duke@435: /*
trims@2708:  * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
duke@435: 
stefank@2314: #include "precompiled.hpp"
stefank@2314: #include "classfile/systemDictionary.hpp"
stefank@2314: #include "gc_implementation/shared/vmGCOperations.hpp"
stefank@2314: #include "gc_interface/collectedHeap.hpp"
stefank@2314: #include "gc_interface/collectedHeap.inline.hpp"
stefank@2314: #include "oops/oop.inline.hpp"
stefank@2314: #include "runtime/init.hpp"
stefank@2314: #include "services/heapDumper.hpp"
stefank@2314: #ifdef TARGET_OS_FAMILY_linux
stefank@2314: # include "thread_linux.inline.hpp"
stefank@2314: #endif
stefank@2314: #ifdef TARGET_OS_FAMILY_solaris
stefank@2314: # include "thread_solaris.inline.hpp"
stefank@2314: #endif
stefank@2314: #ifdef TARGET_OS_FAMILY_windows
stefank@2314: # include "thread_windows.inline.hpp"
stefank@2314: #endif
never@3156: #ifdef TARGET_OS_FAMILY_bsd
never@3156: # include "thread_bsd.inline.hpp"
never@3156: #endif
duke@435: 
duke@435: 
duke@435: #ifdef ASSERT
duke@435: int CollectedHeap::_fire_out_of_memory_count = 0;
duke@435: #endif
duke@435: 
jcoomes@916: size_t CollectedHeap::_filler_array_max_size = 0;
jcoomes@916: 
duke@435: // Memory state functions.
duke@435: 
jmasa@2188: 
jmasa@2188: CollectedHeap::CollectedHeap() : _n_par_threads(0)
jmasa@2188: 
jcoomes@916: {
jcoomes@916:   const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
jcoomes@916:   const size_t elements_per_word = HeapWordSize / sizeof(jint);
jcoomes@916:   _filler_array_max_size = align_object_size(filler_array_hdr_size() +
jcoomes@916:                                              max_len * elements_per_word);
jcoomes@916: 
jcoomes@916:   _barrier_set = NULL;
jcoomes@916:   _is_gc_active = false;
jcoomes@916:   _total_collections = _total_full_collections = 0;
jcoomes@916:   _gc_cause = _gc_lastcause = GCCause::_no_gc;
duke@435:   NOT_PRODUCT(_promotion_failure_alot_count = 0;)
duke@435:   NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
duke@435: 
duke@435:   if (UsePerfData) {
duke@435:     EXCEPTION_MARK;
duke@435: 
duke@435:     // create the gc cause jvmstat counters
duke@435:     _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
duke@435:                              80, GCCause::to_string(_gc_cause), CHECK);
duke@435: 
duke@435:     _perf_gc_lastcause =
duke@435:                 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
duke@435:                              80, GCCause::to_string(_gc_lastcause), CHECK);
duke@435:   }
ysr@1601:   _defer_initial_card_mark = false; // strengthened by subclass in pre_initialize() below.
duke@435: }
duke@435: 
ysr@1601: void CollectedHeap::pre_initialize() {
ysr@1601:   // Used for ReduceInitialCardMarks (when COMPILER2 is used);
ysr@1601:   // otherwise remains unused.
ysr@1903: #ifdef COMPILER2
ysr@1629:   _defer_initial_card_mark =    ReduceInitialCardMarks && can_elide_tlab_store_barriers()
ysr@1629:                              && (DeferInitialCardMark || card_mark_must_follow_store());
ysr@1601: #else
ysr@1601:   assert(_defer_initial_card_mark == false, "Who would set it?");
ysr@1601: #endif
ysr@1601: }
duke@435: 
duke@435: #ifndef PRODUCT
duke@435: void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
duke@435:   if (CheckMemoryInitialization && ZapUnusedHeapArea) {
duke@435:     for (size_t slot = 0; slot < size; slot += 1) {
duke@435:       assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
duke@435:              "Found badHeapWordValue in post-allocation check");
duke@435:     }
duke@435:   }
duke@435: }
duke@435: 
ysr@2533: void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
duke@435:   if (CheckMemoryInitialization && ZapUnusedHeapArea) {
duke@435:     for (size_t slot = 0; slot < size; slot += 1) {
duke@435:       assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),
duke@435:              "Found non badHeapWordValue in pre-allocation check");
duke@435:     }
duke@435:   }
duke@435: }
duke@435: #endif // PRODUCT
duke@435: 
duke@435: #ifdef ASSERT
duke@435: void CollectedHeap::check_for_valid_allocation_state() {
duke@435:   Thread *thread = Thread::current();
duke@435:   // How to choose between a pending exception and a potential
duke@435:   // OutOfMemoryError?  Don't allow pending exceptions.
