forked from mirrors/gotosocial
acc333c40b
When GTS is running in a container runtime which has configured CPU or memory limits or under an init system that uses cgroups to impose CPU and memory limits the values the Go runtime sees for GOMAXPROCS and GOMEMLIMIT are still based on the host resources, not the cgroup. At least for the throttling middlewares which use GOMAXPROCS to configure their queue size, this can result in GTS running with values too big compared to the resources that will actuall be available to it. This introduces 2 dependencies which can pick up resource contraints from the current cgroup and tune the Go runtime accordingly. This should result in the different queues being appropriately sized and in general more predictable performance. These dependencies are a no-op on non-Linux systems or if running in a cgroup that doesn't set a limit on CPU or memory. The automatic tuning of GOMEMLIMIT can be disabled by either explicitly setting GOMEMLIMIT yourself or by setting AUTOMEMLIMIT=off. The automatic tuning of GOMAXPROCS can similarly be counteracted by setting GOMAXPROCS yourself.
125 lines
2.6 KiB
Go
125 lines
2.6 KiB
Go
package dbus
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import (
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"sync"
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)
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// NewSequentialSignalHandler returns an instance of a new
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// signal handler that guarantees sequential processing of signals. It is a
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// guarantee of this signal handler that signals will be written to
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// channels in the order they are received on the DBus connection.
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func NewSequentialSignalHandler() SignalHandler {
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return &sequentialSignalHandler{}
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}
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type sequentialSignalHandler struct {
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mu sync.RWMutex
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closed bool
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signals []*sequentialSignalChannelData
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}
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func (sh *sequentialSignalHandler) DeliverSignal(intf, name string, signal *Signal) {
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sh.mu.RLock()
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defer sh.mu.RUnlock()
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if sh.closed {
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return
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}
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for _, scd := range sh.signals {
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scd.deliver(signal)
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}
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}
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func (sh *sequentialSignalHandler) Terminate() {
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sh.mu.Lock()
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defer sh.mu.Unlock()
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if sh.closed {
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return
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}
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for _, scd := range sh.signals {
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scd.close()
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close(scd.ch)
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}
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sh.closed = true
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sh.signals = nil
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}
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func (sh *sequentialSignalHandler) AddSignal(ch chan<- *Signal) {
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sh.mu.Lock()
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defer sh.mu.Unlock()
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if sh.closed {
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return
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}
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sh.signals = append(sh.signals, newSequentialSignalChannelData(ch))
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}
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func (sh *sequentialSignalHandler) RemoveSignal(ch chan<- *Signal) {
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sh.mu.Lock()
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defer sh.mu.Unlock()
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if sh.closed {
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return
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}
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for i := len(sh.signals) - 1; i >= 0; i-- {
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if ch == sh.signals[i].ch {
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sh.signals[i].close()
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copy(sh.signals[i:], sh.signals[i+1:])
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sh.signals[len(sh.signals)-1] = nil
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sh.signals = sh.signals[:len(sh.signals)-1]
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}
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}
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}
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type sequentialSignalChannelData struct {
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ch chan<- *Signal
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in chan *Signal
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done chan struct{}
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}
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func newSequentialSignalChannelData(ch chan<- *Signal) *sequentialSignalChannelData {
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scd := &sequentialSignalChannelData{
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ch: ch,
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in: make(chan *Signal),
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done: make(chan struct{}),
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}
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go scd.bufferSignals()
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return scd
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}
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func (scd *sequentialSignalChannelData) bufferSignals() {
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defer close(scd.done)
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// Ensure that signals are delivered to scd.ch in the same
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// order they are received from scd.in.
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var queue []*Signal
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for {
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if len(queue) == 0 {
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signal, ok := <- scd.in
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if !ok {
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return
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}
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queue = append(queue, signal)
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}
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select {
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case scd.ch <- queue[0]:
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copy(queue, queue[1:])
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queue[len(queue)-1] = nil
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queue = queue[:len(queue)-1]
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case signal, ok := <-scd.in:
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if !ok {
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return
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}
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queue = append(queue, signal)
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}
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}
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}
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func (scd *sequentialSignalChannelData) deliver(signal *Signal) {
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scd.in <- signal
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}
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func (scd *sequentialSignalChannelData) close() {
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close(scd.in)
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// Ensure that bufferSignals() has exited and won't attempt
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// any future sends on scd.ch
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<-scd.done
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}
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