diff options
Diffstat (limited to 'drivers/gpu/drm/i915/i915_gem_request.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_gem_request.c | 767 |
1 files changed, 767 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c new file mode 100644 index 0000000..6a16616 --- /dev/null +++ b/drivers/gpu/drm/i915/i915_gem_request.c @@ -0,0 +1,767 @@ +/* + * 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 <linux/prefetch.h> + +#include "i915_drv.h" + +static const char *i915_fence_get_driver_name(struct fence *fence) +{ + return "i915"; +} + +static const char *i915_fence_get_timeline_name(struct fence *fence) +{ + /* Timelines are bound by eviction to a VM. However, since + * we only have a global seqno at the moment, we only have + * a single timeline. Note that each timeline will have + * multiple execution contexts (fence contexts) as we allow + * engines within a single timeline to execute in parallel. + */ + return "global"; +} + +static bool i915_fence_signaled(struct fence *fence) +{ + return i915_gem_request_completed(to_request(fence)); +} + +static bool i915_fence_enable_signaling(struct fence *fence) +{ + if (i915_fence_signaled(fence)) + return false; + + intel_engine_enable_signaling(to_request(fence)); + return true; +} + +static signed long i915_fence_wait(struct fence *fence, + bool interruptible, + signed long timeout_jiffies) +{ + s64 timeout_ns, *timeout; + int ret; + + if (timeout_jiffies != MAX_SCHEDULE_TIMEOUT) { + timeout_ns = jiffies_to_nsecs(timeout_jiffies); + timeout = &timeout_ns; + } else { + timeout = NULL; + } + + ret = i915_wait_request(to_request(fence), + interruptible, timeout, + NO_WAITBOOST); + if (ret == -ETIME) + return 0; + + if (ret < 0) + return ret; + + if (timeout_jiffies != MAX_SCHEDULE_TIMEOUT) + timeout_jiffies = nsecs_to_jiffies(timeout_ns); + + return timeout_jiffies; +} + +static void i915_fence_value_str(struct fence *fence, char *str, int size) +{ + snprintf(str, size, "%u", fence->seqno); +} + +static void i915_fence_timeline_value_str(struct fence *fence, char *str, + int size) +{ + snprintf(str, size, "%u", + intel_engine_get_seqno(to_request(fence)->engine)); +} + +static void i915_fence_release(struct fence *fence) +{ + struct drm_i915_gem_request *req = to_request(fence); + + kmem_cache_free(req->i915->requests, req); +} + +const struct 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, + .fence_value_str = i915_fence_value_str, + .timeline_value_str = i915_fence_timeline_value_str, +}; + +int i915_gem_request_add_to_client(struct drm_i915_gem_request *req, + struct drm_file *file) +{ + struct drm_i915_private *dev_private; + struct drm_i915_file_private *file_priv; + + WARN_ON(!req || !file || req->file_priv); + + if (!req || !file) + return -EINVAL; + + if (req->file_priv) + return -EINVAL; + + dev_private = req->i915; + file_priv = file->driver_priv; + + spin_lock(&file_priv->mm.lock); + req->file_priv = file_priv; + list_add_tail(&req->client_list, &file_priv->mm.request_list); + spin_unlock(&file_priv->mm.lock); + + req->pid = get_pid(task_pid(current)); + + return 0; +} + +static inline void +i915_gem_request_remove_from_client(struct drm_i915_gem_request *request) +{ + struct drm_i915_file_private *file_priv = request->file_priv; + + if (!file_priv) + return; + + spin_lock(&file_priv->mm.lock); + list_del(&request->client_list); + request->file_priv = NULL; + spin_unlock(&file_priv->mm.lock); + + put_pid(request->pid); + request->pid = NULL; +} + +void i915_gem_retire_noop(struct i915_gem_active *active, + struct drm_i915_gem_request *request) +{ + /* Space left intentionally blank */ +} + +static void i915_gem_request_retire(struct drm_i915_gem_request *request) +{ + struct i915_gem_active *active, *next; + + trace_i915_gem_request_retire(request); + list_del(&request->link); + + /* 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. + */ + list_del(&request->ring_link); + request->ring->last_retired_head = request->postfix; + + /* 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_gem_request_remove_from_client(request); + + if (request->previous_context) { + if (i915.enable_execlists) + intel_lr_context_unpin(request->previous_context, + request->engine); + } + + i915_gem_context_put(request->ctx); + i915_gem_request_put(request); +} + +void