Rather than going back and forth between the rb_node entry and the virtual_engine type, store the ve local and reuse it. As the container_of conversion from rb_node to virtual_engine requires a variable offset, performing that conversion just once shaves off a bit of code.

v2: Keep a single virtual engine lookup, for typical use.

Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com Cc: stable@vger.kernel.org # v5.4+ --- drivers/gpu/drm/i915/gt/intel_lrc.c | 254 ++++++++++++---------------- 1 file changed, 111 insertions(+), 143 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c index fabb20a6800b..ec533dfe3be9 100644 --- a/drivers/gpu/drm/i915/gt/intel_lrc.c +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c @@ -453,9 +453,15 @@ static int queue_prio(const struct intel_engine_execlists *execlists) return ((p->priority + 1) << I915_USER_PRIORITY_SHIFT) - ffs(p->used); }

+static int virtual_prio(const struct intel_engine_execlists *el) +{ + struct rb_node *rb = rb_first_cached(&el->virtual); + + return rb ? rb_entry(rb, struct ve_node, rb)->prio : INT_MIN; +} + static inline bool need_preempt(const struct intel_engine_cs *engine, - const struct i915_request *rq, - struct rb_node *rb) + const struct i915_request *rq) { int last_prio;

@@ -492,25 +498,6 @@ static inline bool need_preempt(const struct intel_engine_cs *engine, rq_prio(list_next_entry(rq, sched.link)) > last_prio) return true;

- if (rb) { - struct virtual_engine *ve = - rb_entry(rb, typeof(*ve), nodes[engine->id].rb); - bool preempt = false; - - if (engine == ve->siblings[0]) { /* only preempt one sibling */ - struct i915_request *next; - - rcu_read_lock(); - next = READ_ONCE(ve->request); - if (next) - preempt = rq_prio(next) > last_prio; - rcu_read_unlock(); - } - - if (preempt) - return preempt; - } - /* * If the inflight context did not trigger the preemption, then maybe * it was the set of queued requests? Pick the highest priority in @@ -521,7 +508,8 @@ static inline bool need_preempt(const struct intel_engine_cs *engine, * ELSP[0] or ELSP[1] as, thanks again to PI, if it was the same * context, it's priority would not exceed ELSP[0] aka last_prio. */ - return queue_prio(&engine->execlists) > last_prio; + return max(virtual_prio(&engine->execlists), + queue_prio(&engine->execlists)) > last_prio; }

__maybe_unused static inline bool @@ -1806,6 +1794,35 @@ static bool virtual_matches(const struct virtual_engine *ve, return true; }

+static struct virtual_engine * +first_virtual_engine(struct intel_engine_cs *engine) +{ + struct intel_engine_execlists *el = &engine->execlists; + struct rb_node *rb = rb_first_cached(&el->virtual); + + while (rb) { + struct virtual_engine *ve = + rb_entry(rb, typeof(*ve), nodes[engine->id].rb); + struct i915_request *rq = READ_ONCE(ve->request); + + /* lazily cleanup after another engine handled rq */ + if (!rq) { + rb_erase_cached(rb, &el->virtual); + RB_CLEAR_NODE(rb); + rb = rb_first_cached(&el->virtual); + continue; + } + + if (!virtual_matches(ve, rq, engine)) { + rb = rb_next(rb); + continue; + } + return ve; + } + + return NULL; +} + static void virtual_xfer_breadcrumbs(struct virtual_engine *ve) { /* @@ -1889,32 +1906,15 @@ static void defer_active(struct intel_engine_cs *engine)

static bool need_timeslice(const struct intel_engine_cs *engine, - const struct i915_request *rq, - const struct rb_node *rb) + const struct i915_request *rq) { int hint;

if (!intel_engine_has_timeslices(engine)) return false;

