< prev index next > src/hotspot/share/gc/shenandoah/shenandoahHeapRegion.cpp
Print this page
/*
* Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2013, 2019, Red Hat, Inc. All rights reserved.
+ * Copyright (c) 2013, 2020, Red Hat, Inc. All rights reserved.
+ * Copyright Amazon.com Inc. 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
* questions.
*
*/
#include "precompiled.hpp"
+ #include "gc/shared/cardTable.hpp"
#include "gc/shared/space.inline.hpp"
#include "gc/shared/tlab_globals.hpp"
+ #include "gc/shenandoah/shenandoahCardTable.hpp"
+ #include "gc/shenandoah/shenandoahFreeSet.hpp"
#include "gc/shenandoah/shenandoahHeapRegionSet.inline.hpp"
#include "gc/shenandoah/shenandoahHeap.inline.hpp"
#include "gc/shenandoah/shenandoahHeapRegion.hpp"
#include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
+ #include "gc/shenandoah/shenandoahOldGeneration.hpp"
+ #include "gc/shenandoah/shenandoahGeneration.hpp"
+ #include "gc/shenandoah/shenandoahYoungGeneration.hpp"
+ #include "gc/shenandoah/shenandoahScanRemembered.inline.hpp"
#include "jfr/jfrEvents.hpp"
#include "memory/allocation.hpp"
#include "memory/iterator.inline.hpp"
#include "memory/resourceArea.hpp"
#include "memory/universe.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/os.hpp"
#include "runtime/safepoint.hpp"
#include "utilities/powerOfTwo.hpp"
+
size_t ShenandoahHeapRegion::RegionCount = 0;
size_t ShenandoahHeapRegion::RegionSizeBytes = 0;
size_t ShenandoahHeapRegion::RegionSizeWords = 0;
size_t ShenandoahHeapRegion::RegionSizeBytesShift = 0;
size_t ShenandoahHeapRegion::RegionSizeWordsShift = 0;
size_t ShenandoahHeapRegion::RegionSizeBytesMask = 0;
size_t ShenandoahHeapRegion::RegionSizeWordsMask = 0;
- size_t ShenandoahHeapRegion::HumongousThresholdBytes = 0;
- size_t ShenandoahHeapRegion::HumongousThresholdWords = 0;
size_t ShenandoahHeapRegion::MaxTLABSizeBytes = 0;
size_t ShenandoahHeapRegion::MaxTLABSizeWords = 0;
ShenandoahHeapRegion::ShenandoahHeapRegion(HeapWord* start, size_t index, bool committed) :
_index(index),
_bottom(start),
_end(start + RegionSizeWords),
_new_top(nullptr),
_empty_time(os::elapsedTime()),
+ _top_before_promoted(nullptr),
_state(committed ? _empty_committed : _empty_uncommitted),
_top(start),
_tlab_allocs(0),
_gclab_allocs(0),
+ _plab_allocs(0),
_live_data(0),
_critical_pins(0),
- _update_watermark(start) {
+ _update_watermark(start),
+ _age(0)
+ #ifdef SHENANDOAH_CENSUS_NOISE
+ , _youth(0)
+ #endif // SHENANDOAH_CENSUS_NOISE
+ {
assert(Universe::on_page_boundary(_bottom) && Universe::on_page_boundary(_end),
"invalid space boundaries");
if (ZapUnusedHeapArea && committed) {
SpaceMangler::mangle_region(MemRegion(_bottom, _end));
ss.print("Illegal region state transition from \"%s\", at %s\n ", region_state_to_string(_state), method);
print_on(&ss);
fatal("%s", ss.freeze());
}
- void ShenandoahHeapRegion::make_regular_allocation() {
+ void ShenandoahHeapRegion::make_regular_allocation(ShenandoahAffiliation affiliation) {
shenandoah_assert_heaplocked();
-
+ reset_age();
switch (_state) {
case _empty_uncommitted:
do_commit();
case _empty_committed:
+ assert(this->affiliation() == affiliation, "Region affiliation should already be established");
set_state(_regular);
case _regular:
case _pinned:
return;
default:
report_illegal_transition("regular allocation");
}
}
+ // Change affiliation to YOUNG_GENERATION if _state is not _pinned_cset, _regular, or _pinned. This implements
+ // behavior previously performed as a side effect of make_regular_bypass(). This is used by Full GC in non-generational
+ // modes to transition regions from FREE. Note that all non-free regions in single-generational modes are young.