duke@435:   // This is a VM policy failure, so how do we exhaustively test it?
duke@435:   assert(!thread->has_pending_exception(),
duke@435:          "shouldn't be allocating with pending exception");
duke@435:   if (StrictSafepointChecks) {
duke@435:     assert(thread->allow_allocation(),
duke@435:            "Allocation done by thread for which allocation is blocked "
duke@435:            "by No_Allocation_Verifier!");
duke@435:     // Allocation of an oop can always invoke a safepoint,
duke@435:     // hence, the true argument
duke@435:     thread->check_for_valid_safepoint_state(true);
duke@435:   }
duke@435: }
duke@435: #endif
duke@435: 
duke@435: HeapWord* CollectedHeap::allocate_from_tlab_slow(Thread* thread, size_t size) {
duke@435: 
duke@435:   // Retain tlab and allocate object in shared space if
duke@435:   // the amount free in the tlab is too large to discard.
duke@435:   if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
duke@435:     thread->tlab().record_slow_allocation(size);
duke@435:     return NULL;
duke@435:   }
duke@435: 
duke@435:   // Discard tlab and allocate a new one.
duke@435:   // To minimize fragmentation, the last TLAB may be smaller than the rest.
duke@435:   size_t new_tlab_size = thread->tlab().compute_size(size);
duke@435: 
duke@435:   thread->tlab().clear_before_allocation();
duke@435: 
duke@435:   if (new_tlab_size == 0) {
duke@435:     return NULL;
duke@435:   }
duke@435: 
duke@435:   // Allocate a new TLAB...
duke@435:   HeapWord* obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
duke@435:   if (obj == NULL) {
duke@435:     return NULL;
duke@435:   }
duke@435:   if (ZeroTLAB) {
duke@435:     // ..and clear it.
duke@435:     Copy::zero_to_words(obj, new_tlab_size);
duke@435:   } else {
kvn@3092:     // ...and zap just allocated object.
kvn@3092: #ifdef ASSERT
kvn@3092:     // Skip mangling the space corresponding to the object header to
kvn@3092:     // ensure that the returned space is not considered parsable by
kvn@3092:     // any concurrent GC thread.
kvn@3092:     size_t hdr_size = oopDesc::header_size();
kvn@3092:     Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
kvn@3092: #endif // ASSERT
duke@435:   }
duke@435:   thread->tlab().fill(obj, obj + size, new_tlab_size);
duke@435:   return obj;
duke@435: }
duke@435: 
ysr@1462: void CollectedHeap::flush_deferred_store_barrier(JavaThread* thread) {
ysr@1462:   MemRegion deferred = thread->deferred_card_mark();
ysr@1462:   if (!deferred.is_empty()) {
ysr@1601:     assert(_defer_initial_card_mark, "Otherwise should be empty");
ysr@1462:     {
ysr@1462:       // Verify that the storage points to a parsable object in heap
ysr@1462:       DEBUG_ONLY(oop old_obj = oop(deferred.start());)
ysr@1462:       assert(is_in(old_obj), "Not in allocated heap");
ysr@1462:       assert(!can_elide_initializing_store_barrier(old_obj),
ysr@1601:              "Else should have been filtered in new_store_pre_barrier()");
ysr@1462:       assert(!is_in_permanent(old_obj), "Sanity: not expected");
ysr@1462:       assert(old_obj->is_oop(true), "Not an oop");
ysr@1462:       assert(old_obj->is_parsable(), "Will not be concurrently parsable");
ysr@1462:       assert(deferred.word_size() == (size_t)(old_obj->size()),
ysr@1462:              "Mismatch: multiple objects?");
ysr@1462:     }
ysr@1462:     BarrierSet* bs = barrier_set();
ysr@1462:     assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
ysr@1462:     bs->write_region(deferred);
ysr@1462:     // "Clear" the deferred_card_mark field
ysr@1462:     thread->set_deferred_card_mark(MemRegion());
ysr@1462:   }
ysr@1462:   assert(thread->deferred_card_mark().is_empty(), "invariant");
ysr@1462: }
ysr@1462: 
ysr@1462: // Helper for ReduceInitialCardMarks. For performance,
ysr@1462: // compiled code may elide card-marks for initializing stores
ysr@1462: // to a newly allocated object along the fast-path. We
ysr@1462: // compensate for such elided card-marks as follows:
ysr@1462: // (a) Generational, non-concurrent collectors, such as
ysr@1462: //     GenCollectedHeap(ParNew,DefNew,Tenured) and
ysr@1462: //     ParallelScavengeHeap(ParallelGC, ParallelOldGC)
ysr@1462: //     need the card-mark if and only if the region is
ysr@1462: //     in the old gen, and do not care if the card-mark
ysr@1462: //     succeeds or precedes the initializing stores themselves,
ysr@1462: //     so long as the card-mark is completed before the next
ysr@1462: //     scavenge. For all these cases, we can do a card mark
ysr@1462: //     at the point at which we do a slow path allocation
ysr@1601: //     in the old gen, i.e. in this call.
