8347335: ZGC: Use limitless mark stack memory

Reviewed-by: aboldtch, iwalulya

Author: fisk

src/hotspot/share/gc/z/zAddressSpaceLimit.cpp

@@ -39,12 +39,6 @@ static size_t address_space_limit() {
   return SIZE_MAX;
 }
 
-size_t ZAddressSpaceLimit::mark_stack() {
-  // Allow mark stacks to occupy 10% of the address space
-  const size_t limit = address_space_limit() / 10;
-  return align_up(limit, ZMarkStackSpaceExpandSize);
-}
-
 size_t ZAddressSpaceLimit::heap() {
   // Allow the heap to occupy 50% of the address space
   const size_t limit = address_space_limit() / MaxVirtMemFraction;

src/hotspot/share/gc/z/zAddressSpaceLimit.hpp

@@ -29,7 +29,6 @@
 
 class ZAddressSpaceLimit : public AllStatic {
 public:
-  static size_t mark_stack();
   static size_t heap();
 };
 

src/hotspot/share/gc/z/zArguments.cpp

@@ -120,15 +120,6 @@ void ZArguments::select_max_gc_threads() {
 void ZArguments::initialize() {
   GCArguments::initialize();
 
-  // Check mark stack size
-  const size_t mark_stack_space_limit = ZAddressSpaceLimit::mark_stack();
-  if (ZMarkStackSpaceLimit > mark_stack_space_limit) {
-    if (!FLAG_IS_DEFAULT(ZMarkStackSpaceLimit)) {
-      vm_exit_during_initialization("ZMarkStackSpaceLimit too large for limited address space");
-    }
-    FLAG_SET_DEFAULT(ZMarkStackSpaceLimit, mark_stack_space_limit);
-  }
-
   // Enable NUMA by default
   if (FLAG_IS_DEFAULT(UseNUMA)) {
     FLAG_SET_DEFAULT(UseNUMA, true);

src/hotspot/share/gc/z/zBarrierSet.cpp

@@ -101,7 +101,7 @@ void ZBarrierSet::on_thread_attach(Thread* thread) {
 
 void ZBarrierSet::on_thread_detach(Thread* thread) {
   // Flush and free any remaining mark stacks
-  ZHeap::heap()->mark_flush_and_free(thread);
+  ZHeap::heap()->mark_flush(thread);
 }
 
 static void deoptimize_allocation(JavaThread* thread) {

src/hotspot/share/gc/z/zGeneration.cpp

@@ -131,10 +131,6 @@ ZGeneration::ZGeneration(ZGenerationId id, ZPageTable* page_table, ZPageAllocato
     _stat_relocation(),
     _gc_timer(nullptr) {}
 
-bool ZGeneration::is_initialized() const {
-  return _mark.is_initialized();
-}
-
 ZWorkers* ZGeneration::workers() {
   return &_workers;
 }
@@ -151,8 +147,8 @@ void ZGeneration::threads_do(ThreadClosure* tc) const {
   _workers.threads_do(tc);
 }
 
-void ZGeneration::mark_flush_and_free(Thread* thread) {
-  _mark.flush_and_free(thread);
+void ZGeneration::mark_flush(Thread* thread) {
+  _mark.flush(thread);
 }
 
 void ZGeneration::mark_free() {

src/hotspot/share/gc/z/zGeneration.hpp

@@ -99,8 +99,6 @@ class ZGeneration {
   void log_phase_switch(Phase from, Phase to);
 
 public:
-  bool is_initialized() const;
-
   // GC phases
   void set_phase(Phase new_phase);
   bool is_phase_relocate() const;
@@ -161,7 +159,7 @@ class ZGeneration {
   void mark_object(zaddress addr);
   template <bool resurrect, bool gc_thread, bool follow, bool finalizable>
   void mark_object_if_active(zaddress addr);
-  void mark_flush_and_free(Thread* thread);
+  void mark_flush(Thread* thread);
 
   // Relocation
   void synchronize_relocation();

src/hotspot/share/gc/z/zGlobals.hpp

@@ -67,17 +67,6 @@ const int         ZObjectAlignmentLarge         = 1 << ZObjectAlignmentLargeShif
 const size_t      ZCacheLineSize                = ZPlatformCacheLineSize;
 #define           ZCACHE_ALIGNED                ATTRIBUTE_ALIGNED(ZCacheLineSize)
 
-// Mark stack space
-const size_t      ZMarkStackSpaceExpandSize     = (size_t)1 << 25; // 32M
-
-// Mark stack and magazine sizes
-const size_t      ZMarkStackSizeShift           = 11; // 2K
-const size_t      ZMarkStackSize                = (size_t)1 << ZMarkStackSizeShift;
-const size_t      ZMarkStackHeaderSize          = (size_t)1 << 4; // 16B
-const size_t      ZMarkStackSlots               = (ZMarkStackSize - ZMarkStackHeaderSize) / sizeof(uintptr_t);
-const size_t      ZMarkStackMagazineSize        = (size_t)1 << 15; // 32K
-const size_t      ZMarkStackMagazineSlots       = (ZMarkStackMagazineSize / ZMarkStackSize) - 1;
-
 // Mark stripe size
 const size_t      ZMarkStripeShift              = ZGranuleSizeShift;
 

src/hotspot/share/gc/z/zHeap.cpp

@@ -68,7 +68,7 @@ ZHeap::ZHeap()
   assert(_heap == nullptr, "Already initialized");
   _heap = this;
 
-  if (!_page_allocator.is_initialized() || !_young.is_initialized() || !_old.is_initialized()) {
+  if (!_page_allocator.is_initialized()) {
     return;
   }
 
@@ -271,9 +271,9 @@ void ZHeap::keep_alive(oop obj) {
   ZBarrier::mark<ZMark::Resurrect, ZMark::AnyThread, ZMark::Follow, ZMark::Strong>(addr);
 }
 
-void ZHeap::mark_flush_and_free(Thread* thread) {
-  _young.mark_flush_and_free(thread);
-  _old.mark_flush_and_free(thread);
+void ZHeap::mark_flush(Thread* thread) {
+  _young.mark_flush(thread);
+  _old.mark_flush(thread);
 }
 
 bool ZHeap::is_allocating(zaddress addr) const {

src/hotspot/share/gc/z/zHeap.hpp

@@ -99,7 +99,7 @@ class ZHeap {
   bool is_object_live(zaddress addr) const;
   bool is_object_strongly_live(zaddress addr) const;
   void keep_alive(oop obj);
-  void mark_flush_and_free(Thread* thread);
+  void mark_flush(Thread* thread);
 
   // Page allocation
   ZPage* alloc_page(ZPageType type, size_t size, ZAllocationFlags flags, ZPageAge age);

src/hotspot/share/gc/z/zInitialize.cpp

@@ -31,7 +31,6 @@
 #include "gc/z/zInitialize.hpp"
 #include "gc/z/zJNICritical.hpp"
 #include "gc/z/zLargePages.hpp"
-#include "gc/z/zMarkStackAllocator.hpp"
 #include "gc/z/zNMT.hpp"
 #include "gc/z/zNUMA.hpp"
 #include "gc/z/zStat.hpp"