2106 lines
60 KiB
C
2106 lines
60 KiB
C
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/*
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* Copyright © 2008-2015 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*
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*/
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#include <linux/dma-fence-array.h>
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#include <linux/dma-fence-chain.h>
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#include <linux/irq_work.h>
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#include <linux/prefetch.h>
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#include <linux/sched.h>
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#include <linux/sched/clock.h>
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#include <linux/sched/signal.h>
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#include "gem/i915_gem_context.h"
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#include "gt/intel_breadcrumbs.h"
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#include "gt/intel_context.h"
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#include "gt/intel_engine.h"
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#include "gt/intel_engine_heartbeat.h"
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#include "gt/intel_gpu_commands.h"
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#include "gt/intel_reset.h"
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#include "gt/intel_ring.h"
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#include "gt/intel_rps.h"
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#include "i915_active.h"
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#include "i915_drv.h"
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#include "i915_trace.h"
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#include "intel_pm.h"
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struct execute_cb {
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struct irq_work work;
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struct i915_sw_fence *fence;
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struct i915_request *signal;
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};
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static struct kmem_cache *slab_requests;
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static struct kmem_cache *slab_execute_cbs;
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static const char *i915_fence_get_driver_name(struct dma_fence *fence)
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{
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return dev_name(to_request(fence)->engine->i915->drm.dev);
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}
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static const char *i915_fence_get_timeline_name(struct dma_fence *fence)
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{
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const struct i915_gem_context *ctx;
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/*
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* The timeline struct (as part of the ppgtt underneath a context)
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* may be freed when the request is no longer in use by the GPU.
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* We could extend the life of a context to beyond that of all
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* fences, possibly keeping the hw resource around indefinitely,
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* or we just give them a false name. Since
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* dma_fence_ops.get_timeline_name is a debug feature, the occasional
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* lie seems justifiable.
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*/
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if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
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return "signaled";
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ctx = i915_request_gem_context(to_request(fence));
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if (!ctx)
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return "[" DRIVER_NAME "]";
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return ctx->name;
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}
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static bool i915_fence_signaled(struct dma_fence *fence)
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{
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return i915_request_completed(to_request(fence));
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}
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static bool i915_fence_enable_signaling(struct dma_fence *fence)
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{
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return i915_request_enable_breadcrumb(to_request(fence));
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}
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static signed long i915_fence_wait(struct dma_fence *fence,
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bool interruptible,
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signed long timeout)
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{
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return i915_request_wait(to_request(fence),
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interruptible | I915_WAIT_PRIORITY,
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timeout);
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}
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struct kmem_cache *i915_request_slab_cache(void)
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{
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return slab_requests;
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}
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static void i915_fence_release(struct dma_fence *fence)
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{
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struct i915_request *rq = to_request(fence);
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GEM_BUG_ON(rq->guc_prio != GUC_PRIO_INIT &&
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rq->guc_prio != GUC_PRIO_FINI);
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/*
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* The request is put onto a RCU freelist (i.e. the address
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* is immediately reused), mark the fences as being freed now.
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* Otherwise the debugobjects for the fences are only marked as
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* freed when the slab cache itself is freed, and so we would get
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* caught trying to reuse dead objects.
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*/
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i915_sw_fence_fini(&rq->submit);
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i915_sw_fence_fini(&rq->semaphore);
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/*
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* Keep one request on each engine for reserved use under mempressure,
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* do not use with virtual engines as this really is only needed for
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* kernel contexts.
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*/
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if (!intel_engine_is_virtual(rq->engine) &&
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!cmpxchg(&rq->engine->request_pool, NULL, rq)) {
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intel_context_put(rq->context);
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return;
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}
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intel_context_put(rq->context);
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kmem_cache_free(slab_requests, rq);
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}
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const struct dma_fence_ops i915_fence_ops = {
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.get_driver_name = i915_fence_get_driver_name,
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.get_timeline_name = i915_fence_get_timeline_name,
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.enable_signaling = i915_fence_enable_signaling,
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.signaled = i915_fence_signaled,
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.wait = i915_fence_wait,
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.release = i915_fence_release,
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};
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static void irq_execute_cb(struct irq_work *wrk)
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{
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struct execute_cb *cb = container_of(wrk, typeof(*cb), work);
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i915_sw_fence_complete(cb->fence);
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kmem_cache_free(slab_execute_cbs, cb);
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}
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static __always_inline void
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__notify_execute_cb(struct i915_request *rq, bool (*fn)(struct irq_work *wrk))
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{
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struct execute_cb *cb, *cn;
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if (llist_empty(&rq->execute_cb))
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return;
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llist_for_each_entry_safe(cb, cn,
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llist_del_all(&rq->execute_cb),
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work.node.llist)
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fn(&cb->work);
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}
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static void __notify_execute_cb_irq(struct i915_request *rq)
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{
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__notify_execute_cb(rq, irq_work_queue);
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}
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static bool irq_work_imm(struct irq_work *wrk)
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{
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wrk->func(wrk);
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return false;
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}
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void i915_request_notify_execute_cb_imm(struct i915_request *rq)
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{
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__notify_execute_cb(rq, irq_work_imm);
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}
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static void free_capture_list(struct i915_request *request)
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{
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struct i915_capture_list *capture;
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capture = fetch_and_zero(&request->capture_list);
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while (capture) {
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struct i915_capture_list *next = capture->next;
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kfree(capture);
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capture = next;
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}
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}
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static void __i915_request_fill(struct i915_request *rq, u8 val)
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{
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void *vaddr = rq->ring->vaddr;
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u32 head;
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head = rq->infix;
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if (rq->postfix < head) {
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memset(vaddr + head, val, rq->ring->size - head);
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head = 0;
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}
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memset(vaddr + head, val, rq->postfix - head);
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}
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/**
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* i915_request_active_engine
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* @rq: request to inspect
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* @active: pointer in which to return the active engine
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*
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* Fills the currently active engine to the @active pointer if the request
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* is active and still not completed.
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*
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* Returns true if request was active or false otherwise.
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*/
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bool
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i915_request_active_engine(struct i915_request *rq,
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struct intel_engine_cs **active)
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{
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struct intel_engine_cs *engine, *locked;
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bool ret = false;
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/*
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* Serialise with __i915_request_submit() so that it sees
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* is-banned?, or we know the request is already inflight.
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*
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* Note that rq->engine is unstable, and so we double
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* check that we have acquired the lock on the final engine.
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*/
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locked = READ_ONCE(rq->engine);
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spin_lock_irq(&locked->sched_engine->lock);
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while (unlikely(locked != (engine = READ_ONCE(rq->engine)))) {
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spin_unlock(&locked->sched_engine->lock);
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locked = engine;
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spin_lock(&locked->sched_engine->lock);
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}
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if (i915_request_is_active(rq)) {
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if (!__i915_request_is_complete(rq))
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*active = locked;
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ret = true;
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}
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spin_unlock_irq(&locked->sched_engine->lock);
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return ret;
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}
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static void __rq_init_watchdog(struct i915_request *rq)
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{
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rq->watchdog.timer.function = NULL;
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}
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static enum hrtimer_restart __rq_watchdog_expired(struct hrtimer *hrtimer)
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{
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struct i915_request *rq =
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container_of(hrtimer, struct i915_request, watchdog.timer);
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struct intel_gt *gt = rq->engine->gt;
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if (!i915_request_completed(rq)) {
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if (llist_add(&rq->watchdog.link, >->watchdog.list))
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schedule_work(>->watchdog.work);
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} else {
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i915_request_put(rq);
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}
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return HRTIMER_NORESTART;
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}
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static void __rq_arm_watchdog(struct i915_request *rq)
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{
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struct i915_request_watchdog *wdg = &rq->watchdog;
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struct intel_context *ce = rq->context;
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if (!ce->watchdog.timeout_us)
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return;
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i915_request_get(rq);
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hrtimer_init(&wdg->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
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wdg->timer.function = __rq_watchdog_expired;
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hrtimer_start_range_ns(&wdg->timer,
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ns_to_ktime(ce->watchdog.timeout_us *
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NSEC_PER_USEC),
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NSEC_PER_MSEC,
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HRTIMER_MODE_REL);
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}
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static void __rq_cancel_watchdog(struct i915_request *rq)
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{
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struct i915_request_watchdog *wdg = &rq->watchdog;
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if (wdg->timer.function && hrtimer_try_to_cancel(&wdg->timer) > 0)
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i915_request_put(rq);
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}
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bool i915_request_retire(struct i915_request *rq)
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{
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if (!__i915_request_is_complete(rq))
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return false;
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RQ_TRACE(rq, "\n");
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GEM_BUG_ON(!i915_sw_fence_signaled(&rq->submit));
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trace_i915_request_retire(rq);
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i915_request_mark_complete(rq);
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__rq_cancel_watchdog(rq);
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/*
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* We know the GPU must have read the request to have
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* sent us the seqno + interrupt, so use the position
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* of tail of the request to update the last known position
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* of the GPU head.
