Reduce boot-up memory use of V8.

src/heap.cc

Index: src/heap.cc
===================================================================
--- src/heap.cc	(revision 10513)
+++ src/heap.cc	(working copy)
@@ -582,10 +582,11 @@
   PagedSpace* map_space = Heap::map_space();
   PagedSpace* cell_space = Heap::cell_space();
   LargeObjectSpace* lo_space = Heap::lo_space();
+  bool one_old_space_gc_has_been_performed = false;
   bool gc_performed = true;
-  int counter = 0;
-  static const int kThreshold = 20;
-  while (gc_performed && counter++ < kThreshold) {
+  bool old_space_gc_performed;
+  while (gc_performed) {

[Vyacheslav Egorov (Chromium), 2012/01/26 16:12:05]

it seems to me that this loop can go on forever. can you prove that we are not
going to loop here forever doing GC if OS refuses us new pages and we at the
boundary of soft/hard limit?

+    old_space_gc_performed = false;
     gc_performed = false;
     if (!new_space->ReserveSpace(new_space_size)) {
       Heap::CollectGarbage(NEW_SPACE);
@@ -594,22 +595,27 @@
     if (!old_pointer_space->ReserveSpace(pointer_space_size)) {
       Heap::CollectGarbage(OLD_POINTER_SPACE);
       gc_performed = true;
+      old_space_gc_performed = true;
     }
     if (!(old_data_space->ReserveSpace(data_space_size))) {
       Heap::CollectGarbage(OLD_DATA_SPACE);
       gc_performed = true;
+      old_space_gc_performed = true;
     }
     if (!(code_space->ReserveSpace(code_space_size))) {
       Heap::CollectGarbage(CODE_SPACE);
       gc_performed = true;
+      old_space_gc_performed = true;
     }
     if (!(map_space->ReserveSpace(map_space_size))) {
       Heap::CollectGarbage(MAP_SPACE);
       gc_performed = true;
+      old_space_gc_performed = true;
     }
     if (!(cell_space->ReserveSpace(cell_space_size))) {
       Heap::CollectGarbage(CELL_SPACE);
       gc_performed = true;
+      old_space_gc_performed = true;
     }
     // We add a slack-factor of 2 in order to have space for a series of
     // large-object allocations that are only just larger than the page size.
@@ -619,16 +625,18 @@
     // allocation in the other spaces.
     large_object_size += cell_space_size + map_space_size + code_space_size +
         data_space_size + pointer_space_size;
-    if (!(lo_space->ReserveSpace(large_object_size))) {
+
+    // If we already did one GC in order to make space in old space, there is
+    // no sense in doing another one.  We will attempt to force through the
+    // large object space allocation, which comes directly from the OS,
+    // regardless of any soft limit.
+    if (!one_old_space_gc_has_been_performed &&
+        !(lo_space->ReserveSpace(large_object_size))) {
       Heap::CollectGarbage(LO_SPACE);
       gc_performed = true;
     }
+    if (old_space_gc_performed) one_old_space_gc_has_been_performed = true;
   }
-
-  if (gc_performed) {
-    // Failed to reserve the space after several attempts.
-    V8::FatalProcessOutOfMemory("Heap::ReserveSpace");
-  }
 }