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src/share/vm/gc_implementation/shenandoah/shenandoahHeap.cpp
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rev 11156 : [backport] 8220350: Refactor ShenandoahHeap::initialize
Reviewed-by: rkennke, zgu
rev 11157 : [backport] 8220153: Shenandoah does not work with TransparentHugePages properly
Reviewed-by: rkennke, zgu
rev 11158 : [backport] 8220162: Shenandoah should not commit HugeTLBFS memory
Reviewed-by: rkennke, zgu
@@ -77,28 +77,44 @@
void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_nv(p); }
void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_nv(p); }
#endif
-class ShenandoahPretouchTask : public AbstractGangTask {
+class ShenandoahPretouchHeapTask : public AbstractGangTask {
private:
ShenandoahRegionIterator _regions;
- const size_t _bitmap_size;
const size_t _page_size;
- char* _bitmap_base;
public:
- ShenandoahPretouchTask(char* bitmap_base, size_t bitmap_size, size_t page_size) :
- AbstractGangTask("Shenandoah PreTouch"),
- _bitmap_size(bitmap_size),
- _page_size(page_size),
- _bitmap_base(bitmap_base) {}
+ ShenandoahPretouchHeapTask(size_t page_size) :
+ AbstractGangTask("Shenandoah Pretouch Heap"),
+ _page_size(page_size) {}
virtual void work(uint worker_id) {
ShenandoahHeapRegion* r = _regions.next();
while (r != NULL) {
os::pretouch_memory((char*) r->bottom(), (char*) r->end());
+ r = _regions.next();
+ }
+ }
+};
+
+class ShenandoahPretouchBitmapTask : public AbstractGangTask {
+private:
+ ShenandoahRegionIterator _regions;
+ char* _bitmap_base;
+ const size_t _bitmap_size;
+ const size_t _page_size;
+public:
+ ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) :
+ AbstractGangTask("Shenandoah Pretouch Bitmap"),
+ _bitmap_base(bitmap_base),
+ _bitmap_size(bitmap_size),
+ _page_size(page_size) {}
+ virtual void work(uint worker_id) {
+ ShenandoahHeapRegion* r = _regions.next();
+ while (r != NULL) {
size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
assert (end <= _bitmap_size, err_msg("end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size));
os::pretouch_memory(_bitmap_base + start, _bitmap_base + end);
@@ -113,81 +129,66 @@
ShenandoahBrooksPointer::initial_checks();
initialize_heuristics();
+ //
+ // Figure out heap sizing
+ //
+
size_t init_byte_size = collector_policy()->initial_heap_byte_size();
size_t max_byte_size = collector_policy()->max_heap_byte_size();
size_t heap_alignment = collector_policy()->heap_alignment();
+ size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
+
if (ShenandoahAlwaysPreTouch) {
// Enabled pre-touch means the entire heap is committed right away.
init_byte_size = max_byte_size;
}
- Universe::check_alignment(max_byte_size,
- ShenandoahHeapRegion::region_size_bytes(),
- "shenandoah heap");
- Universe::check_alignment(init_byte_size,
- ShenandoahHeapRegion::region_size_bytes(),
- "shenandoah heap");
-
- ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
- heap_alignment);
-
- _reserved.set_word_size(0);
- _reserved.set_start((HeapWord*)heap_rs.base());
- _reserved.set_end((HeapWord*)(heap_rs.base() + heap_rs.size()));
-
- set_barrier_set(new ShenandoahBarrierSet(this));
- ReservedSpace pgc_rs = heap_rs.first_part(max_byte_size);
+ Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap");
+ Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap");
_num_regions = ShenandoahHeapRegion::region_count();
- size_t num_committed_regions = init_byte_size / ShenandoahHeapRegion::region_size_bytes();
+ size_t num_committed_regions = init_byte_size / reg_size_bytes;
num_committed_regions = MIN2(num_committed_regions, _num_regions);
assert(num_committed_regions <= _num_regions, "sanity");
- _initial_size = num_committed_regions * ShenandoahHeapRegion::region_size_bytes();
+ _initial_size = num_committed_regions * reg_size_bytes;
_committed = _initial_size;
- log_info(gc, heap)("Initialize Shenandoah heap with initial size " SIZE_FORMAT "%s",
- byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size));
- if (!os::commit_memory(pgc_rs.base(), _initial_size, false)) {
- vm_exit_out_of_memory(_initial_size, OOM_MMAP_ERROR, "Shenandoah failed to initialize heap");
- }
+ size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
+ size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
- size_t reg_size_words = ShenandoahHeapRegion::region_size_words();
- size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
+ //
+ // Reserve and commit memory for heap
+ //
- _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
- _free_set = new ShenandoahFreeSet(this, _num_regions);
+ ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment);
+ _reserved.set_word_size(0);
+ _reserved.set_start((HeapWord*)heap_rs.base());
+ _reserved.set_end((HeapWord*)(heap_rs.base() + heap_rs.size()));
+ _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize);
+ _heap_region_special = heap_rs.special();
- _collection_set = new ShenandoahCollectionSet(this, (HeapWord*)pgc_rs.base());
+ assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
+ err_msg("Misaligned heap: " PTR_FORMAT, p2i(base())));
- if (ShenandoahPacing) {
- _pacer = new ShenandoahPacer(this);
- _pacer->setup_for_idle();
- } else {
- _pacer = NULL;
+ ReservedSpace sh_rs = heap_rs.first_part(max_byte_size);
+ if (!_heap_region_special) {
+ os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false,
+ "Cannot commit heap memory");
}
- assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
- err_msg("misaligned heap: " PTR_FORMAT, p2i(base())));
-
- // The call below uses stuff (the SATB* things) that are in G1, but probably
- // belong into a shared location.