+ void ShenandoahHeapRegion::make_affiliated_maybe() {
+ shenandoah_assert_heaplocked();
+ assert(!ShenandoahHeap::heap()->mode()->is_generational(), "Only call if non-generational");
+ switch (_state) {
+ case _empty_uncommitted:
+ case _empty_committed:
+ case _cset:
+ case _humongous_start:
+ case _humongous_cont:
+ if (affiliation() != YOUNG_GENERATION) {
+ set_affiliation(YOUNG_GENERATION);
+ }
+ return;
+ case _pinned_cset:
+ case _regular:
+ case _pinned:
+ return;
+ default:
+ assert(false, "Unexpected _state in make_affiliated_maybe");
+ }
+ }
+
void ShenandoahHeapRegion::make_regular_bypass() {
shenandoah_assert_heaplocked();
assert (ShenandoahHeap::heap()->is_full_gc_in_progress() || ShenandoahHeap::heap()->is_degenerated_gc_in_progress(),
"only for full or degen GC");
-
+ reset_age();
switch (_state) {
case _empty_uncommitted:
do_commit();
case _empty_committed:
case _cset:
}
}
void ShenandoahHeapRegion::make_humongous_start() {
shenandoah_assert_heaplocked();
+ reset_age();
switch (_state) {
case _empty_uncommitted:
do_commit();
case _empty_committed:
set_state(_humongous_start);
default:
report_illegal_transition("humongous start allocation");
}
}
- void ShenandoahHeapRegion::make_humongous_start_bypass() {
+ void ShenandoahHeapRegion::make_humongous_start_bypass(ShenandoahAffiliation affiliation) {
shenandoah_assert_heaplocked();
assert (ShenandoahHeap::heap()->is_full_gc_in_progress(), "only for full GC");
-
+ // Don't bother to account for affiliated regions during Full GC. We recompute totals at end.
+ set_affiliation(affiliation);
+ reset_age();
switch (_state) {
case _empty_committed:
case _regular:
case _humongous_start:
case _humongous_cont:
}
}
void ShenandoahHeapRegion::make_humongous_cont() {
shenandoah_assert_heaplocked();
+ reset_age();
switch (_state) {
case _empty_uncommitted:
do_commit();
case _empty_committed:
set_state(_humongous_cont);
default:
report_illegal_transition("humongous continuation allocation");
}
}
- void ShenandoahHeapRegion::make_humongous_cont_bypass() {
+ void ShenandoahHeapRegion::make_humongous_cont_bypass(ShenandoahAffiliation affiliation) {
shenandoah_assert_heaplocked();
assert (ShenandoahHeap::heap()->is_full_gc_in_progress(), "only for full GC");
-
+ set_affiliation(affiliation);
+ // Don't bother to account for affiliated regions during Full GC. We recompute totals at end.
+ reset_age();
switch (_state) {
case _empty_committed:
case _regular:
case _humongous_start:
case _humongous_cont:
shenandoah_assert_heaplocked();
assert(pin_count() == 0, "Should not have pins: " SIZE_FORMAT, pin_count());
switch (_state) {
case _pinned:
+ assert(is_affiliated(), "Pinned region should be affiliated");
set_state(_regular);
return;
case _regular:
case _humongous_start:
return;
}
}
void ShenandoahHeapRegion::make_cset() {
shenandoah_assert_heaplocked();
+ // Leave age untouched. We need to consult the age when we are deciding whether to promote evacuated objects.
