8365880: Shenandoah: Unify memory usage accounting in ShenandoahFreeSet

Reviewed-by: wkemper

Author: kdnilsen

src/hotspot/share/gc/shenandoah/heuristics/shenandoahGlobalHeuristics.cpp

@@ -88,9 +88,10 @@ void ShenandoahGlobalHeuristics::choose_global_collection_set(ShenandoahCollecti
  size_t min_garbage = (free_target > actual_free) ? (free_target - actual_free) : 0;
 
  log_info(gc, ergo)("Adaptive CSet Selection for GLOBAL. Max Young Evacuation: %zu"
- "%s, Max Old Evacuation: %zu%s, Actual Free: %zu%s.",
+ "%s, Max Old Evacuation: %zu%s, Max Either Evacuation: %zu%s, Actual Free: %zu%s.",
  byte_size_in_proper_unit(max_young_cset), proper_unit_for_byte_size(max_young_cset),
  byte_size_in_proper_unit(max_old_cset), proper_unit_for_byte_size(max_old_cset),
+ byte_size_in_proper_unit(unaffiliated_young_memory), proper_unit_for_byte_size(unaffiliated_young_memory),
  byte_size_in_proper_unit(actual_free), proper_unit_for_byte_size(actual_free));
 
  for (size_t idx = 0; idx < size; idx++) {
@@ -133,9 +134,8 @@ void ShenandoahGlobalHeuristics::choose_global_collection_set(ShenandoahCollecti
  cset->add_region(r);
  }
  }
-
  if (regions_transferred_to_old > 0) {
- heap->generation_sizer()->force_transfer_to_old(regions_transferred_to_old);
+ assert(young_evac_reserve > regions_transferred_to_old * region_size_bytes, "young reserve cannot be negative");
  heap->young_generation()->set_evacuation_reserve(young_evac_reserve - regions_transferred_to_old * region_size_bytes);
  heap->old_generation()->set_evacuation_reserve(old_evac_reserve + regions_transferred_to_old * region_size_bytes);
  }

src/hotspot/share/gc/shenandoah/heuristics/shenandoahOldHeuristics.cpp

@@ -606,12 +606,12 @@ void ShenandoahOldHeuristics::set_trigger_if_old_is_fragmented(size_t first_old_
 }
 
 void ShenandoahOldHeuristics::set_trigger_if_old_is_overgrown() {
- size_t old_used = _old_generation->used() + _old_generation->get_humongous_waste();
+ // used() includes humongous waste
+ size_t old_used = _old_generation->used();
  size_t trigger_threshold = _old_generation->usage_trigger_threshold();
  // Detects unsigned arithmetic underflow
  assert(old_used <= _heap->capacity(),
- "Old used (%zu, %zu) must not be more than heap capacity (%zu)",
- _old_generation->used(), _old_generation->get_humongous_waste(), _heap->capacity());
+ "Old used (%zu) must not be more than heap capacity (%zu)", _old_generation->used(), _heap->capacity());
  if (old_used > trigger_threshold) {
  _growth_trigger = true;
  }
@@ -683,7 +683,8 @@ bool ShenandoahOldHeuristics::should_start_gc() {
  if (_growth_trigger) {
  // Growth may be falsely triggered during mixed evacuations, before the mixed-evacuation candidates have been
  // evacuated. Before acting on a false trigger, we check to confirm the trigger condition is still satisfied.
- const size_t current_usage = _old_generation->used() + _old_generation->get_humongous_waste();
+ // _old_generation->used() includes humongous waste.
+ const size_t current_usage = _old_generation->used();
  const size_t trigger_threshold = _old_generation->usage_trigger_threshold();
  const size_t heap_size = heap->capacity();
  const size_t ignore_threshold = (ShenandoahIgnoreOldGrowthBelowPercentage * heap_size) / 100;

src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp

@@ -237,7 +237,6 @@ void ShenandoahFullGC::do_it(GCCause::Cause gc_cause) {
  worker_slices[i] = new ShenandoahHeapRegionSet();
  }
 