ysr@1462: // (b) GenCollectedHeap(ConcurrentMarkSweepGeneration) requires
ysr@1462: //     in addition that the card-mark for an old gen allocated
ysr@1462: //     object strictly follow any associated initializing stores.
ysr@1462: //     In these cases, the memRegion remembered below is
ysr@1462: //     used to card-mark the entire region either just before the next
ysr@1462: //     slow-path allocation by this thread or just before the next scavenge or
ysr@1462: //     CMS-associated safepoint, whichever of these events happens first.
ysr@1462: //     (The implicit assumption is that the object has been fully
ysr@1462: //     initialized by this point, a fact that we assert when doing the
ysr@1462: //     card-mark.)
ysr@1462: // (c) G1CollectedHeap(G1) uses two kinds of write barriers. When a
ysr@1462: //     G1 concurrent marking is in progress an SATB (pre-write-)barrier is
ysr@1462: //     is used to remember the pre-value of any store. Initializing
ysr@1462: //     stores will not need this barrier, so we need not worry about
ysr@1462: //     compensating for the missing pre-barrier here. Turning now
ysr@1462: //     to the post-barrier, we note that G1 needs a RS update barrier
ysr@1462: //     which simply enqueues a (sequence of) dirty cards which may
ysr@1462: //     optionally be refined by the concurrent update threads. Note
ysr@1462: //     that this barrier need only be applied to a non-young write,
ysr@1462: //     but, like in CMS, because of the presence of concurrent refinement
ysr@1462: //     (much like CMS' precleaning), must strictly follow the oop-store.
ysr@1462: //     Thus, using the same protocol for maintaining the intended
ysr@1601: //     invariants turns out, serendepitously, to be the same for both
ysr@1601: //     G1 and CMS.
ysr@1462: //
ysr@1601: // For any future collector, this code should be reexamined with
ysr@1601: // that specific collector in mind, and the documentation above suitably
ysr@1601: // extended and updated.
ysr@1601: oop CollectedHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
ysr@1462:   // If a previous card-mark was deferred, flush it now.
ysr@1462:   flush_deferred_store_barrier(thread);
ysr@1462:   if (can_elide_initializing_store_barrier(new_obj)) {
ysr@1462:     // The deferred_card_mark region should be empty
ysr@1462:     // following the flush above.