switch (_state) {
case _regular:
set_state(_cset);
case _cset:
return;
}
}
void ShenandoahHeapRegion::make_trash() {
shenandoah_assert_heaplocked();
+ reset_age();
switch (_state) {
- case _cset:
- // Reclaiming cset regions
case _humongous_start:
case _humongous_cont:
- // Reclaiming humongous regions
+ {
+ // Reclaiming humongous regions and reclaim humongous waste. When this region is eventually recycled, we'll reclaim
+ // its used memory. At recycle time, we no longer recognize this as a humongous region.
+ decrement_humongous_waste();
+ }
+ case _cset:
+ // Reclaiming cset regions
case _regular:
// Immediate region reclaim
set_state(_trash);
return;
default:
void ShenandoahHeapRegion::make_trash_immediate() {
make_trash();
// On this path, we know there are no marked objects in the region,
// tell marking context about it to bypass bitmap resets.
- ShenandoahHeap::heap()->complete_marking_context()->reset_top_bitmap(this);
+ assert(ShenandoahHeap::heap()->gc_generation()->is_mark_complete(), "Marking should be complete here.");
+ shenandoah_assert_generations_reconciled();
+ ShenandoahHeap::heap()->marking_context()->reset_top_bitmap(this);
}
void ShenandoahHeapRegion::make_empty() {
shenandoah_assert_heaplocked();
+ reset_age();
+ CENSUS_NOISE(clear_youth();)
switch (_state) {
case _trash:
set_state(_empty_committed);
_empty_time = os::elapsedTime();
return;
}
void ShenandoahHeapRegion::reset_alloc_metadata() {
_tlab_allocs = 0;
_gclab_allocs = 0;
+ _plab_allocs = 0;
}
size_t ShenandoahHeapRegion::get_shared_allocs() const {
- return used() - (_tlab_allocs + _gclab_allocs) * HeapWordSize;
+ return used() - (_tlab_allocs + _gclab_allocs + _plab_allocs) * HeapWordSize;
}
size_t ShenandoahHeapRegion::get_tlab_allocs() const {
return _tlab_allocs * HeapWordSize;
}
size_t ShenandoahHeapRegion::get_gclab_allocs() const {
return _gclab_allocs * HeapWordSize;
}
+ size_t ShenandoahHeapRegion::get_plab_allocs() const {
+ return _plab_allocs * HeapWordSize;
+ }
+
void ShenandoahHeapRegion::set_live_data(size_t s) {
assert(Thread::current()->is_VM_thread(), "by VM thread");
_live_data = (s >> LogHeapWordSize);
}
break;
default:
ShouldNotReachHere();
}
+ st->print("|%s", shenandoah_affiliation_code(affiliation()));
+
#define SHR_PTR_FORMAT "%12" PRIxPTR
st->print("|BTE " SHR_PTR_FORMAT ", " SHR_PTR_FORMAT ", " SHR_PTR_FORMAT,
p2i(bottom()), p2i(top()), p2i(end()));
st->print("|TAMS " SHR_PTR_FORMAT,
st->print("|UWM " SHR_PTR_FORMAT,
p2i(_update_watermark));
st->print("|U " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(used()), proper_unit_for_byte_size(used()));
st->print("|T " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(get_tlab_allocs()), proper_unit_for_byte_size(get_tlab_allocs()));
st->print("|G " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(get_gclab_allocs()), proper_unit_for_byte_size(get_gclab_allocs()));
+ if (ShenandoahHeap::heap()->mode()->is_generational()) {
+ st->print("|P " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(get_plab_allocs()), proper_unit_for_byte_size(get_plab_allocs()));
+ }
st->print("|S " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(get_shared_allocs()), proper_unit_for_byte_size(get_shared_allocs()));
st->print("|L " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(get_live_data_bytes()), proper_unit_for_byte_size(get_live_data_bytes()));
st->print("|CP " SIZE_FORMAT_W(3), pin_count());
st->cr();
#undef SHR_PTR_FORMAT
}
- void ShenandoahHeapRegion::oop_iterate(OopIterateClosure* blk) {
- if (!is_active()) return;
- if (is_humongous()) {
- oop_iterate_humongous(blk);
- } else {
- oop_iterate_objects(blk);
+ // oop_iterate without closure, return true if completed without cancellation
+ bool ShenandoahHeapRegion::oop_coalesce_and_fill(bool cancellable) {
+
+ assert(!is_humongous(), "No need to fill or coalesce humongous regions");
+ if (!is_active()) {
+ end_preemptible_coalesce_and_fill();
+ return true;
}
- }
- void ShenandoahHeapRegion::oop_iterate_objects(OopIterateClosure* blk) {
- assert(! is_humongous(), "no humongous region here");
- HeapWord* obj_addr = bottom();
- HeapWord* t = top();
- // Could call objects iterate, but this is easier.