- JavaThread::satb_mark_queue_set().initialize(SATB_Q_CBL_mon,
- SATB_Q_FL_lock,
- 20 /*G1SATBProcessCompletedThreshold */,
- Shared_SATB_Q_lock);
+ //
+ // Reserve and commit memory for bitmap(s)
+ //
- // Reserve space for prev and next bitmap.
- size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
_bitmap_size = MarkBitMap::compute_size(heap_rs.size());
_bitmap_size = align_size_up(_bitmap_size, bitmap_page_size);
- _heap_region = MemRegion((HeapWord*) heap_rs.base(), heap_rs.size() / HeapWordSize);
size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
guarantee(bitmap_bytes_per_region != 0,
err_msg("Bitmap bytes per region should not be zero"));
@@ -208,42 +209,61 @@
guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
err_msg("Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
_bitmap_bytes_per_slice, bitmap_page_size));
- ReservedSpace bitmap0(_bitmap_size, bitmap_page_size);
- MemTracker::record_virtual_memory_type(bitmap0.base(), mtGC);
- _bitmap_region = MemRegion((HeapWord*) bitmap0.base(), bitmap0.size() / HeapWordSize);
+ ReservedSpace bitmap(_bitmap_size, bitmap_page_size);
+ MemTracker::record_virtual_memory_type(bitmap.base(), mtGC);
+ _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize);
+ _bitmap_region_special = bitmap.special();
size_t bitmap_init_commit = _bitmap_bytes_per_slice *
align_size_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
- os::commit_memory_or_exit((char *) (_bitmap_region.start()), bitmap_init_commit, false,
- "couldn't allocate initial bitmap");
+ if (!_bitmap_region_special) {
+ os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false,
+ "Cannot commit bitmap memory");
+ }
- size_t page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
+ _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions);
if (ShenandoahVerify) {
- ReservedSpace verify_bitmap(_bitmap_size, page_size);
- os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), false,
- "couldn't allocate verification bitmap");
+ ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size);
+ if (!verify_bitmap.special()) {
+ os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false,
+ "Cannot commit verification bitmap memory");
+ }
MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
_verification_bit_map.initialize(_heap_region, verify_bitmap_region);
_verifier = new ShenandoahVerifier(this, &_verification_bit_map);
}
- _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions);
+ // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
+ ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
+ MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
+ _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
+ _aux_bitmap_region_special = aux_bitmap.special();
+ _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
+
+ //
+ // Create regions and region sets
+ //
+
+ _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
+ _free_set = new ShenandoahFreeSet(this, _num_regions);
+ _collection_set = new ShenandoahCollectionSet(this, (HeapWord*)sh_rs.base());
{
ShenandoahHeapLocker locker(lock());
+
+ size_t size_words = ShenandoahHeapRegion::region_size_words();
+
for (size_t i = 0; i < _num_regions; i++) {
- ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this,
- (HeapWord*) pgc_rs.base() + reg_size_words * i,
- reg_size_words,
- i,
- i < num_committed_regions);
+ HeapWord* start = (HeapWord*)sh_rs.base() + size_words * i;
+ bool is_committed = i < num_committed_regions;
+ ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this, start, size_words, i, is_committed);
_marking_context->initialize_top_at_mark_start(r);
_regions[i] = r;
assert(!collection_set()->is_in(i), "New region should not be in collection set");
}
@@ -253,48 +273,83 @@
_free_set->rebuild();
}
if (ShenandoahAlwaysPreTouch) {
- assert (!AlwaysPreTouch, "Should have been overridden");
+ assert(!AlwaysPreTouch, "Should have been overridden");
// For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
// before initialize() below zeroes it with initializing thread. For any given region,
// we touch the region and the corresponding bitmaps from the same thread.
ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
- log_info(gc, heap)("Parallel pretouch " SIZE_FORMAT " regions with " SIZE_FORMAT " byte pages",
- _num_regions, page_size);
- ShenandoahPretouchTask cl(bitmap0.base(), _bitmap_size, page_size);
- _workers->run_task(&cl);
+ size_t pretouch_heap_page_size = heap_page_size;
+ size_t pretouch_bitmap_page_size = bitmap_page_size;
+
+#ifdef LINUX
+ // UseTransparentHugePages would madvise that backing memory can be coalesced into huge
+ // pages. But, the kernel needs to know that every small page is used, in order to coalesce
+ // them into huge one. Therefore, we need to pretouch with smaller pages.
