--- a/hotspot/src/share/vm/gc/g1/satbQueue.cpp Fri Nov 20 15:40:23 2015 -0800
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,375 +0,0 @@
-/*
- * Copyright (c) 2001, 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.
- *
- */
-
-#include "precompiled.hpp"
-#include "gc/g1/g1CollectedHeap.inline.hpp"
-#include "gc/g1/satbQueue.hpp"
-#include "gc/shared/collectedHeap.hpp"
-#include "memory/allocation.inline.hpp"
-#include "oops/oop.inline.hpp"
-#include "runtime/mutexLocker.hpp"
-#include "runtime/safepoint.hpp"
-#include "runtime/thread.hpp"
-#include "runtime/vmThread.hpp"
-
-void ObjPtrQueue::flush() {
- // Filter now to possibly save work later. If filtering empties the
- // buffer then flush_impl can deallocate the buffer.
- filter();
- flush_impl();
-}
-
-// Return true if a SATB buffer entry refers to an object that
-// requires marking.
-//
-// The entry must point into the G1 heap. In particular, it must not
-// be a NULL pointer. NULL pointers are pre-filtered and never
-// inserted into a SATB buffer.
-//
-// An entry that is below the NTAMS pointer for the containing heap
-// region requires marking. Such an entry must point to a valid object.
-//
-// An entry that is at least the NTAMS pointer for the containing heap
-// region might be any of the following, none of which should be marked.
-//
-// * A reference to an object allocated since marking started.
-// According to SATB, such objects are implicitly kept live and do
-// not need to be dealt with via SATB buffer processing.
-//
-// * A reference to a young generation object. Young objects are
-// handled separately and are not marked by concurrent marking.
-//
-// * A stale reference to a young generation object. If a young
-// generation object reference is recorded and not filtered out
-// before being moved by a young collection, the reference becomes
-// stale.
-//
-// * A stale reference to an eagerly reclaimed humongous object. If a
-// humongous object is recorded and then reclaimed, the reference
-// becomes stale.
-//
-// The stale reference cases are implicitly handled by the NTAMS
-// comparison. Because of the possibility of stale references, buffer
-// processing must be somewhat circumspect and not assume entries
-// in an unfiltered buffer refer to valid objects.
-
-inline bool requires_marking(const void* entry, G1CollectedHeap* heap) {
- // Includes rejection of NULL pointers.
- assert(heap->is_in_reserved(entry),
- "Non-heap pointer in SATB buffer: " PTR_FORMAT, p2i(entry));
-
- HeapRegion* region = heap->heap_region_containing_raw(entry);
- assert(region != NULL, "No region for " PTR_FORMAT, p2i(entry));
- if (entry >= region->next_top_at_mark_start()) {
- return false;
- }
-
- assert(((oop)entry)->is_oop(true /* ignore mark word */),
- "Invalid oop in SATB buffer: " PTR_FORMAT, p2i(entry));
-
- return true;
-}
-
-// This method removes entries from a SATB buffer that will not be
-// useful to the concurrent marking threads. Entries are retained if
-// they require marking and are not already marked. Retained entries
-// are compacted toward the top of the buffer.
-
-void ObjPtrQueue::filter() {
- G1CollectedHeap* g1h = G1CollectedHeap::heap();
- void** buf = _buf;
- size_t sz = _sz;
-
- if (buf == NULL) {
- // nothing to do
- return;
- }
-
- // Used for sanity checking at the end of the loop.
- debug_only(size_t entries = 0; size_t retained = 0;)
-
- size_t i = sz;
- size_t new_index = sz;
-
- while (i > _index) {
- assert(i > 0, "we should have at least one more entry to process");
- i -= oopSize;
- debug_only(entries += 1;)
- void** p = &buf[byte_index_to_index((int) i)];
- void* entry = *p;
- // NULL the entry so that unused parts of the buffer contain NULLs
- // at the end. If we are going to retain it we will copy it to its
- // final place. If we have retained all entries we have visited so
- // far, we'll just end up copying it to the same place.
