/* * Copyright © 2008-2015 Intel Corporation * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice (including the next * paragraph) shall be included in all copies or substantial portions of the * Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS * IN THE SOFTWARE. * */ #include #include #include #include #include #include "i915_drv.h" static const char *i915_fence_get_driver_name(struct dma_fence *fence) { return "i915"; } static const char *i915_fence_get_timeline_name(struct dma_fence *fence) { /* * The timeline struct (as part of the ppgtt underneath a context) * may be freed when the request is no longer in use by the GPU. * We could extend the life of a context to beyond that of all * fences, possibly keeping the hw resource around indefinitely, * or we just give them a false name. Since * dma_fence_ops.get_timeline_name is a debug feature, the occasional * lie seems justifiable. */ if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) return "signaled"; return to_request(fence)->timeline->common->name; } static bool i915_fence_signaled(struct dma_fence *fence) { return i915_request_completed(to_request(fence)); } static bool i915_fence_enable_signaling(struct dma_fence *fence) { return intel_engine_enable_signaling(to_request(fence), true); } static signed long i915_fence_wait(struct dma_fence *fence, bool interruptible, signed long timeout) { return i915_request_wait(to_request(fence), interruptible, timeout); } static void i915_fence_release(struct dma_fence *fence) { struct i915_request *rq = to_request(fence); /* * The request is put onto a RCU freelist (i.e. the address * is immediately reused), mark the fences as being freed now. * Otherwise the debugobjects for the fences are only marked as * freed when the slab cache itself is freed, and so we would get * caught trying to reuse dead objects. */ i915_sw_fence_fini(&rq->submit); kmem_cache_free(rq->i915->requests, rq); } const struct dma_fence_ops i915_fence_ops = { .get_driver_name = i915_fence_get_driver_name, .get_timeline_name = i915_fence_get_timeline_name, .enable_signaling = i915_fence_enable_signaling, .signaled = i915_fence_signaled, .wait = i915_fence_wait, .release = i915_fence_release, }; static inline void i915_request_remove_from_client(struct i915_request *request) { struct drm_i915_file_private *file_priv; file_priv = request->file_priv; if (!file_priv) return; spin_lock(&file_priv->mm.lock); if (request->file_priv) { list_del(&request->client_link); request->file_priv = NULL; } spin_unlock(&file_priv->mm.lock); } static struct i915_dependency * i915_dependency_alloc(struct drm_i915_private *i915) { return kmem_cache_alloc(i915->dependencies, GFP_KERNEL); } static void i915_dependency_free(struct drm_i915_private *i915, struct i915_dependency *dep) { kmem_cache_free(i915->dependencies, dep); } static void __i915_sched_node_add_dependency(struct i915_sched_node *node, struct i915_sched_node *signal, struct i915_dependency *dep, unsigned long flags) { INIT_LIST_HEAD(&dep->dfs_link); list_add(&dep->wait_link, &signal->waiters_list); list_add(&dep->signal_link, &node->signalers_list); dep->signaler = signal; dep->flags = flags; } static int i915_sched_node_add_dependency(struct drm_i915_private *i915, struct i915_sched_node *node, struct i915_sched_node *signal) { struct i915_dependency *dep; dep = i915_dependency_alloc(i915); if (!dep) return -ENOMEM; __i915_sched_node_add_dependency(node, signal, dep, I915_DEPENDENCY_ALLOC); return 0; } static void i915_sched_node_fini(struct drm_i915_private *i915, struct i915_sched_node *node) { struct i915_dependency *dep, *tmp; GEM_BUG_ON(!list_empty(&node->link)); /* * Everyone we depended upon (the fences we wait to be signaled) * should retire before us and remove themselves from our list. * However, retirement is run independently on each timeline and * so we may be called out-of-order. */ list_for_each_entry_safe(dep, tmp, &node->signalers_list, signal_link) { GEM_BUG_ON(!i915_sched_node_signaled(dep->signaler)); GEM_BUG_ON(!list_empty(&dep->dfs_link)); list_del(&dep->wait_link); if (dep->flags & I915_DEPENDENCY_ALLOC) i915_dependency_free(i915, dep); } /* Remove ourselves from everyone who depends upon us */ list_for_each_entry_safe(dep, tmp, &node->waiters_list, wait_link) { GEM_BUG_ON(dep->signaler != node); GEM_BUG_ON(!list_empty(&dep->dfs_link)); list_del(&dep->signal_link); if (dep->flags & I915_DEPENDENCY_ALLOC) i915_dependency_free(i915, dep); } } static void i915_sched_node_init(struct i915_sched_node *node) { INIT_LIST_HEAD(&node->signalers_list); INIT_LIST_HEAD(&node->waiters_list); INIT_LIST_HEAD(&node->link); node->attr.priority = I915_PRIORITY_INVALID; } static int reset_all_global_seqno(struct drm_i915_private *i915, u32 seqno) { struct intel_engine_cs *engine; enum intel_engine_id id; int ret; /* Carefully