+ if (UseTransparentHugePages) {
+ pretouch_heap_page_size = (size_t)os::vm_page_size();
+ pretouch_bitmap_page_size = (size_t)os::vm_page_size();
}
+#endif
- // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
- ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
- MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
- _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
- _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
+ // OS memory managers may want to coalesce back-to-back pages. Make their jobs
+ // simpler by pre-touching continuous spaces (heap and bitmap) separately.
- _monitoring_support = new ShenandoahMonitoringSupport(this);
+ log_info(gc, init)("Pretouch bitmap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
+ _num_regions, pretouch_bitmap_page_size);
+ ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, pretouch_bitmap_page_size);
+ _workers->run_task(&bcl);
+
+ log_info(gc, init)("Pretouch heap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
+ _num_regions, pretouch_heap_page_size);
+ ShenandoahPretouchHeapTask hcl(pretouch_heap_page_size);
+ _workers->run_task(&hcl);
+ }
+
+ //
+ // Initialize the rest of GC subsystems
+ //
+
+ set_barrier_set(new ShenandoahBarrierSet(this));
+
+ _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC);
+ for (uint worker = 0; worker < _max_workers; worker++) {
+ _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC);
+ Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort));
+ }
+ // The call below uses stuff (the SATB* things) that are in G1, but probably
+ // belong into a shared location.
+ JavaThread::satb_mark_queue_set().initialize(SATB_Q_CBL_mon,
+ SATB_Q_FL_lock,
+ 20 /*G1SATBProcessCompletedThreshold */,
+ Shared_SATB_Q_lock);
+
+ _monitoring_support = new ShenandoahMonitoringSupport(this);
_phase_timings = new ShenandoahPhaseTimings();
+ ShenandoahStringDedup::initialize();
+ ShenandoahCodeRoots::initialize();
if (ShenandoahAllocationTrace) {
_alloc_tracker = new ShenandoahAllocTracker();
}
- ShenandoahStringDedup::initialize();
+ if (ShenandoahPacing) {
+ _pacer = new ShenandoahPacer(this);
+ _pacer->setup_for_idle();
+ } else {
+ _pacer = NULL;
+ }
_control_thread = new ShenandoahControlThread();
- ShenandoahCodeRoots::initialize();
-
- _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC);
- for (uint worker = 0; worker < _max_workers; worker++) {
- _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC);
- Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort));
- }
+ log_info(gc, init)("Initialize Shenandoah heap with initial size " SIZE_FORMAT "%s",
+ byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size));
return JNI_OK;
}
#ifdef _MSC_VER
@@ -336,18 +391,25 @@
}
ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
SharedHeap(policy),
_shenandoah_policy(policy),
+ _heap_region_special(false),
_regions(NULL),
_free_set(NULL),
_collection_set(NULL),
_update_refs_iterator(this),
_bytes_allocated_since_gc_start(0),
_max_workers((uint)MAX2(ConcGCThreads, ParallelGCThreads)),
_ref_processor(NULL),
_marking_context(NULL),
+ _bitmap_size(0),
+ _bitmap_regions_per_slice(0),
+ _bitmap_bytes_per_slice(0),
+ _bitmap_region_special(false),
+ _aux_bitmap_region_special(false),
+ _liveness_cache(NULL),
_aux_bit_map(),
_verifier(NULL),
_pacer(NULL),
_gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
_phase_timings(NULL),
@@ -1143,11 +1205,11 @@
* objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
* is allowed to report dead objects, but is not required to do so.
*/
void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
- if (!os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
+ if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
return;
}
// Reset bitmap
@@ -1170,11 +1232,11 @@
obj->oop_iterate(&oops);
}
assert(oop_stack.is_empty(), "should be empty");
- if (!os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
+ if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
}
}
void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
@@ -2096,10 +2158,15 @@
}
bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
assert_heaplock_owned_by_current_thread();
+ // Bitmaps in special regions do not need commits
+ if (_bitmap_region_special) {
+ return true;
+ }
+
if (is_bitmap_slice_committed(r, true)) {
// Some other region from the group is already committed, meaning the bitmap
// slice is already committed, we exit right away.
return true;
}
@@ -2115,10 +2182,15 @@
}
bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
assert_heaplock_owned_by_current_thread();
+ // Bitmaps in special regions do not need uncommits
+ if (_bitmap_region_special) {
+ return true;
+ }
+
if (is_bitmap_slice_committed(r, true)) {
// Some other region from the group is still committed, meaning the bitmap
// slice is should stay committed, exit right away.
return true;
}
@@ -2537,20 +2609,22 @@
}
}
jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) {
#ifdef ASSERT
+ assert(_liveness_cache != NULL, "sanity");
assert(worker_id < _max_workers, "sanity");
for (uint i = 0; i < num_regions(); i++) {
assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty");
}
#endif
return _liveness_cache[worker_id];
}
void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
assert(worker_id < _max_workers, "sanity");
+ assert(_liveness_cache != NULL, "sanity");
jushort* ld = _liveness_cache[worker_id];
for (uint i = 0; i < num_regions(); i++) {
ShenandoahHeapRegion* r = get_region(i);
jushort live = ld[i];
if (live > 0) {
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