8372150: Parallel: Tighten requirements around heap sizes with NUMA and Large Pages

Reviewed-by: ayang, stefank, aboldtch, stuefe

src/hotspot/share/gc/parallel/parallelArguments.cpp

@@ -37,8 +37,45 @@
 #include "utilities/defaultStream.hpp"
 #include "utilities/powerOfTwo.hpp"
 
-size_t ParallelArguments::conservative_max_heap_alignment() {
-  return compute_heap_alignment();
+static size_t num_young_spaces() {
+  // When using NUMA, we create one MutableNUMASpace for each NUMA node
+  const size_t num_eden_spaces = UseNUMA ? os::numa_get_groups_num() : 1;
+
+  // The young generation must have room for eden + two survivors
+  return num_eden_spaces + 2;
+}
+
+static size_t num_old_spaces() {
+  return 1;
+}
+
+void ParallelArguments::initialize_alignments() {
+  // Initialize card size before initializing alignments
+  CardTable::initialize_card_size();
+  const size_t card_table_alignment = CardTable::ct_max_alignment_constraint();
+  SpaceAlignment = ParallelScavengeHeap::default_space_alignment();
+
+  if (UseLargePages) {
+    const size_t total_spaces = num_young_spaces() + num_old_spaces();
+    const size_t page_size =  os::page_size_for_region_unaligned(MaxHeapSize, total_spaces);
+    ParallelScavengeHeap::set_desired_page_size(page_size);
+
+    if (page_size == os::vm_page_size()) {
+      log_warning(gc, heap)("MaxHeapSize (%zu) must be large enough for %zu * page-size; Disabling UseLargePages for heap",
+                            MaxHeapSize, total_spaces);
+    }
+
+    if (page_size > SpaceAlignment) {
+      SpaceAlignment = page_size;
+    }
+
+    HeapAlignment = lcm(page_size, card_table_alignment);
+
+  } else {
+    assert(is_aligned(SpaceAlignment, os::vm_page_size()), "");
+    ParallelScavengeHeap::set_desired_page_size(os::vm_page_size());
+    HeapAlignment = card_table_alignment;
+  }
 }
 
 void ParallelArguments::initialize() {
@@ -98,49 +135,36 @@ void ParallelArguments::initialize() {
   FullGCForwarding::initialize_flags(heap_reserved_size_bytes());
 }
 
-void ParallelArguments::initialize_alignments() {
-  // Initialize card size before initializing alignments
-  CardTable::initialize_card_size();
-  SpaceAlignment = ParallelScavengeHeap::default_space_alignment();
-  HeapAlignment = compute_heap_alignment();
-}
+size_t ParallelArguments::conservative_max_heap_alignment() {
+  // The card marking array and the offset arrays for old generations are
+  // committed in os pages as well. Make sure they are entirely full (to
+  // avoid partial page problems), e.g. if 512 bytes heap corresponds to 1
+  // byte entry and the os page size is 4096, the maximum heap size should
+  // be 512*4096 = 2MB aligned.
 
-void ParallelArguments::initialize_heap_flags_and_sizes_one_pass() {
-  // Do basic sizing work
-  GenArguments::initialize_heap_flags_and_sizes();
-}
+  size_t alignment = CardTable::ct_max_alignment_constraint();
 
-void ParallelArguments::initialize_heap_flags_and_sizes() {
-  initialize_heap_flags_and_sizes_one_pass();
-
-  if (!UseLargePages) {
-    ParallelScavengeHeap::set_desired_page_size(os::vm_page_size());
-    return;
+  if (UseLargePages) {
+      // In presence of large pages we have to make sure that our
+      // alignment is large page aware.
+      alignment = lcm(os::large_page_size(), alignment);
   }
 
-  // If using large-page, need to update SpaceAlignment so that spaces are page-size aligned.
-  const size_t min_pages = 4; // 1 for eden + 1 for each survivor + 1 for old
-  const size_t page_sz = os::page_size_for_region_aligned(MinHeapSize, min_pages);
-  ParallelScavengeHeap::set_desired_page_size(page_sz);
-
-  if (page_sz == os::vm_page_size()) {
-    log_warning(gc, heap)("MinHeapSize (%zu) must be large enough for 4 * page-size; Disabling UseLargePages for heap", MinHeapSize);
-    return;
-  }
-
-  // Space is largepage-aligned.
-  size_t new_alignment = page_sz;
-  if (new_alignment != SpaceAlignment) {
-    SpaceAlignment = new_alignment;
-    // Redo everything from the start
-    initialize_heap_flags_and_sizes_one_pass();
-  }
-}
-
-size_t ParallelArguments::heap_reserved_size_bytes() {
-  return MaxHeapSize;
+  return alignment;
 }
 
