8368213: ZGC: Cleanup dead code, unimplemented declarations, unused private fields

Reviewed-by: stefank, jsikstro

src/hotspot/share/gc/shared/gcThreadLocalData.hpp

@@ -40,6 +40,6 @@
 // should consider placing frequently accessed fields first in
 // T, so that field offsets relative to Thread are small, which
 // often allows for a more compact instruction encoding.
-typedef uint64_t GCThreadLocalData[43]; // 344 bytes
+typedef uint64_t GCThreadLocalData[40]; // 320 bytes
 
 #endif // SHARE_GC_SHARED_GCTHREADLOCALDATA_HPP

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

@@ -71,8 +71,6 @@ typedef zpointer (*ZBarrierColor)(zaddress, zpointer);
 
 class ZGeneration;
 
-void z_assert_is_barrier_safe();
-
 class ZBarrier : public AllStatic {
   friend class ZContinuation;
   friend class ZStoreBarrierBuffer;

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

@@ -306,8 +306,7 @@ static bool is_young_small(const ZDirectorStats& stats) {
   return young_used_percent <= 5.0;
 }
 
-template <typename PrintFn = void(*)(size_t, double)>
-static bool is_high_usage(const ZDirectorStats& stats, PrintFn* print_function = nullptr) {
+static bool is_high_usage(const ZDirectorStats& stats, bool log = false) {
   // Calculate amount of free memory available. Note that we take the
   // relocation headroom into account to avoid in-place relocation.
   const size_t soft_max_capacity = stats._heap._soft_max_heap_size;
@@ -316,8 +315,9 @@ static bool is_high_usage(const ZDirectorStats& stats, PrintFn* print_function =
   const size_t free = free_including_headroom - MIN2(free_including_headroom, ZHeuristics::relocation_headroom());
   const double free_percent = percent_of(free, soft_max_capacity);
 
-  if (print_function != nullptr) {
-    (*print_function)(free, free_percent);
+  if (log) {
+    log_debug(gc, director)("Rule Minor: High Usage, Free: %zuMB(%.1f%%)",
+                            free / M, free_percent);
   }
 
   // The heap has high usage if there is less than 5% free memory left
@@ -377,19 +377,7 @@ static bool rule_minor_high_usage(const ZDirectorStats& stats) {
   // such that the allocation rate rule doesn't trigger, but the amount of free
   // memory is still slowly but surely heading towards zero. In this situation,
   // we start a GC cycle to avoid a potential allocation stall later.
-
-  const size_t soft_max_capacity = stats._heap._soft_max_heap_size;
-  const size_t used = stats._heap._used;
-  const size_t free_including_headroom = soft_max_capacity - MIN2(soft_max_capacity, used);
-  const size_t free = free_including_headroom - MIN2(free_including_headroom, ZHeuristics::relocation_headroom());
-  const double free_percent = percent_of(free, soft_max_capacity);
-
-  auto print_function = [&](size_t free, double free_percent) {
-    log_debug(gc, director)("Rule Minor: High Usage, Free: %zuMB(%.1f%%)",
-                            free / M, free_percent);
-  };
-
-  return is_high_usage(stats, &print_function);
+  return is_high_usage(stats, true /* log */);
 }
 
 // Major GC rules

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

@@ -701,13 +701,11 @@ uint ZGenerationYoung::compute_tenuring_threshold(ZRelocationSetSelectorStats st
   double young_life_expectancy_sum = 0.0;
   uint young_life_expectancy_samples = 0;
   uint last_populated_age = 0;
-  size_t last_populated_live = 0;
 
   for (ZPageAge age : ZPageAgeRangeAll) {
     const size_t young_live = stats.small(age).live() + stats.medium(age).live() + stats.large(age).live();
     if (young_live > 0) {
       last_populated_age = untype(age);
-      last_populated_live = young_live;
       if (young_live_last > 0) {
         young_life_expectancy_sum += double(young_live) / double(young_live_last);
         young_life_expectancy_samples++;
@@ -721,7 +719,6 @@ uint ZGenerationYoung::compute_tenuring_threshold(ZRelocationSetSelectorStats st
     return 0;
   }
 
-  const size_t young_used_at_mark_start = ZGeneration::young()->stat_heap()->used_generation_at_mark_start();
   const size_t young_garbage = ZGeneration::young()->stat_heap()->garbage_at_mark_end();
   const size_t young_allocated = ZGeneration::young()->stat_heap()->allocated_at_mark_end();
   const size_t soft_max_capacity = ZHeap::heap()->soft_max_capacity();

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

@@ -87,7 +87,6 @@ protected:
 
   void free_empty_pages(ZRelocationSetSelector* selector, int bulk);
   void flip_age_pages(const ZRelocationSetSelector* selector);
-  void flip_age_pages(const ZArray<ZPage*>* pages);
 
   void mark_free();
 