i915_gem_request_retire_upto(struct drm_i915_gem_request *req) +{ + struct intel_engine_cs *engine = req->engine; + struct drm_i915_gem_request *tmp; + + lockdep_assert_held(&req->i915->drm.struct_mutex); + GEM_BUG_ON(list_empty(&req->link)); + + do { + tmp = list_first_entry(&engine->request_list, + typeof(*tmp), link); + + i915_gem_request_retire(tmp); + } while (tmp != req); +} + +static int i915_gem_check_wedge(unsigned int reset_counter, bool interruptible) +{ + if (__i915_terminally_wedged(reset_counter)) + return -EIO; + + if (__i915_reset_in_progress(reset_counter)) { + /* Non-interruptible callers can't handle -EAGAIN, hence return + * -EIO unconditionally for these. + */ + if (!interruptible) + return -EIO; + + return -EAGAIN; + } + + return 0; +} + +static int i915_gem_init_seqno(struct drm_i915_private *dev_priv, u32 seqno) +{ + struct intel_engine_cs *engine; + int ret; + + /* Carefully retire all requests without writing to the rings */ + for_each_engine(engine, dev_priv) { + ret = intel_engine_idle(engine, true); + if (ret) + return ret; + } + i915_gem_retire_requests(dev_priv); + + /* If the seqno wraps around, we need to clear the breadcrumb rbtree */ + if (!i915_seqno_passed(seqno, dev_priv->next_seqno)) { + while (intel_kick_waiters(dev_priv) || + intel_kick_signalers(dev_priv)) + yield(); + } + + /* Finally reset hw state */ + for_each_engine(engine, dev_priv) + intel_engine_init_seqno(engine, seqno); + + return 0; +} + +int i915_gem_set_seqno(struct drm_device *dev, u32 seqno) +{ + struct drm_i915_private *dev_priv = to_i915(dev); + int ret; + + if (seqno == 0) + return -EINVAL; + + /* HWS page needs to be set less than what we + * will inject to ring + */ + ret = i915_gem_init_seqno(dev_priv, seqno - 1); + if (ret) + return ret; + + dev_priv->next_seqno = seqno; + return 0; +} + +static int i915_gem_get_seqno(struct drm_i915_private *dev_priv, u32 *seqno) +{ + /* reserve 0 for non-seqno */ + if (unlikely(dev_priv->next_seqno == 0)) { + int ret; + + ret = i915_gem_init_seqno(dev_priv, 0); + if (ret) + return ret; + + dev_priv->next_seqno = 1; + } + + *seqno = dev_priv->next_seqno++; + return 0; +} + +/** + * i915_gem_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. + * This can be NULL if the request is not directly related to + * any specific user context, in which case this function will + * choose an appropriate context to use. + * + * Returns a pointer to the allocated request if successful, + * or an error code if not. + */ +struct drm_i915_gem_request * +i915_gem_request_alloc(struct intel_engine_cs *engine, + struct i915_gem_context *ctx) +{ + struct drm_i915_private *dev_priv = engine->i915; + unsigned int reset_counter = i915_reset_counter(&dev_priv->gpu_error); + struct drm_i915_gem_request *req; + u32 seqno; + int ret; + + /* ABI: Before userspace accesses the GPU (e.g. execbuffer), report + * EIO if the GPU is already wedged, or EAGAIN to drop the struct_mutex + * and restart. + */ + ret = i915_gem_check_wedge(reset_counter, dev_priv->mm.interruptible); + if (ret) + return ERR_PTR(ret); + + /* Move the oldest request to the slab-cache (if not in use!) */ + req = list_first_entry_or_null(&engine->request_list, + typeof(*req), link); + if (req && i915_gem_request_completed(req)) + i915_gem_request_retire(req); + + req = kmem_cache_zalloc(dev_priv->requests, GFP_KERNEL); + if (!req) + return ERR_PTR(-ENOMEM); + + ret = i915_gem_get_seqno(dev_priv, &seqno); + if (ret) + goto err; + + spin_lock_init(&req->lock); + fence_init(&req->fence, + &i915_fence_ops, + &req->lock, + engine->fence_context, + seqno); + + INIT_LIST_HEAD(&req->active_list); + req->i915 = dev_priv; + req->engine = engine; + req->ctx = i915_gem_context_get(ctx); + + /* + * Reserve space in the ring buffer for all the commands required to + * eventually emit this request. This is to guarantee that the + * i915_add_request() 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. + */ + req->reserved_space = MIN_SPACE_FOR_ADD_REQUEST; + + if (i915.enable_execlists) + ret = intel_logical_ring_alloc_request_extras(req); + else + ret = intel_ring_alloc_request_extras(req); + if (ret) + goto err_ctx; + + return req; + +err_ctx: + i915_gem_context_put(ctx); +err: + kmem_cache_free(dev_priv->requests, req); + return