From: Chris Wilson Date: Fri, 5 Aug 2016 09:14:11 +0000 (+0100) Subject: drm/i915: Enable i915_gem_wait_for_idle() without holding struct_mutex X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=dcff85c8443e;p=linux-beck.git drm/i915: Enable i915_gem_wait_for_idle() without holding struct_mutex The principal motivation for this was to try and eliminate the struct_mutex from i915_gem_suspend - but we still need to hold the mutex current for the i915_gem_context_lost(). (The issue there is that there may be an indirect lockdep cycle between cpu_hotplug (i.e. suspend) and struct_mutex via the stop_machine().) For the moment, enabling last request tracking for the engine, allows us to do busyness checking and waiting without requiring the struct_mutex - which is useful in its own right. As a side-effect of having a robust means for tracking engine busyness, we can replace our other busyness heuristic, that of comparing against the last submitted seqno. For paranoid reasons, we have a semi-ordered check of that seqno inside the hangchecker, which we can now improve to an ordered check of the engine's busyness (removing a locked xchg in the process). v2: Pass along "bool interruptible" as being unlocked we cannot rely on i915->mm.interruptible being stable or even under our control. v3: Replace check Ironlake i915_gpu_busy() with the common precalculated value Signed-off-by: Chris Wilson Reviewed-by: Joonas Lahtinen Link: http://patchwork.freedesktop.org/patch/msgid/1470388464-28458-6-git-send-email-chris@chris-wilson.co.uk --- diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index 24d63e271f4b..1faea382dfeb 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -4925,7 +4925,7 @@ i915_drop_caches_set(void *data, u64 val) return ret; if (val & DROP_ACTIVE) { - ret = i915_gem_wait_for_idle(dev_priv); + ret = i915_gem_wait_for_idle(dev_priv, true); if (ret) goto unlock; } diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index abdfb97096e2..6eff31202336 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -3233,7 +3233,8 @@ int __must_check i915_gem_init(struct drm_device *dev); int __must_check i915_gem_init_hw(struct drm_device *dev); void i915_gem_init_swizzling(struct drm_device *dev); void i915_gem_cleanup_engines(struct drm_device *dev); -int __must_check i915_gem_wait_for_idle(struct drm_i915_private *dev_priv); +int __must_check i915_gem_wait_for_idle(struct drm_i915_private *dev_priv, + bool interruptible); int __must_check i915_gem_suspend(struct drm_device *dev); void i915_gem_resume(struct drm_device *dev); int i915_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf); diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 395f2ceea8fc..f01987ebee87 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -2438,13 +2438,18 @@ static void i915_gem_reset_engine_status(struct intel_engine_cs *engine) static void i915_gem_reset_engine_cleanup(struct intel_engine_cs *engine) { + struct drm_i915_gem_request *request; struct intel_ring *ring; + request = i915_gem_active_peek(&engine->last_request, + &engine->i915->drm.struct_mutex); + /* Mark all pending requests as complete so that any concurrent * (lockless) lookup doesn't try and wait upon the request as we * reset it. */ - intel_engine_init_seqno(engine, engine->last_submitted_seqno); + if (request) + intel_engine_init_seqno(engine, request->fence.seqno); /* * Clear the execlists queue up before freeing the requests, as those @@ -2466,15 +2471,9 @@ static void i915_gem_reset_engine_cleanup(struct intel_engine_cs *engine) * implicit references on things like e.g. ppgtt address spaces through * the request. */ - if (!list_empty(&engine->request_list)) { - struct drm_i915_gem_request *request; - - request = list_last_entry(&engine->request_list, - struct drm_i915_gem_request, - link); - + if (request) i915_gem_request_retire_upto(request); - } + GEM_BUG_ON(intel_engine_is_active(engine)); /* Having flushed all requests from all queues, we know that all * ringbuffers must now be empty. However, since we do not reclaim @@ -2897,18 +2896,17 @@ destroy: return 0; } -int i915_gem_wait_for_idle(struct drm_i915_private *dev_priv) +int i915_gem_wait_for_idle(struct drm_i915_private *dev_priv, + bool interruptible) { struct intel_engine_cs *engine; int ret; - lockdep_assert_held(&dev_priv->drm.struct_mutex); - for_each_engine(engine, dev_priv) { if (engine->last_context == NULL) continue; - ret = intel_engine_idle(engine); + ret = intel_engine_idle(engine, interruptible); if (ret) return ret; } @@ -4080,11 +4078,10 @@ struct i915_vma *i915_gem_obj_to_ggtt_view(struct drm_i915_gem_object *obj, return NULL; } -int -i915_gem_suspend(struct drm_device *dev) +int i915_gem_suspend(struct drm_device *dev) { struct drm_i915_private *dev_priv = to_i915(dev); - int ret = 0; + int