From 2e18fe710ceb8e4f8f067041d18de0560359eecd Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <odigiman@gmail.com>
Date: Sat, 14 Jul 2018 18:07:37 +0100
Subject: [PATCH] MemoryManager: Shut down idle workers during GC to reclaim
 memory workers can be a major memory hog, especially if you have lots of
 them.

---
 src/pocketmine/MemoryManager.php       |  3 +++
 src/pocketmine/scheduler/AsyncPool.php | 13 +++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/src/pocketmine/MemoryManager.php b/src/pocketmine/MemoryManager.php
index 38f56ec47..34cc31f52 100644
--- a/src/pocketmine/MemoryManager.php
+++ b/src/pocketmine/MemoryManager.php
@@ -243,6 +243,9 @@ class MemoryManager{
 
 		if($this->garbageCollectionAsync){
 			$pool = $this->server->getAsyncPool();
+			if(($w = $pool->shutdownUnusedWorkers()) > 0){
+				$this->server->getLogger()->debug("Shut down $w idle async pool workers");
+			}
 			foreach($pool->getRunningWorkers() as $i){
 				$pool->submitTaskToWorker(new GarbageCollectionTask(), $i);
 			}
diff --git a/src/pocketmine/scheduler/AsyncPool.php b/src/pocketmine/scheduler/AsyncPool.php
index dbdb1de9d..f669b00bd 100644
--- a/src/pocketmine/scheduler/AsyncPool.php
+++ b/src/pocketmine/scheduler/AsyncPool.php
@@ -317,6 +317,19 @@ class AsyncPool{
 		$this->collectWorkers();
 	}
 
+	public function shutdownUnusedWorkers() : int{
+		$ret = 0;
+		foreach($this->workerUsage as $i => $usage){
+			if($usage === 0){
+				$this->workers[$i]->quit();
+				unset($this->workers[$i], $this->workerUsage[$i]);
+				$ret++;
+			}
+		}
+
+		return $ret;
+	}
+
 	/**
 	 * Cancels all pending tasks and shuts down all the workers in the pool.
 	 */