ERR_PTR(ret); +} + +static void i915_gem_mark_busy(const struct intel_engine_cs *engine) +{ + struct drm_i915_private *dev_priv = engine->i915; + + dev_priv->gt.active_engines |= intel_engine_flag(engine); + if (dev_priv->gt.awake) + return; + + intel_runtime_pm_get_noresume(dev_priv); + dev_priv->gt.awake = true; + + intel_enable_gt_powersave(dev_priv); + i915_update_gfx_val(dev_priv); + if (INTEL_GEN(dev_priv) >= 6) + gen6_rps_busy(dev_priv); + + queue_delayed_work(dev_priv->wq, + &dev_priv->gt.retire_work, + round_jiffies_up_relative(HZ)); +} + +/* + * 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_add_request(struct drm_i915_gem_request *request, + struct drm_i915_gem_object *obj, + bool flush_caches) +{ + struct intel_engine_cs *engine; + struct intel_ring *ring; + u32 request_start; + u32 reserved_tail; + int ret; + + if (WARN_ON(!request)) + return; + + engine = request->engine; + ring = request->ring; + + /* + * 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_start = ring->tail; + reserved_tail = request->reserved_space; + 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) { + ret = engine->emit_flush(request, EMIT_FLUSH); + + /* Not allowed to fail! */ + WARN(ret, "engine->emit_flush() failed: %d!\n", ret); + } + + trace_i915_gem_request_add(request); + + request->head = request_start; + + /* Whilst this request exists, batch_obj will be on the + * active_list, and so will hold the active reference. Only when this + * request is retired will the the batch_obj be moved onto the + * inactive_list and lose its active reference. Hence we do not need + * to explicitly hold another reference here. + */ + request->batch_obj = obj; + + /* 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. + */ + request->emitted_jiffies = jiffies; + request->previous_seqno = engine->last_submitted_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); + + /* 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. + */ + request->postfix = ring->tail; + + /* Not allowed to fail! */ + ret = engine->emit_request(request); + WARN(ret, "(%s)->emit_request failed: %d!\n", engine->name, ret); + + /* Sanity check that the reserved size was large enough. */ + ret = ring->tail - request_start; + if (ret < 0) + ret += ring->size; + WARN_ONCE(ret > reserved_tail, + "Not enough space reserved (%d bytes) " + "for adding the request (%d bytes)\n", + reserved_tail, ret); + + i915_gem_mark_busy(engine); + engine->submit_request(request); +} + +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; +} + +bool __i915_spin_request(const struct drm_i915_gem_request *req, + int state, unsigned long timeout_us) +{ + unsigned int cpu; + + /* 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. + */ + + timeout_us += local_clock_us(&cpu); + do { + if (i915_gem_request_completed(req)) + return true; + + if (signal_pending_state(state, current)) + break; + + if (busywait_stop(timeout_us, cpu)) + break; + + cpu_relax_lowlatency(); + } while (!need_resched()); + + return false; +} + +/** + * i915_wait_request - wait until execution of request has finished + * @req: duh! + * @interruptible: do an interruptible wait (normally yes) + * @timeout: in - how long to wait (NULL forever); out - how much time remaining + * @rps: client to charge for RPS boosting + * + * Note: It is of utmost importance that the passed in seqno and reset_counter + * values have been read by the caller in an smp safe manner. Where read-side + * locks are involved, it is sufficient to read the reset_counter before + * unlocking the lock that protects the seqno. For lockless tricks, the + * reset_counter _must_ be read before, and an appropriate smp_rmb must be + * inserted. + * + * Returns 0 if the request was found within the alloted time. Else returns the + * errno with remaining time filled in timeout argument. + */ +int i915_wait_request(struct drm_i915_gem_request *req, + bool interruptible, + s64 *timeout, + struct intel_rps_client *rps) +{ + int state = interruptible ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE; + DEFINE_WAIT(reset); + struct intel_wait wait; + unsigned long timeout_remain; + int ret = 0; + + might_sleep(); + + if (i915_gem_request_completed(req)) + return 0; + + timeout_remain = MAX_SCHEDULE_TIMEOUT; + if (timeout) { + if (WARN_ON(*timeout < 