Reapply the semispace growth policy change in isolation....

src/spaces.cc

Index: src/spaces.cc
===================================================================
--- src/spaces.cc	(revision 2713)
+++ src/spaces.cc	(working copy)
@@ -862,8 +862,6 @@
 
   ASSERT(initial_semispace_capacity <= maximum_semispace_capacity);
   ASSERT(IsPowerOf2(maximum_semispace_capacity));
-  maximum_capacity_ = maximum_semispace_capacity;
-  capacity_ = initial_semispace_capacity;
 
   // Allocate and setup the histogram arrays if necessary.
 #if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
@@ -876,15 +874,17 @@
 #undef SET_NAME
 #endif
 
-  ASSERT(size == 2 * maximum_capacity_);
+  ASSERT(size == 2 * maximum_semispace_capacity);
   ASSERT(IsAddressAligned(start, size, 0));
 
-  if (!to_space_.Setup(start, capacity_, maximum_capacity_)) {
+  if (!to_space_.Setup(start,
+                       initial_semispace_capacity,
+                       maximum_semispace_capacity)) {
     return false;
   }
-  if (!from_space_.Setup(start + maximum_capacity_,
-                         capacity_,
-                         maximum_capacity_)) {
+  if (!from_space_.Setup(start + maximum_semispace_capacity,
+                         initial_semispace_capacity,
+                         maximum_semispace_capacity)) {
     return false;
   }
 
@@ -916,7 +916,6 @@
 #endif
 
   start_ = NULL;
-  capacity_ = 0;
   allocation_info_.top = NULL;
   allocation_info_.limit = NULL;
   mc_forwarding_info_.top = NULL;
@@ -952,13 +951,12 @@
 }
 
 
-bool NewSpace::Double() {
-  ASSERT(capacity_ <= maximum_capacity_ / 2);
+bool NewSpace::Grow() {
+  ASSERT(Capacity() < MaximumCapacity());
   // TODO(1240712): Failure to double the from space can result in
   // semispaces of different sizes.  In the event of that failure, the
   // to space doubling should be rolled back before returning false.
-  if (!to_space_.Double() || !from_space_.Double()) return false;
-  capacity_ *= 2;
+  if (!to_space_.Grow() || !from_space_.Grow()) return false;
   allocation_info_.limit = to_space_.high();
   ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
   return true;
@@ -1080,11 +1078,15 @@
 }
 
 
-bool SemiSpace::Double() {
-  if (!MemoryAllocator::CommitBlock(high(), capacity_, executable())) {
+bool SemiSpace::Grow() {
+  // Commit 50% extra space but only up to maximum capacity.
+  int maximum_extra = maximum_capacity_ - capacity_;
+  int extra = Min(RoundUp(capacity_ / 2, OS::AllocateAlignment()),
+                  maximum_extra);
+  if (!MemoryAllocator::CommitBlock(high(), extra, executable())) {
     return false;
   }
-  capacity_ *= 2;
+  capacity_ += extra;
   return true;
 }