54 lines
1.2 KiB
Go
54 lines
1.2 KiB
Go
// Copyright (C) 2014 The Syncthing Authors.
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this file,
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// You can obtain one at http://mozilla.org/MPL/2.0/.
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package model
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import (
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"sync"
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"github.com/syncthing/protocol"
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)
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// deviceActivity tracks the number of outstanding requests per device and can
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// answer which device is least busy. It is safe for use from multiple
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// goroutines.
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type deviceActivity struct {
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act map[protocol.DeviceID]int
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mut sync.Mutex
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}
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func newDeviceActivity() *deviceActivity {
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return &deviceActivity{
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act: make(map[protocol.DeviceID]int),
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}
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}
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func (m *deviceActivity) leastBusy(availability []protocol.DeviceID) protocol.DeviceID {
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m.mut.Lock()
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low := 2<<30 - 1
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var selected protocol.DeviceID
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for _, device := range availability {
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if usage := m.act[device]; usage < low {
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low = usage
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selected = device
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}
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}
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m.mut.Unlock()
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return selected
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}
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func (m *deviceActivity) using(device protocol.DeviceID) {
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m.mut.Lock()
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m.act[device]++
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m.mut.Unlock()
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}
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func (m *deviceActivity) done(device protocol.DeviceID) {
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m.mut.Lock()
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m.act[device]--
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m.mut.Unlock()
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}
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