diff options
Diffstat (limited to 'drivers/gpu/drm/i915/intel_breadcrumbs.c')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_breadcrumbs.c | 605 |
1 files changed, 407 insertions, 198 deletions
diff --git a/drivers/gpu/drm/i915/intel_breadcrumbs.c b/drivers/gpu/drm/i915/intel_breadcrumbs.c index 7044e9a6abf7..9ccbf26124c6 100644 --- a/drivers/gpu/drm/i915/intel_breadcrumbs.c +++ b/drivers/gpu/drm/i915/intel_breadcrumbs.c @@ -27,22 +27,105 @@ #include "i915_drv.h" +static unsigned int __intel_breadcrumbs_wakeup(struct intel_breadcrumbs *b) +{ + struct intel_wait *wait; + unsigned int result = 0; + + lockdep_assert_held(&b->irq_lock); + + wait = b->irq_wait; + if (wait) { + result = ENGINE_WAKEUP_WAITER; + if (wake_up_process(wait->tsk)) + result |= ENGINE_WAKEUP_ASLEEP; + } + + return result; +} + +unsigned int intel_engine_wakeup(struct intel_engine_cs *engine) +{ + struct intel_breadcrumbs *b = &engine->breadcrumbs; + unsigned long flags; + unsigned int result; + + spin_lock_irqsave(&b->irq_lock, flags); + result = __intel_breadcrumbs_wakeup(b); + spin_unlock_irqrestore(&b->irq_lock, flags); + + return result; +} + +static unsigned long wait_timeout(void) +{ + return round_jiffies_up(jiffies + DRM_I915_HANGCHECK_JIFFIES); +} + +static noinline void missed_breadcrumb(struct intel_engine_cs *engine) +{ + DRM_DEBUG_DRIVER("%s missed breadcrumb at %pF, irq posted? %s\n", + engine->name, __builtin_return_address(0), + yesno(test_bit(ENGINE_IRQ_BREADCRUMB, + &engine->irq_posted))); + + set_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings); +} + static void intel_breadcrumbs_hangcheck(unsigned long data) { struct intel_engine_cs *engine = (struct intel_engine_cs *)data; struct intel_breadcrumbs *b = &engine->breadcrumbs; - if (!b->irq_enabled) + if (!b->irq_armed) return; - if (time_before(jiffies, b->timeout)) { - mod_timer(&b->hangcheck, b->timeout); + if (b->hangcheck_interrupts != atomic_read(&engine->irq_count)) { + b->hangcheck_interrupts = atomic_read(&engine->irq_count); + mod_timer(&b->hangcheck, wait_timeout()); return; } - DRM_DEBUG("Hangcheck timer elapsed... %s idle\n", engine->name); - set_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings); - mod_timer(&engine->breadcrumbs.fake_irq, jiffies + 1); + /* We keep the hangcheck timer alive until we disarm the irq, even + * if there are no waiters at present. + * + * If the waiter was currently running, assume it hasn't had a chance + * to process the pending interrupt (e.g, low priority task on a loaded + * system) and wait until it sleeps before declaring a missed interrupt. + * + * If the waiter was asleep (and not even pending a wakeup), then we + * must have missed an interrupt as the GPU has stopped advancing + * but we still have a waiter. Assuming all batches complete within + * DRM_I915_HANGCHECK_JIFFIES [1.5s]! + */ + if (intel_engine_wakeup(engine) & ENGINE_WAKEUP_ASLEEP) { + missed_breadcrumb(engine); + mod_timer(&engine->breadcrumbs.fake_irq, jiffies + 1); + } else { + mod_timer(&b->hangcheck, wait_timeout()); + } +} + +static void intel_breadcrumbs_fake_irq(unsigned long data) +{ + struct intel_engine_cs *engine = (struct intel_engine_cs *)data; + struct intel_breadcrumbs *b = &engine->breadcrumbs; + + /* The timer persists in case we cannot enable interrupts, + * or if we have previously seen seqno/interrupt incoherency + * ("missed interrupt" syndrome, better known as a "missed breadcrumb"). + * Here the worker will wake up every jiffie in order to kick the + * oldest waiter to do the coherent seqno check. + */ + + spin_lock_irq(&b->irq_lock); + if (!