigned long list_count(struct list_head *list)
+{
+ struct list_head *pos;
+ unsigned long count = 0;
+
+ list_for_each(pos, list)
+ count++;
+
+ return count;
+}
+
void intel_engine_dump(struct intel_engine_cs *engine,
struct drm_printer *m,
const char *header, ...)
@@ -1491,6 +1503,7 @@ void intel_engine_dump(struct intel_engine_cs *engine,
hexdump(m, rq->context->lrc_reg_state, PAGE_SIZE);
}
}
+ drm_printf(m, "\tOn hold?: %lu\n", list_count(&engine->active.hold));
spin_unlock_irqrestore(&engine->active.lock, flags);
drm_printf(m, "\tMMIO base: 0x%08x\n", engine->mmio_base);
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
index 00287515e7af17608875f965160adf5b6eaeb846..77e68c7643de88e4039e5e3e19856518a90321b0 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
@@ -295,6 +295,7 @@ struct intel_engine_cs {
struct {
spinlock_t lock;
struct list_head requests;
+ struct list_head hold; /* ready requests, but on hold */
} active;
struct llist_head barrier_tasks;
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 4cd88019fc2df3177af46a3a65a0a402f2611258..43375c44c85a2dd64725c872270100028c6a1bd4 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1635,8 +1635,8 @@ static void defer_request(struct i915_request *rq, struct list_head * const pl)
!i915_request_completed(rq));
GEM_BUG_ON(i915_request_is_active(w));
- if (list_empty(&w->sched.link))
- continue; /* Not yet submitted; unready */
+ if (!i915_request_is_ready(w))
+ continue;
if (rq_prio(w) < rq_prio(rq))
continue;
@@ -2354,6 +2354,145 @@ static void __execlists_submission_tasklet(struct intel_engine_cs *const engine)
}
}
+static void __execlists_hold(struct i915_request *rq)
+{
+ LIST_HEAD(list);
+
+ do {
+ struct i915_dependency *p;
+
+ if (i915_request_is_active(rq))
+ __i915_request_unsubmit(rq);
+
+ RQ_TRACE(rq, "on hold\n");
+ clear_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
+ list_move_tail(&rq->sched.link, &rq->engine->active.hold);
+ i915_request_set_hold(rq);
+
+ list_for_each_entry(p, &rq->sched.waiters_list, wait_link) {
+ struct i915_request *w =
+ container_of(p->waiter, typeof(*w), sched);
+
+ /* Leave semaphores spinning on the other engines */
+ if (w->engine != rq->engine)
+ continue;
+
+ if (!i915_request_is_ready(w))
+ continue;
+
+ if (i915_request_completed(w))
+ continue;
+
+ if (i915_request_on_hold(rq))
+ continue;
+
+ list_move_tail(&w->sched.link, &list);
+ }
+
+ rq = list_first_entry_or_null(&list, typeof(*rq), sched.link);
+ } while (rq);
+}
+
+__maybe_unused
+static void execlists_hold(struct intel_engine_cs *engine,
+ struct i915_request *rq)
+{
+ spin_lock_irq(&engine->active.lock);
+
+ /*
+ * Transfer this request onto the hold queue to prevent it
+ * being resumbitted to HW (and potentially completed) before we have
+ * released it. Since we may have already submitted following
+ * requests, we need to remove those as well.
+ */
+ GEM_BUG_ON(i915_request_on_hold(rq));
+ GEM_BUG_ON(rq->engine != engine);
+ __execlists_hold(rq);
+
+ spin_unlock_irq(&engine->active.lock);
+}
+
+static bool hold_request(const struct i915_request *rq)
+{
+ struct i915_dependency *p;
+
+ /*
+ * If one of our ancestors is on hold, we must also be on hold,
+ * otherwise we will bypass it and execute before it.
+ */
+ list_for_each_entry(p, &rq->sched.signalers_list, signal_link) {
+ const struct i915_request *s =
+ container_of(p->signaler, typeof(*s), sched);
+
+ if (s->engine != rq->engine)
+ continue;
+
+ if (i915_request_on_hold(s))
+ return true;
+ }
+
+ return false;
+}
+
+static void __execlists_unhold(struct i915_request *rq)
+{
+ LIST_HEAD(list);
+
+ do {
+ struct i915_dependency *p;
+
+ GEM_BUG_ON(!i915_request_on_hold(rq));
+ GEM_BUG_ON(!i915_sw_fence_signaled(&rq->submit));
+
+ i915_request_clear_hold(rq);
+ list_move_tail(&rq->sched.link,
+ i915_sched_lookup_priolist(rq->engine,
+ rq_prio(rq)));
+ set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
+ RQ_TRACE(rq, "hold release\n");
+
+ /* Also release any children on this engine that are ready */
+ list_for_each_entry(p, &rq->sched.waiters_list, wait_link) {
+ struct i915_request *w =
+ container_of(p->waiter, typeof(*w), sched);
+
+ if (w->engine != rq->engine)
+ continue;
+
+ if (!i915_request_on_hold(rq))
+ continue;
+
+ /* Check that no other parents are also on hold */
+ if (hold_request(rq))
+ continue;
+
+ list_move_tail(&w->sched.link, &list);
+ }
+
+ rq = list_first_entry_or_null(&list, typeof(*rq), sched.link);
+ } while (rq);
+}
+
+__maybe_unused
+static void execlists_unhold(struct intel_engine_cs *engine,
+ struct i915_request *rq)
+{
+ spin_lock_irq(&engine->active.lock);
+
+ /*
+ * Move this request back to the priority queue, and all of its
+ * children and grandchildren that were suspended along with it.