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*
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* Note this requires that we are always called in request
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* completion order.
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*/
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GEM_BUG_ON(!list_is_first(&rq->link,
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&i915_request_timeline(rq)->requests));
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if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
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/* Poison before we release our space in the ring */
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__i915_request_fill(rq, POISON_FREE);
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rq->ring->head = rq->postfix;
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if (!i915_request_signaled(rq)) {
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spin_lock_irq(&rq->lock);
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dma_fence_signal_locked(&rq->fence);
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spin_unlock_irq(&rq->lock);
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}
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if (test_and_set_bit(I915_FENCE_FLAG_BOOST, &rq->fence.flags))
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atomic_dec(&rq->engine->gt->rps.num_waiters);
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/*
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* We only loosely track inflight requests across preemption,
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* and so we may find ourselves attempting to retire a _completed_
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* request that we have removed from the HW and put back on a run
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* queue.
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*
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* As we set I915_FENCE_FLAG_ACTIVE on the request, this should be
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* after removing the breadcrumb and signaling it, so that we do not
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* inadvertently attach the breadcrumb to a completed request.
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*/
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rq->engine->remove_active_request(rq);
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GEM_BUG_ON(!llist_empty(&rq->execute_cb));
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__list_del_entry(&rq->link); /* poison neither prev/next (RCU walks) */
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intel_context_exit(rq->context);
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intel_context_unpin(rq->context);
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free_capture_list(rq);
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i915_sched_node_fini(&rq->sched);
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i915_request_put(rq);
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return true;
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}
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|
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void i915_request_retire_upto(struct i915_request *rq)
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{
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struct intel_timeline * const tl = i915_request_timeline(rq);
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struct i915_request *tmp;
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RQ_TRACE(rq, "\n");
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GEM_BUG_ON(!__i915_request_is_complete(rq));
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do {
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tmp = list_first_entry(&tl->requests, typeof(*tmp), link);
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GEM_BUG_ON(!i915_request_completed(tmp));
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} while (i915_request_retire(tmp) && tmp != rq);
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}
|
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|
||
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static struct i915_request * const *
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__engine_active(struct intel_engine_cs *engine)
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{
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return READ_ONCE(engine->execlists.active);
|
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}
|
||
|
|
||
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static bool __request_in_flight(const struct i915_request *signal)
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||
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{
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struct i915_request * const *port, *rq;
|
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bool inflight = false;
|
||
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|
||
|
if (!i915_request_is_ready(signal))
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return false;
|
||
|
|
||
|
/*
|
||
|
* Even if we have unwound the request, it may still be on
|
||
|
* the GPU (preempt-to-busy). If that request is inside an
|
||
|
* unpreemptible critical section, it will not be removed. Some
|
||
|
* GPU functions may even be stuck waiting for the paired request
|
||
|
* (__await_execution) to be submitted and cannot be preempted
|
||
|
* until the bond is executing.
|
||
|
*
|
||
|
* As we know that there are always preemption points between
|
||
|
* requests, we know that only the currently executing request
|
||
|
* may be still active even though we have cleared the flag.
|
||
|
* However, we can't rely on our tracking of ELSP[0] to know
|
||
|
* which request is currently active and so maybe stuck, as
|
||
|
* the tracking maybe an event behind. Instead assume that
|
||
|
* if the context is still inflight, then it is still active
|
||
|
* even if the active flag has been cleared.
|
||
|
*
|
||
|
* To further complicate matters, if there a pending promotion, the HW
|
||
|
* may either perform a context switch to the second inflight execlists,
|
||
|
* or it may switch to the pending set of execlists. In the case of the
|
||
|
* latter, it may send the ACK and we process the event copying the
|
||
|
* pending[] over top of inflight[], _overwriting_ our *active. Since
|
||
|
* this implies the HW is arbitrating and not struck in *active, we do
|
||
|
* not worry about complete accuracy, but we do require no read/write
|
||
|
* tearing of the pointer [the read of the pointer must be valid, even
|
||
|
* as the array is being overwritten, for which we require the writes
|
||
|
* to avoid tearing.]
|
||
|
*
|
||
|
* Note that the read of *execlists->active may race with the promotion
|
||
|
* of execlists->pending[] to execlists->inflight[], overwritting
|
||
|
* the value at *execlists->active. This is fine. The promotion implies
|
||
|
* that we received an ACK from the HW, and so the context is not
|
||
|
* stuck -- if we do not see ourselves in *active, the inflight status
|
||
|
* is valid. If instead we see ourselves being copied into *active,
|
||
|
* we are inflight and may signal the callback.
|
||
|
*/
|
||
|
if (!intel_context_inflight(signal->context))
|
||
|
return false;
|
||
|
|
||
|
rcu_read_lock();
|
||
|
for (port = __engine_active(signal->engine);
|
||
|
(rq = READ_ONCE(*port)); /* may race with promotion of pending[] */
|
||
|
port++) {
|
||
|
if (rq->context == signal->context) {
|
||
|
inflight = i915_seqno_passed(rq->fence.seqno,
|
||
|
signal->fence.seqno);
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
rcu_read_unlock();
|
||
|
|
||
|
return inflight;
|
||
|
}
|
||
|
|
||
|
static int
|
||
|
__await_execution(struct i915_request *rq,
|
||
|
struct i915_request *signal,
|
||
|
gfp_t gfp)
|
||
|
{
|
||
|
struct execute_cb *cb;
|
||
|
|
||
|
if (i915_request_is_active(signal))
|
||
|
return 0;
|
||
|
|
||
|
cb = kmem_cache_alloc(slab_execute_cbs, gfp);
|
||
|
if (!cb)
|
||
|
return -ENOMEM;
|
||
|
|
||
|
cb->fence = &rq->submit;
|
||
|
i915_sw_fence_await(cb->fence);
|
||
|
init_irq_work(&cb->work, irq_execute_cb);
|
||
|
|
||
|
/*
|
||
|
* Register the callback first, then see if the signaler is already
|
||
|
* active. This ensures that if we race with the
|
||
|
* __notify_execute_cb from i915_request_submit() and we are not
|
||
|
* included in that list, we get a second bite of the cherry and
|
||
|
* execute it ourselves. After this point, a future
|
||
|
* i915_request_submit() will notify us.
|
||
|
*
|
||
|
* In i915_request_retire() we set the ACTIVE bit on a completed
|
||
|
* request (then flush the execute_cb). So by registering the
|
||
|
* callback first, then checking the ACTIVE bit, we serialise with
|
||
|
* the completed/retired request.
|
||
|
*/
|
||
|
if (llist_add(&cb->work.node.llist, &signal->execute_cb)) {
|
||
|
if (i915_request_is_active(signal) ||
|
||
|
__request_in_flight(signal))
|
||
|
i915_request_notify_execute_cb_imm(signal);
|
||
|
}
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
static bool fatal_error(int error)
|
||
|
{
|
||
|
switch (error) {
|
||
|
case 0: /* not an error! */
|
||
|
case -EAGAIN: /* innocent victim of a GT reset (__i915_request_reset) */
|
||
|
case -ETIMEDOUT: /* waiting for Godot (timer_i915_sw_fence_wake) */
|
||
|
return false;
|
||
|
default:
|
||
|
return true;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
void __i915_request_skip(struct i915_request *rq)
|
||
|
{
|
||
|
GEM_BUG_ON(!fatal_error(rq->fence.error));
|
||
|
|
||
|
if (rq->infix == rq->postfix)
|
||
|
return;
|
||
|
|
||
|
RQ_TRACE(rq, "error: %d\n", rq->fence.error);
|
||
|
|
||
|
/*
|
||
|
* As this request likely depends on state from the lost
|
||
|
* context, clear out all the user operations leaving the
|
||
|
* breadcrumb at the end (so we get the fence notifications).
