From 6a5d1db98ef1da5c632640133898aa42d6916c6c Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 8 Nov 2016 14:37:19 +0000 Subject: drm/i915: Spin until breadcrumb threads are complete When we need to reset the global seqno on wraparound, we have to wait until the current rbtrees are drained (or otherwise the next waiter will be out of sequence). The current mechanism to kick and spin until complete, may exit too early as it would break if the target thread was currently running. Instead, we must wake up the threads, but keep spinning until the trees have been deleted. In order to appease Tvrtko, busy spin rather than yield(). Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Link: http://patchwork.freedesktop.org/patch/msgid/20161108143719.32215-1-chris@chris-wilson.co.uk Reviewed-by: Tvrtko Ursulin --- drivers/gpu/drm/i915/intel_breadcrumbs.c | 31 ++++++++++++------------------- 1 file changed, 12 insertions(+), 19 deletions(-) (limited to 'drivers/gpu/drm/i915/intel_breadcrumbs.c') diff --git a/drivers/gpu/drm/i915/intel_breadcrumbs.c b/drivers/gpu/drm/i915/intel_breadcrumbs.c index c410d3d6465f..c9c46a538edb 100644 --- a/drivers/gpu/drm/i915/intel_breadcrumbs.c +++ b/drivers/gpu/drm/i915/intel_breadcrumbs.c @@ -629,35 +629,28 @@ void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine) cancel_fake_irq(engine); } -unsigned int intel_kick_waiters(struct drm_i915_private *i915) +unsigned int intel_breadcrumbs_busy(struct drm_i915_private *i915) { struct intel_engine_cs *engine; enum intel_engine_id id; unsigned int mask = 0; - /* To avoid the task_struct disappearing beneath us as we wake up - * the process, we must first inspect the task_struct->state under the - * RCU lock, i.e. as we call wake_up_process() we must be holding the - * rcu_read_lock(). - */ - for_each_engine(engine, i915, id) - if (unlikely(intel_engine_wakeup(engine))) - mask |= intel_engine_flag(engine); + for_each_engine(engine, i915, id) { + struct intel_breadcrumbs *b = &engine->breadcrumbs; - return mask; -} + spin_lock_irq(&b->lock); -unsigned int intel_kick_signalers(struct drm_i915_private *i915) -{ - struct intel_engine_cs *engine; - enum intel_engine_id id; - unsigned int mask = 0; + if (b->first_wait) { + wake_up_process(b->first_wait->tsk); + mask |= intel_engine_flag(engine); + } - for_each_engine(engine, i915, id) { - if (unlikely(READ_ONCE(engine->breadcrumbs.first_signal))) { - wake_up_process(engine->breadcrumbs.signaler); + if (b->first_signal) { + wake_up_process(b->signaler); mask |= intel_engine_flag(engine); } + + spin_unlock_irq(&b->lock); } return mask; -- cgit v1.2.3-59-g8ed1b