40 lines
668 B
Go
40 lines
668 B
Go
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package qos
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import (
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"context"
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"errors"
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"sync/atomic"
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"git.frostfs.info/TrueCloudLab/frostfs-qos/scheduling"
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)
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var (
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_ scheduler = (*semaphore)(nil)
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errSemaphoreLimitExceeded = errors.New("semaphore limit exceeded")
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)
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type semaphore struct {
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count atomic.Int64
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limit int64
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}
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func (s *semaphore) Close() {}
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func (s *semaphore) RequestArrival(ctx context.Context, _ string) (scheduling.ReleaseFunc, error) {
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select {
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case <-ctx.Done():
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return nil, ctx.Err()
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default:
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}
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v := s.count.Add(1)
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if v > s.limit {
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s.count.Add(-1)
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return nil, errSemaphoreLimitExceeded
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}
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return func() {
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s.count.Add(-1)
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}, nil
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}
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