|
||
|
*/
|
||
|
__i915_request_fill(rq, 0);
|
||
|
rq->infix = rq->postfix;
|
||
|
}
|
||
|
|
||
|
bool i915_request_set_error_once(struct i915_request *rq, int error)
|
||
|
{
|
||
|
int old;
|
||
|
|
||
|
GEM_BUG_ON(!IS_ERR_VALUE((long)error));
|
||
|
|
||
|
if (i915_request_signaled(rq))
|
||
|
return false;
|
||
|
|
||
|
old = READ_ONCE(rq->fence.error);
|
||
|
do {
|
||
|
if (fatal_error(old))
|
||
|
return false;
|
||
|
} while (!try_cmpxchg(&rq->fence.error, &old, error));
|
||
|
|
||
|
return true;
|
||
|
}
|
||
|
|
||
|
struct i915_request *i915_request_mark_eio(struct i915_request *rq)
|
||
|
{
|
||
|
if (__i915_request_is_complete(rq))
|
||
|
return NULL;
|
||
|
|
||
|
GEM_BUG_ON(i915_request_signaled(rq));
|
||
|
|
||
|
/* As soon as the request is completed, it may be retired */
|
||
|
rq = i915_request_get(rq);
|
||
|
|
||
|
i915_request_set_error_once(rq, -EIO);
|
||
|
i915_request_mark_complete(rq);
|
||
|
|
||
|
return rq;
|
||
|
}
|
||
|
|
||
|
bool __i915_request_submit(struct i915_request *request)
|
||
|
{
|
||
|
struct intel_engine_cs *engine = request->engine;
|
||
|
bool result = false;
|
||
|
|
||
|
RQ_TRACE(request, "\n");
|
||
|
|
||
|
GEM_BUG_ON(!irqs_disabled());
|
||
|
lockdep_assert_held(&engine->sched_engine->lock);
|
||
|
|
||
|
/*
|
||
|
* With the advent of preempt-to-busy, we frequently encounter
|
||
|
* requests that we have unsubmitted from HW, but left running
|
||
|
* until the next ack and so have completed in the meantime. On
|
||
|
* resubmission of that completed request, we can skip
|
||
|
* updating the payload, and execlists can even skip submitting
|
||
|
* the request.
|
||
|
*
|
||
|
* We must remove the request from the caller's priority queue,
|
||
|
* and the caller must only call us when the request is in their
|
||
|
* priority queue, under the sched_engine->lock. This ensures that the
|
||
|
* request has *not* yet been retired and we can safely move
|
||
|
* the request into the engine->active.list where it will be
|
||
|
* dropped upon retiring. (Otherwise if resubmit a *retired*
|
||
|
* request, this would be a horrible use-after-free.)
|
||
|
*/
|
||
|
if (__i915_request_is_complete(request)) {
|
||
|
list_del_init(&request->sched.link);
|
||
|
goto active;
|
||
|
}
|
||
|
|
||
|
if (unlikely(intel_context_is_banned(request->context)))
|
||
|
i915_request_set_error_once(request, -EIO);
|
||
|
|
||
|
if (unlikely(fatal_error(request->fence.error)))
|
||
|
__i915_request_skip(request);
|
||
|
|
||
|
/*
|
||
|
* Are we using semaphores when the gpu is already saturated?
|
||
|
*
|
||
|
* Using semaphores incurs a cost in having the GPU poll a
|
||
|
* memory location, busywaiting for it to change. The continual
|
||
|
* memory reads can have a noticeable impact on the rest of the
|
||
|
* system with the extra bus traffic, stalling the cpu as it too
|
||
|
* tries to access memory across the bus (perf stat -e bus-cycles).
|
||
|
*
|
||
|
* If we installed a semaphore on this request and we only submit
|
||
|
* the request after the signaler completed, that indicates the
|
||
|
* system is overloaded and using semaphores at this time only
|
||
|
* increases the amount of work we are doing. If so, we disable
|
||
|
* further use of semaphores until we are idle again, whence we
|
||
|
* optimistically try again.
|
||
|
*/
|
||
|
if (request->sched.semaphores &&
|
||
|
i915_sw_fence_signaled(&request->semaphore))
|
||
|
engine->saturated |= request->sched.semaphores;
|
||
|
|
||
|
engine->emit_fini_breadcrumb(request,
|
||
|
request->ring->vaddr + request->postfix);
|
||
|
|
||
|
trace_i915_request_execute(request);
|
||
|
if (engine->bump_serial)
|
||
|
engine->bump_serial(engine);
|
||
|
else
|
||
|
engine->serial++;
|
||
|
|
||
|
result = true;
|
||
|
|
||
|
GEM_BUG_ON(test_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags));
|
||
|
engine->add_active_request(request);
|
||
|
active:
|
||
|
clear_bit(I915_FENCE_FLAG_PQUEUE, &request->fence.flags);
|
||
|
set_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags);
|
||
|
|
||
|
/*
|
||
|
* XXX Rollback bonded-execution on __i915_request_unsubmit()?
|
||
|
*
|
||
|
* In the future, perhaps when we have an active time-slicing scheduler,
|
||
|
* it will be interesting to unsubmit parallel execution and remove
|
||
|
* busywaits from the GPU until their master is restarted. This is
|
||
|
* quite hairy, we have to carefully rollback the fence and do a
|
||
|
* preempt-to-idle cycle on the target engine, all the while the
|
||
|
* master execute_cb may refire.
|
||
|
*/
|
||
|
__notify_execute_cb_irq(request);
|
||
|
|
||
|
/* We may be recursing from the signal callback of another i915 fence */
|
||
|
if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &request->fence.flags))
|
||
|
i915_request_enable_breadcrumb(request);
|
||
|
|
||
|
return result;
|
||
|
}
|
||
|
|
||
|
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->sched_engine->lock, flags);
|
||
|
|
||
|
__i915_request_submit(request);
|
||
|
|
||
|
spin_unlock_irqrestore(&engine->sched_engine->lock, flags);
|
||
|
}
|
||
|
|
||
|
void __i915_request_unsubmit(struct i915_request *request)
|
||
|
{
|
||
|
struct intel_engine_cs *engine = request->engine;
|
||
|
|
||
|
/*
|
||
|
* Only unwind in reverse order, required so that the per-context list
|
||
|
* is kept in seqno/ring order.
|
||
|
*/
|
||
|
RQ_TRACE(request, "\n");
|
||
|
|
||
|
GEM_BUG_ON(!irqs_disabled());
|
||
|
lockdep_assert_held(&engine->sched_engine->lock);
|
||
|
|
||
|
/*
|
||
|
* Before we remove this breadcrumb from the signal list, we have
|
||
|
* to ensure that a concurrent dma_fence_enable_signaling() does not
|
||
|
* attach itself. We first mark the request as no longer active and
|
||
|
* make sure that is visible to other cores, and then remove the
|
||
|
* breadcrumb if attached.
|
||
|
*/
|
||
|
GEM_BUG_ON(!test_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags));
|
||
|
clear_bit_unlock(I915_FENCE_FLAG_ACTIVE, &request->fence.flags);
|
||
|
if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &request->fence.flags))
|
||
|
i915_request_cancel_breadcrumb(request);
|
||
|
|
||
|
/* We've already spun, don't charge on resubmitting. */
|
||
|
if (request->sched.semaphores && __i915_request_has_started(request))
|
||
|
request->sched.semaphores = 0;
|
||
|
|
||
|
/*
|
||
|
* 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->sched_engine->lock, flags);
|
||
|
|
||
|
__i915_request_unsubmit(request);
|
||
|
|
||
|
spin_unlock_irqrestore(&engine->sched_engine->lock, flags);
|
||
|
}
|
||
|
|
||
|
void i915_request_cancel(struct i915_request *rq, int error)
|
||
|
{
|
||
|
if (!i915_request_set_error_once(rq, error))
|
||
|
return;
|
||
|
|
||
|
set_bit(I915_FENCE_FLAG_SENTINEL, &rq->fence.flags);
|
||
|
|
||
|
intel_context_cancel_request(rq->context, rq);
|
||
|
}
|
||
|
|
||
|
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);
|
||
|
|
||
|
if (unlikely(fence->error))
|
||
|
i915_request_set_error_once(request, fence->error);
|
||
|
else
|
||
|
__rq_arm_watchdog(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;
|
||
|
}
|
||
|
|
||
|
static int __i915_sw_fence_call
|
||
|
semaphore_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state)
|
||
|
{
|
||
|
struct i915_request *rq = container_of(fence, typeof(*rq), semaphore);
|
||
|
|
||
|
switch (state) {
|
||
|
case FENCE_COMPLETE:
|
||
|
break;
|
||
|
|
||
|
case FENCE_FREE:
|
||
|
i915_request_put(rq);
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
return NOTIFY_DONE;
|
||
|
}
|
||
|
|
||
|
static void retire_requests(struct intel_timeline *tl)
|
||
|
{
|
||
|
struct i915_request *rq, *rn;
|
||
|
|
||
|
list_for_each_entry_safe(rq, rn, &tl->requests, link)
|
||
|
if (!i915_request_retire(rq))
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
static noinline struct i915_request *
|
||
|
request_alloc_slow(struct intel_timeline *tl,
|
||
|
struct i915_request **rsvd,
|
||
|
gfp_t gfp)
|
||
|
{
|
||
|
struct i915_request *rq;
|
||
|
|
||
|
/* If we cannot wait, dip into our reserves */
|
||
|
if (!gfpflags_allow_blocking(gfp)) {
|
||
|
rq = xchg(rsvd, NULL);
|
||
|
if (!rq) /* Use the normal failure path for one final WARN */
|
||
|
goto out;
|
||
|
|
||
|
return rq;
|
||
|
}
|
||
|
|
||
|
if (list_empty(&tl->requests))
|
||
|
goto out;
|
||
|
|
||
|
/* Move our oldest request to the slab-cache (if not in use!) */
|
||
|
rq = list_first_entry(&tl->requests, typeof(*rq), link);
|
||
|
i915_request_retire(rq);
|
||
|
|
||
|
rq = kmem_cache_alloc(slab_requests,
|
||
|
gfp | __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
|
||
|
if (rq)
|
||
|
return rq;
|
||
|
|
||
|
/* Ratelimit ourselves to prevent oom from malicious clients */
|
||
|
rq = list_last_entry(&tl->requests, typeof(*rq), link);
|
||
|
cond_synchronize_rcu(rq->rcustate);
|
||
|
|
||
|
/* Retire our old requests in the hope that we free some */
|
||
|
retire_requests(tl);
|
||
|
|
||
|
out:
|
||
|
return kmem_cache_alloc(slab_requests, gfp);
|
||
|
}
|
||
|
|
||
|
static void __i915_request_ctor(void *arg)
|
||
|
{
|
||
|
struct i915_request *rq = arg;
|
||
|
|
||
|
spin_lock_init(&rq->lock);
|
||
|
i915_sched_node_init(&rq->sched);
|
||
|
i915_sw_fence_init(&rq->submit, submit_notify);
|
||
|
i915_sw_fence_init(&rq->semaphore, semaphore_notify);
|
||
|
|
||
|
rq->capture_list = NULL;
|
||
|
|
||
|
init_llist_head(&rq->execute_cb);
|
||
|
}
|
||
|
|
||
|
struct i915_request *
|
||
|
__i915_request_create(struct intel_context *ce, gfp_t gfp)
|
||
|
{
|
||
|
struct intel_timeline *tl = ce->timeline;
|
||
|
struct i915_request *rq;
|
||
|
u32 seqno;
|
||
|
int ret;
|
||
|
|
||
|
might_alloc(gfp);
|
||
|
|
||
|
/* Check that the caller provided an already pinned context */
|
||
|
__intel_context_pin(ce);
|
||
|
|
||
|
/*
|
||
|
* 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_active_request_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(slab_requests,
|
||
|
gfp | __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
|
||
|
if (unlikely(!rq)) {
|
||
|
rq = request_alloc_slow(tl, &ce->engine->request_pool, gfp);
|
||
|
if (!rq) {
|
||
|
ret = -ENOMEM;
|
||
|
goto err_unreserve;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Hold a reference to the intel_context over life of an i915_request.