ysr@1462:     assert(thread->deferred_card_mark().is_empty(), "Error");
ysr@1462:   } else {
ysr@1601:     MemRegion mr((HeapWord*)new_obj, new_obj->size());
ysr@1601:     assert(!mr.is_empty(), "Error");
ysr@1601:     if (_defer_initial_card_mark) {
ysr@1601:       // Defer the card mark
ysr@1601:       thread->set_deferred_card_mark(mr);
ysr@1601:     } else {
ysr@1601:       // Do the card mark
ysr@1601:       BarrierSet* bs = barrier_set();
ysr@1601:       assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
ysr@1601:       bs->write_region(mr);
ysr@1601:     }
ysr@1462:   }
ysr@1462:   return new_obj;
ysr@1462: }
ysr@1462: 
jcoomes@916: size_t CollectedHeap::filler_array_hdr_size() {
kvn@1926:   return size_t(align_object_offset(arrayOopDesc::header_size(T_INT))); // align to Long
jcoomes@916: }
jcoomes@916: 
jcoomes@916: size_t CollectedHeap::filler_array_min_size() {
kvn@1926:   return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
jcoomes@916: }
jcoomes@916: 
jcoomes@916: size_t CollectedHeap::filler_array_max_size() {
jcoomes@916:   return _filler_array_max_size;
jcoomes@916: }
jcoomes@916: 
jcoomes@916: #ifdef ASSERT
jcoomes@916: void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
jcoomes@916: {
jcoomes@916:   assert(words >= min_fill_size(), "too small to fill");
jcoomes@916:   assert(words % MinObjAlignment == 0, "unaligned size");
jcoomes@916:   assert(Universe::heap()->is_in_reserved(start), "not in heap");
jcoomes@916:   assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
jcoomes@916: }
jcoomes@916: 
johnc@1600: void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
jcoomes@916: {
johnc@1600:   if (ZapFillerObjects && zap) {
jcoomes@916:     Copy::fill_to_words(start + filler_array_hdr_size(),
jcoomes@916:                         words - filler_array_hdr_size(), 0XDEAFBABE);
jcoomes@916:   }
jcoomes@916: }
jcoomes@916: #endif // ASSERT
jcoomes@916: 
jcoomes@916: void
johnc@1600: CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
jcoomes@916: {
jcoomes@916:   assert(words >= filler_array_min_size(), "too small for an array");
jcoomes@916:   assert(words <= filler_array_max_size(), "too big for a single object");
jcoomes@916: 
jcoomes@916:   const size_t payload_size = words - filler_array_hdr_size();
jcoomes@916:   const size_t len = payload_size * HeapWordSize / sizeof(jint);
jcoomes@916: 
jcoomes@916:   // Set the length first for concurrent GC.
jcoomes@916:   ((arrayOop)start)->set_length((int)len);
jcoomes@929:   post_allocation_setup_common(Universe::intArrayKlassObj(), start, words);
johnc@1600:   DEBUG_ONLY(zap_filler_array(start, words, zap);)
jcoomes@916: }
jcoomes@916: 
jcoomes@916: void
johnc@1600: CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
jcoomes@916: {
jcoomes@916:   assert(words <= filler_array_max_size(), "too big for a single object");
jcoomes@916: 
jcoomes@916:   if (words >= filler_array_min_size()) {
johnc@1600:     fill_with_array(start, words, zap);
jcoomes@916:   } else if (words > 0) {
jcoomes@916:     assert(words == min_fill_size(), "unaligned size");
never@1577:     post_allocation_setup_common(SystemDictionary::Object_klass(), start,
jcoomes@916:                                  words);
jcoomes@916:   }
jcoomes@916: }
jcoomes@916: 
johnc@1600: void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
jcoomes@916: {
jcoomes@916:   DEBUG_ONLY(fill_args_check(start, words);)
jcoomes@916:   HandleMark hm;  // Free handles before leaving.
johnc@1600:   fill_with_object_impl(start, words, zap);
jcoomes@916: }
jcoomes@916: 
johnc@1600: void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
jcoomes@916: {
jcoomes@916:   DEBUG_ONLY(fill_args_check(start, words);)
jcoomes@916:   HandleMark hm;  // Free handles before leaving.
jcoomes@916: 
ysr@1904: #ifdef _LP64
jcoomes@916:   // A single array can fill ~8G, so multiple objects are needed only in 64-bit.
jcoomes@916:   // First fill with arrays, ensuring that any remaining space is big enough to
jcoomes@916:   // fill.  The remainder is filled with a single object.
jcoomes@916:   const size_t min = min_fill_size();
jcoomes@916:   const size_t max = filler_array_max_size();
jcoomes@916:   while (words > max) {
jcoomes@916:     const size_t cur = words - max >= min ? max : max - min;
johnc@1600:     fill_with_array(start, cur, zap);
jcoomes@916:     start += cur;
jcoomes@916:     words -= cur;
jcoomes@916:   }
jcoomes@916: #endif
jcoomes@916: 
johnc@1600:   fill_with_object_impl(start, words, zap);
jcoomes@916: }
jcoomes@916: 
duke@435: HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {
duke@435:   guarantee(false, "thread-local allocation buffers not supported");
duke@435:   return NULL;
duke@435: }
duke@435: 
duke@435: void CollectedHeap::ensure_parsability(bool retire_tlabs) {
duke@435:   // The second disjunct in the assertion below makes a concession
duke@435:   // for the start-up verification done while the VM is being
duke@435:   // created. Callers be careful that you know that mutators
duke@435:   // aren't going to interfere -- for instance, this is permissible
duke@435:   // if we are still single-threaded and have either not yet
duke@435:   // started allocating (nothing much to verify) or we have
duke@435:   // started allocating but are now a full-fledged JavaThread
duke@435:   // (and have thus made our TLAB's) available for filling.