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

@@ -789,7 +789,6 @@ typedef ClaimingCLDToOopClosure<ClassLoaderData::_claim_strong> ZMarkOldCLDClosu
 
 class ZMarkOldRootsTask : public ZTask {
 private:
-  ZMark* const                  _mark;
   ZRootsIteratorStrongColored   _roots_colored;
   ZRootsIteratorStrongUncolored _roots_uncolored;
 
@@ -800,9 +799,8 @@ private:
   ZMarkNMethodClosure           _nm_cl;
 
 public:
-  ZMarkOldRootsTask(ZMark* mark)
+  ZMarkOldRootsTask()
     : ZTask("ZMarkOldRootsTask"),
-      _mark(mark),
       _roots_colored(ZGenerationIdOptional::old),
       _roots_uncolored(ZGenerationIdOptional::old),
       _cl_colored(),
@@ -847,7 +845,6 @@ public:
 
 class ZMarkYoungRootsTask : public ZTask {
 private:
-  ZMark* const               _mark;
   ZRootsIteratorAllColored   _roots_colored;
   ZRootsIteratorAllUncolored _roots_uncolored;
 
@@ -858,9 +855,8 @@ private:
   ZMarkYoungNMethodClosure   _nm_cl;
 
 public:
-  ZMarkYoungRootsTask(ZMark* mark)
+  ZMarkYoungRootsTask()
     : ZTask("ZMarkYoungRootsTask"),
-      _mark(mark),
       _roots_colored(ZGenerationIdOptional::young),
       _roots_uncolored(ZGenerationIdOptional::young),
       _cl_colored(),
@@ -928,13 +924,13 @@ void ZMark::resize_workers(uint nworkers) {
 
 void ZMark::mark_young_roots() {
   SuspendibleThreadSetJoiner sts_joiner;
-  ZMarkYoungRootsTask task(this);
+  ZMarkYoungRootsTask task;
   workers()->run(&task);
 }
 
 void ZMark::mark_old_roots() {
   SuspendibleThreadSetJoiner sts_joiner;
-  ZMarkOldRootsTask task(this);
+  ZMarkOldRootsTask task;
   workers()->run(&task);
 }
 

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

@@ -43,9 +43,6 @@ private:
   static ZNMethodTableIteration            _iteration_secondary;
   static ZSafeDelete<ZNMethodTableEntry[]> _safe_delete;
 
-  static ZNMethodTableEntry* create(size_t size);
-  static void destroy(ZNMethodTableEntry* table);
-
   static size_t first_index(const nmethod* nm, size_t size);
   static size_t next_index(size_t prev_index, size_t size);
 
@@ -67,9 +64,6 @@ public:
   static void nmethods_do_begin(bool secondary);
   static void nmethods_do_end(bool secondary);
   static void nmethods_do(bool secondary, NMethodClosure* cl);
-
-  static void unlink(ZWorkers* workers, bool unloading_occurred);
-  static void purge(ZWorkers* workers);
 };
 
 #endif // SHARE_GC_Z_ZNMETHODTABLE_HPP

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

@@ -1060,7 +1060,6 @@ void ZPartition::commit_increased_capacity(ZMemoryAllocation* allocation, const
 
   const size_t already_committed = allocation->harvested();
 
-  const ZVirtualMemory already_committed_vmem = vmem.first_part(already_committed);
   const ZVirtualMemory to_be_committed_vmem = vmem.last_part(already_committed);
 
   // Try to commit the uncommitted physical memory
@@ -1422,7 +1421,6 @@ ZPage* ZPageAllocator::alloc_page(ZPageType type, size_t size, ZAllocationFlags
   const ZPageAllocationStats stats = allocation.stats();
   const int num_harvested_vmems = stats._num_harvested_vmems;
   const size_t harvested = stats._total_harvested;
-  const size_t committed = stats._total_committed_capacity;
 
   if (harvested > 0) {
     ZStatInc(ZCounterMappedCacheHarvest, harvested);
@@ -1963,9 +1961,6 @@ void ZPageAllocator::cleanup_failed_commit_multi_partition(ZMultiPartitionAlloca
       continue;
     }
 
-    // Remove the harvested part
-    const ZVirtualMemory non_harvest_vmem = partial_vmem.last_part(allocation->harvested());
-
     ZArray<ZVirtualMemory>* const partial_vmems = allocation->partial_vmems();
 
     // Keep track of the start index

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

@@ -39,7 +39,6 @@ private:
   uintptr_t              _mark_bad_mask;
   uintptr_t              _store_good_mask;
   uintptr_t              _store_bad_mask;
-  uintptr_t              _uncolor_mask;
   uintptr_t              _nmethod_disarmed;
   ZStoreBarrierBuffer*   _store_barrier_buffer;
   ZMarkThreadLocalStacks _mark_stacks[2];
@@ -51,7 +50,6 @@ private:
       _mark_bad_mask(0),
       _store_good_mask(0),
       _store_bad_mask(0),
-      _uncolor_mask(0),
       _nmethod_disarmed(0),
       _store_barrier_buffer(new ZStoreBarrierBuffer()),
       _mark_stacks(),