ysr@777: /*
drchase@6680:  * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
ysr@777:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
ysr@777:  *
ysr@777:  * This code is free software; you can redistribute it and/or modify it
ysr@777:  * under the terms of the GNU General Public License version 2 only, as
ysr@777:  * published by the Free Software Foundation.
ysr@777:  *
ysr@777:  * This code is distributed in the hope that it will be useful, but WITHOUT
ysr@777:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
ysr@777:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
ysr@777:  * version 2 for more details (a copy is included in the LICENSE file that
ysr@777:  * accompanied this code).
ysr@777:  *
ysr@777:  * You should have received a copy of the GNU General Public License version
ysr@777:  * 2 along with this work; if not, write to the Free Software Foundation,
ysr@777:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
ysr@777:  *
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.
ysr@777:  *
ysr@777:  */
ysr@777: 
stefank@2314: #include "precompiled.hpp"
tonyp@2469: #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
stefank@2314: #include "gc_implementation/g1/satbQueue.hpp"
stefank@2314: #include "memory/allocation.inline.hpp"
stefank@2314: #include "memory/sharedHeap.hpp"
coleenp@4037: #include "oops/oop.inline.hpp"
stefank@2314: #include "runtime/mutexLocker.hpp"
stefank@2314: #include "runtime/thread.hpp"
johnc@3175: #include "runtime/vmThread.hpp"
ysr@777: 
drchase@6680: PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
drchase@6680: 
tonyp@3416: void ObjPtrQueue::flush() {
tonyp@3416:   // The buffer might contain refs into the CSet. We have to filter it
tonyp@3416:   // first before we flush it, otherwise we might end up with an
tonyp@3416:   // enqueued buffer with refs into the CSet which breaks our invariants.
tonyp@3416:   filter();
tonyp@3416:   PtrQueue::flush();
tonyp@3416: }
tonyp@3416: 
tonyp@2469: // This method removes entries from an SATB buffer that will not be
tonyp@2469: // useful to the concurrent marking threads. An entry is removed if it
tonyp@2469: // satisfies one of the following conditions:
tonyp@2469: //
tonyp@2469: // * it points to an object outside the G1 heap (G1's concurrent
tonyp@2469: //     marking only visits objects inside the G1 heap),
tonyp@2469: // * it points to an object that has been allocated since marking
tonyp@2469: //     started (according to SATB those objects do not need to be
tonyp@2469: //     visited during marking), or
tonyp@2469: // * it points to an object that has already been marked (no need to
tonyp@2469: //     process it again).
tonyp@2469: //
tonyp@2469: // The rest of the entries will be retained and are compacted towards
tonyp@3416: // the top of the buffer. Note that, because we do not allow old
tonyp@3416: // regions in the CSet during marking, all objects on the CSet regions
tonyp@3416: // are young (eden or survivors) and therefore implicitly live. So any
tonyp@3416: // references into the CSet will be removed during filtering.
tonyp@2469: 
tonyp@3416: void ObjPtrQueue::filter() {
tonyp@2469:   G1CollectedHeap* g1h = G1CollectedHeap::heap();
tonyp@2469:   void** buf = _buf;
tonyp@2469:   size_t sz = _sz;
tonyp@2469: 
tonyp@3416:   if (buf == NULL) {
tonyp@3416:     // nothing to do
tonyp@3416:     return;
tonyp@3416:   }
tonyp@3416: 
tonyp@2469:   // Used for sanity checking at the end of the loop.
tonyp@2469:   debug_only(size_t entries = 0; size_t retained = 0;)
tonyp@2469: 
tonyp@2469:   size_t i = sz;
tonyp@2469:   size_t new_index = sz;
tonyp@2469: 
tonyp@2469:   while (i > _index) {
tonyp@2469:     assert(i > 0, "we should have at least one more entry to process");
tonyp@2469:     i -= oopSize;
tonyp@2469:     debug_only(entries += 1;)
tonyp@2469:     oop* p = (oop*) &buf[byte_index_to_index((int) i)];
tonyp@2469:     oop obj = *p;
tonyp@2469:     // NULL the entry so that unused parts of the buffer contain NULLs
tonyp@2469:     // at the end. If we are going to retain it we will copy it to its
tonyp@2469:     // final place. If we have retained all entries we have visited so
tonyp@2469:     // far, we'll just end up copying it to the same place.