ret; intel_suspend_gt_powersave(dev_priv); @@ -4102,7 +4099,7 @@ i915_gem_suspend(struct drm_device *dev) if (ret) goto err; - ret = i915_gem_wait_for_idle(dev_priv); + ret = i915_gem_wait_for_idle(dev_priv, true); if (ret) goto err; diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c index 7be425826539..f76c06e92677 100644 --- a/drivers/gpu/drm/i915/i915_gem_evict.c +++ b/drivers/gpu/drm/i915/i915_gem_evict.c @@ -39,7 +39,7 @@ gpu_is_idle(struct drm_i915_private *dev_priv) struct intel_engine_cs *engine; for_each_engine(engine, dev_priv) { - if (!list_empty(&engine->request_list)) + if (intel_engine_is_active(engine)) return false; } @@ -167,7 +167,7 @@ search_again: if (ret) return ret; - ret = i915_gem_wait_for_idle(dev_priv); + ret = i915_gem_wait_for_idle(dev_priv, true); if (ret) return ret; @@ -272,7 +272,7 @@ int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle) return ret; } - ret = i915_gem_wait_for_idle(dev_priv); + ret = i915_gem_wait_for_idle(dev_priv, true); if (ret) return ret; diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c index db97155074d3..c1d79978f409 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -2248,7 +2248,7 @@ static bool do_idling(struct drm_i915_private *dev_priv) if (unlikely(ggtt->do_idle_maps)) { dev_priv->mm.interruptible = false; - if (i915_gem_wait_for_idle(dev_priv)) { + if (i915_gem_wait_for_idle(dev_priv, false)) { DRM_ERROR("Failed to wait for idle; VT'd may hang.\n"); /* Wait a bit, in hopes it avoids the hang */ udelay(10); diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c index 3fecb8f0e041..1f91dc8c4171 100644 --- a/drivers/gpu/drm/i915/i915_gem_request.c +++ b/drivers/gpu/drm/i915/i915_gem_request.c @@ -265,7 +265,7 @@ static int i915_gem_init_seqno(struct drm_i915_private *dev_priv, u32 seqno) /* Carefully retire all requests without writing to the rings */ for_each_engine(engine, dev_priv) { - ret = intel_engine_idle(engine); + ret = intel_engine_idle(engine, true); if (ret) return ret; } @@ -486,7 +486,8 @@ void __i915_add_request(struct drm_i915_gem_request *request, */ request->emitted_jiffies = jiffies; request->previous_seqno = engine->last_submitted_seqno; - smp_store_mb(engine->last_submitted_seqno, request->fence.seqno); + engine->last_submitted_seqno = request->fence.seqno; + i915_gem_active_set(&engine->last_request, request); list_add_tail(&request->link, &engine->request_list); list_add_tail(&request->ring_link, &ring->request_list); @@ -757,7 +758,7 @@ void i915_gem_retire_requests(struct drm_i915_private *dev_priv) for_each_engine(engine, dev_priv) { engine_retire_requests(engine); - if (list_empty(&engine->request_list)) + if (!intel_engine_is_active(engine)) dev_priv->gt.active_engines &= ~intel_engine_flag(engine); } diff --git a/drivers/gpu/drm/i915/i915_gem_request.h b/drivers/gpu/drm/i915/i915_gem_request.h index 15495d1e48e8..3496e28785e7 100644 --- a/drivers/gpu/drm/i915/i915_gem_request.h +++ b/drivers/gpu/drm/i915/i915_gem_request.h @@ -29,6 +29,17 @@ #include "i915_gem.h" +struct intel_wait { + struct rb_node node; + struct task_struct *tsk; + u32 seqno; +}; + +struct intel_signal_node { + struct rb_node node; + struct intel_wait wait; +}; + /** * Request queue structure. * diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c index 1341cb55b6f1..23d70376b104 100644 --- a/drivers/gpu/drm/i915/i915_gem_shrinker.c +++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c @@ -412,7 +412,7 @@ i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr return NOTIFY_DONE; /* Force everything onto the inactive lists */ - ret = i915_gem_wait_for_idle(dev_priv); + ret = i915_gem_wait_for_idle(dev_priv, false); if (ret) goto out; diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index e58650096426..006a855877ad 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -2804,13 +2804,6 @@ static void gen8_disable_vblank(struct drm_device *dev, unsigned int pipe) spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags); } -static bool -ring_idle(struct intel_engine_cs *engine, u32 seqno) -{ - return i915_seqno_passed(seqno, - READ_ONCE(engine->last_submitted_seqno)); -} - static bool ipehr_is_semaphore_wait(struct intel_engine_cs *engine, u32 ipehr) { @@ -3131,7 +3124,7 @@ static void i915_hangcheck_elapsed(struct work_struct *work) user_interrupts = 0; if (engine->hangcheck.seqno == seqno) { - if (ring_idle(engine, seqno)) { + if (!intel_engine_is_active(engine)) { engine->hangcheck.action = HANGCHECK_IDLE; if (busy) { /* Safeguard against driver failure */ diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c index f495969f749b..e9b301ae2d0c 100644 --- a/drivers/gpu/drm/i915/intel_engine_cs.c +++ b/drivers/gpu/drm/i915/intel_engine_cs.c @@ -166,6 +166,12 @@ void intel_engine_init_hangcheck(struct intel_engine_cs *engine) memset(&engine->hangcheck, 