__intel_breadcrumbs_wakeup(b)) + __intel_engine_disarm_breadcrumbs(engine); + spin_unlock_irq(&b->irq_lock); + if (!b->irq_armed) + return; + + mod_timer(&b->fake_irq, jiffies + 1); /* Ensure that even if the GPU hangs, we get woken up. * @@ -56,33 +139,13 @@ static void intel_breadcrumbs_hangcheck(unsigned long data) i915_queue_hangcheck(engine->i915); } -static unsigned long wait_timeout(void) -{ - return round_jiffies_up(jiffies + DRM_I915_HANGCHECK_JIFFIES); -} - -static void intel_breadcrumbs_fake_irq(unsigned long data) -{ - struct intel_engine_cs *engine = (struct intel_engine_cs *)data; - - /* - * The timer persists in case we cannot enable interrupts, - * or if we have previously seen seqno/interrupt incoherency - * ("missed interrupt" syndrome). Here the worker will wake up - * every jiffie in order to kick the oldest waiter to do the - * coherent seqno check. - */ - if (intel_engine_wakeup(engine)) - mod_timer(&engine->breadcrumbs.fake_irq, jiffies + 1); -} - static void irq_enable(struct intel_engine_cs *engine) { /* Enabling the IRQ may miss the generation of the interrupt, but * we still need to force the barrier before reading the seqno, * just in case. */ - engine->breadcrumbs.irq_posted = true; + set_bit(ENGINE_IRQ_BREADCRUMB, &engine->irq_posted); /* Caller disables interrupts */ spin_lock(&engine->i915->irq_lock); @@ -96,61 +159,123 @@ static void irq_disable(struct intel_engine_cs *engine) spin_lock(&engine->i915->irq_lock); engine->irq_disable(engine); spin_unlock(&engine->i915->irq_lock); +} - engine->breadcrumbs.irq_posted = false; +void __intel_engine_disarm_breadcrumbs(struct intel_engine_cs *engine) +{ + struct intel_breadcrumbs *b = &engine->breadcrumbs; + + lockdep_assert_held(&b->irq_lock); + GEM_BUG_ON(b->irq_wait); + + if (b->irq_enabled) { + irq_disable(engine); + b->irq_enabled = false; + } + + b->irq_armed = false; } -static void __intel_breadcrumbs_enable_irq(struct intel_breadcrumbs *b) +void intel_engine_disarm_breadcrumbs(struct intel_engine_cs *engine) { - struct intel_engine_cs *engine = - container_of(b, struct intel_engine_cs, breadcrumbs); - struct drm_i915_private *i915 = engine->i915; + struct intel_breadcrumbs *b = &engine->breadcrumbs; + struct intel_wait *wait, *n, *first; - assert_spin_locked(&b->lock); - if (b->rpm_wakelock) + if (!b->irq_armed) return; - /* Since we are waiting on a request, the GPU should be busy - * and should have its own rpm reference. For completeness, - * record an rpm reference for ourselves to cover the - * interrupt we unmask. + /* We only disarm the irq when we are idle (all requests completed), + * so if the bottom-half remains asleep, it missed the request + * completion. */ - intel_runtime_pm_get_noresume(i915); - b->rpm_wakelock = true; - /* No interrupts? Kick the waiter every jiffie! */ - if (intel_irqs_enabled(i915)) { - if (!test_bit(engine->id, &i915->gpu_error.test_irq_rings)) - irq_enable(engine); - b->irq_enabled = true; + spin_lock_irq(&b->rb_lock); + + spin_lock(&b->irq_lock); + first = fetch_and_zero(&b->irq_wait); + __intel_engine_disarm_breadcrumbs(engine); + spin_unlock(&b->irq_lock); + + rbtree_postorder_for_each_entry_safe(wait, n, &b->waiters, node) { + RB_CLEAR_NODE(&wait->node); + if (wake_up_process(wait->tsk) && wait == first) + missed_breadcrumb(engine); } + b->waiters = RB_ROOT; + + spin_unlock_irq(&b->rb_lock); +} - if (!b->irq_enabled || - test_bit(engine->id, &i915->gpu_error.missed_irq_rings)) { +static bool use_fake_irq(const struct intel_breadcrumbs *b) +{ + const struct intel_engine_cs *engine = + container_of(b, struct intel_engine_cs, breadcrumbs); + + if (!test_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings)) + return false; + + /* Only start with the heavy weight fake irq timer if we have not + * seen any interrupts since enabling it the first time. If the + * interrupts are still arriving, it means we made a mistake in our + * engine->seqno_barrier(), a timing error that should be transient + * and unlikely to