|
||
|
* Without this an i915_request can exist after the context has been
|
||
|
* destroyed (e.g. request retired, context closed, but user space holds
|
||
|
* a reference to the request from an out fence). In the case of GuC
|
||
|
* submission + virtual engine, the engine that the request references
|
||
|
* is also destroyed which can trigger bad pointer dref in fence ops
|
||
|
* (e.g. i915_fence_get_driver_name). We could likely change these
|
||
|
* functions to avoid touching the engine but let's just be safe and
|
||
|
* hold the intel_context reference. In execlist mode the request always
|
||
|
* eventually points to a physical engine so this isn't an issue.
|
||
|
*/
|
||
|
rq->context = intel_context_get(ce);
|
||
|
rq->engine = ce->engine;
|
||
|
rq->ring = ce->ring;
|
||
|
rq->execution_mask = ce->engine->mask;
|
||
|
|
||
|
ret = intel_timeline_get_seqno(tl, rq, &seqno);
|
||
|
if (ret)
|
||
|
goto err_free;
|
||
|
|
||
|
dma_fence_init(&rq->fence, &i915_fence_ops, &rq->lock,
|
||
|
tl->fence_context, seqno);
|
||
|
|
||
|
RCU_INIT_POINTER(rq->timeline, tl);
|
||
|
rq->hwsp_seqno = tl->hwsp_seqno;
|
||
|
GEM_BUG_ON(__i915_request_is_complete(rq));
|
||
|
|
||
|
rq->rcustate = get_state_synchronize_rcu(); /* acts as smp_mb() */
|
||
|
|
||
|
rq->guc_prio = GUC_PRIO_INIT;
|
||
|
|
||
|
/* We bump the ref for the fence chain */
|
||
|
i915_sw_fence_reinit(&i915_request_get(rq)->submit);
|
||
|
i915_sw_fence_reinit(&i915_request_get(rq)->semaphore);
|
||
|
|
||
|
i915_sched_node_reinit(&rq->sched);
|
||
|
|
||
|
/* No zalloc, everything must be cleared after use */
|
||
|
rq->batch = NULL;
|
||
|
__rq_init_watchdog(rq);
|
||
|
GEM_BUG_ON(rq->capture_list);
|
||
|
GEM_BUG_ON(!llist_empty(&rq->execute_cb));
|
||
|
|
||
|
/*
|
||
|
* 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.
|
||
|
*
|
||
|
* Note that due to how we add reserved_space to intel_ring_begin()
|
||
|
* we need to double our request to ensure that if we need to wrap
|
||
|
* around inside i915_request_add() there is sufficient space at
|
||
|
* the beginning of the ring as well.
|
||
|
*/
|
||
|
rq->reserved_space =
|
||
|
2 * rq->engine->emit_fini_breadcrumb_dw * sizeof(u32);
|
||
|
|
||
|
/*
|
||
|
* 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;
|
||
|
|
||
|
ret = rq->engine->request_alloc(rq);
|
||
|
if (ret)
|
||
|
goto err_unwind;
|
||
|
|
||
|
rq->infix = rq->ring->emit; /* end of header; start of user payload */
|
||
|
|
||
|
intel_context_mark_active(ce);
|
||
|
list_add_tail_rcu(&rq->link, &tl->requests);
|
||
|
|
||
|
return rq;
|
||
|
|
||
|
err_unwind:
|
||
|
ce->ring->emit = rq->head;
|
||
|
|
||
|
/* Make sure we didn't add ourselves to external state before freeing */
|
||
|
GEM_BUG_ON(!list_empty(&rq->sched.signalers_list));
|
||
|
GEM_BUG_ON(!list_empty(&rq->sched.waiters_list));
|
||
|
|
||
|
err_free:
|
||
|
intel_context_put(ce);
|
||
|
kmem_cache_free(slab_requests, rq);
|
||
|
err_unreserve:
|
||
|
intel_context_unpin(ce);
|
||
|
return ERR_PTR(ret);
|
||
|
}
|
||
|
|
||
|
struct i915_request *
|
||
|
i915_request_create(struct intel_context *ce)
|
||
|
{
|
||
|
struct i915_request *rq;
|
||
|
struct intel_timeline *tl;
|
||
|
|
||
|
tl = intel_context_timeline_lock(ce);
|
||
|
if (IS_ERR(tl))
|
||
|
return ERR_CAST(tl);
|
||
|
|
||
|
/* Move our oldest request to the slab-cache (if not in use!) */
|
||
|
rq = list_first_entry(&tl->requests, typeof(*rq), link);
|
||
|
if (!list_is_last(&rq->link, &tl->requests))
|
||
|
i915_request_retire(rq);
|
||
|
|
||
|
intel_context_enter(ce);
|
||
|
rq = __i915_request_create(ce, GFP_KERNEL);
|
||
|
intel_context_exit(ce); /* active reference transferred to request */
|
||
|
if (IS_ERR(rq))
|
||
|
goto err_unlock;
|
||
|
|
||
|
/* Check that we do not interrupt ourselves with a new request */
|
||
|
rq->cookie = lockdep_pin_lock(&tl->mutex);
|
||
|
|
||
|
return rq;
|
||
|
|
||
|
err_unlock:
|
||
|
intel_context_timeline_unlock(tl);
|
||
|
return rq;
|
||
|
}
|
||
|
|
||
|
static int
|
||
|
i915_request_await_start(struct i915_request *rq, struct i915_request *signal)
|
||
|
{
|
||
|
struct dma_fence *fence;
|
||
|
int err;
|
||
|
|
||
|
if (i915_request_timeline(rq) == rcu_access_pointer(signal->timeline))
|
||
|
return 0;
|
||
|
|
||
|
if (i915_request_started(signal))
|
||
|
return 0;
|
||
|
|
||
|
/*
|
||
|
* The caller holds a reference on @signal, but we do not serialise
|
||
|
* against it being retired and removed from the lists.
|
||
|
*
|
||
|
* We do not hold a reference to the request before @signal, and
|
||
|
* so must be very careful to ensure that it is not _recycled_ as
|
||
|
* we follow the link backwards.
|
||
|
*/
|
||
|
fence = NULL;
|
||
|
rcu_read_lock();
|
||
|
do {
|
||
|
struct list_head *pos = READ_ONCE(signal->link.prev);
|
||
|
struct i915_request *prev;
|
||
|
|
||
|
/* Confirm signal has not been retired, the link is valid */
|
||
|
if (unlikely(__i915_request_has_started(signal)))
|
||
|
break;
|
||
|
|
||
|
/* Is signal the earliest request on its timeline? */
|
||
|
if (pos == &rcu_dereference(signal->timeline)->requests)
|
||
|
break;
|
||
|
|
||
|
/*
|
||
|
* Peek at the request before us in the timeline. That
|
||
|
* request will only be valid before it is retired, so
|
||
|
* after acquiring a reference to it, confirm that it is
|
||
|
* still part of the signaler's timeline.