0, sizeof(engine->hangcheck)); } +static void intel_engine_init_requests(struct intel_engine_cs *engine) +{ + init_request_active(&engine->last_request, NULL); + INIT_LIST_HEAD(&engine->request_list); +} + /** * intel_engines_setup_common - setup engine state not requiring hw access * @engine: Engine to setup. @@ -177,13 +183,13 @@ void intel_engine_init_hangcheck(struct intel_engine_cs *engine) */ void intel_engine_setup_common(struct intel_engine_cs *engine) { - INIT_LIST_HEAD(&engine->request_list); INIT_LIST_HEAD(&engine->buffers); INIT_LIST_HEAD(&engine->execlist_queue); spin_lock_init(&engine->execlist_lock); engine->fence_context = fence_context_alloc(1); + intel_engine_init_requests(engine); intel_engine_init_hangcheck(engine); i915_gem_batch_pool_init(engine, &engine->batch_pool); } diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 6bd352a8f30e..eedcacef7d5c 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -6328,19 +6328,11 @@ EXPORT_SYMBOL_GPL(i915_gpu_lower); */ bool i915_gpu_busy(void) { - struct drm_i915_private *dev_priv; - struct intel_engine_cs *engine; bool ret = false; spin_lock_irq(&mchdev_lock); - if (!i915_mch_dev) - goto out_unlock; - dev_priv = i915_mch_dev; - - for_each_engine(engine, dev_priv) - ret |= !list_empty(&engine->request_list); - -out_unlock: + if (i915_mch_dev) + ret = i915_mch_dev->gt.awake; spin_unlock_irq(&mchdev_lock); return ret; diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index 4593a65cae84..322274a239e4 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -2227,24 +2227,6 @@ void intel_engine_cleanup(struct intel_engine_cs *engine) engine->i915 = NULL; } -int intel_engine_idle(struct intel_engine_cs *engine) -{ - struct drm_i915_gem_request *req; - - /* Wait upon the last request to be completed */ - if (list_empty(&engine->request_list)) - return 0; - - req = list_entry(engine->request_list.prev, - struct drm_i915_gem_request, - link); - - /* Make sure we do not trigger any retires */ - return i915_wait_request(req, - req->i915->mm.interruptible, - NULL, NULL); -} - int intel_ring_alloc_request_extras(struct drm_i915_gem_request *request) { int ret; diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h index 88952bf10b9d..43e545e44352 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.h +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h @@ -3,6 +3,7 @@ #include #include "i915_gem_batch_pool.h" +#include "i915_gem_request.h" #define I915_CMD_HASH_ORDER 9 @@ -307,6 +308,13 @@ struct intel_engine_cs { */ u32 last_submitted_seqno; + /* An RCU guarded pointer to the last request. No reference is + * held to the request, users must carefully acquire a reference to + * the request using i915_gem_active_get_request_rcu(), or hold the + * struct_mutex. + */ + struct i915_gem_active last_request; + struct i915_gem_context *last_context; struct intel_engine_hangcheck hangcheck; @@ -465,7 +473,6 @@ static inline u32 intel_ring_offset(struct intel_ring *ring, u32 value) int __intel_ring_space(int head, int tail, int size); void intel_ring_update_space(struct intel_ring *ring); -int __must_check intel_engine_idle(struct intel_engine_cs *engine); void intel_engine_init_seqno(struct intel_engine_cs *engine, u32 seqno); int intel_init_pipe_control(struct intel_engine_cs *engine, int size); @@ -475,6 +482,14 @@ void intel_engine_setup_common(struct intel_engine_cs *engine); int intel_engine_init_common(struct intel_engine_cs *engine); void intel_engine_cleanup_common(struct intel_engine_cs *engine); +static inline int intel_engine_idle(struct intel_engine_cs *engine, + bool interruptible) +{ + /* Wait upon the last request to be completed */ + return i915_gem_active_wait_unlocked(&engine->last_request, + interruptible, NULL, NULL); +} + int intel_init_render_ring_buffer(struct intel_engine_cs *engine); int intel_init_bsd_ring_buffer(struct intel_engine_cs *engine); int intel_init_bsd2_ring_buffer(struct intel_engine_cs *engine); @@ -504,17 +519,6 @@ static inline u32 intel_hws_seqno_address(struct intel_engine_cs *engine) } /* intel_breadcrumbs.c -- user interrupt bottom-half for waiters */ -struct intel_wait { - struct rb_node node; - struct task_struct *tsk; - u32 seqno; -}; - -struct intel_signal_node { - struct rb_node node; - struct intel_wait wait; -}; - int intel_engine_init_breadcrumbs(struct intel_engine_cs *engine); static inline void intel_wait_init(struct intel_wait *wait, u32 seqno) @@ -561,4 +565,9 @@ void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine); unsigned int intel_kick_waiters(struct drm_i915_private *i915); unsigned int intel_kick_signalers(struct drm_i915_private *i915); +static inline bool intel_engine_is_active(struct intel_engine_cs *engine) +{ + return i915_gem_active_isset(&engine->last_request); +} + #endif /* _INTEL_RINGBUFFER_H_ */