- hint = engine->execlists.queue_priority_hint; - - if (rb) { - const struct virtual_engine *ve = - rb_entry(rb, typeof(*ve), nodes[engine->id].rb); - const struct intel_engine_cs *inflight = - intel_context_inflight(&ve->context); - - if (!inflight || inflight == engine) { - struct i915_request *next; - - rcu_read_lock(); - next = READ_ONCE(ve->request); - if (next) - hint = max(hint, rq_prio(next)); - rcu_read_unlock(); - } - } + hint = max(engine->execlists.queue_priority_hint, + virtual_prio(&engine->execlists));

if (!list_is_last(&rq->sched.link, &engine->active.requests)) hint = max(hint, rq_prio(list_next_entry(rq, sched.link))); @@ -2053,6 +2053,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine) struct i915_request **port = execlists->pending; struct i915_request ** const last_port = port + execlists->port_mask; struct i915_request * const *active = execlists->active; + struct virtual_engine *ve; struct i915_request *last; unsigned long flags; struct rb_node *rb; @@ -2081,26 +2082,6 @@ static void execlists_dequeue(struct intel_engine_cs *engine) */ spin_lock_irqsave(&engine->active.lock, flags);

- for (rb = rb_first_cached(&execlists->virtual); rb; ) { - struct virtual_engine *ve = - rb_entry(rb, typeof(*ve), nodes[engine->id].rb); - struct i915_request *rq = READ_ONCE(ve->request); - - if (!rq) { /* lazily cleanup after another engine handled rq */ - rb_erase_cached(rb, &execlists->virtual); - RB_CLEAR_NODE(rb); - rb = rb_first_cached(&execlists->virtual); - continue; - } - - if (!virtual_matches(ve, rq, engine)) { - rb = rb_next(rb); - continue; - } - - break; - } - /* * If the queue is higher priority than the last * request in the currently active context, submit afresh. @@ -2123,7 +2104,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine) if ((last = *active)) { if (i915_request_completed(last)) { goto check_secondary; - } else if (need_preempt(engine, last, rb)) { + } else if (need_preempt(engine, last)) { ENGINE_TRACE(engine, "preempting last=%llx:%lld, prio=%d, hint=%d\n", last->fence.context, @@ -2149,7 +2130,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine) __unwind_incomplete_requests(engine);

last = NULL; - } else if (need_timeslice(engine, last, rb) && + } else if (need_timeslice(engine, last) && timeslice_expired(execlists, last)) { ENGINE_TRACE(engine, "expired last=%llx:%lld, prio=%d, hint=%d, yield?=%s\n", @@ -2201,111 +2182,98 @@ static void execlists_dequeue(struct intel_engine_cs *engine) } }

- while (rb) { /* XXX virtual is always taking precedence */ - struct virtual_engine *ve = - rb_entry(rb, typeof(*ve), nodes[engine->id].rb); + /* XXX virtual is always taking precedence */ + while ((ve = first_virtual_engine(engine))) { struct i915_request *rq;

spin_lock(&ve->base.active.lock);

rq = ve->request; - if (unlikely(!rq)) { /* lost the race to a sibling */ - spin_unlock(&ve->base.active.lock); - rb_erase_cached(rb, &execlists->virtual); - RB_CLEAR_NODE(rb); - rb = rb_first_cached(&execlists->virtual); - continue; - } + if (unlikely(!rq)) /* lost the race to a sibling */ + goto unlock;

- GEM_BUG_ON(rq != ve->request); GEM_BUG_ON(rq->engine != &ve->base); GEM_BUG_ON(rq->context != &ve->context);

- if (rq_prio(rq) >= queue_prio(execlists)) { - if (!virtual_matches(ve, rq, engine)) { - spin_unlock(&ve->base.active.lock); - rb = rb_next(rb); - continue; - } + if (unlikely(rq_prio(rq) < queue_prio(execlists))) { + spin_unlock(&ve->base.active.lock); + break; + }

- if (last && !can_merge_rq(last, rq)) { - spin_unlock(&ve->base.active.lock); - spin_unlock_irqrestore(&engine->active.lock, flags); - start_timeslice(engine, rq_prio(rq)); - return; /* leave this for another sibling */ - } + GEM_BUG_ON(!virtual_matches(ve, rq, engine));