|
||
|
*/
|
||
|
prev = list_entry(pos, typeof(*prev), link);
|
||
|
if (!i915_request_get_rcu(prev))
|
||
|
break;
|
||
|
|
||
|
/* After the strong barrier, confirm prev is still attached */
|
||
|
if (unlikely(READ_ONCE(prev->link.next) != &signal->link)) {
|
||
|
i915_request_put(prev);
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
fence = &prev->fence;
|
||
|
} while (0);
|
||
|
rcu_read_unlock();
|
||
|
if (!fence)
|
||
|
return 0;
|
||
|
|
||
|
err = 0;
|
||
|
if (!intel_timeline_sync_is_later(i915_request_timeline(rq), fence))
|
||
|
err = i915_sw_fence_await_dma_fence(&rq->submit,
|
||
|
fence, 0,
|
||
|
I915_FENCE_GFP);
|
||
|
dma_fence_put(fence);
|
||
|
|
||
|
return err;
|
||
|
}
|
||
|
|
||
|
static intel_engine_mask_t
|
||
|
already_busywaiting(struct i915_request *rq)
|
||
|
{
|
||
|
/*
|
||
|
* Polling a semaphore causes bus traffic, delaying other users of
|
||
|
* both the GPU and CPU. We want to limit the impact on others,
|
||
|
* while taking advantage of early submission to reduce GPU
|
||
|
* latency. Therefore we restrict ourselves to not using more
|
||
|
* than one semaphore from each source, and not using a semaphore
|
||
|
* if we have detected the engine is saturated (i.e. would not be
|
||
|
* submitted early and cause bus traffic reading an already passed
|
||
|
* semaphore).
|
||
|
*
|
||
|
* See the are-we-too-late? check in __i915_request_submit().
|
||
|
*/
|
||
|
return rq->sched.semaphores | READ_ONCE(rq->engine->saturated);
|
||
|
}
|
||
|
|
||
|
static int
|
||
|
__emit_semaphore_wait(struct i915_request *to,
|
||
|
struct i915_request *from,
|
||
|
u32 seqno)
|
||
|
{
|
||
|
const int has_token = GRAPHICS_VER(to->engine->i915) >= 12;
|
||
|
u32 hwsp_offset;
|
||
|
int len, err;
|
||
|
u32 *cs;
|
||
|
|
||
|
GEM_BUG_ON(GRAPHICS_VER(to->engine->i915) < 8);
|
||
|
GEM_BUG_ON(i915_request_has_initial_breadcrumb(to));
|
||
|
|
||
|
/* We need to pin the signaler's HWSP until we are finished reading. */
|
||
|
err = intel_timeline_read_hwsp(from, to, &hwsp_offset);
|
||
|
if (err)
|
||
|
return err;
|
||
|
|
||
|
len = 4;
|
||
|
if (has_token)
|
||
|
len += 2;
|
||
|
|
||
|
cs = intel_ring_begin(to, len);
|
||
|
if (IS_ERR(cs))
|
||
|
return PTR_ERR(cs);
|
||
|
|
||
|
/*
|
||
|
* Using greater-than-or-equal here means we have to worry
|
||
|
* about seqno wraparound. To side step that issue, we swap
|
||
|
* the timeline HWSP upon wrapping, so that everyone listening
|
||
|
* for the old (pre-wrap) values do not see the much smaller
|
||
|
* (post-wrap) values than they were expecting (and so wait
|
||
|
* forever).
|
||
|
*/
|
||
|
*cs++ = (MI_SEMAPHORE_WAIT |
|
||
|
MI_SEMAPHORE_GLOBAL_GTT |
|
||
|
MI_SEMAPHORE_POLL |
|
||
|
MI_SEMAPHORE_SAD_GTE_SDD) +
|
||
|
has_token;
|
||
|
*cs++ = seqno;
|
||
|
*cs++ = hwsp_offset;
|
||
|
*cs++ = 0;
|
||
|
if (has_token) {
|
||
|
*cs++ = 0;
|
||
|
*cs++ = MI_NOOP;
|
||
|
}
|
||
|
|
||
|
intel_ring_advance(to, cs);
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
static int
|
||
|
emit_semaphore_wait(struct i915_request *to,
|
||
|
struct i915_request *from,
|
||
|
gfp_t gfp)
|
||
|
{
|
||
|
const intel_engine_mask_t mask = READ_ONCE(from->engine)->mask;
|
||
|
struct i915_sw_fence *wait = &to->submit;
|
||
|
|
||
|
if (!intel_context_use_semaphores(to->context))
|
||
|
goto await_fence;
|
||
|
|
||
|
if (i915_request_has_initial_breadcrumb(to))
|
||
|
goto await_fence;
|
||
|
|
||
|
/*
|
||
|
* If this or its dependents are waiting on an external fence
|
||
|
* that may fail catastrophically, then we want to avoid using
|
||
|
* sempahores as they bypass the fence signaling metadata, and we
|
||
|
* lose the fence->error propagation.
|
||
|
*/
|
||
|
if (from->sched.flags & I915_SCHED_HAS_EXTERNAL_CHAIN)
|
||
|
goto await_fence;
|
||
|
|
||
|
/* Just emit the first semaphore we see as request space is limited. */
|
||
|
if (already_busywaiting(to) & mask)
|
||
|
goto await_fence;
|
||
|
|
||
|
if (i915_request_await_start(to, from) < 0)
|
||
|
goto await_fence;
|
||
|
|
||
|
/* Only submit our spinner after the signaler is running! */
|
||
|
if (__await_execution(to, from, gfp))
|
||
|
goto await_fence;
|
||
|
|
||
|
if (__emit_semaphore_wait(to, from, from->fence.seqno))
|
||
|
goto await_fence;
|
||
|
|
||
|
to->sched.semaphores |= mask;
|
||
|
wait = &to->semaphore;
|
||
|
|
||
|
await_fence:
|
||
|
return i915_sw_fence_await_dma_fence(wait,
|
||
|
&from->fence, 0,
|
||
|
I915_FENCE_GFP);
|
||
|
}
|
||
|
|
||
|
static bool intel_timeline_sync_has_start(struct intel_timeline *tl,
|
||
|
struct dma_fence *fence)
|
||
|
{
|
||
|
return __intel_timeline_sync_is_later(tl,
|
||
|
fence->context,
|
||
|
fence->seqno - 1);
|
||
|
}
|
||
|
|
||
|
static int intel_timeline_sync_set_start(struct intel_timeline *tl,
|
||
|
const struct dma_fence *fence)
|
||
|
{
|
||
|
return __intel_timeline_sync_set(tl, fence->context, fence->seqno - 1);
|
||
|
}
|
||
|
|
||
|
static int
|
||
|
__i915_request_await_execution(struct i915_request *to,
|
||
|
struct i915_request *from)
|
||
|
{
|
||
|
int err;
|
||
|
|
||
|
GEM_BUG_ON(intel_context_is_barrier(from->context));
|
||
|
|
||
|
/* Submit both requests at the same time */
|
||
|
err = __await_execution(to, from, I915_FENCE_GFP);
|
||
|
if (err)
|
||
|
return err;
|
||
|
|
||
|
/* Squash repeated depenendices to the same timelines */
|
||
|
if (intel_timeline_sync_has_start(i915_request_timeline(to),
|
||
|
&from->fence))
|
||
|
return 0;
|
||
|
|
||
|
/*
|
||
|
* Wait until the start of this request.
|
||
|
*
|
||
|
* The execution cb fires when we submit the request to HW. But in
|
||
|
* many cases this may be long before the request itself is ready to
|
||
|
* run (consider that we submit 2 requests for the same context, where
|
||
|
* the request of interest is behind an indefinite spinner). So we hook
|
||
|
* up to both to reduce our queues and keep the execution lag minimised
|
||
|
* in the worst case, though we hope that the await_start is elided.
|
||
|
*/
|
||
|
err = i915_request_await_start(to, from);
|
||
|
if (err < 0)
|
||
|
return err;
|
||
|
|
||
|
/*
|
||
|
* Ensure both start together [after all semaphores in signal]
|
||
|
*
|
||
|
* Now that we are queued to the HW at roughly the same time (thanks
|
||
|
* to the execute cb) and are ready to run at roughly the same time
|
||
|
* (thanks to the await start), our signaler may still be indefinitely
|
||
|
* delayed by waiting on a semaphore from a remote engine. If our
|
||
|
* signaler depends on a semaphore, so indirectly do we, and we do not
|
||
|
* want to start our payload until our signaler also starts theirs.
|
||
|
* So we wait.