+ ShenandoahGenerationalHeap* heap = ShenandoahGenerationalHeap::heap();
+ ShenandoahMarkingContext* marking_context = heap->marking_context();
+
+ // Expect marking to be completed before these threads invoke this service.
+ assert(heap->gc_generation()->is_mark_complete(), "sanity");
+ shenandoah_assert_generations_reconciled();
+
+ // All objects above TAMS are considered live even though their mark bits will not be set. Note that young-
+ // gen evacuations that interrupt a long-running old-gen concurrent mark may promote objects into old-gen
+ // while the old-gen concurrent marking is ongoing. These newly promoted objects will reside above TAMS
+ // and will be treated as live during the current old-gen marking pass, even though they will not be
+ // explicitly marked.
+ HeapWord* t = marking_context->top_at_mark_start(this);
+
+ // Resume coalesce and fill from this address
+ HeapWord* obj_addr = resume_coalesce_and_fill();
+
while (obj_addr < t) {
oop obj = cast_to_oop(obj_addr);
- obj_addr += obj->oop_iterate_size(blk);
+ if (marking_context->is_marked(obj)) {
+ assert(obj->klass() != nullptr, "klass should not be nullptr");
+ obj_addr += obj->size();
+ } else {
+ // Object is not marked. Coalesce and fill dead object with dead neighbors.
+ HeapWord* next_marked_obj = marking_context->get_next_marked_addr(obj_addr, t);
+ assert(next_marked_obj <= t, "next marked object cannot exceed top");
+ size_t fill_size = next_marked_obj - obj_addr;
+ assert(fill_size >= ShenandoahHeap::min_fill_size(), "previously allocated object known to be larger than min_size");
+ ShenandoahHeap::fill_with_object(obj_addr, fill_size);
+ heap->old_generation()->card_scan()->coalesce_objects(obj_addr, fill_size);
+ obj_addr = next_marked_obj;
+ }
+ if (cancellable && heap->cancelled_gc()) {
+ suspend_coalesce_and_fill(obj_addr);
+ return false;
+ }
+ }
+ // Mark that this region has been coalesced and filled
+ end_preemptible_coalesce_and_fill();
+ return true;
+ }
+
+ size_t get_card_count(size_t words) {
+ assert(words % CardTable::card_size_in_words() == 0, "Humongous iteration must span whole number of cards");
+ assert(CardTable::card_size_in_words() * (words / CardTable::card_size_in_words()) == words,
+ "slice must be integral number of cards");
+ return words / CardTable::card_size_in_words();
+ }
+
+ void ShenandoahHeapRegion::oop_iterate_humongous_slice_dirty(OopIterateClosure* blk,
+ HeapWord* start, size_t words, bool write_table) const {
+ assert(is_humongous(), "only humongous region here");
+
+ ShenandoahHeapRegion* r = humongous_start_region();
+ oop obj = cast_to_oop(r->bottom());
+ size_t num_cards = get_card_count(words);
+
+ ShenandoahGenerationalHeap* heap = ShenandoahGenerationalHeap::heap();
+ ShenandoahScanRemembered* scanner = heap->old_generation()->card_scan();
+ size_t card_index = scanner->card_index_for_addr(start);
+ if (write_table) {
+ while (num_cards-- > 0) {
+ if (scanner->is_write_card_dirty(card_index++)) {
+ obj->oop_iterate(blk, MemRegion(start, start + CardTable::card_size_in_words()));
+ }
+ start += CardTable::card_size_in_words();
+ }
+ } else {
+ while (num_cards-- > 0) {
+ if (scanner->is_card_dirty(card_index++)) {
+ obj->oop_iterate(blk, MemRegion(start, start + CardTable::card_size_in_words()));
+ }
+ start += CardTable::card_size_in_words();
+ }
}
}
- void ShenandoahHeapRegion::oop_iterate_humongous(OopIterateClosure* blk) {
+ void ShenandoahHeapRegion::oop_iterate_humongous_slice_all(OopIterateClosure* cl, HeapWord* start, size_t words) const {
assert(is_humongous(), "only humongous region here");
- // Find head.
