src/hotspot/share/gc/g1/g1ParScanThreadState.inline.hpp
changeset 47216 71c04702a3d5
parent 46646 5165b3a5b44a
child 47885 5caa1d5f74c1
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/g1/g1ParScanThreadState.inline.hpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,149 @@
+/*
+ * Copyright (c) 2014, 2015, 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
+ * 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_G1_G1PARSCANTHREADSTATE_INLINE_HPP
+#define SHARE_VM_GC_G1_G1PARSCANTHREADSTATE_INLINE_HPP
+
+#include "gc/g1/g1ParScanThreadState.hpp"
+#include "gc/g1/g1RemSet.inline.hpp"
+#include "oops/oop.inline.hpp"
+
+template <class T> void G1ParScanThreadState::do_oop_evac(T* p, HeapRegion* from) {
+  assert(!oopDesc::is_null(oopDesc::load_decode_heap_oop(p)),
+         "Reference should not be NULL here as such are never pushed to the task queue.");
+  oop obj = oopDesc::load_decode_heap_oop_not_null(p);
+
+  // Although we never intentionally push references outside of the collection
+  // set, due to (benign) races in the claim mechanism during RSet scanning more
+  // than one thread might claim the same card. So the same card may be
+  // processed multiple times. So redo this check.
+  const InCSetState in_cset_state = _g1h->in_cset_state(obj);
+  if (in_cset_state.is_in_cset()) {
+    markOop m = obj->mark();
+    if (m->is_marked()) {
+      obj = (oop) m->decode_pointer();
+    } else {
+      obj = copy_to_survivor_space(in_cset_state, obj, m);
+    }
+    oopDesc::encode_store_heap_oop(p, obj);
+  } else if (in_cset_state.is_humongous()) {
+    _g1h->set_humongous_is_live(obj);
+  } else {
+    assert(in_cset_state.is_default() || in_cset_state.is_ext(),
+         "In_cset_state must be NotInCSet or Ext here, but is " CSETSTATE_FORMAT, in_cset_state.value());
+  }
+
+  assert(obj != NULL, "Must be");
+  if (!HeapRegion::is_in_same_region(p, obj)) {
+    update_rs(from, p, obj);
+  }
+}
+
+template <class T> inline void G1ParScanThreadState::push_on_queue(T* ref) {
+  assert(verify_ref(ref), "sanity");
+  _refs->push(ref);
+}
+
+inline void G1ParScanThreadState::do_oop_partial_array(oop* p) {
+  assert(has_partial_array_mask(p), "invariant");
+  oop from_obj = clear_partial_array_mask(p);
+
+  assert(_g1h->is_in_reserved(from_obj), "must be in heap.");
+  assert(from_obj->is_objArray(), "must be obj array");
+  objArrayOop from_obj_array = objArrayOop(from_obj);
+  // The from-space object contains the real length.
+  int length                 = from_obj_array->length();
+
+  assert(from_obj->is_forwarded(), "must be forwarded");
+  oop to_obj                 = from_obj->forwardee();
+  assert(from_obj != to_obj, "should not be chunking self-forwarded objects");
+  objArrayOop to_obj_array   = objArrayOop(to_obj);
+  // We keep track of the next start index in the length field of the
+  // to-space object.
+  int next_index             = to_obj_array->length();
+  assert(0 <= next_index && next_index < length,
+         "invariant, next index: %d, length: %d", next_index, length);
+
+  int start                  = next_index;
+  int end                    = length;
+  int remainder              = end - start;
+  // We'll try not to push a range that's smaller than ParGCArrayScanChunk.
+  if (remainder > 2 * ParGCArrayScanChunk) {
+    end = start + ParGCArrayScanChunk;
+    to_obj_array->set_length(end);
+    // Push the remainder before we process the range in case another
+    // worker has run out of things to do and can steal it.
+    oop* from_obj_p = set_partial_array_mask(from_obj);
+    push_on_queue(from_obj_p);
+  } else {
+    assert(length == end, "sanity");
+    // We'll process the final range for this object. Restore the length
+    // so that the heap remains parsable in case of evacuation failure.
+    to_obj_array->set_length(end);
+  }
+  _scanner.set_region(_g1h->heap_region_containing(to_obj));
+  // Process indexes [start,end). It will also process the header
+  // along with the first chunk (i.e., the chunk with start == 0).
+  // Note that at this point the length field of to_obj_array is not
+  // correct given that we are using it to keep track of the next
+  // start index. oop_iterate_range() (thankfully!) ignores the length
+  // field and only relies on the start / end parameters.  It does
+  // however return the size of the object which will be incorrect. So
+  // we have to ignore it even if we wanted to use it.
+  to_obj_array->oop_iterate_range(&_scanner, start, end);
+}
+
+template <class T> inline void G1ParScanThreadState::deal_with_reference(T* ref_to_scan) {
+  if (!has_partial_array_mask(ref_to_scan)) {
+    HeapRegion* r = _g1h->heap_region_containing(ref_to_scan);
+    do_oop_evac(ref_to_scan, r);
+  } else {
+    do_oop_partial_array((oop*)ref_to_scan);
+  }
+}
+
+inline void G1ParScanThreadState::dispatch_reference(StarTask ref) {
+  assert(verify_task(ref), "sanity");
+  if (ref.is_narrow()) {
+    deal_with_reference((narrowOop*)ref);
+  } else {
+    deal_with_reference((oop*)ref);
+  }
+}
+
+void G1ParScanThreadState::steal_and_trim_queue(RefToScanQueueSet *task_queues) {
+  StarTask stolen_task;
+  while (task_queues->steal(_worker_id, &_hash_seed, stolen_task)) {
+    assert(verify_task(stolen_task), "sanity");
+    dispatch_reference(stolen_task);
+
+    // We've just processed a reference and we might have made
+    // available new entries on the queues. So we have to make sure
+    // we drain the queues as necessary.
+    trim_queue();
+  }
+}
+
+#endif // SHARE_VM_GC_G1_G1PARSCANTHREADSTATE_INLINE_HPP
+