De-hardcode link concurrency for Windows.

pylib/gyp/generator/ninja.py

 # Copyright (c) 2013 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import copy
 import hashlib
 import json
 import multiprocessing
 import os.path
 import re
@@ skipping 1539 matching lines @@
         ("ullAvailVirtual", ctypes.c_ulonglong),
         ("sullAvailExtendedVirtual", ctypes.c_ulonglong),
       ]
 
     stat = MEMORYSTATUSEX()
     stat.dwLength = ctypes.sizeof(stat)
     ctypes.windll.kernel32.GlobalMemoryStatusEx(ctypes.byref(stat))
 
     mem_limit = max(1, stat.ullTotalPhys / (4 * (2 ** 30)))  # total / 4GB
     hard_cap = max(1, int(os.getenv('GYP_LINK_CONCURRENCY_MAX', 2**32)))
-    # return min(mem_limit, hard_cap)
-    # TODO(scottmg): Temporary speculative fix for OOM on builders
-    # See http://crbug.com/333000.
-    return 2
+    return min(mem_limit, hard_cap)
   elif sys.platform.startswith('linux'):
     with open("/proc/meminfo") as meminfo:
       memtotal_re = re.compile(r'^MemTotal:\s*(\d*)\s*kB')
       for line in meminfo:
         match = memtotal_re.match(line)
         if not match:
           continue
         # Allow 8Gb per link on Linux because Gold is quite memory hungry
         return max(1, int(match.group(1)) / (8 * (2 ** 20)))
     return 1
@@ skipping 567 matching lines @@
           arglists.append(
               (target_list, target_dicts, data, params, config_name))
         pool.map(CallGenerateOutputForConfig, arglists)
       except KeyboardInterrupt, e:
         pool.terminate()
         raise e
     else:
       for config_name in config_names:
         GenerateOutputForConfig(target_list, target_dicts, data, params,
                                 config_name)