- ShenandoahGenerationalHeap::TransferResult result;
  {
  // The rest of code performs region moves, where region status is undefined
  // until all phases run together.
@@ -251,14 +250,7 @@ void ShenandoahFullGC::do_it(GCCause::Cause gc_cause) {
 
  phase4_compact_objects(worker_slices);
 
- result = phase5_epilog();
- }
- if (heap->mode()->is_generational()) {
- LogTarget(Info, gc, ergo) lt;
- if (lt.is_enabled()) {
- LogStream ls(lt);
- result.print_on("Full GC", &ls);
- }
+ phase5_epilog();
  }
 
  // Resize metaspace
@@ -984,23 +976,6 @@ class ShenandoahPostCompactClosure : public ShenandoahHeapRegionClosure {
  r->set_live_data(live);
  r->reset_alloc_metadata();
  }
-
- void update_generation_usage() {
- if (_is_generational) {
- _heap->old_generation()->establish_usage(_old_regions, _old_usage, _old_humongous_waste);
- _heap->young_generation()->establish_usage(_young_regions, _young_usage, _young_humongous_waste);
- } else {
- assert(_old_regions == 0, "Old regions only expected in generational mode");
- assert(_old_usage == 0, "Old usage only expected in generational mode");
- assert(_old_humongous_waste == 0, "Old humongous waste only expected in generational mode");
- }
-
- // In generational mode, global usage should be the sum of young and old. This is also true
- // for non-generational modes except that there are no old regions.
- _heap->global_generation()->establish_usage(_old_regions + _young_regions,
- _old_usage + _young_usage,
- _old_humongous_waste + _young_humongous_waste);
- }
 };
 
 void ShenandoahFullGC::compact_humongous_objects() {
@@ -1120,10 +1095,9 @@ void ShenandoahFullGC::phase4_compact_objects(ShenandoahHeapRegionSet** worker_s
  }
 }
 
-ShenandoahGenerationalHeap::TransferResult ShenandoahFullGC::phase5_epilog() {
+void ShenandoahFullGC::phase5_epilog() {
  GCTraceTime(Info, gc, phases) time("Phase 5: Full GC epilog", _gc_timer);
  ShenandoahHeap* heap = ShenandoahHeap::heap();
- ShenandoahGenerationalHeap::TransferResult result;
 
  // Reset complete bitmap. We're about to reset the complete-top-at-mark-start pointer
  // and must ensure the bitmap is in sync.
@@ -1138,12 +1112,6 @@ ShenandoahGenerationalHeap::TransferResult ShenandoahFullGC::phase5_epilog() {
  ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_copy_objects_rebuild);
  ShenandoahPostCompactClosure post_compact;
  heap->heap_region_iterate(&post_compact);
- post_compact.update_generation_usage();
-
- if (heap->mode()->is_generational()) {
- ShenandoahGenerationalFullGC::balance_generations_after_gc(heap);
- }
-
  heap->collection_set()->clear();
  size_t young_cset_regions, old_cset_regions;
  size_t first_old, last_old, num_old;
@@ -1166,11 +1134,7 @@ ShenandoahGenerationalHeap::TransferResult ShenandoahFullGC::phase5_epilog() {
  _preserved_marks->restore(heap->workers());
  _preserved_marks->reclaim();
 
- // We defer generation resizing actions until after cset regions have been recycled. We do this even following an
- // abbreviated cycle.
  if (heap->mode()->is_generational()) {
- result = ShenandoahGenerationalFullGC::balance_generations_after_rebuilding_free_set();
  ShenandoahGenerationalFullGC::rebuild_remembered_set(heap);
  }
- return result;
 }

src/hotspot/share/gc/shenandoah/shenandoahFreeSet.hpp

@@ -82,8 +82,7 @@ class ShenandoahFullGC : public ShenandoahGC {
  void phase2_calculate_target_addresses(ShenandoahHeapRegionSet** worker_slices);
  void phase3_update_references();
  void phase4_compact_objects(ShenandoahHeapRegionSet** worker_slices);
- ShenandoahGenerationalHeap::TransferResult phase5_epilog();
-
+ void phase5_epilog();
  void distribute_slices(ShenandoahHeapRegionSet** worker_slices);
  void calculate_target_humongous_objects();
  void compact_humongous_objects();