Add methods to enable configuration of ResourceConstraints based on limits derived at runtime.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 0a38fa9f32b2b3e3932a178d756c80b44b1a0c1e..0bed005feef1b9fb61490f78ab89e1ab21cbcb53 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -633,6 +633,44 @@ bool SetResourceConstraints(ResourceConstraints* constraints) {
 }
 
 
+bool ConfigureResourceConstraintsForCurrentPlatform(

[Hannes Payer (out of office), 2013/09/24 07:31:00]

We had another discussion about that function right now... can we move it to a
separate file like v8-defaults.h? Adding it to the api is problematic for many
reasons, e.g., it hard to get rid of stuff added to the api.

[rmcilroy, 2013/09/24 10:50:55]

Done.  Kept the implementation here in api.cc though since that seems to be the
model with other split out includes (e.g., v8-testing.h, etc).

+    ResourceConstraints* constraints) {
+  if (constraints == NULL) {
+    return false;
+  }
+

[Hannes Payer (out of office), 2013/09/24 07:31:00]

Please add a comment which specifies the given configuration values, e.g., young
space has to be a power of 2 and old space has to be a multiple of
Page::kPageSize.

[rmcilroy, 2013/09/24 10:50:55]

Done.

+#if V8_TARGET_ARCH_X64
+  uintptr_t lump_of_memory = i::Max(2 * i::MB, i::Page::kPageSize);
+#else
+  uintptr_t lump_of_memory = i::Max(i::MB, i::Page::kPageSize);
+#endif
+
+  uintptr_t physical_memory = i::OS::TotalPhysicalMemory();
+  if (physical_memory > 2ul * i::GB) {
+    constraints->set_max_young_space_size(8 * 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(4 * 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(1 * lump_of_memory);
+    constraints->set_max_old_space_size(96 * lump_of_memory);
+    constraints->set_max_executable_size(96 * lump_of_memory);
+  }
+  return true;
+}
+
+
+bool SetDefaultResourceConstraintsForCurrentPlatform() {
+  ResourceConstraints constraints;
+  if (!ConfigureResourceConstraintsForCurrentPlatform(&constraints))
+    return false;
+  return SetResourceConstraints(&constraints);
+}
+
+
 i::Object** V8::GlobalizeReference(i::Isolate* isolate, i::Object** obj) {
   if (IsDeadCheck(isolate, "V8::Persistent::New")) return NULL;
   LOG_API(isolate, "Persistent::New");