retire all requests without writing to the rings */ ret = i915_gem_wait_for_idle(i915, I915_WAIT_INTERRUPTIBLE | I915_WAIT_LOCKED); if (ret) return ret; GEM_BUG_ON(i915->gt.active_requests); /* If the seqno wraps around, we need to clear the breadcrumb rbtree */ for_each_engine(engine, i915, id) { struct i915_gem_timeline *timeline; struct intel_timeline *tl = engine->timeline; GEM_TRACE("%s seqno %d (current %d) -> %d\n", engine->name, tl->seqno, intel_engine_get_seqno(engine), seqno); if (!i915_seqno_passed(seqno, tl->seqno)) { /* Flush any waiters before we reuse the seqno */ intel_engine_disarm_breadcrumbs(engine); GEM_BUG_ON(!list_empty(&engine->breadcrumbs.signals)); } /* Check we are idle before we fiddle with hw state! */ GEM_BUG_ON(!intel_engine_is_idle(engine)); GEM_BUG_ON(i915_gem_active_isset(&engine->timeline->last_request)); /* Finally reset hw state */ intel_engine_init_global_seqno(engine, seqno); tl->seqno = seqno; list_for_each_entry(timeline, &i915->gt.timelines, link) memset(timeline->engine[id].global_sync, 0, sizeof(timeline->engine[id].global_sync)); } return 0; } int i915_gem_set_global_seqno(struct drm_device *dev, u32 seqno) { struct drm_i915_private *i915 = to_i915(dev); lockdep_assert_held(&i915->drm.struct_mutex); if (seqno == 0) return -EINVAL; /* HWS page needs to be set less than what we will inject to ring */ return reset_all_global_seqno(i915, seqno - 1); } static int reserve_engine(struct intel_engine_cs *engine) { struct drm_i915_private *i915 = engine->i915; u32 active = ++engine->timeline->inflight_seqnos; u32 seqno = engine->timeline->seqno; int ret; /* Reservation is fine until we need to wrap around */ if (unlikely(add_overflows(seqno, active))) { ret = reset_all_global_seqno(i915, 0); if (ret) { engine->timeline->inflight_seqnos--; return ret; } } if (!i915->gt.active_requests++) i915_gem_unpark(i915); return 0; } static void unreserve_engine(struct intel_engine_cs *engine) { struct drm_i915_private *i915 = engine->i915; if (!--i915->gt.active_requests) i915_gem_park(i915); GEM_BUG_ON(!engine->timeline->inflight_seqnos); engine->timeline->inflight_seqnos--; } void i915_gem_retire_noop(struct i915_gem_active *active, struct i915_request *request) { /* Space left intentionally blank */ } static void advance_ring(struct i915_request *request) { unsigned int tail; /* * We know the GPU must have read the request to have * sent us the seqno + interrupt, so use the position * of tail of the request to update the last known position * of the GPU head. * * Note this requires that we are always called in request * completion order. */ if (list_is_last(&request->ring_link, &request->ring->request_list)) { /* * We may race here with execlists resubmitting this request * as we retire it. The resubmission will move the ring->tail * forwards (to request->wa_tail). We either read the * current value that was written to hw, or the value that * is just about to be. Either works, if we miss the last two * noops - they are safe to be replayed on a reset. */ tail = READ_ONCE(request->tail); } else { tail = request->postfix; } list_del(&request->ring_link); request->ring->head = tail; } static void free_capture_list(struct i915_request *request) { struct i915_capture_list *capture; capture = request->capture_list; while (capture) { struct i915_capture_list *next = capture->next; kfree(capture); capture = next; } } static void i915_request_retire(struct i915_request *request) { struct intel_engine_cs *engine = request->engine; struct i915_gem_active *active, *next; GEM_TRACE("%s fence %llx:%d, global=%d, current %d\n", engine->name, request->fence.context, request->fence.seqno, request->global_seqno, intel_engine_get_seqno(engine)); lockdep_assert_held(&request->i915->drm.struct_mutex); GEM_BUG_ON(!i915_sw_fence_signaled(&request->submit)); GEM_BUG_ON(!i915_request_completed(request)); GEM_BUG_ON(!request->i915->gt.active_requests); trace_i915_request_retire(request); spin_lock_irq(&engine->timeline->lock); list_del_init(&request->link); spin_unlock_irq(&engine->timeline->lock); unreserve_engine(request->engine); advance_ring(request); free_capture_list(request); /* * Walk through the active list, calling retire on each. This allows * objects to track their GPU activity and mark themselves as idle * when their *last* active request is completed (updating state * tracking lists for eviction, active references for GEM, etc). * * As the ->retire() may free the node, we decouple it first and * pass along the auxiliary information (to avoid dereferencing * the node after the callback). */ list_for_each_entry_safe(active, next, &request->active_list, link) { /* * In microbenchmarks or focusing upon time inside the kernel, * we may spend an inordinate amount of time simply handling * the retirement of requests and processing their