8294751: Zero: Allow larger default heaps

Reviewed-by: iklam, rkennke

Author: shipilev

src/hotspot/share/compiler/compiler_globals_pd.hpp

@@ -70,8 +70,15 @@ define_pd_global(uintx,  NonNMethodCodeHeapSize,     32*M);
 define_pd_global(uintx,  CodeCacheExpansionSize,     32*K);
 define_pd_global(uintx,  CodeCacheMinBlockLength,    1);
 define_pd_global(uintx,  CodeCacheMinimumUseSpace,   200*K);
+#ifndef ZERO
 define_pd_global(bool, NeverActAsServerClassMachine, true);
 define_pd_global(uint64_t,MaxRAM,                    1ULL*G);
+#else
+// Zero runs without compilers. Do not let this code to force
+// the GC mode and default heap settings.
+define_pd_global(bool, NeverActAsServerClassMachine, false);
+define_pd_global(uint64_t,MaxRAM,                    128ULL*G);
+#endif
 #define CI_COMPILER_COUNT 0
 #else
 

src/hotspot/share/runtime/arguments.cpp

@@ -3152,12 +3152,6 @@ jint Arguments::finalize_vm_init_args(bool patch_mod_javabase) {
 #ifdef ZERO
   // Zero always runs in interpreted mode
   set_mode_flags(_int);
-
-  // Zero runs without compilers. Do not let compiler selection code
-  // to force it into Serial GC, let the GC ergonomics decide.
-  if (FLAG_IS_DEFAULT(NeverActAsServerClassMachine)) {
-    FLAG_SET_ERGO(NeverActAsServerClassMachine, false);
-  }
 #endif
 
   // eventually fix up InitialTenuringThreshold if only MaxTenuringThreshold is set