Mercurial > hg > graal-jvmci-8
view src/share/vm/gc_implementation/g1/satbQueue.cpp @ 23287:bd88fd590f4e
Restore G1 changes from e13c65f874e5 after merge
author | Gilles Duboscq <gilles.m.duboscq@oracle.com> |
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date | Fri, 08 Jan 2016 15:46:55 +0100 |
parents | dd9cc155639c |
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/* * 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_implementation/g1/g1CollectedHeap.inline.hpp" #include "gc_implementation/g1/satbQueue.hpp" #include "memory/allocation.inline.hpp" #include "memory/sharedHeap.hpp" #include "oops/oop.inline.hpp" #include "runtime/mutexLocker.hpp" #include "runtime/safepoint.hpp" #include "runtime/thread.hpp" #include "runtime/vmThread.hpp" PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 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), err_msg("Non-heap pointer in SATB buffer: " PTR_FORMAT, p2i(entry))); HeapRegion* region = heap->heap_region_containing_raw(entry); assert(region != NULL, err_msg("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 */), err_msg("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 alwaysr 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, 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(); }