+
ShenandoahHeapRegion* r = humongous_start_region();
- assert(r->is_humongous_start(), "need humongous head here");
oop obj = cast_to_oop(r->bottom());
- obj->oop_iterate(blk, MemRegion(bottom(), top()));
+
+ // Scan all data, regardless of whether cards are dirty
+ obj->oop_iterate(cl, MemRegion(start, start + words));
}
ShenandoahHeapRegion* ShenandoahHeapRegion::humongous_start_region() const {
ShenandoahHeap* heap = ShenandoahHeap::heap();
assert(is_humongous(), "Must be a part of the humongous region");
assert(r->is_humongous_start(), "Must be");
return r;
}
void ShenandoahHeapRegion::recycle() {
+ shenandoah_assert_heaplocked();
+ ShenandoahHeap* heap = ShenandoahHeap::heap();
+ ShenandoahGeneration* generation = heap->generation_for(affiliation());
+
+ heap->decrease_used(generation, used());
+ generation->decrement_affiliated_region_count();
+
set_top(bottom());
clear_live_data();
-
reset_alloc_metadata();
- ShenandoahHeap::heap()->marking_context()->reset_top_at_mark_start(this);
+ heap->marking_context()->reset_top_at_mark_start(this);
+
set_update_watermark(bottom());
make_empty();
+ set_affiliation(FREE);
if (ZapUnusedHeapArea) {
SpaceMangler::mangle_region(MemRegion(bottom(), end()));
}
}
if (FLAG_IS_DEFAULT(ShenandoahMinRegionSize)) {
FLAG_SET_DEFAULT(ShenandoahMinRegionSize, MIN_REGION_SIZE);
}
+ // Generational Shenandoah needs this alignment for card tables.
