1 /* 2 * SPDX-License-Identifier: MIT 3 * 4 * Copyright © 2018 Intel Corporation 5 */ 6 7 #ifndef _I915_SCHEDULER_H_ 8 #define _I915_SCHEDULER_H_ 9 10 #include <linux/bitops.h> 11 #include <linux/kernel.h> 12 13 #include <uapi/drm/i915_drm.h> 14 15 struct drm_i915_private; 16 struct i915_request; 17 struct intel_engine_cs; 18 19 enum { 20 I915_PRIORITY_MIN = I915_CONTEXT_MIN_USER_PRIORITY - 1, 21 I915_PRIORITY_NORMAL = I915_CONTEXT_DEFAULT_PRIORITY, 22 I915_PRIORITY_MAX = I915_CONTEXT_MAX_USER_PRIORITY + 1, 23 24 I915_PRIORITY_INVALID = INT_MIN 25 }; 26 27 #define I915_USER_PRIORITY_SHIFT 3 28 #define I915_USER_PRIORITY(x) ((x) << I915_USER_PRIORITY_SHIFT) 29 30 #define I915_PRIORITY_COUNT BIT(I915_USER_PRIORITY_SHIFT) 31 #define I915_PRIORITY_MASK (I915_PRIORITY_COUNT - 1) 32 33 #define I915_PRIORITY_WAIT ((u8)BIT(0)) 34 #define I915_PRIORITY_NEWCLIENT ((u8)BIT(1)) 35 #define I915_PRIORITY_NOSEMAPHORE ((u8)BIT(2)) 36 37 #define __NO_PREEMPTION (I915_PRIORITY_WAIT) 38 39 struct i915_sched_attr { 40 /** 41 * @priority: execution and service priority 42 * 43 * All clients are equal, but some are more equal than others! 44 * 45 * Requests from a context with a greater (more positive) value of 46 * @priority will be executed before those with a lower @priority 47 * value, forming a simple QoS. 48 * 49 * The &drm_i915_private.kernel_context is assigned the lowest priority. 50 */ 51 int priority; 52 }; 53 54 /* 55 * "People assume that time is a strict progression of cause to effect, but 56 * actually, from a nonlinear, non-subjective viewpoint, it's more like a big 57 * ball of wibbly-wobbly, timey-wimey ... stuff." -The Doctor, 2015 58 * 59 * Requests exist in a complex web of interdependencies. Each request 60 * has to wait for some other request to complete before it is ready to be run 61 * (e.g. we have to wait until the pixels have been rendering into a texture 62 * before we can copy from it). We track the readiness of a request in terms 63 * of fences, but we also need to keep the dependency tree for the lifetime 64 * of the request (beyond the life of an individual fence). We use the tree 65 * at various points to reorder the requests whilst keeping the requests 66 * in order with respect to their various dependencies. 67 * 68 * There is no active component to the "scheduler". As we know the dependency 69 * DAG of each request, we are able to insert it into a sorted queue when it 70 * is ready, and are able to reorder its portion of the graph to accommodate 71 * dynamic priority changes. 72 */ 73 struct i915_sched_node { 74 struct list_head signalers_list; /* those before us, we depend upon */ 75 struct list_head waiters_list; /* those after us, they depend upon us */ 76 struct list_head link; 77 struct i915_sched_attr attr; 78 unsigned int flags; 79 #define I915_SCHED_HAS_SEMAPHORE BIT(0) 80 }; 81 82 struct i915_dependency { 83 struct i915_sched_node *signaler; 84 struct list_head signal_link; 85 struct list_head wait_link; 86 struct list_head dfs_link; 87 unsigned long flags; 88 #define I915_DEPENDENCY_ALLOC BIT(0) 89 }; 90 91 struct i915_priolist { 92 struct list_head requests[I915_PRIORITY_COUNT]; 93 struct rb_node node; 94 unsigned long used; 95 int priority; 96 }; 97 98 #define priolist_for_each_request(it, plist, idx) \ 99 for (idx = 0; idx < ARRAY_SIZE((plist)->requests); idx++) \ 100 list_for_each_entry(it, &(plist)->requests[idx], sched.link) 101 102 #define priolist_for_each_request_consume(it, n, plist, idx) \ 103 for (; \ 104 (plist)->used ? (idx = __ffs((plist)->used)), 1 : 0; \ 105 (plist)->used &= ~BIT(idx)) \ 106 list_for_each_entry_safe(it, n, \ 107 &(plist)->requests[idx], \ 108 sched.link) 109 110 void i915_sched_node_init(struct i915_sched_node *node); 111 112 bool __i915_sched_node_add_dependency(struct i915_sched_node *node, 113 struct i915_sched_node *signal, 114 struct i915_dependency *dep, 115 unsigned long flags); 116 117 int i915_sched_node_add_dependency(struct i915_sched_node *node, 118 struct i915_sched_node *signal); 119 120 void i915_sched_node_fini(struct i915_sched_node *node); 121 122 void i915_schedule(struct i915_request *request, 123 const struct i915_sched_attr *attr); 124 125 void i915_schedule_bump_priority(struct i915_request *rq, unsigned int bump); 126 127 struct list_head * 128 i915_sched_lookup_priolist(struct intel_engine_cs *engine, int prio); 129 130 void __i915_priolist_free(struct i915_priolist *p); 131 static inline void i915_priolist_free(struct i915_priolist *p) 132 { 133 if (p->priority != I915_PRIORITY_NORMAL) 134 __i915_priolist_free(p); 135 } 136 137 #endif /* _I915_SCHEDULER_H_ */ 138