From 0b02befa828c0be67a5416e10a0244e181fde0d3 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Thu, 28 Jun 2018 21:12:04 +0100 Subject: [PATCH] drm/i915/execlists: Pull submit after dequeue under timeline lock In the next patch, we will begin processing the CSB from inside the submission path (underneath an irqsoff section, and even from inside interrupt handlers). This means that updating the execlists->port[] will no longer be serialised by the tasklet but needs to be locked by the engine->timeline.lock instead. Pull dequeue and submit under the same lock for protection. (An alternate future plan is to keep the in/out arrays separate for concurrent processing and reduced lock coverage.) Signed-off-by: Chris Wilson Reviewed-by: Tvrtko Ursulin Link: https://patchwork.freedesktop.org/patch/msgid/20180628201211.13837-2-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/intel_lrc.c | 32 ++++++++++++-------------------- 1 file changed, 12 insertions(+), 20 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index 46572976c942..af94949d08c8 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -567,7 +567,7 @@ static void complete_preempt_context(struct intel_engine_execlists *execlists) execlists_clear_active(execlists, EXECLISTS_ACTIVE_PREEMPT); } -static bool __execlists_dequeue(struct intel_engine_cs *engine) +static void __execlists_dequeue(struct intel_engine_cs *engine) { struct intel_engine_execlists * const execlists = &engine->execlists; struct execlist_port *port = execlists->port; @@ -622,11 +622,11 @@ static bool __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)) - return false; + return; if (need_preempt(engine, last, execlists->queue_priority)) { inject_preempt_context(engine); - return false; + return; } /* @@ -651,7 +651,7 @@ static bool __execlists_dequeue(struct intel_engine_cs *engine) * priorities of the ports haven't been switch. */ if (port_count(&port[1])) - return false; + return; /* * WaIdleLiteRestore:bdw,skl @@ -751,8 +751,10 @@ static bool __execlists_dequeue(struct intel_engine_cs *engine) port != execlists->port ? rq_prio(last) : INT_MIN; execlists->first = rb; - if (submit) + if (submit) { port_assign(port, last); + execlists_submit_ports(engine); + } /* We must always keep the beast fed if we have work piled up */ GEM_BUG_ON(execlists->first && !port_isset(execlists->port)); @@ -761,24 +763,19 @@ static bool __execlists_dequeue(struct intel_engine_cs *engine) if (last) execlists_user_begin(execlists, execlists->port); - return submit; + /* If the engine is now idle, so should be the flag; and vice versa. */ + GEM_BUG_ON(execlists_is_active(&engine->execlists, + EXECLISTS_ACTIVE_USER) == + !port_isset(engine->execlists.port)); } 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); + __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)); } void @@ -1162,11 +1159,6 @@ static void execlists_submission_tasklet(unsigned long data) if (!execlists_is_active(&engine->execlists, EXECLISTS_ACTIVE_PREEMPT)) execlists_dequeue(engine); - - /* If the engine is now idle, so should be the flag; and vice versa. */ - GEM_BUG_ON(execlists_is_active(&engine->execlists, - EXECLISTS_ACTIVE_USER) == - !port_isset(engine->execlists.port)); } static void queue_request(struct intel_engine_cs *engine, -- GitLab