+ if (strcmp(ShenandoahGCMode, "generational") == 0) {
+ max_heap_size = align_up(max_heap_size , CardTable::ct_max_alignment_constraint());
+ }
+
size_t region_size;
if (FLAG_IS_DEFAULT(ShenandoahRegionSize)) {
if (ShenandoahMinRegionSize > max_heap_size / MIN_NUM_REGIONS) {
err_msg message("Max heap size (" SIZE_FORMAT "%s) is too low to afford the minimum number "
"of regions (" SIZE_FORMAT ") of minimum region size (" SIZE_FORMAT "%s).",
guarantee(RegionCount == 0, "we should only set it once");
RegionCount = align_up(max_heap_size, RegionSizeBytes) / RegionSizeBytes;
guarantee(RegionCount >= MIN_NUM_REGIONS, "Should have at least minimum regions");
- guarantee(HumongousThresholdWords == 0, "we should only set it once");
- HumongousThresholdWords = RegionSizeWords * ShenandoahHumongousThreshold / 100;
- HumongousThresholdWords = align_down(HumongousThresholdWords, MinObjAlignment);
- assert (HumongousThresholdWords <= RegionSizeWords, "sanity");
-
- guarantee(HumongousThresholdBytes == 0, "we should only set it once");
- HumongousThresholdBytes = HumongousThresholdWords * HeapWordSize;
- assert (HumongousThresholdBytes <= RegionSizeBytes, "sanity");
-
guarantee(MaxTLABSizeWords == 0, "we should only set it once");
- MaxTLABSizeWords = MIN2(RegionSizeWords, HumongousThresholdWords);
- MaxTLABSizeWords = align_down(MaxTLABSizeWords, MinObjAlignment);
+ MaxTLABSizeWords = align_down(RegionSizeWords, MinObjAlignment);
guarantee(MaxTLABSizeBytes == 0, "we should only set it once");
MaxTLABSizeBytes = MaxTLABSizeWords * HeapWordSize;
assert (MaxTLABSizeBytes > MinTLABSize, "should be larger");
}
size_t ShenandoahHeapRegion::pin_count() const {
return Atomic::load(&_critical_pins);
}
+
+ void ShenandoahHeapRegion::set_affiliation(ShenandoahAffiliation new_affiliation) {
+ ShenandoahHeap* heap = ShenandoahHeap::heap();
+
+ ShenandoahAffiliation region_affiliation = heap->region_affiliation(this);
+ {
+ ShenandoahMarkingContext* const ctx = heap->complete_marking_context();
+ log_debug(gc)("Setting affiliation of Region " SIZE_FORMAT " from %s to %s, top: " PTR_FORMAT ", TAMS: " PTR_FORMAT
+ ", watermark: " PTR_FORMAT ", top_bitmap: " PTR_FORMAT,
+ index(), shenandoah_affiliation_name(region_affiliation), shenandoah_affiliation_name(new_affiliation),
+ p2i(top()), p2i(ctx->top_at_mark_start(this)), p2i(_update_watermark), p2i(ctx->top_bitmap(this)));
+ }
+
+ #ifdef ASSERT
+ {
+ // During full gc, heap->complete_marking_context() is not valid, may equal nullptr.
+ ShenandoahMarkingContext* const ctx = heap->complete_marking_context();
+ size_t idx = this->index();
+ HeapWord* top_bitmap = ctx->top_bitmap(this);
+
+ assert(ctx->is_bitmap_range_within_region_clear(top_bitmap, _end),
+ "Region " SIZE_FORMAT ", bitmap should be clear between top_bitmap: " PTR_FORMAT " and end: " PTR_FORMAT, idx,
+ p2i(top_bitmap), p2i(_end));
+ }
+ #endif
+
+ if (region_affiliation == new_affiliation) {
+ return;
+ }
+
+ if (!heap->mode()->is_generational()) {
+ log_trace(gc)("Changing affiliation of region %zu from %s to %s",
+ index(), affiliation_name(), shenandoah_affiliation_name(new_affiliation));
+ heap->set_affiliation(this, new_affiliation);
+ return;
+ }
+
+ switch (new_affiliation) {
+ case FREE:
+ assert(!has_live(), "Free region should not have live data");
+ break;
+ case YOUNG_GENERATION:
+ reset_age();
+ break;
+ case OLD_GENERATION:
+ break;
+ default:
+ ShouldNotReachHere();
+ return;
+ }
+ heap->set_affiliation(this, new_affiliation);
+ }
+
+ void ShenandoahHeapRegion::decrement_humongous_waste() const {
+ assert(is_humongous(), "Should only use this for humongous regions");
+ size_t waste_bytes = free();
+ if (waste_bytes > 0) {
+ ShenandoahHeap* heap = ShenandoahHeap::heap();
+ ShenandoahGeneration* generation = heap->generation_for(affiliation());
+ heap->decrease_humongous_waste(generation, waste_bytes);
+ }
+ }
< prev index next >