# HG changeset patch # User kbarrett # Date 1446845440 18000 # Node ID 2bae5bf9e431be35e6c90b9e3e66b2fe9eeac622 # Parent 229ed95d8958a1a03818a39a908b40f92cbe43ca 8077571: ObjPtrQueue is poorly named Summary: Renamed to SATBMarkQueue and renamed files. Reviewed-by: brutisso, tschatzl, dholmes, twisti diff -r 229ed95d8958 -r 2bae5bf9e431 hotspot/src/jdk.vm.ci/share/classes/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotVMConfig.java --- a/hotspot/src/jdk.vm.ci/share/classes/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotVMConfig.java Mon Nov 09 11:35:45 2015 +0000 +++ b/hotspot/src/jdk.vm.ci/share/classes/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotVMConfig.java Fri Nov 06 16:30:40 2015 -0500 @@ -1063,7 +1063,7 @@ @HotSpotVMField(name = "JavaThread::_osthread", type = "OSThread*", get = HotSpotVMField.Type.OFFSET) @Stable public int osThreadOffset; @HotSpotVMField(name = "JavaThread::_dirty_card_queue", type = "DirtyCardQueue", get = HotSpotVMField.Type.OFFSET) @Stable public int javaThreadDirtyCardQueueOffset; @HotSpotVMField(name = "JavaThread::_is_method_handle_return", type = "int", get = HotSpotVMField.Type.OFFSET) @Stable public int threadIsMethodHandleReturnOffset; - @HotSpotVMField(name = "JavaThread::_satb_mark_queue", type = "ObjPtrQueue", get = HotSpotVMField.Type.OFFSET) @Stable public int javaThreadSatbMarkQueueOffset; + @HotSpotVMField(name = "JavaThread::_satb_mark_queue", type = "SATBMarkQueue", get = HotSpotVMField.Type.OFFSET) @Stable public int javaThreadSatbMarkQueueOffset; @HotSpotVMField(name = "JavaThread::_vm_result", type = "oop", get = HotSpotVMField.Type.OFFSET) @Stable public int threadObjectResultOffset; @HotSpotVMField(name = "JavaThread::_jvmci_counters", type = "jlong*", get = HotSpotVMField.Type.OFFSET) @Stable public int jvmciCountersThreadOffset; diff -r 229ed95d8958 -r 2bae5bf9e431 hotspot/src/share/vm/gc/g1/g1SATBCardTableModRefBS.cpp --- a/hotspot/src/share/vm/gc/g1/g1SATBCardTableModRefBS.cpp Mon Nov 09 11:35:45 2015 +0000 +++ b/hotspot/src/share/vm/gc/g1/g1SATBCardTableModRefBS.cpp Fri Nov 06 16:30:40 2015 -0500 @@ -26,7 +26,7 @@ #include "gc/g1/g1CollectedHeap.inline.hpp" #include "gc/g1/g1SATBCardTableModRefBS.hpp" #include "gc/g1/heapRegion.hpp" -#include "gc/g1/satbQueue.hpp" +#include "gc/g1/satbMarkQueue.hpp" #include "gc/shared/memset_with_concurrent_readers.hpp" #include "oops/oop.inline.hpp" #include "runtime/atomic.inline.hpp" diff -r 229ed95d8958 -r 2bae5bf9e431 hotspot/src/share/vm/gc/g1/satbMarkQueue.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/hotspot/src/share/vm/gc/g1/satbMarkQueue.cpp Fri Nov 06 16:30:40 2015 -0500 @@ -0,0 +1,370 @@ +/* + * 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/satbMarkQueue.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" + +SATBMarkQueue::SATBMarkQueue(SATBMarkQueueSet* qset, bool permanent) : + // SATB queues are only active during marking cycles. We create + // them with their active field set to false. If a thread is + // created during a cycle and its SATB queue needs to be activated + // before the thread starts running, we'll need to set its active + // field to true. This is done in JavaThread::initialize_queues(). + PtrQueue(qset, permanent, false /* active */) +{ } + +void SATBMarkQueue::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(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 SATBMarkQueue::filter() { + G1CollectedHeap* g1h = G1CollectedHeap::heap(); + void** buf = _buf; + + 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;) + + assert(_index <= _sz, "invariant"); + void** limit = &buf[byte_index_to_index(_index)]; + void** src = &buf[byte_index_to_index(_sz)]; + void** dst = src; + + while (limit < src) { + DEBUG_ONLY(entries += 1;) + --src; + void* entry = *src; + // 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. + *src = NULL; + + if (requires_marking(entry, g1h) && !g1h->isMarkedNext((oop)entry)) { + --dst; + assert(*dst == NULL, "filtering destination should be clear"); + *dst = entry; + DEBUG_ONLY(retained += 1;); + } + } + size_t new_index = pointer_delta(dst, buf, 1); + +#ifdef ASSERT + size_t entries_calc = (_sz - _index) / sizeof(void*); + 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) / sizeof(void*); + 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 SATBMarkQueue::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 percent_used = ((_sz - _index) * 100) / _sz; + bool should_enqueue = percent_used > G1SATBBufferEnqueueingThresholdPercent; + return should_enqueue; +} + +void SATBMarkQueue::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(_index), + byte_index_to_index(_sz - _index)); + _index = _sz; + } +} + +#ifndef PRODUCT +// Helpful for debugging + +void SATBMarkQueue::print(const char* name) { + print(name, _buf, _index, _sz); +} + +void SATBMarkQueue::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 + +SATBMarkQueueSet::SATBMarkQueueSet() : + PtrQueueSet(), + _shared_satb_queue(this, true /* permanent */) { } + +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 = SATBMarkQueue::byte_index_to_index(_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); + SATBMarkQueue::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(); +} diff -r 229ed95d8958 -r 2bae5bf9e431 hotspot/src/share/vm/gc/g1/satbMarkQueue.hpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/hotspot/src/share/vm/gc/g1/satbMarkQueue.hpp Fri Nov 06 16:30:40 2015 -0500 @@ -0,0 +1,117 @@ +/* + * 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. + * + */ + +#ifndef SHARE_VM_GC_G1_SATBMARKQUEUE_HPP +#define SHARE_VM_GC_G1_SATBMARKQUEUE_HPP + +#include "gc/g1/ptrQueue.hpp" +#include "memory/allocation.hpp" + +class JavaThread; +class SATBMarkQueueSet; + +// Base class for processing the contents of a SATB buffer. +class SATBBufferClosure : public StackObj { +protected: + ~SATBBufferClosure() { } + +public: + // Process the SATB entries in the designated buffer range. + virtual void do_buffer(void** buffer, size_t size) = 0; +}; + +// A PtrQueue whose elements are (possibly stale) pointers to object heads. +class SATBMarkQueue: public PtrQueue { + friend class SATBMarkQueueSet; + +private: + // Filter out unwanted entries from the buffer. + void filter(); + +public: + SATBMarkQueue(SATBMarkQueueSet* qset, bool permanent = false); + + // Process queue entries and free resources. + void flush(); + + // Apply cl to the active part of the buffer. + // Prerequisite: Must be at a safepoint. + void apply_closure_and_empty(SATBBufferClosure* cl); + + // Overrides PtrQueue::should_enqueue_buffer(). See the method's + // definition for more information. + virtual bool should_enqueue_buffer(); + +#ifndef PRODUCT + // Helpful for debugging + void print(const char* name); + static void print(const char* name, void** buf, size_t index, size_t sz); +#endif // PRODUCT +}; + +class SATBMarkQueueSet: public PtrQueueSet { + SATBMarkQueue _shared_satb_queue; + +#ifdef ASSERT + void dump_active_states(bool expected_active); + void verify_active_states(bool expected_active); +#endif // ASSERT + +public: + SATBMarkQueueSet(); + + void initialize(Monitor* cbl_mon, Mutex* fl_lock, + int process_completed_threshold, + Mutex* lock); + + static void handle_zero_index_for_thread(JavaThread* t); + + // Apply "set_active(active)" to all SATB queues in the set. It should be + // called only with the world stopped. The method will