Tweak default max heap size constants for platforms with swap.

src/defaults.cc

Index: src/defaults.cc
diff --git a/src/defaults.cc b/src/defaults.cc
index 301155f94dcb24f758eecf7f2d113ab026853381..eb9e0deab0f3211798504b1c7ccc4a7e27d031fc 100644
--- a/src/defaults.cc
+++ b/src/defaults.cc
@@ -33,6 +33,14 @@
 
 namespace v8 {
 
+
+#if V8_OS_ANDROID
+const bool kOsHasSwap = false;
+#else
+const bool kOsHasSwap = true;
+#endif
+
+
 bool ConfigureResourceConstraintsForCurrentPlatform(
     ResourceConstraints* constraints) {
   if (constraints == NULL) {
@@ -44,18 +52,22 @@ bool ConfigureResourceConstraintsForCurrentPlatform(
 
   // The young_space_size should be a power of 2 and old_generation_size should
   // be a multiple of Page::kPageSize.
-  if (physical_memory > 2ul * i::GB) {
+  if (physical_memory <= 512ul * i::MB) {

[Hannes Payer (out of office), 2013/10/02 12:59:17]

This change will increase the maximum used heap size on low memory devices. I
hope this is intended.

[rmcilroy, 2013/10/02 13:05:56]

Yes, this is intended.

+    constraints->set_max_young_space_size(2 * lump_of_memory);
+    constraints->set_max_old_space_size(128 * lump_of_memory);
+    constraints->set_max_executable_size(96 * lump_of_memory);
+  } else if (physical_memory <= (kOsHasSwap ? 768ul * i::MB : 1ul * i::GB)) {
+    constraints->set_max_young_space_size(8 * lump_of_memory);
+    constraints->set_max_old_space_size(256 * lump_of_memory);

[Hannes Payer (out of office), 2013/10/02 12:59:17]

Same here.

[rmcilroy, 2013/10/02 13:05:56]

Also intended.  Thanks for checking!

+    constraints->set_max_executable_size(192 * lump_of_memory);
+  } else if (physical_memory <= (kOsHasSwap ? 1ul * i::GB : 2ul * i::GB)) {
+    constraints->set_max_young_space_size(16 * lump_of_memory);
+    constraints->set_max_old_space_size(512 * lump_of_memory);
+    constraints->set_max_executable_size(256 * lump_of_memory);
+  } else {
     constraints->set_max_young_space_size(16 * lump_of_memory);
     constraints->set_max_old_space_size(700 * lump_of_memory);
     constraints->set_max_executable_size(256 * lump_of_memory);
-  } else if (physical_memory > 512ul * i::MB) {
-    constraints->set_max_young_space_size(8 * lump_of_memory);
-    constraints->set_max_old_space_size(192 * lump_of_memory);
-    constraints->set_max_executable_size(192 * lump_of_memory);
-  } else /* (physical_memory <= 512GB) */ {
-    constraints->set_max_young_space_size(2 * lump_of_memory);
-    constraints->set_max_old_space_size(96 * lump_of_memory);
-    constraints->set_max_executable_size(96 * lump_of_memory);
   }
   return true;
 }
@@ -68,4 +80,4 @@ bool SetDefaultResourceConstraintsForCurrentPlatform() {
   return SetResourceConstraints(&constraints);
 }
 
-}  // namespace v8::internal
+}  // namespace v8