root/drivers/gpu/drm/i915/i915_scheduler.h

INCLUDED FROM

DEFINITIONS

1. i915_priolist_free
2. i915_scheduler_need_preempt

   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_ */