Function RestartWorkers

worker.go:239–250

RestartWorkers attempts to restart all workers gracefully. All workers must be restarted at the same time to prevent issues with opcache resetting. Blocks until every worker thread has yielded; force-kill is armed after a grace period to wake threads parked in blocking syscalls so a stuck sleep does

()

// blocking syscalls so a stuck sleep doesn't make this hang for the
// full duration of the syscall.
func RestartWorkers() {
	// disallow scaling threads while restarting workers
	scalingMu.Lock()
	defer scalingMu.Unlock()

	threadsToRestart := drainWorkerThreads()

	for _, thread := range threadsToRestart {
		thread.drainChan = make(chan struct{})
		thread.state.Set(state.Ready)
	}
}

func (worker *worker) attachThread(thread *phpThread) {
	worker.threadMutex.Lock()