jdk-sandbox: comparison src/hotspot/share/gc/shared/collectedHeap.cpp

equal deleted inserted replaced

-:040293c73621
+:120b61d50f85
 /*
-* Copyright (c) 2001, 2017, Oracle and/or its affiliates. All rights reserved.
+* Copyright (c) 2001, 2018, 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.
 _barrier_set(NULL),
 _is_gc_active(false),
 _total_collections(0),
 _total_full_collections(0),
 _gc_cause(GCCause::_no_gc),
-_gc_lastcause(GCCause::_no_gc),
+_gc_lastcause(GCCause::_no_gc)
-_defer_initial_card_mark(false) // strengthened by subclass in pre_initialize() below.
 {
 const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
 const size_t elements_per_word = HeapWordSize / sizeof(jint);
 _filler_array_max_size = align_object_size(filler_array_hdr_size() +
 max_len / elements_per_word);
 void CollectedHeap::set_barrier_set(BarrierSet* barrier_set) {
 _barrier_set = barrier_set;
 BarrierSet::set_bs(barrier_set);
 }
-void CollectedHeap::pre_initialize() {
-// Used for ReduceInitialCardMarks (when COMPILER2 is used);
-// otherwise remains unused.
-#if COMPILER2_OR_JVMCI
-_defer_initial_card_mark = is_server_compilation_mode_vm() &&  ReduceInitialCardMarks && can_elide_tlab_store_barriers()
-&& (DeferInitialCardMark || card_mark_must_follow_store());
-#else
-assert(_defer_initial_card_mark == false, "Who would set it?");
-#endif
-}
 #ifndef PRODUCT
 void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
 for (size_t slot = 0; slot < size; slot += 1) {
 assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
 }
 thread->tlab().fill(obj, obj + size, new_tlab_size);
 return obj;
 }
-void CollectedHeap::flush_deferred_store_barrier(JavaThread* thread) {
-MemRegion deferred = thread->deferred_card_mark();
-if (!deferred.is_empty()) {
-assert(_defer_initial_card_mark, "Otherwise should be empty");
-{
-// Verify that the storage points to a parsable object in heap
-DEBUG_ONLY(oop old_obj = oop(deferred.start());)
-assert(is_in(old_obj), "Not in allocated heap");
-assert(!can_elide_initializing_store_barrier(old_obj),
-"Else should have been filtered in new_store_pre_barrier()");
-assert(oopDesc::is_oop(old_obj, true), "Not an oop");
-assert(deferred.word_size() == (size_t)(old_obj->size()),
-"Mismatch: multiple objects?");
-}
-BarrierSet* bs = barrier_set();
-bs->write_region(deferred);
-// "Clear" the deferred_card_mark field
-thread->set_deferred_card_mark(MemRegion());
-}
-assert(thread->deferred_card_mark().is_empty(), "invariant");
-}
 size_t CollectedHeap::max_tlab_size() const {
 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
 // This restriction could be removed by enabling filling with multiple arrays.
 // If we compute that the reasonable way as
 //    header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
 // which is fine, since we'll be able to fill that.
 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
 sizeof(jint) *
 ((juint) max_jint / (size_t) HeapWordSize);
 return align_down(max_int_size, MinObjAlignment);
-}
-// Helper for ReduceInitialCardMarks. For performance,
-// compiled code may elide card-marks for initializing stores
-// to a newly allocated object along the fast-path. We
-// compensate for such elided card-marks as follows:
-// (a) Generational, non-concurrent collectors, such as
-//     GenCollectedHeap(ParNew,DefNew,Tenured) and
-//     ParallelScavengeHeap(ParallelGC, ParallelOldGC)
-//     need the card-mark if and only if the region is
-//     in the old gen, and do not care if the card-mark
-//     succeeds or precedes the initializing stores themselves,
-//     so long as the card-mark is completed before the next
-//     scavenge. For all these cases, we can do a card mark
-//     at the point at which we do a slow path allocation
-//     in the old gen, i.e. in this call.