+ */
+ __execlists_unhold(rq);
+
+ if (rq_prio(rq) > engine->execlists.queue_priority_hint) {
+ engine->execlists.queue_priority_hint = rq_prio(rq);
+ tasklet_hi_schedule(&engine->execlists.tasklet);
+ }
+
+ spin_unlock_irq(&engine->active.lock);
+}
+
static noinline void preempt_reset(struct intel_engine_cs *engine)
{
const unsigned int bit = I915_RESET_ENGINE + engine->id;
@@ -2466,6 +2605,13 @@ static void submit_queue(struct intel_engine_cs *engine,
__submit_queue_imm(engine);
}
+static bool ancestor_on_hold(const struct intel_engine_cs *engine,
+ const struct i915_request *rq)
+{
+ GEM_BUG_ON(i915_request_on_hold(rq));
+ return !list_empty(&engine->active.hold) && hold_request(rq);
+}
+
static void execlists_submit_request(struct i915_request *request)
{
struct intel_engine_cs *engine = request->engine;
@@ -2474,12 +2620,17 @@ static void execlists_submit_request(struct i915_request *request)
/* Will be called from irq-context when using foreign fences. */
spin_lock_irqsave(&engine->active.lock, flags);
- queue_request(engine, request);
+ if (unlikely(ancestor_on_hold(engine, request))) {
+ list_add_tail(&request->sched.link, &engine->active.hold);
+ i915_request_set_hold(request);
+ } else {
+ queue_request(engine, request);
- GEM_BUG_ON(RB_EMPTY_ROOT(&engine->execlists.queue.rb_root));
- GEM_BUG_ON(list_empty(&request->sched.link));
+ GEM_BUG_ON(RB_EMPTY_ROOT(&engine->execlists.queue.rb_root));
+ GEM_BUG_ON(list_empty(&request->sched.link));
- submit_queue(engine, request);
+ submit_queue(engine, request);
+ }
spin_unlock_irqrestore(&engine->active.lock, flags);
}
@@ -3320,6 +3471,10 @@ static void execlists_reset_cancel(struct intel_engine_cs *engine)
i915_priolist_free(p);
}
+ /* On-hold requests will be flushed to timeline upon their release */
+ list_for_each_entry(rq, &engine->active.hold, sched.link)
+ mark_eio(rq);
+
/* Cancel all attached virtual engines */
while ((rb = rb_first_cached(&execlists->virtual))) {
struct virtual_engine *ve =
diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c
index 15cda024e3e4577424a4c8580b03bfee2f3027d3..b208c2176bbd63826c81da833f56d51e9ebe1019 100644
--- a/drivers/gpu/drm/i915/gt/selftest_lrc.c
+++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c
@@ -285,6 +285,108 @@ static int live_unlite_preempt(void *arg)
return live_unlite_restore(arg, I915_USER_PRIORITY(I915_PRIORITY_MAX));
}
+static int live_hold_reset(void *arg)
+{
+ struct intel_gt *gt = arg;
+ struct intel_engine_cs *engine;
+ enum intel_engine_id id;
+ struct igt_spinner spin;
+ int err = 0;
+
+ /*
+ * In order to support offline error capture for fast preempt reset,
+ * we need to decouple the guilty request and ensure that it and its
+ * descendents are not executed while the capture is in progress.