callbacks. * Of which, this loop itself is particularly hot due to the * cache misses when jumping around the list of i915_gem_active. * So we try to keep this loop as streamlined as possible and * also prefetch the next i915_gem_active to try and hide * the likely cache miss. */ prefetchw(next); INIT_LIST_HEAD(&active->link); RCU_INIT_POINTER(active->request, NULL); active->retire(active, request); } i915_request_remove_from_client(request); /* Retirement decays the ban score as it is a sign of ctx progress */ atomic_dec_if_positive(&request->ctx->ban_score); /* * The backing object for the context is done after switching to the * *next* context. Therefore we cannot retire the previous context until * the next context has already started running. However, since we * cannot take the required locks at i915_request_submit() we * defer the unpinning of the active context to now, retirement of * the subsequent request. */ if (engine->last_retired_context) engine->context_unpin(engine, engine->last_retired_context); engine->last_retired_context = request->ctx; spin_lock_irq(&request->lock); if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &request->fence.flags)) dma_fence_signal_locked(&request->fence); if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &request->fence.flags)) intel_engine_cancel_signaling(request); if (request->waitboost) { GEM_BUG_ON(!atomic_read(&request->i915->gt_pm.rps.num_waiters)); atomic_dec(&request->i915->gt_pm.rps.num_waiters); } spin_unlock_irq(&request->lock); i915_sched_node_fini(request->i915, &request->sched); i915_request_put(request); } void i915_request_retire_upto(struct i915_request *rq) { struct intel_engine_cs *engine = rq->engine; struct i915_request *tmp; lockdep_assert_held(&rq->i915->drm.struct_mutex); GEM_BUG_ON(!i915_request_completed(rq)); if (list_empty(&rq->link)) return; do { tmp = list_first_entry(&engine->timeline->requests, typeof(*tmp), link); i915_request_retire(tmp); } while (tmp != rq); } static u32 timeline_get_seqno(struct intel_timeline *tl) { return ++tl->seqno; } static void move_to_timeline(struct i915_request *request, struct intel_timeline *timeline) { GEM_BUG_ON(request->timeline == request->engine->timeline); lockdep_assert_held(&request->engine->timeline->lock); spin_lock(&request->timeline->lock); list_move_tail(&request->link, &timeline->requests); spin_unlock(&request->timeline->lock); } void __i915_request_submit(struct i915_request *request) { struct intel_engine_cs *engine = request->engine; u32 seqno; GEM_TRACE("%s fence %llx:%d -> global=%d, current %d\n", engine->name, request->fence.context, request->fence.seqno, engine->timeline->seqno + 1, intel_engine_get_seqno(engine)); GEM_BUG_ON(!irqs_disabled()); lockdep_assert_held(&engine->timeline->lock); GEM_BUG_ON(request->global_seqno); seqno = timeline_get_seqno(engine->timeline); GEM_BUG_ON(!seqno); GEM_BUG_ON(i915_seqno_passed(intel_engine_get_seqno(engine), seqno)); /* We may be recursing from the signal callback of another i915 fence */ spin_lock_nested(&request->lock, SINGLE_DEPTH_NESTING); request->global_seqno = seqno; if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &request->fence.flags)) intel_engine_enable_signaling(request, false); spin_unlock(&request->lock); engine->emit_breadcrumb(request, request->ring->vaddr + request->postfix); /* Transfer from per-context onto the global per-engine timeline */ move_to_timeline(request, engine->timeline); trace_i915_request_execute(request); wake_up_all(&request->execute); } void i915_request_submit(struct i915_request *request) { struct intel_engine_cs *engine = request->engine; unsigned long flags; /* Will be called from irq-context when using foreign fences. */ spin_lock_irqsave(&engine->timeline->lock, flags); __i915_request_submit(request); spin_unlock_irqrestore(&engine->timeline->lock, flags); } void __i915_request_unsubmit(struct i915_request *request) { struct intel_engine_cs *engine = request->engine; GEM_TRACE("%s fence %llx:%d <- global=%d, current %d\n", engine->name, request->fence.context, request->fence.seqno, request->global_seqno, intel_engine_get_seqno(engine)); GEM_BUG_ON(!irqs_disabled()); lockdep_assert_held(&engine->timeline->lock); /* * Only unwind in reverse order, required so that the per-context list * is kept in seqno/ring order. */ GEM_BUG_ON(!request->global_seqno); GEM_BUG_ON(request->global_seqno != engine->timeline->seqno); GEM_BUG_ON(i915_seqno_passed(intel_engine_get_seqno(engine), request->global_seqno)); engine->timeline->seqno--; /* We may be recursing from the signal callback of another i915 fence */ spin_lock_nested(&request->lock, SINGLE_DEPTH_NESTING); request->global_seqno = 0; if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &request->fence.flags)) intel_engine_cancel_signaling(request); spin_unlock(&request->lock); /* Transfer