55 lines
1.3 KiB
Go
55 lines
1.3 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 https://mozilla.org/MPL/2.0/.
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package model
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import (
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"github.com/syncthing/syncthing/lib/protocol"
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"github.com/syncthing/syncthing/lib/sync"
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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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mut: sync.NewMutex(),
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}
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}
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// Returns the index of the least busy device, or -1 if all are too busy.
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func (m *deviceActivity) leastBusy(availability []Availability) int {
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m.mut.Lock()
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low := 2<<30 - 1
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best := -1
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for i := range availability {
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if usage := m.act[availability[i].ID]; usage < low {
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low = usage
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best = i
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}
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}
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m.mut.Unlock()
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return best
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}
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func (m *deviceActivity) using(availability Availability) {
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m.mut.Lock()
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m.act[availability.ID]++
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m.mut.Unlock()
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}
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func (m *deviceActivity) done(availability Availability) {
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m.mut.Lock()
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m.act[availability.ID]--
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m.mut.Unlock()
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}
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