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/list.h> 12 #include <linux/kernel.h> 13 14 #include "i915_scheduler_types.h" 15 16 #define priolist_for_each_request(it, plist, idx) \ 17 for (idx = 0; idx < ARRAY_SIZE((plist)->requests); idx++) \ 18 list_for_each_entry(it, &(plist)->requests[idx], sched.link) 19 20 #define priolist_for_each_request_consume(it, n, plist, idx) \ 21 for (; \ 22 (plist)->used ? (idx = __ffs((plist)->used)), 1 : 0; \ 23 (plist)->used &= ~BIT(idx)) \ 24 list_for_each_entry_safe(it, n, \ 25 &(plist)->requests[idx], \ 26 sched.link) 27 28 void i915_sched_node_init(struct i915_sched_node *node); 29 30 bool __i915_sched_node_add_dependency(struct i915_sched_node *node, 31 struct i915_sched_node *signal, 32 struct i915_dependency *dep, 33 unsigned long flags); 34 35 int i915_sched_node_add_dependency(struct i915_sched_node *node, 36 struct i915_sched_node *signal); 37 38 void i915_sched_node_fini(struct i915_sched_node *node); 39 40 void i915_schedule(struct i915_request *request, 41 const struct i915_sched_attr *attr); 42 43 void i915_schedule_bump_priority(struct i915_request *rq, unsigned int bump); 44 45 struct list_head * 46 i915_sched_lookup_priolist(struct intel_engine_cs *engine, int prio); 47 48 void __i915_priolist_free(struct i915_priolist *p); 49 static inline void i915_priolist_free(struct i915_priolist *p) 50 { 51 if (p->priority != I915_PRIORITY_NORMAL) 52 __i915_priolist_free(p); 53 } 54 55 static inline bool i915_scheduler_need_preempt(int prio, int active) 56 { 57 /* 58 * Allow preemption of low -> normal -> high, but we do 59 * not allow low priority tasks to preempt other low priority 60 * tasks under the impression that latency for low priority 61 * tasks does not matter (as much as background throughput), 62 * so kiss. 63 * 64 * More naturally we would write 65 * prio >= max(0, last); 66 * except that we wish to prevent triggering preemption at the same 67 * priority level: the task that is running should remain running 68 * to preserve FIFO ordering of dependencies. 69 */ 70 return prio > max(I915_PRIORITY_NORMAL - 1, active); 71 } 72 73 #endif /* _I915_SCHEDULER_H_ */ 74