back from the global per-engine timeline to per-context */ move_to_timeline(request, request->timeline); /* * We don't need to wake_up any waiters on request->execute, they * will get woken by any other event or us re-adding this request * to the engine timeline (__i915_request_submit()). The waiters * should be quite adapt at finding that the request now has a new * global_seqno to the one they went to sleep on. */ } void i915_request_unsubmit(struct i915_request *request) { struct intel_engine_cs *engine = request->engine; unsigned long flags; /* Will be called from irq-context when using foreign fences. */ spin_lock_irqsave(&engine->timeline->lock, flags); __i915_request_unsubmit(request); spin_unlock_irqrestore(&engine->timeline->lock, flags); } static int __i915_sw_fence_call submit_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state) { struct i915_request *request = container_of(fence, typeof(*request), submit); switch (state) { case FENCE_COMPLETE: trace_i915_request_submit(request); /* * We need to serialize use of the submit_request() callback * with its hotplugging performed during an emergency * i915_gem_set_wedged(). We use the RCU mechanism to mark the * critical section in order to force i915_gem_set_wedged() to * wait until the submit_request() is completed before * proceeding. */ rcu_read_lock(); request->engine->submit_request(request); rcu_read_unlock(); break; case FENCE_FREE: i915_request_put(request); break; } return NOTIFY_DONE; } /** * i915_request_alloc - allocate a request structure * * @engine: engine that we wish to issue the request on. * @ctx: context that the request will be associated with. * * Returns a pointer to the allocated request if successful, * or an error code if not. */ struct i915_request * i915_request_alloc(struct intel_engine_cs *engine, struct i915_gem_context *ctx) { struct drm_i915_private *i915 = engine->i915; struct i915_request *rq; struct intel_ring *ring; int ret; lockdep_assert_held(&i915->drm.struct_mutex); /* * Preempt contexts are reserved for exclusive use to inject a * preemption context switch. They are never to be used for any trivial * request! */ GEM_BUG_ON(ctx == i915->preempt_context); /* * ABI: Before userspace accesses the GPU (e.g. execbuffer), report * EIO if the GPU is already wedged. */ if (i915_terminally_wedged(&i915->gpu_error)) return ERR_PTR(-EIO); /* * Pinning the contexts may generate requests in order to acquire * GGTT space, so do this first before we reserve a seqno for * ourselves. */ ring = engine->context_pin(engine, ctx); if (IS_ERR(ring)) return ERR_CAST(ring); GEM_BUG_ON(!ring); ret = reserve_engine(engine); if (ret) goto err_unpin; ret = intel_ring_wait_for_space(ring, MIN_SPACE_FOR_ADD_REQUEST); if (ret) goto err_unreserve; /* Move the oldest request to the slab-cache (if not in use!) */ rq = list_first_entry_or_null(&engine->timeline->requests, typeof(*rq), link); if (rq && i915_request_completed(rq)) i915_request_retire(rq); /* * Beware: Dragons be flying overhead. * * We use RCU to look up requests in flight. The lookups may * race with the request being allocated from the slab freelist. * That is the request we are writing to here, may be in the process * of being read by __i915_gem_active_get_rcu(). As such, * we have to be very careful when overwriting the contents. During * the RCU lookup, we change chase the request->engine pointer, * read the request->global_seqno and increment the reference count. * * The reference count is incremented atomically. If it is zero, * the lookup knows the request is unallocated and complete. Otherwise, * it is either still in use, or has been reallocated and reset * with dma_fence_init(). This increment is safe for release as we * check that the request we have a reference to and matches the active * request. * * Before we increment the refcount, we chase the request->engine * pointer. We must not call kmem_cache_zalloc() or else we set * that pointer to NULL and cause a crash during the lookup. If * we see the request is completed (based on the value of the * old engine and seqno), the lookup is complete and reports NULL. * If we decide the request is not completed (new engine or seqno), * then we grab a reference and double check that it is still the * active request - which it won't be and restart the lookup. * * Do not use kmem_cache_zalloc() here! */ rq = kmem_cache_alloc(i915->requests, GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN); if (unlikely(!rq)) { /* Ratelimit ourselves to prevent oom from malicious clients */ ret = i915_gem_wait_for_idle(i915, I915_WAIT_LOCKED | I915_WAIT_INTERRUPTIBLE); if (ret) goto err_unreserve; /* * We've forced the client to stall and catch up with whatever * backlog there might have been. As we are assuming that we * caused the mempressure, now is an opportune time