tonyp@2469:     *p = NULL;
tonyp@2469: 
tonyp@2469:     bool retain = g1h->is_obj_ill(obj);
tonyp@2469:     if (retain) {
tonyp@2469:       assert(new_index > 0, "we should not have already filled up the buffer");
tonyp@2469:       new_index -= oopSize;
tonyp@2469:       assert(new_index >= i,
tonyp@2469:              "new_index should never be below i, as we alwaysr compact 'up'");
tonyp@2469:       oop* new_p = (oop*) &buf[byte_index_to_index((int) new_index)];
tonyp@2469:       assert(new_p >= p, "the destination location should never be below "
tonyp@2469:              "the source as we always compact 'up'");
tonyp@2469:       assert(*new_p == NULL,
tonyp@2469:              "we should have already cleared the destination location");
tonyp@2469:       *new_p = obj;
tonyp@2469:       debug_only(retained += 1;)
tonyp@2469:     }
tonyp@2469:   }
tonyp@3416: 
tonyp@3416: #ifdef ASSERT
tonyp@2469:   size_t entries_calc = (sz - _index) / oopSize;
tonyp@2469:   assert(entries == entries_calc, "the number of entries we counted "
tonyp@2469:          "should match the number of entries we calculated");
tonyp@2469:   size_t retained_calc = (sz - new_index) / oopSize;
tonyp@2469:   assert(retained == retained_calc, "the number of retained entries we counted "
tonyp@2469:          "should match the number of retained entries we calculated");
tonyp@3416: #endif // ASSERT
tonyp@3416: 
tonyp@3416:   _index = new_index;
tonyp@3416: }
tonyp@3416: 
tonyp@3416: // This method will first apply the above filtering to the buffer. If
tonyp@3416: // post-filtering a large enough chunk of the buffer has been cleared
tonyp@3416: // we can re-use the buffer (instead of enqueueing it) and we can just
tonyp@3416: // allow the mutator to carry on executing using the same buffer
tonyp@3416: // instead of replacing it.
tonyp@3416: 
tonyp@3416: bool ObjPtrQueue::should_enqueue_buffer() {
tonyp@3416:   assert(_lock == NULL || _lock->owned_by_self(),
tonyp@3416:          "we should have taken the lock before calling this");
tonyp@3416: 
tonyp@3416:   // Even if G1SATBBufferEnqueueingThresholdPercent == 0 we have to
tonyp@3416:   // filter the buffer given that this will remove any references into
tonyp@3416:   // the CSet as we currently assume that no such refs will appear in
tonyp@3416:   // enqueued buffers.
tonyp@3416: 
tonyp@3416:   // This method should only be called if there is a non-NULL buffer
tonyp@3416:   // that is full.
tonyp@3416:   assert(_index == 0, "pre-condition");
tonyp@3416:   assert(_buf != NULL, "pre-condition");
tonyp@3416: 
tonyp@3416:   filter();
tonyp@3416: 
tonyp@3416:   size_t sz = _sz;
tonyp@3416:   size_t all_entries = sz / oopSize;
tonyp@3416:   size_t retained_entries = (sz - _index) / oopSize;
tonyp@3416:   size_t perc = retained_entries * 100 / all_entries;
tonyp@2469:   bool should_enqueue = perc > (size_t) G1SATBBufferEnqueueingThresholdPercent;
tonyp@2469:   return should_enqueue;
tonyp@2469: }
tonyp@2469: 
ysr@777: void ObjPtrQueue::apply_closure(ObjectClosure* cl) {
ysr@777:   if (_buf != NULL) {
ysr@777:     apply_closure_to_buffer(cl, _buf, _index, _sz);
tonyp@3416:   }
tonyp@3416: }
tonyp@3416: 
tonyp@3416: void ObjPtrQueue::apply_closure_and_empty(ObjectClosure* cl) {
tonyp@3416:   if (_buf != NULL) {
tonyp@3416:     apply_closure_to_buffer(cl, _buf, _index, _sz);
ysr@777:     _index = _sz;
ysr@777:   }
ysr@777: }
ysr@777: 
ysr@777: void ObjPtrQueue::apply_closure_to_buffer(ObjectClosure* cl,
ysr@777:                                           void** buf, size_t index, size_t sz) {
ysr@777:   if (cl == NULL) return;
ysr@777:   for (size_t i = index; i < sz; i += oopSize) {
ysr@777:     oop obj = (oop)buf[byte_index_to_index((int)i)];
ysr@777:     // There can be NULL entries because of destructors.