reoccur. + */ + return atomic_read(&engine->irq_count) == b->hangcheck_interrupts; +} + +static void enable_fake_irq(struct intel_breadcrumbs *b) +{ + /* Ensure we never sleep indefinitely */ + if (!b->irq_enabled || use_fake_irq(b)) mod_timer(&b->fake_irq, jiffies + 1); - } else { - /* Ensure we never sleep indefinitely */ - GEM_BUG_ON(!time_after(b->timeout, jiffies)); - mod_timer(&b->hangcheck, b->timeout); - } + else + mod_timer(&b->hangcheck, wait_timeout()); } -static void __intel_breadcrumbs_disable_irq(struct intel_breadcrumbs *b) +static void __intel_breadcrumbs_enable_irq(struct intel_breadcrumbs *b) { struct intel_engine_cs *engine = container_of(b, struct intel_engine_cs, breadcrumbs); + struct drm_i915_private *i915 = engine->i915; - assert_spin_locked(&b->lock); - if (!b->rpm_wakelock) + lockdep_assert_held(&b->irq_lock); + if (b->irq_armed) return; - if (b->irq_enabled) { - irq_disable(engine); - b->irq_enabled = false; + /* The breadcrumb irq will be disarmed on the interrupt after the + * waiters are signaled. This gives us a single interrupt window in + * which we can add a new waiter and avoid the cost of re-enabling + * the irq. + */ + b->irq_armed = true; + GEM_BUG_ON(b->irq_enabled); + + if (I915_SELFTEST_ONLY(b->mock)) { + /* For our mock objects we want to avoid interaction + * with the real hardware (which is not set up). So + * we simply pretend we have enabled the powerwell + * and the irq, and leave it up to the mock + * implementation to call intel_engine_wakeup() + * itself when it wants to simulate a user interrupt, + */ + return; + } + + /* Since we are waiting on a request, the GPU should be busy + * and should have its own rpm reference. This is tracked + * by i915->gt.awake, we can forgo holding our own wakref + * for the interrupt as before i915->gt.awake is released (when + * the driver is idle) we disarm the breadcrumbs. + */ + + /* No interrupts? Kick the waiter every jiffie! */ + if (intel_irqs_enabled(i915)) { + if (!test_bit(engine->id, &i915->gpu_error.test_irq_rings)) + irq_enable(engine); + b->irq_enabled = true; } - intel_runtime_pm_put(engine->i915); - b->rpm_wakelock = false; + enable_fake_irq(b); } static inline struct intel_wait *to_wait(struct rb_node *node) @@ -161,10 +286,16 @@ static inline struct intel_wait *to_wait(struct rb_node *node) static inline void __intel_breadcrumbs_finish(struct intel_breadcrumbs *b, struct intel_wait *wait) { - assert_spin_locked(&b->lock); + lockdep_assert_held(&b->rb_lock); + GEM_BUG_ON(b->irq_wait == wait); /* This request is completed, so remove it from the tree, mark it as - * complete, and *then* wake up the associated task. + * complete, and *then* wake up the associated task. N.B. when the + * task wakes up, it will find the empty rb_node, discern that it + * has already been removed from the tree and skip the serialisation + * of the b->rb_lock and b->irq_lock. This means that the destruction + * of the intel_wait is not serialised with the interrupt handler + * by the waiter - it must instead be serialised by the caller. */ rb_erase(&wait->node, &b->waiters); RB_CLEAR_NODE(&wait->node); @@ -172,6 +303,25 @@ static inline void __intel_breadcrumbs_finish(struct intel_breadcrumbs *b, wake_up_process(wait->tsk); /* implicit smp_wmb() */ } +static inline void __intel_breadcrumbs_next(struct intel_engine_cs *engine, + struct rb_node *next) +{ + struct intel_breadcrumbs *b = &engine->breadcrumbs; + + spin_lock(&b->irq_lock); + GEM_BUG_ON(!b->irq_armed); + GEM_BUG_ON(!b->irq_wait); + b->irq_wait = to_wait(next); + spin_unlock(&b->irq_lock); + + /* We always wake up the next waiter that takes over as the bottom-half + * as we may delegate not only the irq-seqno barrier to the next waiter + * but also the task of waking up concurrent waiters. + */ + if (next) + wake_up_process(to_wait(next)->tsk); +} + static bool __intel_engine_add_wait(struct intel_engine_cs *engine, struct intel_wait *wait) { @@ -235,44 +385,10 @@ static bool __intel_engine_add_wait(struct intel_engine_cs *engine, } rb_link_node(&wait->node, parent, p); rb_insert_color(&wait->node, &b->waiters); - GEM_BUG_ON(!first && !rcu_access_pointer(b->irq_seqno_bh)); - - if (completed) { - struct rb_node *next = rb_next(completed); - - GEM_BUG_ON(!next && !first); - if (next && next != &wait->node) { - GEM_BUG_ON(first); - b->timeout = wait_timeout(); - b->first_wait = to_wait(next); - rcu_assign_pointer(b->irq_seqno_bh, b->first_wait->tsk); - /* As there is a delay between reading the current - * seqno, processing the completed tasks and selecting - * the next waiter, we may have missed the interrupt - * and so need for the next bottom-half to wakeup. - * - * Also as we enable the IRQ, we may miss the - * interrupt for that seqno, so we have to wake up - * the next bottom-half in order to do a coherent check - * in case the seqno passed. - */ - __intel_breadcrumbs_enable_irq(b); - if (READ_ONCE(b->irq_posted)) - wake_up_process(to_wait(next)->tsk); - } - - do { - struct intel_wait *crumb = to_wait(completed); - completed = rb_prev(completed); - __intel_breadcrumbs_finish(b, crumb); - } while (completed); - } if (first) { - GEM_BUG_ON(rb_first(&b->waiters) != &wait->node); - b->timeout = wait_timeout(); - b->first_wait = wait; - rcu_assign_pointer(b->irq_seqno_bh, wait->tsk); + spin_lock(&b->irq_lock); + b->irq_wait = wait; /* After assigning ourselves as the new bottom-half, we must * perform a cursory check to prevent a missed interrupt. * Either we miss the interrupt whilst programming the hardware, @@ -282,10 +398,31 @@ static bool __intel_engine_add_wait(struct intel_engine_cs *engine, * and so we miss the wake up. */ __intel_breadcrumbs_enable_irq(b); + spin_unlock(&b->irq_lock); + } + + if (completed) { + /* Advance the bottom-half (b->irq_wait) before we wake up + * the waiters who may scribble over their intel_wait + * just as the interrupt handler is dereferencing it via + * b->irq_wait. + */ + if (!first) { + struct rb_node *next = rb_next(completed); + GEM_BUG_ON(next == &wait->node); + __intel_breadcrumbs_next(engine, next); + } + + do { + struct intel_wait *crumb = to_wait(completed); + completed = rb_prev(completed); + __intel_breadcrumbs_finish(b, crumb); + } while (completed); } - GEM_BUG_ON(!rcu_access_pointer(b->irq_seqno_bh)); - GEM_BUG_ON(!b->first_wait); - GEM_BUG_ON(rb_first(&b->waiters) != &b->first_wait->node); + + GEM_BUG_ON(!b->irq_wait); + GEM_BUG_ON(!b->irq_armed); + GEM_BUG_ON(rb_first(&b->waiters) != &b->irq_wait->node); return first; } @@ -296,9 +433,9 @@ bool intel_engine_add_wait(struct intel_engine_cs *engine, struct intel_breadcrumbs *b = &engine->breadcrumbs; bool first; - spin_lock_irq(&b->lock); + spin_lock_irq(&b->rb_lock); first = __intel_engine_add_wait(engine, wait); - spin_unlock_irq(&b->lock); + spin_unlock_irq(&b->rb_lock); return first; } @@ -317,29 +454,20 @@ static inline int wakeup_priority(struct intel_breadcrumbs *b, return tsk->prio; } -void intel_engine_remove_wait(struct intel_engine_cs *engine, - struct intel_wait *wait) +static void __intel_engine_remove_wait(struct intel_engine_cs *engine, + struct intel_wait *wait) { struct intel_breadcrumbs *b = &engine->breadcrumbs; - /* Quick check to see if this waiter was already decoupled from - * the tree by the bottom-half to avoid contention on the spinlock - * by the herd. - */ - if (RB_EMPTY_NODE(&wait->node)) - return; - - spin_lock_irq(&b->lock); + lockdep_assert_held(&b->rb_lock); if (RB_EMPTY_NODE(&wait->node)) - goto out_unlock; + goto out; - if (b->first_wait == wait) { + if (b->irq_wait == wait) { const int priority = wakeup_priority(b, wait->tsk); struct rb_node *next; - GEM_BUG_ON(rcu_access_pointer(b->irq_seqno_bh) != wait->tsk); - /* We are the current bottom-half. Find the next candidate, * the first waiter in the queue on the remaining oldest * request. As multiple seqnos may complete in the time it @@ -372,25 +500,7 @@ void intel_engine_remove_wait(struct intel_engine_cs *engine, } } - if (next) { - /* In our haste, we may have completed the first waiter - * before we enabled the interrupt. Do so now as we - * have a second waiter for a future seqno. Afterwards, - * we have to wake up that waiter in case we missed - * the interrupt, or if we have to handle an - * exception rather than a seqno completion. - */ - b->timeout = wait_timeout(); - b->first_wait = to_wait(next); - rcu_assign_pointer(b->irq_seqno_bh, b->first_wait->tsk); - if (b->first_wait->seqno != wait->seqno) - __intel_breadcrumbs_enable_irq(b); - wake_up_process(b->first_wait->tsk); - } else { - b->first_wait = NULL; - rcu_assign_pointer(b->irq_seqno_bh, NULL); - __intel_breadcrumbs_disable_irq(b); - } + __intel_breadcrumbs_next(engine, next); } else { GEM_BUG_ON(rb_first(&b->waiters) == &wait->node); } @@ -398,15 +508,37 @@ void intel_engine_remove_wait(struct intel_engine_cs *engine, GEM_BUG_ON(RB_EMPTY_NODE(&wait->node)); rb_erase(&wait->node, &b->waiters); -out_unlock: - GEM_BUG_ON(b->first_wait == wait); +out: + GEM_BUG_ON(b->irq_wait == wait); GEM_BUG_ON(rb_first(&b->waiters) != - (b->first_wait ? &b->first_wait->node : NULL)); - GEM_BUG_ON(!rcu_access_pointer(b->irq_seqno_bh) ^ RB_EMPTY_ROOT(&b->waiters)); - spin_unlock_irq(&b->lock); + (b->irq_wait ? &b->irq_wait->node : NULL)); +} + +void intel_engine_remove_wait(struct intel_engine_cs *engine, + struct intel_wait *wait) +{ + struct intel_breadcrumbs *b = &engine->breadcrumbs; + + /* Quick check to see if this waiter was already decoupled from + * the tree by the bottom-half to avoid contention on the spinlock + * by the herd. + */ + if (RB_EMPTY_NODE(&wait->node)) { + GEM_BUG_ON(READ_ONCE(b->irq_wait) == wait); + return; + } + + spin_lock_irq(&b->rb_lock); + __intel_engine_remove_wait(engine, wait); + spin_unlock_irq(&b->rb_lock); } -static bool signal_complete(struct drm_i915_gem_request *request) +static bool signal_valid(const struct drm_i915_gem_request *request) +{ + return intel_wait_check_request(&request->signaling.wait, request); +} + +static bool signal_complete(const struct drm_i915_gem_request *request) { if (!request) return false; @@ -415,7 +547,7 @@ static bool signal_complete(struct drm_i915_gem_request *request) * signalled that this wait is already completed. */ if (intel_wait_complete(&request->signaling.wait)) - return true; + return signal_valid(request); /* Carefully check if the request is complete, giving time for the * seqno to be visible or if the GPU hung. @@ -448,6 +580,8 @@ static int intel_breadcrumbs_signaler(void *arg) signaler_set_rtpriority(); do { + bool do_schedule = true; + set_current_state(TASK_INTERRUPTIBLE); /* We are either woken up by the interrupt bottom-half, @@ -458,40 +592,73 @@ static int intel_breadcrumbs_signaler(void *arg) * need to wait for a new interrupt from the GPU or for * a new client. */ - request = READ_ONCE(b->first_signal); + rcu_read_lock(); + request = rcu_dereference(b->first_signal); + if (request) + request = i915_gem_request_get_rcu(request); + rcu_read_unlock(); if (signal_complete(request)) { - /* Wake up all other completed waiters and select the - * next bottom-half for the next user interrupt. - */ - intel_engine_remove_wait(engine, - &request->signaling.wait); - local_bh_disable(); dma_fence_signal(&request->fence); local_bh_enable(); /* kick start the tasklets */ + spin_lock_irq(&b->rb_lock); + + /* Wake up all other completed waiters and select the + * next bottom-half