duke@435:   assert(SafepointSynchronize::is_at_safepoint() ||
duke@435:          !is_init_completed(),
duke@435:          "Should only be called at a safepoint or at start-up"
duke@435:          " otherwise concurrent mutator activity may make heap "
duke@435:          " unparsable again");
ysr@1601:   const bool use_tlab = UseTLAB;
ysr@1601:   const bool deferred = _defer_initial_card_mark;
ysr@1601:   // The main thread starts allocating via a TLAB even before it
ysr@1601:   // has added itself to the threads list at vm boot-up.
ysr@1601:   assert(!use_tlab || Threads::first() != NULL,
ysr@1601:          "Attempt to fill tlabs before main thread has been added"
ysr@1601:          " to threads list is doomed to failure!");
ysr@1601:   for (JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
ysr@1601:      if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
ysr@1601: #ifdef COMPILER2
ysr@1601:      // The deferred store barriers must all have been flushed to the
ysr@1601:      // card-table (or other remembered set structure) before GC starts
ysr@1601:      // processing the card-table (or other remembered set).
ysr@1601:      if (deferred) flush_deferred_store_barrier(thread);
ysr@1601: #else
ysr@1601:      assert(!deferred, "Should be false");
ysr@1601:      assert(thread->deferred_card_mark().is_empty(), "Should be empty");
ysr@1601: #endif
duke@435:   }
duke@435: }
duke@435: 
duke@435: void CollectedHeap::accumulate_statistics_all_tlabs() {
duke@435:   if (UseTLAB) {
duke@435:     assert(SafepointSynchronize::is_at_safepoint() ||
duke@435:          !is_init_completed(),
duke@435:          "should only accumulate statistics on tlabs at safepoint");
duke@435: 
duke@435:     ThreadLocalAllocBuffer::accumulate_statistics_before_gc();
duke@435:   }
duke@435: }
duke@435: 
duke@435: void CollectedHeap::resize_all_tlabs() {
duke@435:   if (UseTLAB) {
duke@435:     assert(SafepointSynchronize::is_at_safepoint() ||
duke@435:          !is_init_completed(),
duke@435:          "should only resize tlabs at safepoint");
duke@435: 
duke@435:     ThreadLocalAllocBuffer::resize_all_tlabs();
duke@435:   }
duke@435: }
ysr@1050: 
ysr@1050: void CollectedHeap::pre_full_gc_dump() {
ysr@1050:   if (HeapDumpBeforeFullGC) {
ysr@3067:     TraceTime tt("Heap Dump (before full gc): ", PrintGCDetails, false, gclog_or_tty);
ysr@1050:     // We are doing a "major" collection and a heap dump before
ysr@1050:     // major collection has been requested.
ysr@1050:     HeapDumper::dump_heap();
ysr@1050:   }
ysr@1050:   if (PrintClassHistogramBeforeFullGC) {
ysr@3067:     TraceTime tt("Class Histogram (before full gc): ", PrintGCDetails, true, gclog_or_tty);
ysr@1050:     VM_GC_HeapInspection inspector(gclog_or_tty, false /* ! full gc */, false /* ! prologue */);
ysr@1050:     inspector.doit();
ysr@1050:   }
ysr@1050: }
ysr@1050: 
ysr@1050: void CollectedHeap::post_full_gc_dump() {
ysr@1050:   if (HeapDumpAfterFullGC) {
ysr@3067:     TraceTime tt("Heap Dump (after full gc): ", PrintGCDetails, false, gclog_or_tty);
ysr@1050:     HeapDumper::dump_heap();
ysr@1050:   }
ysr@1050:   if (PrintClassHistogramAfterFullGC) {
ysr@3067:     TraceTime tt("Class Histogram (after full gc): ", PrintGCDetails, true, gclog_or_tty);
ysr@1050:     VM_GC_HeapInspection inspector(gclog_or_tty, false /* ! full gc */, false /* ! prologue */);
ysr@1050:     inspector.doit();
ysr@1050:   }
ysr@1050: }