- *p = NULL;
-
- if (requires_marking(entry, g1h) && !g1h->isMarkedNext((oop)entry)) {
- assert(new_index > 0, "we should not have already filled up the buffer");
- new_index -= oopSize;
- assert(new_index >= i,
- "new_index should never be below i, as we always compact 'up'");
- void** new_p = &buf[byte_index_to_index((int) new_index)];
- assert(new_p >= p, "the destination location should never be below "
- "the source as we always compact 'up'");
- assert(*new_p == NULL,
- "we should have already cleared the destination location");
- *new_p = entry;
- debug_only(retained += 1;)
- }
- }
-
-#ifdef ASSERT
- size_t entries_calc = (sz - _index) / oopSize;
- assert(entries == entries_calc, "the number of entries we counted "
- "should match the number of entries we calculated");
- size_t retained_calc = (sz - new_index) / oopSize;
- assert(retained == retained_calc, "the number of retained entries we counted "
- "should match the number of retained entries we calculated");
-#endif // ASSERT
-
- _index = new_index;
-}
-
-// This method will first apply the above filtering to the buffer. If
-// post-filtering a large enough chunk of the buffer has been cleared
-// we can re-use the buffer (instead of enqueueing it) and we can just
-// allow the mutator to carry on executing using the same buffer
-// instead of replacing it.
-
-bool ObjPtrQueue::should_enqueue_buffer() {
- assert(_lock == NULL || _lock->owned_by_self(),
- "we should have taken the lock before calling this");
-
- // If G1SATBBufferEnqueueingThresholdPercent == 0 we could skip filtering.
-
- // This method should only be called if there is a non-NULL buffer
- // that is full.
- assert(_index == 0, "pre-condition");
- assert(_buf != NULL, "pre-condition");
-
- filter();
-
- size_t sz = _sz;
- size_t all_entries = sz / oopSize;
- size_t retained_entries = (sz - _index) / oopSize;
- size_t perc = retained_entries * 100 / all_entries;
- bool should_enqueue = perc > (size_t) G1SATBBufferEnqueueingThresholdPercent;
- return should_enqueue;
-}
-
-void ObjPtrQueue::apply_closure_and_empty(SATBBufferClosure* cl) {
- assert(SafepointSynchronize::is_at_safepoint(),
- "SATB queues must only be processed at safepoints");
- if (_buf != NULL) {
- assert(_index % sizeof(void*) == 0, "invariant");
- assert(_sz % sizeof(void*) == 0, "invariant");
- assert(_index <= _sz, "invariant");
- cl->do_buffer(_buf + byte_index_to_index((int)_index),
- byte_index_to_index((int)(_sz - _index)));
- _index = _sz;
- }
-}
-
-#ifndef PRODUCT
-// Helpful for debugging
-
-void ObjPtrQueue::print(const char* name) {
- print(name, _buf, _index, _sz);
-}
-
-void ObjPtrQueue::print(const char* name,
- void** buf, size_t index, size_t sz) {
- gclog_or_tty->print_cr(" SATB BUFFER [%s] buf: " PTR_FORMAT " "
- "index: " SIZE_FORMAT " sz: " SIZE_FORMAT,
- name, p2i(buf), index, sz);
-}
-#endif // PRODUCT
-
-#ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
-#pragma warning( disable:4355 ) // 'this' : used in base member initializer list
-#endif // _MSC_VER
-
-SATBMarkQueueSet::SATBMarkQueueSet() :
- PtrQueueSet(),
- _shared_satb_queue(this, true /*perm*/) { }
-
-void SATBMarkQueueSet::initialize(Monitor* cbl_mon, Mutex* fl_lock,
- int process_completed_threshold,
- Mutex* lock) {
- PtrQueueSet::initialize(cbl_mon, fl_lock, process_completed_threshold, -1);
- _shared_satb_queue.set_lock(lock);
-}
-
-void SATBMarkQueueSet::handle_zero_index_for_thread(JavaThread* t) {
- t->satb_mark_queue().handle_zero_index();
-}
-
-#ifdef ASSERT
-void SATBMarkQueueSet::dump_active_states(bool expected_active) {
- gclog_or_tty->print_cr("Expected SATB active state: %s",
- expected_active ? "ACTIVE" : "INACTIVE");
- gclog_or_tty->print_cr("Actual SATB active states:");
- gclog_or_tty->print_cr(" Queue set: %s", is_active() ? "ACTIVE" : "INACTIVE");
- for (JavaThread* t = Threads::first(); t; t = t->next()) {
- gclog_or_tty->print_cr(" Thread \"%s\" queue: %s", t->name(),
- t->satb_mark_queue().is_active() ? "ACTIVE" : "INACTIVE");
- }
- gclog_or_tty->print_cr(" Shared queue: %s",
- shared_satb_queue()->is_active() ? "ACTIVE" : "INACTIVE");
-}
-
