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Diffstat (limited to 'drivers/gpu/drm/i915/i915_scheduler.h')
-rw-r--r--drivers/gpu/drm/i915/i915_scheduler.h18
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_scheduler.h b/drivers/gpu/drm/i915/i915_scheduler.h
index 07d243acf553..7eefccff39bf 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.h
+++ b/drivers/gpu/drm/i915/i915_scheduler.h
@@ -52,4 +52,22 @@ static inline void i915_priolist_free(struct i915_priolist *p)
__i915_priolist_free(p);
}
+static inline bool i915_scheduler_need_preempt(int prio, int active)
+{
+ /*
+ * Allow preemption of low -> normal -> high, but we do
+ * not allow low priority tasks to preempt other low priority
+ * tasks under the impression that latency for low priority
+ * tasks does not matter (as much as background throughput),
+ * so kiss.
+ *
+ * More naturally we would write
+ * prio >= max(0, last);
+ * except that we wish to prevent triggering preemption at the same
+ * priority level: the task that is running should remain running
+ * to preserve FIFO ordering of dependencies.
+ */
+ return prio > max(I915_PRIORITY_NORMAL - 1, active);
+}
+
#endif /* _I915_SCHEDULER_H_ */