|
||
|
*
|
||
|
* However, there is also a second condition for which we need to wait
|
||
|
* for the precise start of the signaler. Consider that the signaler
|
||
|
* was submitted in a chain of requests following another context
|
||
|
* (with just an ordinary intra-engine fence dependency between the
|
||
|
* two). In this case the signaler is queued to HW, but not for
|
||
|
* immediate execution, and so we must wait until it reaches the
|
||
|
* active slot.
|
||
|
*/
|
||
|
if (intel_engine_has_semaphores(to->engine) &&
|
||
|
!i915_request_has_initial_breadcrumb(to)) {
|
||
|
err = __emit_semaphore_wait(to, from, from->fence.seqno - 1);
|
||
|
if (err < 0)
|
||
|
return err;
|
||
|
}
|
||
|
|
||
|
/* Couple the dependency tree for PI on this exposed to->fence */
|
||
|
if (to->engine->sched_engine->schedule) {
|
||
|
err = i915_sched_node_add_dependency(&to->sched,
|
||
|
&from->sched,
|
||
|
I915_DEPENDENCY_WEAK);
|
||
|
if (err < 0)
|
||
|
return err;
|
||
|
}
|
||
|
|
||
|
return intel_timeline_sync_set_start(i915_request_timeline(to),
|
||
|
&from->fence);
|
||
|
}
|
||
|
|
||
|
static void mark_external(struct i915_request *rq)
|
||
|
{
|
||
|
/*
|
||
|
* The downside of using semaphores is that we lose metadata passing
|
||
|
* along the signaling chain. This is particularly nasty when we
|
||
|
* need to pass along a fatal error such as EFAULT or EDEADLK. For
|
||
|
* fatal errors we want to scrub the request before it is executed,
|
||
|
* which means that we cannot preload the request onto HW and have
|
||
|
* it wait upon a semaphore.
|
||
|
*/
|
||
|
rq->sched.flags |= I915_SCHED_HAS_EXTERNAL_CHAIN;
|
||
|
}
|
||
|
|
||
|
static int
|
||
|
__i915_request_await_external(struct i915_request *rq, struct dma_fence *fence)
|
||
|
{
|
||
|
mark_external(rq);
|
||
|
return i915_sw_fence_await_dma_fence(&rq->submit, fence,
|
||
|
i915_fence_context_timeout(rq->engine->i915,
|
||
|
fence->context),
|
||
|
I915_FENCE_GFP);
|
||
|
}
|
||
|
|
||
|
static int
|
||
|
i915_request_await_external(struct i915_request *rq, struct dma_fence *fence)
|
||
|
{
|
||
|
struct dma_fence *iter;
|
||
|
int err = 0;
|
||
|
|
||
|
if (!to_dma_fence_chain(fence))
|
||
|
return __i915_request_await_external(rq, fence);
|
||
|
|
||
|
dma_fence_chain_for_each(iter, fence) {
|
||
|
struct dma_fence_chain *chain = to_dma_fence_chain(iter);
|
||
|
|
||
|
if (!dma_fence_is_i915(chain->fence)) {
|
||
|
err = __i915_request_await_external(rq, iter);
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
err = i915_request_await_dma_fence(rq, chain->fence);
|
||
|
if (err < 0)
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
dma_fence_put(iter);
|
||
|
return err;
|
||
|
}
|
||
|
|
||
|
int
|
||
|
i915_request_await_execution(struct i915_request *rq,
|
||
|
struct dma_fence *fence)
|
||
|
{
|
||
|
struct dma_fence **child = &fence;
|
||
|
unsigned int nchild = 1;
|
||
|
int ret;
|
||
|
|
||
|
if (dma_fence_is_array(fence)) {
|
||
|
struct dma_fence_array *array = to_dma_fence_array(fence);
|
||
|
|
||
|
/* XXX Error for signal-on-any fence arrays */
|
||
|
|
||
|
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;
|
||
|
|
||
|
if (fence->context == rq->fence.context)
|
||
|
continue;
|
||
|
|
||
|
/*
|
||
|
* We don't squash repeated fence dependencies here as we
|
||
|
* want to run our callback in all cases.
|
||
|
*/
|
||
|
|
||
|
if (dma_fence_is_i915(fence))
|
||
|
ret = __i915_request_await_execution(rq,
|
||
|
to_request(fence));
|
||
|
else
|
||
|
ret = i915_request_await_external(rq, fence);
|
||
|
if (ret < 0)
|
||
|
return ret;
|
||
|
} while (--nchild);
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
static int
|
||
|
await_request_submit(struct i915_request *to, struct i915_request *from)
|
||
|
{
|
||
|
/*
|
||
|
* If we are waiting on a virtual engine, then it may be
|
||
|
* constrained to execute on a single engine *prior* to submission.
|
||
|
* When it is submitted, it will be first submitted to the virtual
|
||
|
* engine and then passed to the physical engine. We cannot allow
|
||
|
* the waiter to be submitted immediately to the physical engine
|
||
|
* as it may then bypass the virtual request.
|
||
|
*/
|
||
|
if (to->engine == READ_ONCE(from->engine))
|
||
|
return i915_sw_fence_await_sw_fence_gfp(&to->submit,
|
||
|
&from->submit,
|
||
|
I915_FENCE_GFP);
|
||
|
else
|
||
|
return __i915_request_await_execution(to, from);
|
||
|
}
|
||
|
|
||
|
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)) {
|
||
|
i915_sw_fence_set_error_once(&to->submit, from->fence.error);
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
if (to->engine->sched_engine->schedule) {
|
||
|
ret = i915_sched_node_add_dependency(&to->sched,
|
||
|
&from->sched,
|
||
|
I915_DEPENDENCY_EXTERNAL);
|
||
|
if (ret < 0)
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
if (!intel_engine_uses_guc(to->engine) &&
|
||
|
is_power_of_2(to->execution_mask | READ_ONCE(from->execution_mask)))
|
||
|
ret = await_request_submit(to, from);
|
||
|
else
|
||
|
ret = emit_semaphore_wait(to, from, I915_FENCE_GFP);
|
||
|
if (ret < 0)
|
||
|
return ret;
|
||
|
|
||
|
return 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 &&
|
||
|
intel_timeline_sync_is_later(i915_request_timeline(rq),
|
||
|
fence))
|
||
|
continue;
|
||
|
|
||
|
if (dma_fence_is_i915(fence))
|
||
|
ret = i915_request_await_request(rq, to_request(fence));
|
||
|
else
|
||
|
ret = i915_request_await_external(rq, fence);
|
||
|
if (ret < 0)
|
||
|
return ret;
|
||
|
|
||
|
/* Record the latest fence used against each timeline */
|
||
|
if (fence->context)
|
||
|
intel_timeline_sync_set(i915_request_timeline(rq),
|
||
|
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 = dma_resv_get_fences(obj->base.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 = dma_resv_get_excl_unlocked(obj->base.resv);
|
||
|
}
|
||
|
|
||
|
if (excl) {
|
||
|
if (ret == 0)
|
||
|
ret = i915_request_await_dma_fence(to, excl);
|
||
|
|
||
|
dma_fence_put(excl);
|
||
|
}
|
||
|
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
static struct i915_request *
|
||
|
__i915_request_add_to_timeline(struct i915_request *rq)
|
||
|
{
|
||
|
struct intel_timeline *timeline = i915_request_timeline(rq);
|
||
|
struct i915_request *prev;
|
||
|
|
||
|
/*
|
||
|
* Dependency tracking and request ordering along the timeline
|
||
|
* is special cased so that we can eliminate redundant ordering
|
||
|
* operations while building the request (we know that the timeline
|
||
|
* itself is ordered, and here we guarantee it).
|
||
|
*
|
||
|
* As we know we will need to emit tracking along the timeline,
|
||
|
* we embed the hooks into our request struct -- at the cost of
|
||
|
* having to have specialised no-allocation interfaces (which will
|
||
|
* be beneficial elsewhere).
|
||
|
*
|
||
|
* A second benefit to open-coding i915_request_await_request is
|
||
|
* that we can apply a slight variant of the rules specialised
|
||
|
* for timelines that jump between engines (such as virtual engines).
|
||
|
* If we consider the case of virtual engine, we must emit a dma-fence
|
||
|
* to prevent scheduling of the second request until the first is
|
||
|
* complete (to maximise our greedy late load balancing) and this
|
||
|
* precludes optimising to use semaphores serialisation of a single
|
||
|
* timeline across engines.
|
||
|
*/
|
||
|
prev = to_request(__i915_active_fence_set(&timeline->last_request,
|
||
|
&rq->fence));
|
||
|
if (prev && !__i915_request_is_complete(prev)) {
|
||
|
bool uses_guc = intel_engine_uses_guc(rq->engine);
|
||
|
|
||
|
/*
|
||
|
* The requests are supposed to be kept in order. However,
|
||
|
* we need to be wary in case the timeline->last_request
|
||
|
* is used as a barrier for external modification to this
|
||
|
* context.