- ENGINE_TRACE(engine, - "virtual rq=%llx:%lld%s, new engine? %s\n", - rq->fence.context, - rq->fence.seqno, - i915_request_completed(rq) ? "!" : - i915_request_started(rq) ? "*" : - "", - yesno(engine != ve->siblings[0])); - - WRITE_ONCE(ve->request, NULL); - WRITE_ONCE(ve->base.execlists.queue_priority_hint, - INT_MIN); - rb_erase_cached(rb, &execlists->virtual); - RB_CLEAR_NODE(rb); + if (last && !can_merge_rq(last, rq)) { + spin_unlock(&ve->base.active.lock); + spin_unlock_irqrestore(&engine->active.lock, flags); + start_timeslice(engine, rq_prio(rq)); + return; /* leave this for another sibling */ + }

- GEM_BUG_ON(!(rq->execution_mask & engine->mask)); - WRITE_ONCE(rq->engine, engine); + ENGINE_TRACE(engine, + "virtual rq=%llx:%lld%s, new engine? %s\n", + rq->fence.context, + rq->fence.seqno, + i915_request_completed(rq) ? "!" : + i915_request_started(rq) ? "*" : + "", + yesno(engine != ve->siblings[0]));

- if (engine != ve->siblings[0]) { - u32 *regs = ve->context.lrc_reg_state; - unsigned int n; + WRITE_ONCE(ve->request, NULL); + WRITE_ONCE(ve->base.execlists.queue_priority_hint, INT_MIN);

- GEM_BUG_ON(READ_ONCE(ve->context.inflight)); + rb = &ve->nodes[engine->id].rb; + rb_erase_cached(rb, &execlists->virtual); + RB_CLEAR_NODE(rb);

- if (!intel_engine_has_relative_mmio(engine)) - virtual_update_register_offsets(regs, - engine); + GEM_BUG_ON(!(rq->execution_mask & engine->mask)); + WRITE_ONCE(rq->engine, engine);

- if (!list_empty(&ve->context.signals)) - virtual_xfer_breadcrumbs(ve); + if (engine != ve->siblings[0]) { + u32 *regs = ve->context.lrc_reg_state; + unsigned int n;

- /* - * Move the bound engine to the top of the list - * for future execution. We then kick this - * tasklet first before checking others, so that - * we preferentially reuse this set of bound - * registers. - */ - for (n = 1; n < ve->num_siblings; n++) { - if (ve->siblings[n] == engine) { - swap(ve->siblings[n], - ve->siblings[0]); - break; - } - } + GEM_BUG_ON(READ_ONCE(ve->context.inflight));

- GEM_BUG_ON(ve->siblings[0] != engine); - } + if (!intel_engine_has_relative_mmio(engine)) + virtual_update_register_offsets(regs, engine);

- if (__i915_request_submit(rq)) { - submit = true; - last = rq; - } - i915_request_put(rq); + if (!list_empty(&ve->context.signals)) + virtual_xfer_breadcrumbs(ve);

/* - * Hmm, we have a bunch of virtual engine requests, - * but the first one was already completed (thanks - * preempt-to-busy!). Keep looking at the veng queue - * until we have no more relevant requests (i.e. - * the normal submit queue has higher priority). + * Move the bound engine to the top of the list for + * future execution. We then kick this tasklet first + * before checking others, so that we preferentially + * reuse this set of bound registers. */ - if (!submit) { - spin_unlock(&ve->base.active.lock); - rb = rb_first_cached(&execlists->virtual); - continue; + for (n = 1; n < ve->num_siblings; n++) { + if (ve->siblings[n] == engine) { + swap(ve->siblings[n], ve->siblings[0]); + break; + } } + + GEM_BUG_ON(ve->siblings[0] != engine); + } + + if (__i915_request_submit(rq)) { + submit = true; + last = rq; }

+ i915_request_put(rq); +unlock: spin_unlock(&ve->base.active.lock); - break; + + /* + * Hmm, we have a bunch of virtual engine requests, + * but the first one was already completed (thanks + * preempt-to-busy!). Keep looking at the veng queue + * until we have no more relevant requests (i.e. + * the normal submit queue has higher priority). + */ + if (submit) + break; }

while ((rb = rb_first_cached(&execlists->queue))) {