 CollectedHeap* ParallelArguments::create_heap() {
   return new ParallelScavengeHeap();
 }
+
+size_t ParallelArguments::young_gen_size_lower_bound() {
+  return num_young_spaces() * SpaceAlignment;
+}
+
+size_t ParallelArguments::old_gen_size_lower_bound() {
+  return num_old_spaces() * SpaceAlignment;
+}
+
+size_t ParallelArguments::heap_reserved_size_bytes() {
+  return MaxHeapSize;
+}

src/hotspot/share/gc/parallel/parallelArguments.hpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2017, Red Hat, Inc. and/or its affiliates.
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,21 +26,16 @@
 #ifndef SHARE_GC_PARALLEL_PARALLELARGUMENTS_HPP
 #define SHARE_GC_PARALLEL_PARALLELARGUMENTS_HPP
 
-#include "gc/shared/gcArguments.hpp"
 #include "gc/shared/genArguments.hpp"
 
-class CollectedHeap;
-
 class ParallelArguments : public GenArguments {
 private:
   virtual void initialize_alignments();
-  virtual void initialize_heap_flags_and_sizes();
-
-  void initialize_heap_flags_and_sizes_one_pass();
-
   virtual void initialize();
   virtual size_t conservative_max_heap_alignment();
   virtual CollectedHeap* create_heap();
+  virtual size_t young_gen_size_lower_bound();
+  virtual size_t old_gen_size_lower_bound();
 
 public:
   static size_t heap_reserved_size_bytes();

src/hotspot/share/gc/serial/serialArguments.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2017, Red Hat, Inc. and/or its affiliates.
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -27,11 +28,49 @@
 #include "gc/shared/fullGCForwarding.hpp"
 #include "gc/shared/gcArguments.hpp"
 
+static size_t compute_heap_alignment() {
+  // The card marking array and the offset arrays for old generations are
+  // committed in os pages as well. Make sure they are entirely full (to
+  // avoid partial page problems), e.g. if 512 bytes heap corresponds to 1
+  // byte entry and the os page size is 4096, the maximum heap size should
+  // be 512*4096 = 2MB aligned.
+
+  size_t alignment = CardTable::ct_max_alignment_constraint();
+
+  if (UseLargePages) {
+      // In presence of large pages we have to make sure that our
+      // alignment is large page aware.
+      alignment = lcm(os::large_page_size(), alignment);
+  }
+
+  return alignment;
+}
+
+void SerialArguments::initialize_alignments() {
+  // Initialize card size before initializing alignments
+  CardTable::initialize_card_size();
+  SpaceAlignment = (size_t)Generation::GenGrain;
+  HeapAlignment = compute_heap_alignment();
+}
+
 void SerialArguments::initialize() {
   GCArguments::initialize();
   FullGCForwarding::initialize_flags(MaxHeapSize);
 }
 
+size_t SerialArguments::conservative_max_heap_alignment() {
+  return MAX2((size_t)Generation::GenGrain, compute_heap_alignment());
+}
+
 CollectedHeap* SerialArguments::create_heap() {
   return new SerialHeap();
 }
+
+size_t SerialArguments::young_gen_size_lower_bound() {
+  // The young generation must be aligned and have room for eden + two survivors
+  return 3 * SpaceAlignment;
+}
+
+size_t SerialArguments::old_gen_size_lower_bound() {
+  return SpaceAlignment;
+}

src/hotspot/share/gc/serial/serialArguments.hpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2017, Red Hat, Inc. and/or its affiliates.
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -27,12 +28,14 @@
 
 #include "gc/shared/genArguments.hpp"
 
-class CollectedHeap;
-
 class SerialArguments : public GenArguments {
 private:
+  virtual void initialize_alignments();
   virtual void initialize();
+  virtual size_t conservative_max_heap_alignment();
   virtual CollectedHeap* create_heap();
+  virtual size_t young_gen_size_lower_bound();
+  virtual size_t old_gen_size_lower_bound();
 };
 
 #endif // SHARE_GC_SERIAL_SERIALARGUMENTS_HPP

src/hotspot/share/gc/shared/gcArguments.cpp

@@ -62,24 +62,6 @@ void GCArguments::initialize_heap_sizes() {
   initialize_size_info();
 }
 
-size_t GCArguments::compute_heap_alignment() {
-  // The card marking array and the offset arrays for old generations are
-  // committed in os pages as well. Make sure they are entirely full (to
-  // avoid partial page problems), e.g. if 512 bytes heap corresponds to 1
-  // byte entry and the os page size is 4096, the maximum heap size should
-  // be 512*4096 = 2MB aligned.
-
-  size_t alignment = CardTable::ct_max_alignment_constraint();
-
-  if (UseLargePages) {
-      // In presence of large pages we have to make sure that our
-      // alignment is large page aware.
-      alignment = lcm(os::large_page_size(), alignment);
-  }
-
-  return alignment;
-}
-
 #ifdef ASSERT
 void GCArguments::assert_flags() {
   assert(InitialHeapSize <= MaxHeapSize, "Ergonomics decided on incompatible initial and maximum heap sizes");