|
||
|
*/
|
||
|
GEM_BUG_ON(prev->context == rq->context &&
|
||
|
i915_seqno_passed(prev->fence.seqno,
|
||
|
rq->fence.seqno));
|
||
|
|
||
|
if ((!uses_guc &&
|
||
|
is_power_of_2(READ_ONCE(prev->engine)->mask | rq->engine->mask)) ||
|
||
|
(uses_guc && prev->context == rq->context))
|
||
|
i915_sw_fence_await_sw_fence(&rq->submit,
|
||
|
&prev->submit,
|
||
|
&rq->submitq);
|
||
|
else
|
||
|
__i915_sw_fence_await_dma_fence(&rq->submit,
|
||
|
&prev->fence,
|
||
|
&rq->dmaq);
|
||
|
if (rq->engine->sched_engine->schedule)
|
||
|
__i915_sched_node_add_dependency(&rq->sched,
|
||
|
&prev->sched,
|
||
|
&rq->dep,
|
||
|
0);
|
||
|
}
|
||
|
if (prev)
|
||
|
i915_request_put(prev);
|
||
|
|
||
|
/*
|
||
|
* 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 != rq->fence.seqno);
|
||
|
|
||
|
return prev;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* 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).
|
||
|
*/
|
||
|
struct i915_request *__i915_request_commit(struct i915_request *rq)
|
||
|
{
|
||
|
struct intel_engine_cs *engine = rq->engine;
|
||
|
struct intel_ring *ring = rq->ring;
|
||
|
u32 *cs;
|
||
|
|
||
|
RQ_TRACE(rq, "\n");
|
||
|
|
||
|
/*
|
||
|
* 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.
|
||
|
*/
|
||
|
GEM_BUG_ON(rq->reserved_space > ring->space);
|
||
|
rq->reserved_space = 0;
|
||
|
rq->emitted_jiffies = jiffies;
|
||
|
|
||
|
/*
|
||
|
* 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(rq, engine->emit_fini_breadcrumb_dw);
|
||
|
GEM_BUG_ON(IS_ERR(cs));
|
||
|
rq->postfix = intel_ring_offset(rq, cs);
|
||
|
|
||
|
return __i915_request_add_to_timeline(rq);
|
||
|
}
|
||
|
|
||
|
void __i915_request_queue_bh(struct i915_request *rq)
|
||
|
{
|
||
|
i915_sw_fence_commit(&rq->semaphore);
|
||
|
i915_sw_fence_commit(&rq->submit);
|
||
|
}
|
||
|
|
||
|
void __i915_request_queue(struct i915_request *rq,
|
||
|
const struct i915_sched_attr *attr)
|
||
|
{
|
||
|
/*
|
||
|
* 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.
|
||
|
*/
|
||
|
if (attr && rq->engine->sched_engine->schedule)
|
||
|
rq->engine->sched_engine->schedule(rq, attr);
|
||
|
|
||
|
local_bh_disable();
|
||
|
__i915_request_queue_bh(rq);
|
||
|
local_bh_enable(); /* kick tasklets */
|
||
|
}
|
||
|
|
||
|
void i915_request_add(struct i915_request *rq)
|
||
|
{
|
||
|
struct intel_timeline * const tl = i915_request_timeline(rq);
|
||
|
struct i915_sched_attr attr = {};
|
||
|
struct i915_gem_context *ctx;
|
||
|
|
||
|
lockdep_assert_held(&tl->mutex);
|
||
|
lockdep_unpin_lock(&tl->mutex, rq->cookie);
|
||
|
|
||
|
trace_i915_request_add(rq);
|
||
|
__i915_request_commit(rq);
|
||
|
|
||
|
/* XXX placeholder for selftests */
|
||
|
rcu_read_lock();
|
||
|
ctx = rcu_dereference(rq->context->gem_context);
|
||
|
if (ctx)
|
||
|
attr = ctx->sched;
|
||
|
rcu_read_unlock();
|
||
|
|
||
|
__i915_request_queue(rq, &attr);
|
||
|
|
||
|
mutex_unlock(&tl->mutex);
|
||
|
}
|
||
|
|
||
|
static unsigned long local_clock_ns(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();
|
||
|
put_cpu();
|
||
|
|
||
|
return t;
|
||
|
}
|
||
|
|
||
|
static bool busywait_stop(unsigned long timeout, unsigned int cpu)
|
||
|
{
|
||
|
unsigned int this_cpu;
|
||
|
|
||
|
if (time_after(local_clock_ns(&this_cpu), timeout))
|
||
|
return true;
|
||
|
|
||
|
return this_cpu != cpu;
|
||
|
}
|
||
|
|
||
|
static bool __i915_spin_request(struct i915_request * const rq, int state)
|
||
|
{
|
||
|
unsigned long timeout_ns;
|
||
|
unsigned int cpu;
|
||
|
|
||
|
/*
|
||
|
* 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 context and so we can
|
||
|
* tell if the request has been started. If the request is not even
|
||
|
* running yet, it is a fair assumption that it will not complete
|
||
|
* within our relatively short timeout.
|
||
|
*/
|
||
|
if (!i915_request_is_running(rq))
|
||
|
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.
|
||
|
*/
|
||
|
|
||
|
timeout_ns = READ_ONCE(rq->engine->props.max_busywait_duration_ns);
|
||
|
timeout_ns += local_clock_ns(&cpu);
|
||
|
do {
|
||
|
if (dma_fence_is_signaled(&rq->fence))
|
||
|
return true;
|
||
|
|
||
|
if (signal_pending_state(state, current))
|
||
|
break;
|
||
|
|
||
|
if (busywait_stop(timeout_ns, cpu))
|
||
|
break;
|
||
|
|
||
|
cpu_relax();
|
||
|
} while (!need_resched());
|
||
|
|
||
|
return false;
|
||
|
}
|
||
|
|
||
|
struct request_wait {
|
||
|
struct dma_fence_cb cb;
|
||
|
struct task_struct *tsk;
|
||
|
};
|
||
|
|
||
|
static void request_wait_wake(struct dma_fence *fence, struct dma_fence_cb *cb)
|
||
|
{
|
||
|
struct request_wait *wait = container_of(cb, typeof(*wait), cb);
|
||
|
|
||
|
wake_up_process(fetch_and_zero(&wait->tsk));
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* 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).
|
||
|
*
|
||
|
* 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;
|
||
|
struct request_wait wait;
|
||
|
|
||
|
might_sleep();
|
||
|
GEM_BUG_ON(timeout < 0);
|
||
|
|
||
|
if (dma_fence_is_signaled(&rq->fence))
|
||
|
return timeout;
|
||
|
|
||
|
if (!timeout)
|
||
|
return -ETIME;
|
||
|
|
||
|
trace_i915_request_wait_begin(rq, flags);
|
||
|
|
||
|
/*
|
||
|
* We must never wait on the GPU while holding a lock as we
|
||
|
* may need to perform a GPU reset. So while we don't need to
|
||
|
* serialise wait/reset with an explicit lock, we do want
|
||
|
* lockdep to detect potential dependency cycles.
|
||
|
*/
|
||
|
mutex_acquire(&rq->engine->gt->reset.mutex.dep_map, 0, 0, _THIS_IP_);
|
||
|
|
||
|
/*
|
||
|
* Optimistic spin before touching IRQs.
|
||
|
*
|
||
|
* We may use a rather large value here to offset the penalty of
|
||
|
* switching away from the active task. Frequently, the client will
|
||
|
* wait upon an old swapbuffer to throttle itself to remain within a
|
||
|
* frame of the gpu. If the client is running in lockstep with the gpu,
|
||
|
* then it should not be waiting long at all, and a sleep now will incur
|
||
|
* extra scheduler latency in producing the next frame. To try to
|
||
|
* avoid adding the cost of enabling/disabling the interrupt to the
|
||
|
* short wait, we first spin to see if the request would have completed
|
||
|
* in the time taken to setup the interrupt.
|
||
|
*
|
||
|
* We need upto 5us to enable the irq, and upto 20us to hide the
|
||
|
* scheduler latency of a context switch, ignoring the secondary
|
||
|
* impacts from a context switch such as cache eviction.
|
||
|
*
|
||
|
* The scheme used for low-latency IO is called "hybrid interrupt
|
||
|
* polling". The suggestion there is to sleep until just before you
|
||
|
* expect to be woken by the device interrupt and then poll for its
|
||
|
* completion. That requires having a good predictor for the request
|
||
|
* duration, which we currently lack.
|
||
|
*/
|
||
|
if (IS_ACTIVE(CONFIG_DRM_I915_MAX_REQUEST_BUSYWAIT) &&
|
||
|
__i915_spin_request(rq, state))
|
||
|
goto out;
|
||
|
|
||
|
/*
|
||
|
* 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 sleep. 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).
|
||
|
*/
|
||
|
if (flags & I915_WAIT_PRIORITY && !i915_request_started(rq))
|
||
|
intel_rps_boost(rq);
|
||
|
|
||
|
wait.tsk = current;
|
||
|
if (dma_fence_add_callback(&rq->fence, &wait.cb, request_wait_wake))
|
||
|
goto out;
|
||
|
|
||
|
/*
|
||
|
* Flush the submission tasklet, but only if it may help this request.