for the next user interrupt. + */ + __intel_engine_remove_wait(engine, + &request->signaling.wait); + /* Find the next oldest signal. Note that as we have * not been holding the lock, another client may * have installed an even older signal than the one * we just completed - so double check we are still * the oldest before picking the next one. */ - spin_lock_irq(&b->lock); - if (request == b->first_signal) { + if (request == rcu_access_pointer(b->first_signal)) { struct rb_node *rb = rb_next(&request->signaling.node); - b->first_signal = rb ? to_signaler(rb) : NULL; + rcu_assign_pointer(b->first_signal, + rb ? to_signaler(rb) : NULL); } rb_erase(&request->signaling.node, &b->signals); - spin_unlock_irq(&b->lock); + RB_CLEAR_NODE(&request->signaling.node); + + spin_unlock_irq(&b->rb_lock); i915_gem_request_put(request); - } else { - if (kthread_should_stop()) + + /* If the engine is saturated we may be continually + * processing completed requests. This angers the + * NMI watchdog if we never let anything else + * have access to the CPU. Let's pretend to be nice + * and relinquish the CPU if we burn through the + * entire RT timeslice! + */ + do_schedule = need_resched(); + } + + if (unlikely(do_schedule)) { + DEFINE_WAIT(exec); + + if (kthread_should_park()) + kthread_parkme(); + + if (kthread_should_stop()) { + GEM_BUG_ON(request); break; + } + + if (request) + add_wait_queue(&request->execute, &exec); schedule(); + + if (request) + remove_wait_queue(&request->execute, &exec); } + i915_gem_request_put(request); } while (1); __set_current_state(TASK_RUNNING); @@ -504,24 +671,29 @@ void intel_engine_enable_signaling(struct drm_i915_gem_request *request) struct intel_breadcrumbs *b = &engine->breadcrumbs; struct rb_node *parent, **p; bool first, wakeup; + u32 seqno; /* Note that we may be called from an interrupt handler on another * device (e.g. nouveau signaling a fence completion causing us * to submit a request, and so enable signaling). As such, - * we need to make sure that all other users of b->lock protect + * we need to make sure that all other users of b->rb_lock protect * against interrupts, i.e. use spin_lock_irqsave. */ /* locked by dma_fence_enable_sw_signaling() (irqsafe fence->lock) */ - assert_spin_locked(&request->lock); - if (!request->global_seqno) + GEM_BUG_ON(!irqs_disabled()); + lockdep_assert_held(&request->lock); + + seqno = i915_gem_request_global_seqno(request); + if (!seqno) return; request->signaling.wait.tsk = b->signaler; - request->signaling.wait.seqno = request->global_seqno; + request->signaling.wait.request = request; + request->signaling.wait.seqno = seqno; i915_gem_request_get(request); - spin_lock(&b->lock); + spin_lock(&b->rb_lock); /* First add ourselves into the list of waiters, but register our * bottom-half as the signaller thread. As per usual, only the oldest @@ -542,8 +714,8 @@ void intel_engine_enable_signaling(struct drm_i915_gem_request *request) p = &b->signals.rb_node; while (*p) { parent = *p; - if (i915_seqno_passed(request->global_seqno, - to_signaler(parent)->global_seqno)) { + if (i915_seqno_passed(seqno, + to_signaler(parent)->signaling.wait.seqno)) { p = &parent->rb_right; first = false; } else { @@ -553,20 +725,52 @@ void intel_engine_enable_signaling(struct drm_i915_gem_request *request) rb_link_node(&request->signaling.node, parent, p); rb_insert_color(&request->signaling.node, &b->signals); if (first) - smp_store_mb(b->first_signal, request); + rcu_assign_pointer(b->first_signal, request); - spin_unlock(&b->lock); + spin_unlock(&b->rb_lock); if (wakeup) wake_up_process(b->signaler); } +void intel_engine_cancel_signaling(struct drm_i915_gem_request *request) +{ + struct intel_engine_cs *engine = request->engine; + struct intel_breadcrumbs *b = &engine->breadcrumbs; + + GEM_BUG_ON(!irqs_disabled()); + lockdep_assert_held(&request->lock); + GEM_BUG_ON(!request->signaling.wait.seqno); + + spin_lock(&b->rb_lock); + + if (!RB_EMPTY_NODE(&request->signaling.node)) { + if (request == rcu_access_pointer(b->first_signal)) { + struct rb_node *rb = + rb_next(&request->signaling.node); + rcu_assign_pointer(b->first_signal, + rb ? to_signaler(rb) : NULL); + } + rb_erase(&request->signaling.node, &b->signals); + RB_CLEAR_NODE(&request->signaling.node); + i915_gem_request_put(request); + } + + __intel_engine_remove_wait(engine, &request->signaling.wait); + + spin_unlock(&b->rb_lock); + + request->signaling.wait.seqno = 0; +} + int intel_engine_init_breadcrumbs(struct intel_engine_cs *engine) { struct intel_breadcrumbs *b = &engine->breadcrumbs; struct task_struct *tsk; - spin_lock_init(&b->lock); + spin_lock_init(&b->rb_lock); + spin_lock_init(&b->irq_lock); + setup_timer(&b->fake_irq, intel_breadcrumbs_fake_irq, (unsigned long)engine); @@ -604,20 +808,26 @@ void intel_engine_reset_breadcrumbs(struct intel_engine_cs *engine) struct intel_breadcrumbs *b = &engine->breadcrumbs; cancel_fake_irq(engine); - spin_lock_irq(&b->lock); + spin_lock_irq(&b->irq_lock); - __intel_breadcrumbs_disable_irq(b); - if (intel_engine_has_waiter(engine)) { - b->timeout = wait_timeout(); - __intel_breadcrumbs_enable_irq(b); - if (READ_ONCE(b->irq_posted)) - wake_up_process(b->first_wait->tsk); - } else { - /* sanitize the IMR and unmask any auxiliary interrupts */ + if (b->irq_enabled) + irq_enable(engine); + else irq_disable(engine); - } - spin_unlock_irq(&b->lock); + /* We set the IRQ_BREADCRUMB bit when we enable the irq presuming the + * GPU is active and may have already executed the MI_USER_INTERRUPT + * before the CPU is ready to receive. However, the engine is currently + * idle (we haven't started it yet), there is no possibility for a + * missed interrupt as we enabled the irq and so we can clear the + * immediate wakeup (until a real interrupt arrives for the waiter). + */ + clear_bit(ENGINE_IRQ_BREADCRUMB, &engine->irq_posted); + + if (b->irq_armed) + enable_fake_irq(b); + + spin_unlock_irq(&b->irq_lock); } void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine) @@ -625,9 +835,9 @@ void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine) struct intel_breadcrumbs *b = &engine->breadcrumbs; /* The engines should be idle and all requests accounted for! */ - WARN_ON(READ_ONCE(b->first_wait)); + WARN_ON(READ_ONCE(b->irq_wait)); WARN_ON(!RB_EMPTY_ROOT(&b->waiters)); - WARN_ON(READ_ONCE(b->first_signal)); + WARN_ON(rcu_access_pointer(b->first_signal)); WARN_ON(!RB_EMPTY_ROOT(&b->signals)); if (!IS_ERR_OR_NULL(b->signaler)) @@ -636,29 +846,28 @@ void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine) cancel_fake_irq(engine); } -unsigned int intel_breadcrumbs_busy(struct drm_i915_private *i915) +bool intel_breadcrumbs_busy(struct intel_engine_cs *engine) { - struct intel_engine_cs *engine; - enum intel_engine_id id; - unsigned int mask = 0; - - for_each_engine(engine, i915, id) { - struct intel_breadcrumbs *b = &engine->breadcrumbs; - - spin_lock_irq(&b->lock); + struct intel_breadcrumbs *b = &engine->breadcrumbs; + bool busy = false; - if (b->first_wait) { - wake_up_process(b->first_wait->tsk); - mask |= intel_engine_flag(engine); - } + spin_lock_irq(&b->rb_lock); - if (b->first_signal) { - wake_up_process(b->signaler); - mask |= intel_engine_flag(engine); - } + if (b->irq_wait) { + wake_up_process(b->irq_wait->tsk); + busy = true; + } - spin_unlock_irq(&b->lock); + if (rcu_access_pointer(b->first_signal)) { + wake_up_process(b->signaler); + busy = true; } - return mask; + spin_unlock_irq(&b->rb_lock); + + return busy; } + +#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST) +#include "selftests/intel_breadcrumbs.c" +#endif |