-// (b) GenCollectedHeap(ConcurrentMarkSweepGeneration) requires
-//     in addition that the card-mark for an old gen allocated
-//     object strictly follow any associated initializing stores.
-//     In these cases, the memRegion remembered below is
-//     used to card-mark the entire region either just before the next
-//     slow-path allocation by this thread or just before the next scavenge or
-//     CMS-associated safepoint, whichever of these events happens first.
-//     (The implicit assumption is that the object has been fully
-//     initialized by this point, a fact that we assert when doing the
-//     card-mark.)
-// (c) G1CollectedHeap(G1) uses two kinds of write barriers. When a
-//     G1 concurrent marking is in progress an SATB (pre-write-)barrier
-//     is used to remember the pre-value of any store. Initializing
-//     stores will not need this barrier, so we need not worry about
-//     compensating for the missing pre-barrier here. Turning now
-//     to the post-barrier, we note that G1 needs a RS update barrier
-//     which simply enqueues a (sequence of) dirty cards which may
-//     optionally be refined by the concurrent update threads. Note
-//     that this barrier need only be applied to a non-young write,
-//     but, like in CMS, because of the presence of concurrent refinement
-//     (much like CMS' precleaning), must strictly follow the oop-store.
-//     Thus, using the same protocol for maintaining the intended
-//     invariants turns out, serendepitously, to be the same for both
-//     G1 and CMS.
-//
-// For any future collector, this code should be reexamined with
-// that specific collector in mind, and the documentation above suitably
-// extended and updated.
-oop CollectedHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
-// If a previous card-mark was deferred, flush it now.
-flush_deferred_store_barrier(thread);
-if (can_elide_initializing_store_barrier(new_obj) ||
-new_obj->is_typeArray()) {
-// Arrays of non-references don't need a pre-barrier.
-// The deferred_card_mark region should be empty
-// following the flush above.
-assert(thread->deferred_card_mark().is_empty(), "Error");
-} else {
-MemRegion mr((HeapWord*)new_obj, new_obj->size());
-assert(!mr.is_empty(), "Error");
-if (_defer_initial_card_mark) {
-// Defer the card mark
-thread->set_deferred_card_mark(mr);
-} else {
-// Do the card mark
-BarrierSet* bs = barrier_set();
-bs->write_region(mr);
-}
-}
-return new_obj;
 }
 size_t CollectedHeap::filler_array_hdr_size() {
 return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long
 }
 !is_init_completed(),
 "Should only be called at a safepoint or at start-up"
 " otherwise concurrent mutator activity may make heap "
 " unparsable again");
 const bool use_tlab = UseTLAB;
-const bool deferred = _defer_initial_card_mark;
 // The main thread starts allocating via a TLAB even before it
 // has added itself to the threads list at vm boot-up.
 JavaThreadIteratorWithHandle jtiwh;
 assert(!use_tlab || jtiwh.length() > 0,
 "Attempt to fill tlabs before main thread has been added"
 " to threads list is doomed to failure!");
+BarrierSet *bs = barrier_set();
 for (; JavaThread *thread = jtiwh.next(); ) {
 if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
-#if COMPILER2_OR_JVMCI
+bs->make_parsable(thread);
-// The deferred store barriers must all have been flushed to the
-// card-table (or other remembered set structure) before GC starts
-// processing the card-table (or other remembered set).
-if (deferred) flush_deferred_store_barrier(thread);
-#else
-assert(!deferred, "Should be false");
-assert(thread->deferred_card_mark().is_empty(), "Should be empty");
-#endif
 }
 }
 void CollectedHeap::accumulate_statistics_all_tlabs() {
 if (UseTLAB) {

changeset 48961	120b61d50f85
parent 48168	cb5d2d4453d0
child 49045	9b556b613a07