|
||
|
*
|
||
|
* We sometimes experience some latency between the HW interrupts and
|
||
|
* tasklet execution (mostly due to ksoftirqd latency, but it can also
|
||
|
* be due to lazy CS events), so lets run the tasklet manually if there
|
||
|
* is a chance it may submit this request. If the request is not ready
|
||
|
* to run, as it is waiting for other fences to be signaled, flushing
|
||
|
* the tasklet is busy work without any advantage for this client.
|
||
|
*
|
||
|
* If the HW is being lazy, this is the last chance before we go to
|
||
|
* sleep to catch any pending events. We will check periodically in
|
||
|
* the heartbeat to flush the submission tasklets as a last resort
|
||
|
* for unhappy HW.
|
||
|
*/
|
||
|
if (i915_request_is_ready(rq))
|
||
|
__intel_engine_flush_submission(rq->engine, false);
|
||
|
|
||
|
for (;;) {
|
||
|
set_current_state(state);
|
||
|
|
||
|
if (dma_fence_is_signaled(&rq->fence))
|
||
|
break;
|
||
|
|
||
|
if (signal_pending_state(state, current)) {
|
||
|
timeout = -ERESTARTSYS;
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
if (!timeout) {
|
||
|
timeout = -ETIME;
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
timeout = io_schedule_timeout(timeout);
|
||
|
}
|
||
|
__set_current_state(TASK_RUNNING);
|
||
|
|
||
|
if (READ_ONCE(wait.tsk))
|
||
|
dma_fence_remove_callback(&rq->fence, &wait.cb);
|
||
|
GEM_BUG_ON(!list_empty(&wait.cb.node));
|
||
|
|
||
|
out:
|
||
|
mutex_release(&rq->engine->gt->reset.mutex.dep_map, _THIS_IP_);
|
||
|
trace_i915_request_wait_end(rq);
|
||
|
return timeout;
|
||
|
}
|
||
|
|
||
|
static int print_sched_attr(const struct i915_sched_attr *attr,
|
||
|
char *buf, int x, int len)
|
||
|
{
|
||
|
if (attr->priority == I915_PRIORITY_INVALID)
|
||
|
return x;
|
||
|
|
||
|
x += snprintf(buf + x, len - x,
|
||
|
" prio=%d", attr->priority);
|
||
|
|
||
|
return x;
|
||
|
}
|
||
|
|
||
|
static char queue_status(const struct i915_request *rq)
|
||
|
{
|
||
|
if (i915_request_is_active(rq))
|
||
|
return 'E';
|
||
|
|
||
|
if (i915_request_is_ready(rq))
|
||
|
return intel_engine_is_virtual(rq->engine) ? 'V' : 'R';
|
||
|
|
||
|
return 'U';
|
||
|
}
|
||
|
|
||
|
static const char *run_status(const struct i915_request *rq)
|
||
|
{
|
||
|
if (__i915_request_is_complete(rq))
|
||
|
return "!";
|
||
|
|
||
|
if (__i915_request_has_started(rq))
|
||
|
return "*";
|
||
|
|
||
|
if (!i915_sw_fence_signaled(&rq->semaphore))
|
||
|
return "&";
|
||
|
|
||
|
return "";
|
||
|
}
|
||
|
|
||
|
static const char *fence_status(const struct i915_request *rq)
|
||
|
{
|
||
|
if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &rq->fence.flags))
|
||
|
return "+";
|
||
|
|
||
|
if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &rq->fence.flags))
|
||
|
return "-";
|
||
|
|
||
|
return "";
|
||
|
}
|
||
|
|
||
|
void i915_request_show(struct drm_printer *m,
|
||
|
const struct i915_request *rq,
|
||
|
const char *prefix,
|
||
|
int indent)
|
||
|
{
|
||
|
const char *name = rq->fence.ops->get_timeline_name((struct dma_fence *)&rq->fence);
|
||
|
char buf[80] = "";
|
||
|
int x = 0;
|
||
|
|
||
|
/*
|
||
|
* The prefix is used to show the queue status, for which we use
|
||
|
* the following flags:
|
||
|
*
|
||
|
* U [Unready]
|
||
|
* - initial status upon being submitted by the user
|
||
|
*
|
||
|
* - the request is not ready for execution as it is waiting
|
||
|
* for external fences
|
||
|
*
|
||
|
* R [Ready]
|
||
|
* - all fences the request was waiting on have been signaled,
|
||
|
* and the request is now ready for execution and will be
|
||
|
* in a backend queue
|
||
|
*
|
||
|
* - a ready request may still need to wait on semaphores
|
||
|
* [internal fences]
|
||
|
*
|
||
|
* V [Ready/virtual]
|
||
|
* - same as ready, but queued over multiple backends
|
||
|
*
|
||
|
* E [Executing]
|
||
|
* - the request has been transferred from the backend queue and
|
||
|
* submitted for execution on HW
|
||
|
*
|
||
|
* - a completed request may still be regarded as executing, its
|
||
|
* status may not be updated until it is retired and removed
|
||
|
* from the lists
|
||
|
*/
|
||
|
|
||
|
x = print_sched_attr(&rq->sched.attr, buf, x, sizeof(buf));
|
||
|
|
||
|
drm_printf(m, "%s%.*s%c %llx:%lld%s%s %s @ %dms: %s\n",
|
||
|
prefix, indent, " ",
|
||
|
queue_status(rq),
|
||
|
rq->fence.context, rq->fence.seqno,
|
||
|
run_status(rq),
|
||
|
fence_status(rq),
|
||
|
buf,
|
||
|
jiffies_to_msecs(jiffies - rq->emitted_jiffies),
|
||
|
name);
|
||
|
}
|
||
|
|
||
|
static bool engine_match_ring(struct intel_engine_cs *engine, struct i915_request *rq)
|
||
|
{
|
||
|
u32 ring = ENGINE_READ(engine, RING_START);
|
||
|
|
||
|
return ring == i915_ggtt_offset(rq->ring->vma);
|
||
|
}
|
||
|
|
||
|
static bool match_ring(struct i915_request *rq)
|
||
|
{
|
||
|
struct intel_engine_cs *engine;
|
||
|
bool found;
|
||
|
int i;
|
||
|
|
||
|
if (!intel_engine_is_virtual(rq->engine))
|
||
|
return engine_match_ring(rq->engine, rq);
|
||
|
|
||
|
found = false;
|
||
|
i = 0;
|
||
|
while ((engine = intel_engine_get_sibling(rq->engine, i++))) {
|
||
|
found = engine_match_ring(engine, rq);
|
||
|
if (found)
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
return found;
|
||
|
}
|
||
|
|
||
|
enum i915_request_state i915_test_request_state(struct i915_request *rq)
|
||
|
{
|
||
|
if (i915_request_completed(rq))
|
||
|
return I915_REQUEST_COMPLETE;
|
||
|
|
||
|
if (!i915_request_started(rq))
|
||
|
return I915_REQUEST_PENDING;
|
||
|
|
||
|
if (match_ring(rq))
|
||
|
return I915_REQUEST_ACTIVE;
|
||
|
|
||
|
return I915_REQUEST_QUEUED;
|
||
|
}
|
||
|
|
||
|
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
|
||
|
#include "selftests/mock_request.c"
|
||
|
#include "selftests/i915_request.c"
|
||
|
#endif
|
||
|
|
||
|
void i915_request_module_exit(void)
|
||
|
{
|
||
|
kmem_cache_destroy(slab_execute_cbs);
|
||
|
kmem_cache_destroy(slab_requests);
|
||
|
}
|
||
|
|
||
|
int __init i915_request_module_init(void)
|
||
|
{
|
||
|
slab_requests =
|
||
|
kmem_cache_create("i915_request",
|
||
|
sizeof(struct i915_request),
|
||
|
__alignof__(struct i915_request),
|
||
|
SLAB_HWCACHE_ALIGN |
|
||
|
SLAB_RECLAIM_ACCOUNT |
|
||
|
SLAB_TYPESAFE_BY_RCU,
|
||
|
__i915_request_ctor);
|
||
|
if (!slab_requests)
|
||
|
return -ENOMEM;
|
||
|
|
||
|
slab_execute_cbs = KMEM_CACHE(execute_cb,
|
||
|
SLAB_HWCACHE_ALIGN |
|
||
|
SLAB_RECLAIM_ACCOUNT |
|
||
|
SLAB_TYPESAFE_BY_RCU);
|
||
|
if (!slab_execute_cbs)
|
||
|
goto err_requests;
|
||
|
|
||
|
return 0;
|
||
|
|
||
|
err_requests:
|
||
|
kmem_cache_destroy(slab_requests);
|
||
|
return -ENOMEM;
|
||
|
}
|