ysr@777:     if (obj != NULL) {
ysr@777:       cl->do_object(obj);
ysr@777:     }
ysr@777:   }
ysr@777: }
ysr@1280: 
tonyp@3416: #ifndef PRODUCT
tonyp@3416: // Helpful for debugging
tonyp@3416: 
tonyp@3416: void ObjPtrQueue::print(const char* name) {
tonyp@3416:   print(name, _buf, _index, _sz);
tonyp@3416: }
tonyp@3416: 
tonyp@3416: void ObjPtrQueue::print(const char* name,
tonyp@3416:                         void** buf, size_t index, size_t sz) {
tonyp@3416:   gclog_or_tty->print_cr("  SATB BUFFER [%s] buf: "PTR_FORMAT" "
tonyp@3416:                          "index: "SIZE_FORMAT" sz: "SIZE_FORMAT,
tonyp@3416:                          name, buf, index, sz);
tonyp@3416: }
tonyp@3416: #endif // PRODUCT
tonyp@3416: 
ysr@1280: #ifdef ASSERT
ysr@1280: void ObjPtrQueue::verify_oops_in_buffer() {
ysr@1280:   if (_buf == NULL) return;
ysr@1280:   for (size_t i = _index; i < _sz; i += oopSize) {
ysr@1280:     oop obj = (oop)_buf[byte_index_to_index((int)i)];
ysr@1280:     assert(obj != NULL && obj->is_oop(true /* ignore mark word */),
ysr@1280:            "Not an oop");
ysr@1280:   }
ysr@1280: }
ysr@1280: #endif
ysr@1280: 
ysr@777: #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
ysr@777: #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
ysr@777: #endif // _MSC_VER
ysr@777: 
ysr@777: SATBMarkQueueSet::SATBMarkQueueSet() :
tonyp@3416:   PtrQueueSet(), _closure(NULL), _par_closures(NULL),
tonyp@3416:   _shared_satb_queue(this, true /*perm*/) { }
ysr@777: 
ysr@777: void SATBMarkQueueSet::initialize(Monitor* cbl_mon, Mutex* fl_lock,
iveresov@1546:                                   int process_completed_threshold,
ysr@777:                                   Mutex* lock) {
iveresov@1546:   PtrQueueSet::initialize(cbl_mon, fl_lock, process_completed_threshold, -1);
ysr@777:   _shared_satb_queue.set_lock(lock);
ysr@777:   if (ParallelGCThreads > 0) {
zgu@3900:     _par_closures = NEW_C_HEAP_ARRAY(ObjectClosure*, ParallelGCThreads, mtGC);
ysr@777:   }
ysr@777: }
ysr@777: 
ysr@777: void SATBMarkQueueSet::handle_zero_index_for_thread(JavaThread* t) {
ysr@1280:   DEBUG_ONLY(t->satb_mark_queue().verify_oops_in_buffer();)
ysr@777:   t->satb_mark_queue().handle_zero_index();
ysr@777: }
ysr@777: 
tonyp@1752: #ifdef ASSERT
pliden@6396: void SATBMarkQueueSet::dump_active_states(bool expected_active) {
pliden@6396:   gclog_or_tty->print_cr("Expected SATB active state: %s",
pliden@6396:                          expected_active ? "ACTIVE" : "INACTIVE");
pliden@6396:   gclog_or_tty->print_cr("Actual SATB active states:");
pliden@6396:   gclog_or_tty->print_cr("  Queue set: %s", is_active() ? "ACTIVE" : "INACTIVE");
pliden@6396:   for (JavaThread* t = Threads::first(); t; t = t->next()) {
pliden@6396:     gclog_or_tty->print_cr("  Thread \"%s\" queue: %s", t->name(),
pliden@6396:                            t->satb_mark_queue().is_active() ? "ACTIVE" : "INACTIVE");
pliden@6396:   }
pliden@6396:   gclog_or_tty->print_cr("  Shared queue: %s",
pliden@6396:                          shared_satb_queue()->is_active() ? "ACTIVE" : "INACTIVE");
pliden@6396: }
pliden@6396: 
pliden@6396: void SATBMarkQueueSet::verify_active_states(bool expected_active) {
pliden@6396:   // Verify queue set state
pliden@6396:   if (is_active() != expected_active) {
