2 * SPDX-License-Identifier: MIT
4 * Copyright © 2018 Intel Corporation
7 #ifndef _I915_SCHEDULER_H_
8 #define _I915_SCHEDULER_H_
10 #include <linux/bitops.h>
11 #include <linux/list.h>
12 #include <linux/kernel.h>
14 #include "i915_scheduler_types.h"
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)
20 #define priolist_for_each_request_consume(it, n, plist, idx) \
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], \
28 void i915_sched_node_init(struct i915_sched_node *node);
30 bool __i915_sched_node_add_dependency(struct i915_sched_node *node,
31 struct i915_sched_node *signal,
32 struct i915_dependency *dep,
35 int i915_sched_node_add_dependency(struct i915_sched_node *node,
36 struct i915_sched_node *signal);
38 void i915_sched_node_fini(struct i915_sched_node *node);
40 void i915_schedule(struct i915_request *request,
41 const struct i915_sched_attr *attr);
43 void i915_schedule_bump_priority(struct i915_request *rq, unsigned int bump);
46 i915_sched_lookup_priolist(struct intel_engine_cs *engine, int prio);
48 void __i915_priolist_free(struct i915_priolist *p);
49 static inline void i915_priolist_free(struct i915_priolist *p)
51 if (p->priority != I915_PRIORITY_NORMAL)
52 __i915_priolist_free(p);
55 static inline bool i915_scheduler_need_preempt(int prio, int active)
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),
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.
70 return prio > max(I915_PRIORITY_NORMAL - 1, active);
73 #endif /* _I915_SCHEDULER_H_ */