-void SATBMarkQueueSet::verify_active_states(bool expected_active) {
- // Verify queue set state
- if (is_active() != expected_active) {
- dump_active_states(expected_active);
- guarantee(false, "SATB queue set has an unexpected active state");
- }
-
- // Verify thread queue states
- for (JavaThread* t = Threads::first(); t; t = t->next()) {
- if (t->satb_mark_queue().is_active() != expected_active) {
- dump_active_states(expected_active);
- guarantee(false, "Thread SATB queue has an unexpected active state");
- }
- }
-
- // Verify shared queue state
- if (shared_satb_queue()->is_active() != expected_active) {
- dump_active_states(expected_active);
- guarantee(false, "Shared SATB queue has an unexpected active state");
- }
-}
-#endif // ASSERT
-
-void SATBMarkQueueSet::set_active_all_threads(bool active, bool expected_active) {
- assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
-#ifdef ASSERT
- verify_active_states(expected_active);
-#endif // ASSERT
- _all_active = active;
- for (JavaThread* t = Threads::first(); t; t = t->next()) {
- t->satb_mark_queue().set_active(active);
- }
- shared_satb_queue()->set_active(active);
-}
-
-void SATBMarkQueueSet::filter_thread_buffers() {
- for(JavaThread* t = Threads::first(); t; t = t->next()) {
- t->satb_mark_queue().filter();
- }
- shared_satb_queue()->filter();
-}
-
-bool SATBMarkQueueSet::apply_closure_to_completed_buffer(SATBBufferClosure* cl) {
- BufferNode* nd = NULL;
- {
- MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
- if (_completed_buffers_head != NULL) {
- nd = _completed_buffers_head;
- _completed_buffers_head = nd->next();
- if (_completed_buffers_head == NULL) _completed_buffers_tail = NULL;
- _n_completed_buffers--;
- if (_n_completed_buffers == 0) _process_completed = false;
- }
- }
- if (nd != NULL) {
- void **buf = BufferNode::make_buffer_from_node(nd);
- // Skip over NULL entries at beginning (e.g. push end) of buffer.
- // Filtering can result in non-full completed buffers; see
- // should_enqueue_buffer.
- assert(_sz % sizeof(void*) == 0, "invariant");
- size_t limit = ObjPtrQueue::byte_index_to_index((int)_sz);
- for (size_t i = 0; i < limit; ++i) {
- if (buf[i] != NULL) {
- // Found the end of the block of NULLs; process the remainder.
- cl->do_buffer(buf + i, limit - i);
- break;
- }
- }
- deallocate_buffer(buf);
- return true;
- } else {
- return false;
- }
-}
-
-#ifndef PRODUCT
-// Helpful for debugging
-
-#define SATB_PRINTER_BUFFER_SIZE 256
-
-void SATBMarkQueueSet::print_all(const char* msg) {
- char buffer[SATB_PRINTER_BUFFER_SIZE];
- assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
-
- gclog_or_tty->cr();
- gclog_or_tty->print_cr("SATB BUFFERS [%s]", msg);
-
- BufferNode* nd = _completed_buffers_head;
- int i = 0;
- while (nd != NULL) {
- void** buf = BufferNode::make_buffer_from_node(nd);
- jio_snprintf(buffer, SATB_PRINTER_BUFFER_SIZE, "Enqueued: %d", i);
- ObjPtrQueue::print(buffer, buf, 0, _sz);
- nd = nd->next();
- i += 1;
- }
-
- for (JavaThread* t = Threads::first(); t; t = t->next()) {
- jio_snprintf(buffer, SATB_PRINTER_BUFFER_SIZE, "Thread: %s", t->name());
- t->satb_mark_queue().print(buffer);
- }
-
- shared_satb_queue()->print("Shared");
-
- gclog_or_tty->cr();
-}
-#endif // PRODUCT
-
-void SATBMarkQueueSet::abandon_partial_marking() {
- BufferNode* buffers_to_delete = NULL;
- {
- MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
- while (_completed_buffers_head != NULL) {
- BufferNode* nd = _completed_buffers_head;
- _completed_buffers_head = nd->next();
- nd->set_next(buffers_to_delete);
- buffers_to_delete = nd;
- }
- _completed_buffers_tail = NULL;
- _n_completed_buffers = 0;
- DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
- }
- while (buffers_to_delete != NULL) {
- BufferNode* nd = buffers_to_delete;
- buffers_to_delete = nd->next();
- deallocate_buffer(BufferNode::make_buffer_from_node(nd));
- }
- assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
- // So we can safely manipulate these queues.
- for (JavaThread* t = Threads::first(); t; t = t->next()) {
- t->satb_mark_queue().reset();
- }
- shared_satb_queue()->reset();
-}