43 lines
1.4 KiB
Go
43 lines
1.4 KiB
Go
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package watchdog
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// NewWatermarkPolicy creates a watchdog policy that schedules GC at concrete
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// watermarks. When queried, it will determine the next trigger point based
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// on the current utilisation. If the last watermark is surpassed,
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// the policy will be disarmed. It is recommended to set an extreme watermark
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// as the last element (e.g. 0.99) to prevent the policy from disarming too soon.
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func NewWatermarkPolicy(watermarks ...float64) PolicyCtor {
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return func(limit uint64) (Policy, error) {
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p := new(watermarkPolicy)
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p.limit = limit
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p.thresholds = make([]uint64, 0, len(watermarks))
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for _, m := range watermarks {
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p.thresholds = append(p.thresholds, uint64(float64(limit)*m))
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}
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Logger.Infof("initialized watermark watchdog policy; watermarks: %v; thresholds: %v", p.watermarks, p.thresholds)
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return p, nil
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}
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}
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type watermarkPolicy struct {
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// watermarks are the percentual amounts of limit.
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watermarks []float64
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// thresholds are the absolute trigger points of this policy.
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thresholds []uint64
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limit uint64
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}
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var _ Policy = (*watermarkPolicy)(nil)
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func (w *watermarkPolicy) Evaluate(_ UtilizationType, used uint64) (next uint64) {
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Logger.Debugf("watermark policy: evaluating; utilization: %d/%d (used/limit)", used, w.limit)
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var i int
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for ; i < len(w.thresholds); i++ {
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t := w.thresholds[i]
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if used < t {
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return t
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}
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}
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// we reached the maximum threshold, so we disable this policy.
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return PolicyTempDisabled
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}
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