From 4413c474b18f116f96157599b7cc418a6471ed31 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 8 May 2018 22:03:17 +0100 Subject: drm/i915/execlists: Make submission tasklet hardirq safe Prepare to allow the execlists submission to be run from underneath a hardirq timer context (and not just the current softirq context) as is required for fast preemption resets and context switches. Signed-off-by: Chris Wilson Reviewed-by: Tvrtko Ursulin Link: https://patchwork.freedesktop.org/patch/msgid/20180508210318.10274-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/intel_lrc.c | 42 +++++++++++++++++++++++++++------------- 1 file changed, 29 insertions(+), 13 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index da08225fc482..d3c00f60c1b0 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -356,10 +356,13 @@ execlists_unwind_incomplete_requests(struct intel_engine_execlists *execlists) { struct intel_engine_cs *engine = container_of(execlists, typeof(*engine), execlists); + unsigned long flags; + + spin_lock_irqsave(&engine->timeline.lock, flags); - spin_lock_irq(&engine->timeline.lock); __unwind_incomplete_requests(engine); - spin_unlock_irq(&engine->timeline.lock); + + spin_unlock_irqrestore(&engine->timeline.lock, flags); } static inline void @@ -553,7 +556,7 @@ static void inject_preempt_context(struct intel_engine_cs *engine) execlists_set_active(&engine->execlists, EXECLISTS_ACTIVE_PREEMPT); } -static void execlists_dequeue(struct intel_engine_cs *engine) +static bool __execlists_dequeue(struct intel_engine_cs *engine) { struct intel_engine_execlists * const execlists = &engine->execlists; struct execlist_port *port = execlists->port; @@ -563,6 +566,8 @@ static void execlists_dequeue(struct intel_engine_cs *engine) struct rb_node *rb; bool submit = false; + lockdep_assert_held(&engine->timeline.lock); + /* Hardware submission is through 2 ports. Conceptually each port * has a (RING_START, RING_HEAD, RING_TAIL) tuple. RING_START is * static for a context, and unique to each, so we only execute @@ -584,7 +589,6 @@ static void execlists_dequeue(struct intel_engine_cs *engine) * and context switches) submission. */ - spin_lock_irq(&engine->timeline.lock); rb = execlists->first; GEM_BUG_ON(rb_first(&execlists->queue) != rb); @@ -599,7 +603,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine) EXECLISTS_ACTIVE_USER)); GEM_BUG_ON(!port_count(&port[0])); if (port_count(&port[0]) > 1) - goto unlock; + return false; /* * If we write to ELSP a second time before the HW has had @@ -609,11 +613,11 @@ static void execlists_dequeue(struct intel_engine_cs *engine) * the HW to indicate that it has had a chance to respond. */ if (!execlists_is_active(execlists, EXECLISTS_ACTIVE_HWACK)) - goto unlock; + return false; if (need_preempt(engine, last, execlists->queue_priority)) { inject_preempt_context(engine); - goto unlock; + return false; } /* @@ -638,7 +642,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine) * priorities of the ports haven't been switch. */ if (port_count(&port[1])) - goto unlock; + return false; /* * WaIdleLiteRestore:bdw,skl @@ -743,13 +747,25 @@ done: /* We must always keep the beast fed if we have work piled up */ GEM_BUG_ON(execlists->first && !port_isset(execlists->port)); -unlock: - spin_unlock_irq(&engine->timeline.lock); - - if (submit) { + /* Re-evaluate the executing context setup after each preemptive kick */ + if (last) execlists_user_begin(execlists, execlists->port); + + return submit; +} + +static void execlists_dequeue(struct intel_engine_cs *engine) +{ + struct intel_engine_execlists * const execlists = &engine->execlists; + unsigned long flags; + bool submit; + + spin_lock_irqsave(&engine->timeline.lock, flags); + submit = __execlists_dequeue(engine); + spin_unlock_irqrestore(&engine->timeline.lock, flags); + + if (submit) execlists_submit_ports(engine); - } GEM_BUG_ON(port_isset(execlists->port) && !execlists_is_active(execlists, EXECLISTS_ACTIVE_USER)); -- cgit v1.2.3