to * recover as much memory from the request pool as is possible. * Having already penalized the client to stall, we spend * a little extra time to re-optimise page allocation. */ kmem_cache_shrink(i915->requests); rcu_barrier(); /* Recover the TYPESAFE_BY_RCU pages */ rq = kmem_cache_alloc(i915->requests, GFP_KERNEL); if (!rq) { ret = -ENOMEM; goto err_unreserve; } } rq->timeline = i915_gem_context_lookup_timeline(ctx, engine); GEM_BUG_ON(rq->timeline == engine->timeline); spin_lock_init(&rq->lock); dma_fence_init(&rq->fence, &i915_fence_ops, &rq->lock, rq->timeline->fence_context, timeline_get_seqno(rq->timeline)); /* We bump the ref for the fence chain */ i915_sw_fence_init(&i915_request_get(rq)->submit, submit_notify); init_waitqueue_head(&rq->execute); i915_sched_node_init(&rq->sched); INIT_LIST_HEAD(&rq->active_list); rq->i915 = i915; rq->engine = engine; rq->ctx = ctx; rq->ring = ring; /* No zalloc, must clear what we need by hand */ rq->global_seqno = 0; rq->signaling.wait.seqno = 0; rq->file_priv = NULL; rq->batch = NULL; rq->capture_list = NULL; rq->waitboost = false; /* * Reserve space in the ring buffer for all the commands required to * eventually emit this request. This is to guarantee that the * i915_request_add() call can't fail. Note that the reserve may need * to be redone if the request is not actually submitted straight * away, e.g. because a GPU scheduler has deferred it. */ rq->reserved_space = MIN_SPACE_FOR_ADD_REQUEST; GEM_BUG_ON(rq->reserved_space < engine->emit_breadcrumb_sz); /* * Record the position of the start of the request so that * should we detect the updated seqno part-way through the * GPU processing the request, we never over-estimate the * position of the head. */ rq->head = rq->ring->emit; /* Unconditionally invalidate GPU caches and TLBs. */ ret = engine->emit_flush(rq, EMIT_INVALIDATE); if (ret) goto err_unwind; ret = engine->request_alloc(rq); if (ret) goto err_unwind; /* Check that we didn't interrupt ourselves with a new request */ GEM_BUG_ON(rq->timeline->seqno != rq->fence.seqno); return rq; err_unwind: rq->ring->emit = rq->head; /* Make sure we didn't add ourselves to external state before freeing */ GEM_BUG_ON(!list_empty(&rq->active_list)); GEM_BUG_ON(!list_empty(&rq->sched.signalers_list)); GEM_BUG_ON(!list_empty(&rq->sched.waiters_list)); kmem_cache_free(i915->requests, rq); err_unreserve: unreserve_engine(engine); err_unpin: engine->context_unpin(engine, ctx); return ERR_PTR(ret); } static int i915_request_await_request(struct i915_request *to, struct i915_request *from) { int ret; GEM_BUG_ON(to == from); GEM_BUG_ON(to->timeline == from->timeline); if (i915_request_completed(from)) return 0; if (to->engine->schedule) { ret = i915_sched_node_add_dependency(to->i915, &to->sched, &from->sched); if (ret < 0) return ret; } if (to->engine == from->engine) { ret = i915_sw_fence_await_sw_fence_gfp(&to->submit, &from->submit, I915_FENCE_GFP); return ret < 0 ? ret : 0; } if (to->engine->semaphore.sync_to) { u32 seqno; GEM_BUG_ON(!from->engine->semaphore.signal); seqno = i915_request_global_seqno(from); if (!seqno) goto await_dma_fence; if (seqno <= to->timeline->global_sync[from->engine->id]) return 0; trace_i915_gem_ring_sync_to(to, from); ret = to->engine->semaphore.sync_to(to, from); if (ret) return ret; to->timeline->global_sync[from->engine->id] = seqno; return 0; } await_dma_fence: ret = i915_sw_fence_await_dma_fence(&to->submit, &from->fence, 0, I915_FENCE_GFP); return ret < 0 ? ret : 0; } int i915_request_await_dma_fence(struct i915_request *rq, struct dma_fence *fence) { struct dma_fence **child = &fence; unsigned int nchild = 1; int ret; /* * Note that if the fence-array was created in signal-on-any mode, * we should *not* decompose it into its individual fences. However, * we don't currently store which mode the fence-array is operating * in. Fortunately, the only user of signal-on-any is private to * amdgpu and we should not see any incoming fence-array from * sync-file being in signal-on-any mode. */ if (dma_fence_is_array(fence)) { struct dma_fence_array *array = to_dma_fence_array(fence); child = array->fences; nchild = array->num_fences; GEM_BUG_ON(!nchild); } do { fence = *child++; if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) continue; /* * Requests on the same timeline are explicitly ordered, along * with their dependencies, by i915_request_add() which ensures * that requests are submitted in-order through each ring. */ if (fence->context == rq->fence.context) continue; /* Squash repeated waits to the same timelines */ if (fence->context != rq->i915->mm.unordered_timeline && intel_timeline_sync_is_later(rq->timeline, fence)) continue; if (dma_fence_is_i915(fence)) ret = i915_request_await_request(rq, to_request(fence)); else ret = i915_sw_fence_await_dma_fence(&rq->submit, fence, I915_FENCE_TIMEOUT, I915_FENCE_GFP); if (ret < 0) return ret; /* Record the latest fence used against each timeline */ if (fence->context != rq->i915->mm.unordered_timeline) intel_timeline_sync_set(rq->timeline, fence); } while (--nchild); return 0; } /** * i915_request_await_object - set this request to (async) wait upon a bo * @to: request we are wishing to use * @obj: object which may be in use on another ring. * @write: whether the wait is on behalf of a writer * * This code is meant to abstract object synchronization with the GPU. * Conceptually we serialise writes between engines inside the GPU. * We only allow one engine to write into a buffer at any time, but * multiple readers. To ensure each has a coherent view of memory, we must: * * - If there is an outstanding write request to the object, the new * request must wait for it to complete (either CPU or in hw, requests * on the same ring will be naturally ordered). * * - If we are a write request (pending_write_domain is set), the new * request must wait for outstanding read requests to complete. * * Returns 0 if successful, else propagates up the lower layer error. */ int i915_request_await_object(struct i915_request *to, struct drm_i915_gem_object *obj, bool write) { struct dma_fence *excl; int ret = 0; if (write) { struct dma_fence **shared; unsigned int count, i; ret = reservation_object_get_fences_rcu(obj->resv, &excl, &count, &shared); if (ret) return ret; for (i = 0; i < count; i++) { ret = i915_request_await_dma_fence(to, shared[i]); if (ret) break; dma_fence_put(shared[i]); } for (; i < count; i++) dma_fence_put(shared[i]); kfree(shared); } else { excl = reservation_object_get_excl_rcu(obj->resv); } if (excl) { if (ret == 0) ret = i915_request_await_dma_fence(to, excl); dma_fence_put(excl); } return ret; } /* * NB: This function is not allowed to fail. Doing so would mean the the * request is not being tracked for completion but the work itself is * going to happen on the hardware. This would be a Bad Thing(tm). */ void __i915_request_add(struct i915_request *request, bool flush_caches) { struct intel_engine_cs *engine = request->engine; struct intel_ring *ring = request->ring; struct intel_timeline *timeline = request->timeline; struct i915_request *prev; u32 *cs; int err; GEM_TRACE("%s fence %llx:%d\n", engine->name, request->fence.context, request->fence.seqno); lockdep_assert_held(&request->i915->drm.struct_mutex); trace_i915_request_add(request); /* * Make sure that no request gazumped us - if it was allocated after * our i915_request_alloc() and called __i915_request_add() before * us, the timeline will hold its seqno which is later than ours. */ GEM_BUG_ON(timeline->seqno != request->fence.seqno); /* * To ensure that this call will not fail, space for its emissions * should already have been reserved in the ring buffer. Let the ring * know that it is time to use that space up. */ request->reserved_space = 0; /* * Emit any outstanding flushes - execbuf can fail to emit the flush * after having emitted the batchbuffer command. Hence we need to fix * things up similar to emitting the lazy request. The difference here * is that the flush _must_ happen before the next request, no matter * what. */ if (flush_caches) { err = engine->emit_flush(request, EMIT_FLUSH); /* Not allowed to fail! */ WARN(err, "engine->emit_flush() failed: %d!\n", err); } /* * Record the position of the start of the breadcrumb so that * should we detect the updated seqno part-way through the * GPU processing the request, we never over-estimate the * position of the ring's HEAD. */ cs = intel_ring_begin(request, engine->emit_breadcrumb_sz); GEM_BUG_ON(IS_ERR(cs)); request->postfix = intel_ring_offset(request, cs); /* * Seal the request and mark it as pending execution. Note that * we may inspect this state, without holding any locks, during * hangcheck. Hence we apply the barrier to ensure that we do not * see a more recent value in the hws than we are tracking. */ prev = i915_gem_active_raw(&timeline->last_request, &request->i915->drm.struct_mutex); if (prev && !i915_request_completed(prev)) { i915_sw_fence_await_sw_fence(&request->submit, &prev->submit, &request->submitq); if (engine->schedule) __i915_sched_node_add_dependency(&request->sched, &prev->sched, &request->dep, 0); } spin_lock_irq(&timeline->lock); list_add_tail(&request->link, &timeline->requests); spin_unlock_irq(&timeline->lock); GEM_BUG_ON(timeline->seqno != request->fence.seqno); i915_gem_active_set(&timeline->last_request, request); list_add_tail(&request->ring_link, &ring->request_list); request->emitted_jiffies = jiffies; /* * Let the backend know a new request has arrived that may need * to adjust the existing execution schedule due to a high priority * request - i.e. we may want to preempt the current request in order * to run a high