+ */
+
+ if (!intel_has_reset_engine(gt))
+ return 0;
+
+ if (igt_spinner_init(&spin, gt))
+ return -ENOMEM;
+
+ for_each_engine(engine, gt, id) {
+ struct intel_context *ce;
+ unsigned long heartbeat;
+ struct i915_request *rq;
+
+ ce = intel_context_create(engine);
+ if (IS_ERR(ce)) {
+ err = PTR_ERR(ce);
+ break;
+ }
+
+ engine_heartbeat_disable(engine, &heartbeat);
+
+ rq = igt_spinner_create_request(&spin, ce, MI_ARB_CHECK);
+ if (IS_ERR(rq)) {
+ err = PTR_ERR(rq);
+ goto out;
+ }
+ i915_request_add(rq);
+
+ if (!igt_wait_for_spinner(&spin, rq)) {
+ intel_gt_set_wedged(gt);
+ err = -ETIME;
+ goto out;
+ }
+
+ /* We have our request executing, now remove it and reset */
+
+ if (test_and_set_bit(I915_RESET_ENGINE + id,
+ >->reset.flags)) {
+ spin_unlock_irq(&engine->active.lock);
+ intel_gt_set_wedged(gt);
+ err = -EBUSY;
+ goto out;
+ }
+ tasklet_disable(&engine->execlists.tasklet);
+
+ engine->execlists.tasklet.func(engine->execlists.tasklet.data);
+ GEM_BUG_ON(execlists_active(&engine->execlists) != rq);
+
+ execlists_hold(engine, rq);
+ GEM_BUG_ON(!i915_request_on_hold(rq));
+
+ intel_engine_reset(engine, NULL);
+ GEM_BUG_ON(rq->fence.error != -EIO);
+
+ tasklet_enable(&engine->execlists.tasklet);
+ clear_and_wake_up_bit(I915_RESET_ENGINE + id,
+ >->reset.flags);
+
+ /* Check that we do not resubmit the held request */
+ i915_request_get(rq);
+ if (!i915_request_wait(rq, 0, HZ / 5)) {
+ pr_err("%s: on hold request completed!\n",
+ engine->name);
+ i915_request_put(rq);
+ err = -EIO;
+ goto out;
+ }
+ GEM_BUG_ON(!i915_request_on_hold(rq));
+
+ /* But is resubmitted on release */
+ execlists_unhold(engine, rq);
+ if (i915_request_wait(rq, 0, HZ / 5) < 0) {
+ pr_err("%s: held request did not complete!\n",
+ engine->name);
+ intel_gt_set_wedged(gt);
+ err = -ETIME;
+ }
+ i915_request_put(rq);
+
+out:
+ engine_heartbeat_enable(engine, heartbeat);
+ intel_context_put(ce);
+ if (err)
+ break;
+ }
+
+ igt_spinner_fini(&spin);
+ return err;
+}
+
static int
emit_semaphore_chain(struct i915_request *rq, struct i915_vma *vma, int idx)
{
@@ -3315,6 +3417,7 @@ int intel_execlists_live_selftests(struct drm_i915_private *i915)
SUBTEST(live_sanitycheck),
SUBTEST(live_unlite_switch),
SUBTEST(live_unlite_preempt),
+ SUBTEST(live_hold_reset),
SUBTEST(live_timeslice_preempt),
SUBTEST(live_timeslice_queue),
SUBTEST(live_busywait_preempt),
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index 6f5bbfa95513cff3c98d9e300bdc72586d15340c..f57eadcf3583a4888c61bbcc0b419442658af392 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -90,6 +90,13 @@ enum {
*/
I915_FENCE_FLAG_SIGNAL,
+ /*
+ * I915_FENCE_FLAG_HOLD - this request is currently on hold
+ *
+ * This request has been suspended, pending an ongoing investigation.
+ */
+ I915_FENCE_FLAG_HOLD,
+
/*
* I915_FENCE_FLAG_NOPREEMPT - this request should not be preempted
*
@@ -471,6 +478,27 @@ static inline bool i915_request_is_running(const struct i915_request *rq)
return __i915_request_has_started(rq);
}
+/**
+ * i915_request_is_running - check if the request is ready for execution
+ * @rq: the request
+ *
+ * Upon construction, the request is instructed to wait upon various
+ * signals before it is ready to be executed by the HW. That is, we do
+ * not want to start execution and read data before it is written. In practice,
+ * this is controlled with a mixture of interrupts and semaphores. Once
+ * the submit fence is completed, the backend scheduler will place the
+ * request into its queue and from there submit it for execution. So we
+ * can detect when a request is eligible for execution (and is under control
+ * of the scheduler) by querying where it is in any of the scheduler's lists.
+ *
+ * Returns true if the request is ready for execution (it may be inflight),
+ * false otherwise.
+ */
+static inline bool i915_request_is_ready(const struct i915_request *rq)
+{
+ return !list_empty(&rq->sched.link);
+}
+
static inline bool i915_request_completed(const struct i915_request *rq)
{
if (i915_request_signaled(rq))
@@ -500,6 +528,21 @@ static inline bool i915_request_has_sentinel(const struct i915_request *rq)
return unlikely(test_bit(I915_FENCE_FLAG_SENTINEL, &rq->fence.flags));
}
+static inline bool i915_request_on_hold(const struct i915_request *rq)
+{
+ return unlikely(test_bit(I915_FENCE_FLAG_HOLD, &rq->fence.flags));
+}
+
+static inline void i915_request_set_hold(struct i915_request *rq)
+{
+ set_bit(I915_FENCE_FLAG_HOLD, &rq->fence.flags);
+}
+
+static inline void i915_request_clear_hold(struct i915_request *rq)
+{
+ clear_bit(I915_FENCE_FLAG_HOLD, &rq->fence.flags);
+}
+
static inline struct intel_timeline *
i915_request_timeline(struct i915_request *rq)
{