Use homogeneous space compaction for non low memory devices.

Saves nearly as much memory without needing the foreground
transition.

TODO: Pass in these flags from AndroidRuntime.cpp.

Bug: 16401001
Change-Id: Iecad0cc0c04fdf9cabe6f9d7f87c761a94b4142c

1 files changed, 5 insertions, 1 deletions

diff --git a/runtime/parsed_options.cc b/runtime/parsed_options.cc
index 3ef7a17615..27f776544a 100644
--- a/runtime/parsed_options.cc
+++ b/runtime/parsed_options.cc
@@ -206,7 +206,7 @@ bool ParsedOptions::Parse(const RuntimeOptions& options, bool ignore_unrecognize
   // If background_collector_type_ is kCollectorTypeNone, it defaults to the collector_type_ after
   // parsing options. If you set this to kCollectorTypeHSpaceCompact then we will do an hspace
   // compaction when we transition to background instead of a normal collector transition.
-  background_collector_type_ = gc::kCollectorTypeSS;
+  background_collector_type_ = gc::kCollectorTypeHomogeneousSpaceCompact;
   stack_size_ = 0;  // 0 means default.
   max_spins_before_thin_lock_inflation_ = Monitor::kDefaultMaxSpinsBeforeThinLockInflation;
   low_memory_mode_ = false;
@@ -394,6 +394,10 @@ bool ParsedOptions::Parse(const RuntimeOptions& options, bool ignore_unrecognize
     } else if (option == "-XX:IgnoreMaxFootprint") {
       ignore_max_footprint_ = true;
     } else if (option == "-XX:LowMemoryMode") {
+      if (background_collector_type_ == gc::kCollectorTypeHomogeneousSpaceCompact) {
+        // Use semispace instead of homogenous space compact for low memory mode.
+        background_collector_type_ = gc::kCollectorTypeSS;
+      }
       low_memory_mode_ = true;
       // TODO Might want to turn off must_relocate here.
     } else if (option == "-XX:UseTLAB") {