priority dependency chain *before* we can execute this * request. * * This is called before the request is ready to run so that we can * decide whether to preempt the entire chain so that it is ready to * run at the earliest possible convenience. */ rcu_read_lock(); if (engine->schedule) engine->schedule(request, &request->ctx->sched); rcu_read_unlock(); local_bh_disable(); i915_sw_fence_commit(&request->submit); local_bh_enable(); /* Kick the execlists tasklet if just scheduled */ /* * In typical scenarios, we do not expect the previous request on * the timeline to be still tracked by timeline->last_request if it * has been completed. If the completed request is still here, that * implies that request retirement is a long way behind submission, * suggesting that we haven't been retiring frequently enough from * the combination of retire-before-alloc, waiters and the background * retirement worker. So if the last request on this timeline was * already completed, do a catch up pass, flushing the retirement queue * up to this client. Since we have now moved the heaviest operations * during retirement onto secondary workers, such as freeing objects * or contexts, retiring a bunch of requests is mostly list management * (and cache misses), and so we should not be overly penalizing this * client by performing excess work, though we may still performing * work on behalf of others -- but instead we should benefit from * improved resource management. (Well, that's the theory at least.) */ if (prev && i915_request_completed(prev)) i915_request_retire_upto(prev); } static unsigned long local_clock_us(unsigned int *cpu) { unsigned long t; /* * Cheaply and approximately convert from nanoseconds to microseconds. * The result and subsequent calculations are also defined in the same * approximate microseconds units. The principal source of timing * error here is from the simple truncation. * * Note that local_clock() is only defined wrt to the current CPU; * the comparisons are no longer valid if we switch CPUs. Instead of * blocking preemption for the entire busywait, we can detect the CPU * switch and use that as indicator of system load and a reason to * stop busywaiting, see busywait_stop(). */ *cpu = get_cpu(); t = local_clock() >> 10; put_cpu(); return t; } static bool busywait_stop(unsigned long timeout, unsigned int cpu) { unsigned int this_cpu; if (time_after(local_clock_us(&this_cpu), timeout)) return true; return this_cpu != cpu; } static bool __i915_spin_request(const struct i915_request *rq, u32 seqno, int state, unsigned long timeout_us) { struct intel_engine_cs *engine = rq->engine; unsigned int irq, cpu; GEM_BUG_ON(!seqno); /* * Only wait for the request if we know it is likely to complete. * * We don't track the timestamps around requests, nor the average * request length, so we do not have a good indicator that this * request will complete within the timeout. What we do know is the * order in which requests are executed by the engine and so we can * tell if the request has started. If the request hasn't started yet, * it is a fair assumption that it will not complete within our * relatively short timeout. */ if (!i915_seqno_passed(intel_engine_get_seqno(engine), seqno - 1)) return false; /* * When waiting for high frequency requests, e.g. during synchronous * rendering split between the CPU and GPU, the finite amount of time * required to set up the irq and wait upon it limits the response * rate. By busywaiting on the request completion for a short while we * can service the high frequency waits as quick as possible. However, * if it is a slow request, we want to sleep as quickly as possible. * The tradeoff between waiting and sleeping is roughly the time it * takes to sleep on a request, on the order of a microsecond. */ irq = atomic_read(&engine->irq_count); timeout_us += local_clock_us(&cpu); do { if (i915_seqno_passed(intel_engine_get_seqno(engine), seqno)) return seqno == i915_request_global_seqno(rq); /* * Seqno are meant to be ordered *before* the interrupt. If * we see an interrupt without a corresponding seqno advance, * assume we won't see one in the near future but require * the engine->seqno_barrier() to fixup coherency. */ if (atomic_read(&engine->irq_count) != irq) break; if (signal_pending_state(state, current)) break; if (busywait_stop(timeout_us, cpu)) break; cpu_relax(); } while (!need_resched()); return false; } static bool __i915_wait_request_check_and_reset(struct i915_request *request) { struct i915_gpu_error *error = &request->i915->gpu_error; if (likely(!i915_reset_handoff(error))) return false; __set_current_state(TASK_RUNNING); i915_reset(request->i915, error->stalled_mask, error->reason); return true; } /** * i915_request_wait - wait until execution of request has finished * @rq: the request to wait upon * @flags: how to