worker: pass resource limits to child.

preparing for: nodejs/node#26628 (comment)

Author: chjj

lib/process/parent.js

@@ -50,7 +50,8 @@ const {
 const {
   BTHREADS_WORKER_ID: WORKER_ID,
   BTHREADS_WORKER_DATA: WORKER_DATA,
-  BTHREADS_WORKER_STDIN: WORKER_STDIN
+  BTHREADS_WORKER_STDIN: WORKER_STDIN,
+  BTHREADS_WORKER_LIMITS: WORKER_LIMITS
 } = process.env;
 
 /**
@@ -63,6 +64,7 @@ class Parent extends MessagePortBase {
 
     this._workerId = WORKER_ID >>> 0;
     this._workerData = encoding.parse(WORKER_DATA);
+    this._workerLimits = encoding.parse(WORKER_LIMITS);
     this._parser = new Parser(this);
     this._ports = new Map();
     this._closed = false;

lib/process/worker.js

@@ -108,7 +108,6 @@ class Worker extends EventEmitter {
 
   _init(file, options) {
     const bin = process.execPath || process.argv[0];
-    const limits = options.resourceLimits;
     const args = [];
 
     // Validate filename.
@@ -187,18 +186,29 @@ class Worker extends EventEmitter {
     }
 
     // Enforce resource limits.
-    if (limits) {
+    const limits = new Uint32Array(3);
+
+    if (options.resourceLimits) {
       const argsLen = args.length;
-      const maxOld = limits.maxOldSpaceSizeMb;
-      const maxSemi = limits.maxSemiSpaceSizeMb;
+      const { maxOldSpaceSizeMb,
+              maxSemiSpaceSizeMb,
+              codeRangeSizeMb } = options.resourceLimits;
+
+      if (typeof maxOldSpaceSizeMb === 'number')
+        limits[0] = Math.max(maxOldSpaceSizeMb, 2);
+
+      if (typeof maxSemiSpaceSizeMb === 'number')
+        limits[1] = maxSemiSpaceSizeMb;
+
+      if (typeof codeRangeSizeMb === 'number')
+        limits[2] = codeRangeSizeMb;
 
-      if (typeof maxOld === 'number')
-        args.push(`--max-old-space-size=${Math.max(maxOld, 2)}`);
+      if (limits[0] > 0)
+        args.push(`--max-old-space-size=${limits[0]}`);
 
-      if (typeof maxSemi === 'number')
-        args.push(`--max-semi-space-size=${maxSemi}`);
+      if (limits[1] > 0)
+        args.push(`--max-semi-space-size=${limits[1]}`);
 
-      // Todo: figure out how to do codeRangeSizeMb.
       this._limits = args.length > argsLen;
     }
 
@@ -226,7 +236,8 @@ class Worker extends EventEmitter {
         BTHREADS_WORKER_ID: this.threadId.toString(10),
         BTHREADS_WORKER_DATA: encoding.stringify(options.workerData),
         BTHREADS_WORKER_STDIN: options.stdin ? '1' : '0',
-        BTHREADS_WORKER_EVAL: options.eval ? '1' : '0'
+        BTHREADS_WORKER_EVAL: options.eval ? '1' : '0',
+        BTHREADS_WORKER_LIMITS: encoding.stringify(limits)
       })
     };