src/share/vm/runtime/arguments.cpp

rev 5146 : [mq]: first-patch

@@ -24,12 +24,18 @@
 
 #include "precompiled.hpp"
 #include "classfile/javaAssertions.hpp"
 #include "classfile/symbolTable.hpp"
 #include "compiler/compilerOracle.hpp"
+#if INCLUDE_ALL_GCS
+#include "gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp"
+#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
+#include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
+#endif // INCLUDE_ALL_GCS
 #include "memory/allocation.inline.hpp"
 #include "memory/cardTableRS.hpp"
+#include "memory/genCollectedHeap.hpp"
 #include "memory/referenceProcessor.hpp"
 #include "memory/universe.inline.hpp"
 #include "oops/oop.inline.hpp"
 #include "prims/jvmtiExport.hpp"
 #include "runtime/arguments.hpp"

@@ -50,13 +56,10 @@
 # include "os_windows.inline.hpp"
 #endif
 #ifdef TARGET_OS_FAMILY_bsd
 # include "os_bsd.inline.hpp"
 #endif
-#if INCLUDE_ALL_GCS
-#include "gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp"
-#endif // INCLUDE_ALL_GCS
 
 // Note: This is a special bug reporting site for the JVM
 #define DEFAULT_VENDOR_URL_BUG "http://bugreport.sun.com/bugreport/crash.jsp"
 #define DEFAULT_JAVA_LAUNCHER  "generic"
 

@@ -88,10 +91,11 @@
 int     Arguments::_num_jvm_args                = 0;
 char*  Arguments::_java_command                 = NULL;
 SystemProperty* Arguments::_system_properties   = NULL;
 const char*  Arguments::_gc_log_filename        = NULL;
 bool   Arguments::_has_profile                  = false;
+size_t Arguments::_conservative_max_heap_alignment = 0;
 uintx  Arguments::_min_heap_size                = 0;
 Arguments::Mode Arguments::_mode                = _mixed;
 bool   Arguments::_java_compiler                = false;
 bool   Arguments::_xdebug_mode                  = false;
 const char*  Arguments::_java_vendor_url_bug    = DEFAULT_VENDOR_URL_BUG;

@@ -1389,14 +1393,21 @@
     return false;
   }
   return true;
 }
 
-inline uintx max_heap_for_compressed_oops() {
+uintx Arguments::max_heap_for_compressed_oops() {
   // Avoid sign flip.
   assert(OopEncodingHeapMax > (uint64_t)os::vm_page_size(), "Unusual page size");
-  LP64_ONLY(return OopEncodingHeapMax - os::vm_page_size());
+  // we need to fit both the NULL page and the heap into the memory budget, while
+  // keeping alignment constraints of the heap. To guarantee the latter, as the
+  // NULL page is located before the heap, we pad the NULL page to the conservative
+  // maximum alignment that the GC may ever impose upon the heap.
+  size_t displacement_due_to_null_page = align_size_up_(os::vm_page_size(),
+    Arguments::conservative_max_heap_alignment());
+
+  LP64_ONLY(return OopEncodingHeapMax - displacement_due_to_null_page);
   NOT_LP64(ShouldNotReachHere(); return 0);
 }
 
 bool Arguments::should_auto_select_low_pause_collector() {
   if (UseAutoGCSelectPolicy &&

@@ -1473,10 +1484,27 @@
   }
 #endif // _LP64
 #endif // !ZERO
 }
 
+void Arguments::set_conservative_max_heap_alignment() {
+  // The conservative maximum required alignment for the heap is the maximum of
+  // the alignments imposed by several sources: any requirements from the heap
+  // itself, the collector policy and the maximum page size we may run the VM
+  // with.
+  size_t heap_alignment = GenCollectedHeap::max_heap_alignment();
+#if INCLUDE_ALL_GCS
+  if (UseParallelGC) {
+    heap_alignment = ParallelScavengeHeap::conservative_max_heap_alignment();
+  } else if (UseG1GC) {
+    heap_alignment = G1CollectedHeap::conservative_max_heap_alignment();
+  }
+#endif // INCLUDE_ALL_GCS
+  _conservative_max_heap_alignment = MAX3(heap_alignment, os::max_page_size(),
+    CollectorPolicy::compute_max_alignment());
+}
+
 void Arguments::set_ergonomics_flags() {
 
   if (os::is_server_class_machine()) {
     // If no other collector is requested explicitly,
     // let the VM select the collector based on

@@ -1501,10 +1529,12 @@
         (FLAG_IS_DEFAULT(UseSharedSpaces) || !UseSharedSpaces)) {
       no_shared_spaces();
     }
   }
 
+  set_conservative_max_heap_alignment();
+
 #ifndef ZERO
 #ifdef _LP64
   set_use_compressed_oops();
 
   // set_use_compressed_klass_ptrs() must be called after calling

@@ -3515,10 +3545,12 @@
     FLAG_SET_DEFAULT(PrintSharedSpaces, false);
   }
   no_shared_spaces();
 #endif // INCLUDE_CDS
 
+  os::init_ergo();
+
   // Set flags based on ergonomics.
   set_ergonomics_flags();
 
   set_shared_spaces_flags();