99 lines
2.7 KiB
Go
99 lines
2.7 KiB
Go
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// Copyright 2018 Google Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package memevent implements the memory usage events controller, which
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// periodically emits events via the eventchannel.
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package memevent
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import (
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"sync"
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"time"
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"gvisor.googlesource.com/gvisor/pkg/eventchannel"
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"gvisor.googlesource.com/gvisor/pkg/log"
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"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
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pb "gvisor.googlesource.com/gvisor/pkg/sentry/kernel/memevent/memory_events_go_proto"
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"gvisor.googlesource.com/gvisor/pkg/sentry/usage"
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)
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// MemoryEvents describes the configuration for the global memory event emitter.
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type MemoryEvents struct {
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k *kernel.Kernel
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// The period is how often to emit an event. The memory events goroutine
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// will ensure a minimum of one event is emitted per this period, regardless
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// how of much memory usage has changed.
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period time.Duration
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// Writing to this channel indicates the memory goroutine should stop.
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stop chan struct{}
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// done is used to signal when the memory event goroutine has exited.
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done sync.WaitGroup
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}
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// New creates a new MemoryEvents.
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func New(k *kernel.Kernel, period time.Duration) *MemoryEvents {
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return &MemoryEvents{
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k: k,
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period: period,
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stop: make(chan struct{}),
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}
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}
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// Stop stops the memory usage events emitter goroutine. Stop must not be called
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// concurrently with Start and may only be called once.
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func (m *MemoryEvents) Stop() {
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close(m.stop)
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m.done.Wait()
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}
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// Start starts the memory usage events emitter goroutine. Start must not be
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// called concurrently with Stop and may only be called once.
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func (m *MemoryEvents) Start() {
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if m.period == 0 {
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return
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}
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go m.run() // S/R-SAFE: doesn't interact with saved state.
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}
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func (m *MemoryEvents) run() {
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m.done.Add(1)
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ticker := time.NewTicker(m.period)
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defer ticker.Stop()
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for {
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select {
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case <-m.stop:
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m.done.Done()
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return
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case <-ticker.C:
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m.emit()
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}
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}
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}
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func (m *MemoryEvents) emit() {
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totalPlatform, err := m.k.Platform.Memory().TotalUsage()
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if err != nil {
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log.Warningf("Failed to fetch memory usage for memory events: %v", err)
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return
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}
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snapshot, _ := usage.MemoryAccounting.Copy()
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total := totalPlatform + snapshot.Mapped
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eventchannel.Emit(&pb.MemoryUsageEvent{Total: total})
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}
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