Linux (and Android): Implement GetDefaultConcurrentLinks() for Linux Builds

pylib/gyp/generator/ninja.py

Index: pylib/gyp/generator/ninja.py
diff --git a/pylib/gyp/generator/ninja.py b/pylib/gyp/generator/ninja.py
index 25f5780dd26a5f77ad9d27662cd904b1e39e8cfc..58ea28b7e520a05c1251c1d54a4d2a526452f6f7 100644
--- a/pylib/gyp/generator/ninja.py
+++ b/pylib/gyp/generator/ninja.py
@@ -1483,6 +1483,16 @@ def GetDefaultConcurrentLinks():
     ctypes.windll.kernel32.GlobalMemoryStatusEx(ctypes.byref(stat))
 
     return max(1, stat.ullTotalPhys / (4 * (2 ** 30)))  # total / 4GB
+  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)))

[Nico, 2013/08/27 22:01:04]

Isn't 2**20 a megabyte, not a gigabyte?

...ah, /proc/meminfo stores kB, not bytes. This isn't super clear, maybe

  available_memory_bytes = int(match.group(1)) * 1024
  return max(1, available_memory_bytes / (8 * (2 ** 30)))

would be a bit clearer?

+    return 1
   else:
     # TODO(scottmg): Implement this for other platforms.
     return 1