pliden@6396:     dump_active_states(expected_active);
pliden@6396:     guarantee(false, "SATB queue set has an unexpected active state");
pliden@6396:   }
pliden@6396: 
pliden@6396:   // Verify thread queue states
pliden@6396:   for (JavaThread* t = Threads::first(); t; t = t->next()) {
pliden@6396:     if (t->satb_mark_queue().is_active() != expected_active) {
pliden@6396:       dump_active_states(expected_active);
pliden@6396:       guarantee(false, "Thread SATB queue has an unexpected active state");
pliden@6396:     }
pliden@6396:   }
pliden@6396: 
pliden@6396:   // Verify shared queue state
pliden@6396:   if (shared_satb_queue()->is_active() != expected_active) {
pliden@6396:     dump_active_states(expected_active);
pliden@6396:     guarantee(false, "Shared SATB queue has an unexpected active state");
tonyp@1752:   }
tonyp@1752: }
tonyp@1752: #endif // ASSERT
tonyp@1752: 
pliden@6396: void SATBMarkQueueSet::set_active_all_threads(bool active, bool expected_active) {
tonyp@1752:   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
tonyp@1752: #ifdef ASSERT
pliden@6396:   verify_active_states(expected_active);
pliden@6396: #endif // ASSERT
pliden@6396:   _all_active = active;
pliden@6396:   for (JavaThread* t = Threads::first(); t; t = t->next()) {
pliden@6396:     t->satb_mark_queue().set_active(active);
tonyp@1752:   }
pliden@6396:   shared_satb_queue()->set_active(active);
ysr@777: }
ysr@777: 
tonyp@3416: void SATBMarkQueueSet::filter_thread_buffers() {
tonyp@3416:   for(JavaThread* t = Threads::first(); t; t = t->next()) {
tonyp@3416:     t->satb_mark_queue().filter();
tonyp@3416:   }
tonyp@3416:   shared_satb_queue()->filter();
tonyp@3416: }
tonyp@3416: 
ysr@777: void SATBMarkQueueSet::set_closure(ObjectClosure* closure) {
ysr@777:   _closure = closure;
ysr@777: }
ysr@777: 
ysr@777: void SATBMarkQueueSet::set_par_closure(int i, ObjectClosure* par_closure) {
ysr@777:   assert(ParallelGCThreads > 0 && _par_closures != NULL, "Precondition");
ysr@777:   _par_closures[i] = par_closure;
ysr@777: }
ysr@777: 
ysr@777: bool SATBMarkQueueSet::apply_closure_to_completed_buffer_work(bool par,
vkempik@6552:                                                               uint worker) {
iveresov@1546:   BufferNode* nd = NULL;
ysr@777:   {
ysr@777:     MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
ysr@777:     if (_completed_buffers_head != NULL) {
ysr@777:       nd = _completed_buffers_head;
iveresov@1546:       _completed_buffers_head = nd->next();
ysr@777:       if (_completed_buffers_head == NULL) _completed_buffers_tail = NULL;
ysr@777:       _n_completed_buffers--;
ysr@777:       if (_n_completed_buffers == 0) _process_completed = false;
ysr@777:     }
ysr@777:   }
ysr@777:   ObjectClosure* cl = (par ? _par_closures[worker] : _closure);
ysr@777:   if (nd != NULL) {
iveresov@1546:     void **buf = BufferNode::make_buffer_from_node(nd);
iveresov@1546:     ObjPtrQueue::apply_closure_to_buffer(cl, buf, 0, _sz);
iveresov@1546:     deallocate_buffer(buf);
ysr@777:     return true;
ysr@777:   } else {
ysr@777:     return false;
ysr@777:   }
ysr@777: }
ysr@777: 
tonyp@3416: void SATBMarkQueueSet::iterate_completed_buffers_read_only(ObjectClosure* cl) {
tonyp@3416:   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
