--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/shenandoah/shenandoahConcurrentMark.inline.hpp Mon Dec 10 15:47:44 2018 +0100
@@ -0,0 +1,278 @@
+/*
+ * Copyright (c) 2015, 2018, Red Hat, Inc. All rights reserved.
+ *
+ * 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.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAHCONCURRENTMARK_INLINE_HPP
+#define SHARE_VM_GC_SHENANDOAH_SHENANDOAHCONCURRENTMARK_INLINE_HPP
+
+#include "gc/shenandoah/shenandoahAsserts.hpp"
+#include "gc/shenandoah/shenandoahBrooksPointer.hpp"
+#include "gc/shenandoah/shenandoahBarrierSet.inline.hpp"
+#include "gc/shenandoah/shenandoahConcurrentMark.hpp"
+#include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
+#include "gc/shenandoah/shenandoahStringDedup.hpp"
+#include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
+#include "memory/iterator.inline.hpp"
+#include "oops/oop.inline.hpp"
+#include "runtime/prefetch.inline.hpp"
+
+template <class T>
+void ShenandoahConcurrentMark::do_task(ShenandoahObjToScanQueue* q, T* cl, jushort* live_data, ShenandoahMarkTask* task) {
+ oop obj = task->obj();
+
+ shenandoah_assert_not_forwarded_except(NULL, obj, _heap->is_concurrent_traversal_in_progress() && _heap->cancelled_gc());
+ shenandoah_assert_marked(NULL, obj);
+ shenandoah_assert_not_in_cset_except(NULL, obj, _heap->cancelled_gc());
+
+ if (task->is_not_chunked()) {
+ if (obj->is_instance()) {
+ // Case 1: Normal oop, process as usual.
+ obj->oop_iterate(cl);
+ } else if (obj->is_objArray()) {
+ // Case 2: Object array instance and no chunk is set. Must be the first
+ // time we visit it, start the chunked processing.
+ do_chunked_array_start<T>(q, cl, obj);
+ } else {
+ // Case 3: Primitive array. Do nothing, no oops there. We use the same
+ // performance tweak TypeArrayKlass::oop_oop_iterate_impl is using:
+ // We skip iterating over the klass pointer since we know that
+ // Universe::TypeArrayKlass never moves.
+ assert (obj->is_typeArray(), "should be type array");
+ }
+ // Count liveness the last: push the outstanding work to the queues first
+ count_liveness(live_data, obj);
+ } else {
+ // Case 4: Array chunk, has sensible chunk id. Process it.
+ do_chunked_array<T>(q, cl, obj, task->chunk(), task->pow());
+ }
+}
+
+inline void ShenandoahConcurrentMark::count_liveness(jushort* live_data, oop obj) {
+ size_t region_idx = _heap->heap_region_index_containing(obj);
+ ShenandoahHeapRegion* region = _heap->get_region(region_idx);
+ size_t size = obj->size() + ShenandoahBrooksPointer::word_size();
+
+ if (!region->is_humongous_start()) {
+ assert(!region->is_humongous(), "Cannot have continuations here");
+ size_t max = (1 << (sizeof(jushort) * 8)) - 1;
+ if (size >= max) {
+ // too big, add to region data directly
+ region->increase_live_data_gc_words(size);
+ } else {
+ jushort cur = live_data[region_idx];
+ size_t new_val = cur + size;
+ if (new_val >= max) {
+ // overflow, flush to region data
+ region->increase_live_data_gc_words(new_val);
+ live_data[region_idx] = 0;
+ } else {
+ // still good, remember in locals
+ live_data[region_idx] = (jushort) new_val;
+ }
+ }
+ } else {
+ shenandoah_assert_in_correct_region(NULL, obj);
+ size_t num_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
+
+ for (size_t i = region_idx; i < region_idx + num_regions; i++) {
+ ShenandoahHeapRegion* chain_reg = _heap->get_region(i);
+ assert(chain_reg->is_humongous(), "Expecting a humongous region");
+ chain_reg->increase_live_data_gc_words(chain_reg->used() >> LogHeapWordSize);
+ }
+ }
+}
+
+template <class T>
+inline void ShenandoahConcurrentMark::do_chunked_array_start(ShenandoahObjToScanQueue* q, T* cl, oop obj) {
+ assert(obj->is_objArray(), "expect object array");
+ objArrayOop array = objArrayOop(obj);
+ int len = array->length();
+
+ if (len <= (int) ObjArrayMarkingStride*2) {
+ // A few slices only, process directly
+ array->oop_iterate_range(cl, 0, len);
+ } else {
+ int bits = log2_long((size_t) len);
+ // Compensate for non-power-of-two arrays, cover the array in excess:
+ if (len != (1 << bits)) bits++;
+
+ // Only allow full chunks on the queue. This frees do_chunked_array() from checking from/to
+ // boundaries against array->length(), touching the array header on every chunk.
+ //
+ // To do this, we cut the prefix in full-sized chunks, and submit them on the queue.
+ // If the array is not divided in chunk sizes, then there would be an irregular tail,
+ // which we will process separately.
+
+ int last_idx = 0;
+
+ int chunk = 1;
+ int pow = bits;
+
+ // Handle overflow
+ if (pow >= 31) {
+ assert (pow == 31, "sanity");
+ pow--;
+ chunk = 2;
+ last_idx = (1 << pow);
+ bool pushed = q->push(ShenandoahMarkTask(array, 1, pow));
+ assert(pushed, "overflow queue should always succeed pushing");
+ }
+
+ // Split out tasks, as suggested in ObjArrayChunkedTask docs. Record the last
+ // successful right boundary to figure out the irregular tail.
