Make the speed of incrmental marking depend also on the rate

src/arm/code-stubs-arm.cc

Index: src/arm/code-stubs-arm.cc
===================================================================
--- src/arm/code-stubs-arm.cc	(revision 12583)
+++ src/arm/code-stubs-arm.cc	(working copy)
@@ -7431,6 +7431,16 @@
   Label need_incremental;
   Label need_incremental_pop_scratch;
 
+  __ and_(regs_.scratch0(), regs_.object(), Operand(~Page::kPageAlignmentMask));
+  __ ldr(regs_.scratch1(),
+         MemOperand(regs_.scratch0(),
+                    MemoryChunk::kWriteBarrierCounterOffset));
+  __ sub(regs_.scratch1(), Immediate(1), SetCC);
+  __ str(regs_.scratch1(),
+         MemOperand(regs_.scratch0(),
+                    MemoryChunk::kWriteBarrierCounterOffset));
+  __ b(mi, &need_incremental);
+
   // Let's look at the color of the object:  If it is not black we don't have
   // to inform the incremental marker.
   __ JumpIfBlack(regs_.object(), regs_.scratch0(), regs_.scratch1(), &on_black);