wait * @timeout: how long to wait in jiffies * * i915_request_wait() waits for the request to be completed, for a * maximum of @timeout jiffies (with MAX_SCHEDULE_TIMEOUT implying an * unbounded wait). * * If the caller holds the struct_mutex, the caller must pass I915_WAIT_LOCKED * in via the flags, and vice versa if the struct_mutex is not held, the caller * must not specify that the wait is locked. * * Returns the remaining time (in jiffies) if the request completed, which may * be zero or -ETIME if the request is unfinished after the timeout expires. * May return -EINTR is called with I915_WAIT_INTERRUPTIBLE and a signal is * pending before the request completes. */ long i915_request_wait(struct i915_request *rq, unsigned int flags, long timeout) { const int state = flags & I915_WAIT_INTERRUPTIBLE ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE; wait_queue_head_t *errq = &rq->i915->gpu_error.wait_queue; DEFINE_WAIT_FUNC(reset, default_wake_function); DEFINE_WAIT_FUNC(exec, default_wake_function); struct intel_wait wait; might_sleep(); #if IS_ENABLED(CONFIG_LOCKDEP) GEM_BUG_ON(debug_locks && !!lockdep_is_held(&rq->i915->drm.struct_mutex) != !!(flags & I915_WAIT_LOCKED)); #endif GEM_BUG_ON(timeout < 0); if (i915_request_completed(rq)) return timeout; if (!timeout) return -ETIME; trace_i915_request_wait_begin(rq, flags); add_wait_queue(&rq->execute, &exec); if (flags & I915_WAIT_LOCKED) add_wait_queue(errq, &reset); intel_wait_init(&wait, rq); restart: do { set_current_state(state); if (intel_wait_update_request(&wait, rq)) break; if (flags & I915_WAIT_LOCKED && __i915_wait_request_check_and_reset(rq)) continue; if (signal_pending_state(state, current)) { timeout = -ERESTARTSYS; goto complete; } if (!timeout) { timeout = -ETIME; goto complete; } timeout = io_schedule_timeout(timeout); } while (1); GEM_BUG_ON(!intel_wait_has_seqno(&wait)); GEM_BUG_ON(!i915_sw_fence_signaled(&rq->submit)); /* Optimistic short spin before touching IRQs */ if (__i915_spin_request(rq, wait.seqno, state, 5)) goto complete; set_current_state(state); if (intel_engine_add_wait(rq->engine, &wait)) /* * In order to check that we haven't missed the interrupt * as we enabled it, we need to kick ourselves to do a * coherent check on the seqno before we sleep. */ goto wakeup; if (flags & I915_WAIT_LOCKED) __i915_wait_request_check_and_reset(rq); for (;;) { if (signal_pending_state(state, current)) { timeout = -ERESTARTSYS; break; } if (!timeout) { timeout = -ETIME; break; } timeout = io_schedule_timeout(timeout); if (intel_wait_complete(&wait) && intel_wait_check_request(&wait, rq)) break; set_current_state(state); wakeup: /* * Carefully check if the request is complete, giving time * for the seqno to be visible following the interrupt. * We also have to check in case we are kicked by the GPU * reset in order to drop the struct_mutex. */ if (__i915_request_irq_complete(rq)) break; /* * If the GPU is hung, and we hold the lock, reset the GPU * and then check for completion. On a full reset, the engine's * HW seqno will be advanced passed us and we are complete. * If we do a partial reset, we have to wait for the GPU to * resume and update the breadcrumb. * * If we don't hold the mutex, we can just wait for the worker * to come along and update the breadcrumb (either directly * itself, or indirectly by recovering the GPU). */ if (flags & I915_WAIT_LOCKED && __i915_wait_request_check_and_reset(rq)) continue; /* Only spin if we know the GPU is processing this request */ if (__i915_spin_request(rq, wait.seqno, state, 2)) break; if (!intel_wait_check_request(&wait, rq)) { intel_engine_remove_wait(rq->engine, &wait); goto restart; } } intel_engine_remove_wait(rq->engine, &wait); complete: __set_current_state(TASK_RUNNING); if (flags & I915_WAIT_LOCKED) remove_wait_queue(errq, &reset); remove_wait_queue(&rq->execute, &exec); trace_i915_request_wait_end(rq); return timeout; } static void engine_retire_requests(struct intel_engine_cs *engine) { struct i915_request *request, *next; u32 seqno = intel_engine_get_seqno(engine); LIST_HEAD(retire); spin_lock_irq(&engine->timeline->lock); list_for_each_entry_safe(request, next, &engine->timeline->requests, link) { if (!i915_seqno_passed(seqno, request->global_seqno)) break; list_move_tail(&request->link, &retire); } spin_unlock_irq(&engine->timeline->lock); list_for_each_entry_safe(request, next, &retire, link) i915_request_retire(request); } void i915_retire_requests(struct drm_i915_private *i915) { struct intel_engine_cs *engine; enum intel_engine_id id; lockdep_assert_held(&i915->drm.struct_mutex); if (!i915->gt.active_requests) return; for_each_engine(engine, i915, id) engine_retire_requests(engine); } #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST) #include "selftests/mock_request.c" #include "selftests/i915_request.c" #endif