+ while ((1 << pow) > (int)ObjArrayMarkingStride &&
+ (chunk*2 < ShenandoahMarkTask::chunk_size())) {
+ pow--;
+ int left_chunk = chunk*2 - 1;
+ int right_chunk = chunk*2;
+ int left_chunk_end = left_chunk * (1 << pow);
+ if (left_chunk_end < len) {
+ bool pushed = q->push(ShenandoahMarkTask(array, left_chunk, pow));
+ assert(pushed, "overflow queue should always succeed pushing");
+ chunk = right_chunk;
+ last_idx = left_chunk_end;
+ } else {
+ chunk = left_chunk;
+ }
+ }
+
+ // Process the irregular tail, if present
+ int from = last_idx;
+ if (from < len) {
+ array->oop_iterate_range(cl, from, len);
+ }
+ }
+}
+
+template <class T>
+inline void ShenandoahConcurrentMark::do_chunked_array(ShenandoahObjToScanQueue* q, T* cl, oop obj, int chunk, int pow) {
+ assert(obj->is_objArray(), "expect object array");
+ objArrayOop array = objArrayOop(obj);
+
+ assert (ObjArrayMarkingStride > 0, "sanity");
+
+ // Split out tasks, as suggested in ObjArrayChunkedTask docs. Avoid pushing tasks that
+ // are known to start beyond the array.
+ while ((1 << pow) > (int)ObjArrayMarkingStride && (chunk*2 < ShenandoahMarkTask::chunk_size())) {
+ pow--;
+ chunk *= 2;
+ bool pushed = q->push(ShenandoahMarkTask(array, chunk - 1, pow));
+ assert(pushed, "overflow queue should always succeed pushing");
+ }
+
+ int chunk_size = 1 << pow;
+
+ int from = (chunk - 1) * chunk_size;
+ int to = chunk * chunk_size;
+
+#ifdef ASSERT
+ int len = array->length();
+ assert (0 <= from && from < len, "from is sane: %d/%d", from, len);
+ assert (0 < to && to <= len, "to is sane: %d/%d", to, len);
+#endif
+
+ array->oop_iterate_range(cl, from, to);
+}
+
+class ShenandoahSATBBufferClosure : public SATBBufferClosure {
+private:
+ ShenandoahObjToScanQueue* _queue;
+ ShenandoahHeap* _heap;
+ ShenandoahMarkingContext* const _mark_context;
+public:
+ ShenandoahSATBBufferClosure(ShenandoahObjToScanQueue* q) :
+ _queue(q),
+ _heap(ShenandoahHeap::heap()),
+ _mark_context(_heap->marking_context())
+ {
+ }
+
+ void do_buffer(void **buffer, size_t size) {
+ if (_heap->has_forwarded_objects()) {
+ if (ShenandoahStringDedup::is_enabled()) {
+ do_buffer_impl<RESOLVE, ENQUEUE_DEDUP>(buffer, size);
+ } else {
+ do_buffer_impl<RESOLVE, NO_DEDUP>(buffer, size);
+ }
+ } else {
+ if (ShenandoahStringDedup::is_enabled()) {
+ do_buffer_impl<NONE, ENQUEUE_DEDUP>(buffer, size);
+ } else {
+ do_buffer_impl<NONE, NO_DEDUP>(buffer, size);
+ }
+ }
+ }
+
+ template<UpdateRefsMode UPDATE_REFS, StringDedupMode STRING_DEDUP>
+ void do_buffer_impl(void **buffer, size_t size) {
+ for (size_t i = 0; i < size; ++i) {
+ oop *p = (oop *) &buffer[i];
+ ShenandoahConcurrentMark::mark_through_ref<oop, UPDATE_REFS, STRING_DEDUP>(p, _heap, _queue, _mark_context);
+ }
+ }
+};
+
+template<class T, UpdateRefsMode UPDATE_REFS, StringDedupMode STRING_DEDUP>
+inline void ShenandoahConcurrentMark::mark_through_ref(T *p, ShenandoahHeap* heap, ShenandoahObjToScanQueue* q, ShenandoahMarkingContext* const mark_context) {
+ T o = RawAccess<>::oop_load(p);
+ if (!CompressedOops::is_null(o)) {
+ oop obj = CompressedOops::decode_not_null(o);
+ switch (UPDATE_REFS) {
+ case NONE:
+ break;
+ case RESOLVE:
+ obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
+ break;
+ case SIMPLE:
+ // We piggy-back reference updating to the marking tasks.
+ obj = heap->update_with_forwarded_not_null(p, obj);
+ break;
+ case CONCURRENT:
+ obj = heap->maybe_update_with_forwarded_not_null(p, obj);
+ break;
+ default:
+ ShouldNotReachHere();
+ }
+
+ // Note: Only when concurrently updating references can obj become NULL here.
+ // It happens when a mutator thread beats us by writing another value. In that
+ // case we don't need to do anything else.
+ if (UPDATE_REFS != CONCURRENT || !CompressedOops::is_null(obj)) {
+ shenandoah_assert_not_forwarded(p, obj);
+ shenandoah_assert_not_in_cset_except(p, obj, heap->cancelled_gc());
+
+ if (mark_context->mark(obj)) {
+ bool pushed = q->push(ShenandoahMarkTask(obj));
+ assert(pushed, "overflow queue should always succeed pushing");
+
+ if ((STRING_DEDUP == ENQUEUE_DEDUP) && ShenandoahStringDedup::is_candidate(obj)) {
+ assert(ShenandoahStringDedup::is_enabled(), "Must be enabled");
+ ShenandoahStringDedup::enqueue_candidate(obj);
+ }
+ }
+
+ shenandoah_assert_marked(p, obj);
+ }
+ }
+}
+
+#endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHCONCURRENTMARK_INLINE_HPP