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

@@ -45,6 +45,8 @@ protected:
 
 public:
   virtual void initialize();
+
+  // Return the (conservative) maximum heap alignment
   virtual size_t conservative_max_heap_alignment() = 0;
 
   // Used by heap size heuristics to determine max
@@ -59,8 +61,6 @@ public:
   }
 
   void initialize_heap_sizes();
-
-  static size_t compute_heap_alignment();
 };
 
 #endif // SHARE_GC_SHARED_GCARGUMENTS_HPP

src/hotspot/share/gc/shared/genArguments.cpp

@@ -42,17 +42,6 @@ size_t MaxOldSize = 0;
 // See more in JDK-8346005
 size_t OldSize = ScaleForWordSize(4*M);
 
-size_t GenArguments::conservative_max_heap_alignment() { return (size_t)Generation::GenGrain; }
-
-static size_t young_gen_size_lower_bound() {
-  // The young generation must be aligned and have room for eden + two survivors
-  return 3 * SpaceAlignment;
-}
-
-static size_t old_gen_size_lower_bound() {
-  return SpaceAlignment;
-}
-
 size_t GenArguments::scale_by_NewRatio_aligned(size_t base_size, size_t alignment) {
   return align_down_bounded(base_size / (NewRatio + 1), alignment);
 }
@@ -64,13 +53,6 @@ static size_t bound_minus_alignment(size_t desired_size,
   return MIN2(desired_size, max_minus);
 }
 
-void GenArguments::initialize_alignments() {
-  // Initialize card size before initializing alignments
-  CardTable::initialize_card_size();
-  SpaceAlignment = (size_t)Generation::GenGrain;
-  HeapAlignment = compute_heap_alignment();
-}
-
 void GenArguments::initialize_heap_flags_and_sizes() {
   GCArguments::initialize_heap_flags_and_sizes();
 

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

@@ -38,17 +38,16 @@ extern size_t OldSize;
 class GenArguments : public GCArguments {
   friend class TestGenCollectorPolicy; // Testing
 private:
-  virtual void initialize_alignments();
   virtual void initialize_size_info();
 
-  // Return the (conservative) maximum heap alignment
-  virtual size_t conservative_max_heap_alignment();
-
   DEBUG_ONLY(void assert_flags();)
   DEBUG_ONLY(void assert_size_info();)
 
   static size_t scale_by_NewRatio_aligned(size_t base_size, size_t alignment);
 
+  virtual size_t young_gen_size_lower_bound() = 0;
+  virtual size_t old_gen_size_lower_bound() = 0;
+
 protected:
   virtual void initialize_heap_flags_and_sizes();
 };

src/hotspot/share/gc/shared/jvmFlagConstraintsGC.cpp

@@ -250,7 +250,7 @@ static JVMFlag::Error MaxSizeForHeapAlignment(const char* name, size_t value, bo
   } else
 #endif
   {
-    heap_alignment = GCArguments::compute_heap_alignment();
+    heap_alignment = Arguments::conservative_max_heap_alignment();
   }
 
   return MaxSizeForAlignment(name, value, heap_alignment, verbose);

src/hotspot/share/runtime/arguments.cpp

@@ -1478,10 +1478,9 @@ void Arguments::set_conservative_max_heap_alignment() {
   // the alignments imposed by several sources: any requirements from the heap
   // itself and the maximum page size we may run the VM with.
   size_t heap_alignment = GCConfig::arguments()->conservative_max_heap_alignment();
-  _conservative_max_heap_alignment = MAX4(heap_alignment,
+  _conservative_max_heap_alignment = MAX3(heap_alignment,
                                           os::vm_allocation_granularity(),
-                                          os::max_page_size(),
-                                          GCArguments::compute_heap_alignment());
+                                          os::max_page_size());
   assert(is_power_of_2(_conservative_max_heap_alignment), "Expected to be a power-of-2");
 }
 

test/hotspot/gtest/gc/shared/test_collectorPolicy.cpp

@@ -140,17 +140,6 @@ class TestGenCollectorPolicy {
       ASSERT_EQ(param, NewSize);
     }
   };
-
-  class SetMaxNewSizeCmd : public BinaryExecutor {
-   public:
-    SetMaxNewSizeCmd(size_t param1, size_t param2) : BinaryExecutor(param1, param2) { }
-    void execute() {
-      size_t heap_alignment = GCArguments::compute_heap_alignment();
-      size_t new_size_value = align_up(MaxHeapSize, heap_alignment)
-              - param1 + param2;
-      FLAG_SET_CMDLINE(MaxNewSize, new_size_value);
-    }
-  };
 };