0)) + return -EINVAL; + + if (*timeout == 0) + return -ETIME; + + /* Record current time in case interrupted, or wedged */ + timeout_remain = nsecs_to_jiffies_timeout(*timeout); + *timeout += ktime_get_raw_ns(); + } + + trace_i915_gem_request_wait_begin(req); + + /* This client is about to stall waiting for the GPU. In many cases + * this is undesirable and limits the throughput of the system, as + * many clients cannot continue processing user input/output whilst + * blocked. RPS autotuning may take tens of milliseconds to respond + * to the GPU load and thus incurs additional latency for the client. + * We can circumvent that by promoting the GPU frequency to maximum + * before we wait. This makes the GPU throttle up much more quickly + * (good for benchmarks and user experience, e.g. window animations), + * but at a cost of spending more power processing the workload + * (bad for battery). Not all clients even want their results + * immediately and for them we should just let the GPU select its own + * frequency to maximise efficiency. To prevent a single client from + * forcing the clocks too high for the whole system, we only allow + * each client to waitboost once in a busy period. + */ + if (IS_RPS_CLIENT(rps) && INTEL_GEN(req->i915) >= 6) + gen6_rps_boost(req->i915, rps, req->emitted_jiffies); + + /* Optimistic short spin before touching IRQs */ + if (i915_spin_request(req, state, 5)) + goto complete; + + set_current_state(state); + add_wait_queue(&req->i915->gpu_error.wait_queue, &reset); + + intel_wait_init(&wait, req->fence.seqno); + if (intel_engine_add_wait(req->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; + + for (;;) { + if (signal_pending_state(state, current)) { + ret = -ERESTARTSYS; + break; + } + + timeout_remain = io_schedule_timeout(timeout_remain); + if (timeout_remain == 0) { + ret = -ETIME; + break; + } + + if (intel_wait_complete(&wait)) + 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(req)) + break; + + /* Only spin if we know the GPU is processing this request */ + if (i915_spin_request(req, state, 2)) + break; + } + remove_wait_queue(&req->i915->gpu_error.wait_queue, &reset); + + intel_engine_remove_wait(req->engine, &wait); + __set_current_state(TASK_RUNNING); +complete: + trace_i915_gem_request_wait_end(req); + + if (timeout) { + *timeout -= ktime_get_raw_ns(); + if (*timeout < 0) + *timeout = 0; + + /* + * Apparently ktime isn't accurate enough and occasionally has a + * bit of mismatch in the jiffies<->nsecs<->ktime loop. So patch + * things up to make the test happy. We allow up to 1 jiffy. + * + * This is a regrssion from the timespec->ktime conversion. + */ + if (ret == -ETIME && *timeout < jiffies_to_usecs(1)*1000) + *timeout = 0; + } + + if (IS_RPS_USER(rps) && + req->fence.seqno == req->engine->last_submitted_seqno) { + /* The GPU is now idle and this client has stalled. + * Since no other client has submitted a request in the + * meantime, assume that this client is the only one + * supplying work to the GPU but is unable to keep that + * work supplied because it is waiting. Since the GPU is + * then never kept fully busy, RPS autoclocking will + * keep the clocks relatively low, causing further delays. + * Compensate by giving the synchronous client credit for + * a waitboost next time. + */ + spin_lock(&req->i915->rps.client_lock); + list_del_init(&rps->link); + spin_unlock(&req->i915->rps.client_lock); + } + + return ret; +} + +static void engine_retire_requests(struct intel_engine_cs *engine) +{ + struct drm_i915_gem_request *request, *next; + + list_for_each_entry_safe(request, next, &engine->request_list, link) { + if (!i915_gem_request_completed(request)) + break; + + i915_gem_request_retire(request); + } +} + +void i915_gem_retire_requests(struct drm_i915_private *dev_priv) +{ + struct intel_engine_cs *engine; + + lockdep_assert_held(&dev_priv->drm.struct_mutex); + + if (dev_priv->gt.active_engines == 0) + return; + + GEM_BUG_ON(!dev_priv->gt.awake); + + for_each_engine(engine, dev_priv) { + engine_retire_requests(engine); + if (!intel_engine_is_active(engine)) + dev_priv->gt.active_engines &= ~intel_engine_flag(engine); + } + + if (dev_priv->gt.active_engines == 0) + queue_delayed_work(dev_priv->wq, + &dev_priv->gt.idle_work, + msecs_to_jiffies(100)); +} |