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 2 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 36 struct i915_sched_attr { 37 /** 38 * @priority: execution and service priority 39 * 40 * All clients are equal, but some are more equal than others! 41 * 42 * Requests from a context with a greater (more positive) value of 43 * @priority will be executed before those with a lower @priority 44 * value, forming a simple QoS. 45 * 46 * The &drm_i915_private.kernel_context is assigned the lowest priority. 47 */ 48 int priority; 49 }; 50 51 /* 52 * "People assume that time is a strict progression of cause to effect, but 53 * actually, from a nonlinear, non-subjective viewpoint, it's more like a big 54 * ball of wibbly-wobbly, timey-wimey ... stuff." -The Doctor, 2015 55 * 56 * Requests exist in a complex web of interdependencies. Each request 57 * has to wait for some other request to complete before it is ready to be run 58 * (e.g. we have to wait until the pixels have been rendering into a texture 59 * before we can copy from it). We track the readiness of a request in terms 60 * of fences, but we also need to keep the dependency tree for the lifetime 61 * of the request (beyond the life of an individual fence). We use the tree 62 * at various points to reorder the requests whilst keeping the requests 63 * in order with respect to their various dependencies. 64 * 65 * There is no active component to the "scheduler". As we know the dependency 66 * DAG of each request, we are able to insert it into a sorted queue when it 67 * is ready, and are able to reorder its portion of the graph to accommodate 68 * dynamic priority changes. 69 */ 70 struct i915_sched_node { 71 struct list_head signalers_list; /* those before us, we depend upon */ 72 struct list_head waiters_list; /* those after us, they depend upon us */ 73 struct list_head link; 74 struct i915_sched_attr attr; 75 }; 76 77 struct i915_dependency { 78 struct i915_sched_node *signaler; 79 struct list_head signal_link; 80 struct list_head wait_link; 81 struct list_head dfs_link; 82 unsigned long flags; 83 #define I915_DEPENDENCY_ALLOC BIT(0) 84 }; 85 86 void i915_sched_node_init(struct i915_sched_node *node); 87 88 bool __i915_sched_node_add_dependency(struct i915_sched_node *node, 89 struct i915_sched_node *signal, 90 struct i915_dependency *dep, 91 unsigned long flags); 92 93 int i915_sched_node_add_dependency(struct drm_i915_private *i915, 94 struct i915_sched_node *node, 95 struct i915_sched_node *signal); 96 97 void i915_sched_node_fini(struct drm_i915_private *i915, 98 struct i915_sched_node *node); 99 100 void i915_schedule(struct i915_request *request, 101 const struct i915_sched_attr *attr); 102 103 void i915_schedule_bump_priority(struct i915_request *rq, unsigned int bump); 104 105 struct list_head * 106 i915_sched_lookup_priolist(struct intel_engine_cs *engine, int prio); 107 108 #endif /* _I915_SCHEDULER_H_ */ 109