tonyp@3416:   assert(cl != NULL, "pre-condition");
tonyp@3416: 
tonyp@3416:   BufferNode* nd = _completed_buffers_head;
tonyp@3416:   while (nd != NULL) {
tonyp@3416:     void** buf = BufferNode::make_buffer_from_node(nd);
tonyp@3416:     ObjPtrQueue::apply_closure_to_buffer(cl, buf, 0, _sz);
tonyp@3416:     nd = nd->next();
tonyp@3416:   }
tonyp@3416: }
tonyp@3416: 
tonyp@3416: void SATBMarkQueueSet::iterate_thread_buffers_read_only(ObjectClosure* cl) {
tonyp@3416:   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
tonyp@3416:   assert(cl != NULL, "pre-condition");
tonyp@3416: 
tonyp@3416:   for (JavaThread* t = Threads::first(); t; t = t->next()) {
tonyp@3416:     t->satb_mark_queue().apply_closure(cl);
tonyp@3416:   }
tonyp@3416:   shared_satb_queue()->apply_closure(cl);
tonyp@3416: }
tonyp@3416: 
tonyp@3416: #ifndef PRODUCT
tonyp@3416: // Helpful for debugging
tonyp@3416: 
tonyp@3416: #define SATB_PRINTER_BUFFER_SIZE 256
tonyp@3416: 
tonyp@3416: void SATBMarkQueueSet::print_all(const char* msg) {
tonyp@3416:   char buffer[SATB_PRINTER_BUFFER_SIZE];
tonyp@3416:   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
tonyp@3416: 
tonyp@3416:   gclog_or_tty->cr();
tonyp@3416:   gclog_or_tty->print_cr("SATB BUFFERS [%s]", msg);
tonyp@3416: 
tonyp@3416:   BufferNode* nd = _completed_buffers_head;
tonyp@3416:   int i = 0;
tonyp@3416:   while (nd != NULL) {
tonyp@3416:     void** buf = BufferNode::make_buffer_from_node(nd);
tonyp@3416:     jio_snprintf(buffer, SATB_PRINTER_BUFFER_SIZE, "Enqueued: %d", i);
tonyp@3416:     ObjPtrQueue::print(buffer, buf, 0, _sz);
tonyp@3416:     nd = nd->next();
tonyp@3416:     i += 1;
tonyp@3416:   }
tonyp@3416: 
tonyp@3416:   for (JavaThread* t = Threads::first(); t; t = t->next()) {
tonyp@3416:     jio_snprintf(buffer, SATB_PRINTER_BUFFER_SIZE, "Thread: %s", t->name());
tonyp@3416:     t->satb_mark_queue().print(buffer);
tonyp@3416:   }
tonyp@3416: 
tonyp@3416:   shared_satb_queue()->print("Shared");
tonyp@3416: 
tonyp@3416:   gclog_or_tty->cr();
tonyp@3416: }
tonyp@3416: #endif // PRODUCT
tonyp@3416: 
ysr@777: void SATBMarkQueueSet::abandon_partial_marking() {
iveresov@1546:   BufferNode* buffers_to_delete = NULL;
ysr@777:   {
ysr@777:     MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
ysr@777:     while (_completed_buffers_head != NULL) {
iveresov@1546:       BufferNode* nd = _completed_buffers_head;
iveresov@1546:       _completed_buffers_head = nd->next();
iveresov@1546:       nd->set_next(buffers_to_delete);
ysr@777:       buffers_to_delete = nd;
ysr@777:     }
ysr@777:     _completed_buffers_tail = NULL;
ysr@777:     _n_completed_buffers = 0;
ysr@1280:     DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
ysr@777:   }
ysr@777:   while (buffers_to_delete != NULL) {
iveresov@1546:     BufferNode* nd = buffers_to_delete;
iveresov@1546:     buffers_to_delete = nd->next();
iveresov@1546:     deallocate_buffer(BufferNode::make_buffer_from_node(nd));
ysr@777:   }
ysr@777:   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
ysr@777:   // So we can safely manipulate these queues.
ysr@777:   for (JavaThread* t = Threads::first(); t; t = t->next()) {
ysr@777:     t->satb_mark_queue().reset();
ysr@777:   }
tonyp@3416:  shared_satb_queue()->reset();
ysr@777: }