diff -r 6b9b9c3e0a39 -r 7d2d5871559d hotspot/src/share/vm/gc/g1/satbQueue.cpp --- a/hotspot/src/share/vm/gc/g1/satbQueue.cpp Thu Nov 12 14:13:49 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(); -}