assert that the + // SATB queues of all threads it visits, as well as the SATB queue + // set itself, has an active value same as expected_active. + void set_active_all_threads(bool active, bool expected_active); + + // Filter all the currently-active SATB buffers. + void filter_thread_buffers(); + + // If there exists some completed buffer, pop and process it, and + // return true. Otherwise return false. Processing a buffer + // consists of applying the closure to the buffer range starting + // with the first non-NULL entry to the end of the buffer; the + // leading entries may be NULL due to filtering. + bool apply_closure_to_completed_buffer(SATBBufferClosure* cl); + +#ifndef PRODUCT + // Helpful for debugging + void print_all(const char* msg); +#endif // PRODUCT + + SATBMarkQueue* shared_satb_queue() { return &_shared_satb_queue; } + + // If a marking is being abandoned, reset any unprocessed log buffers. + void abandon_partial_marking(); +}; + +#endif // SHARE_VM_GC_G1_SATBMARKQUEUE_HPP diff -r 229ed95d8958 -r 2bae5bf9e431 hotspot/src/share/vm/gc/g1/satbQueue.cpp --- a/hotspot/src/share/vm/gc/g1/satbQueue.cpp Mon Nov 09 11:35:45 2015 +0000 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,370 +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" - -ObjPtrQueue::ObjPtrQueue(SATBMarkQueueSet* qset, bool permanent) : - // SATB queues are only active during marking cycles. We create - // them with their active field set to false. If a thread is - // created during a cycle and its SATB queue needs to be activated - // before the thread starts running, we'll need to set its active - // field to true. This is done in JavaThread::initialize_queues(). - PtrQueue(qset, permanent, false /* active */) -{ } - -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(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; - - 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;) - - assert(_index <= _sz, "invariant"); - void** limit = &buf[byte_index_to_index(_index)]; - void** src = &buf[byte_index_to_index(_sz)]; - void** dst = src; - - while (limit < src) { - DEBUG_ONLY(entries += 1;) - --src; - void* entry = *src; - // 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. - *src = NULL; - - if (requires_marking(entry, g1h) && !g1h->isMarkedNext((oop)entry)) { - --dst; - assert(*dst == NULL, "filtering destination should be clear"); - *dst = entry; - DEBUG_ONLY(retained += 1;); - } - } - size_t new_index = pointer_delta(dst, buf, 1); - -#ifdef ASSERT - size_t entries_calc = (_sz - _index) / sizeof(void*); - 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) / sizeof(void*); - 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 percent_used = ((_sz - _index) * 100) / _sz; - bool should_enqueue = percent_used > 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(_index), - byte_index_to_index(_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 - -SATBMarkQueueSet::SATBMarkQueueSet() : - PtrQueueSet(), - _shared_satb_queue(this, true /* permanent */) { } - -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(_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(); -} diff -r 229ed95d8958 -r 2bae5bf9e431 hotspot/src/share/vm/gc/g1/satbQueue.hpp --- a/hotspot/src/share/vm/gc/g1/satbQueue.hpp Mon Nov 09 11:35:45 2015 +0000 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,117 +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. - * - */ - -#ifndef SHARE_VM_GC_G1_SATBQUEUE_HPP -#define SHARE_VM_GC_G1_SATBQUEUE_HPP - -#include "gc/g1/ptrQueue.hpp" -#include "memory/allocation.hpp" - -class JavaThread; -class SATBMarkQueueSet; - -// Base class for processing the contents of a SATB buffer. -class SATBBufferClosure : public StackObj { -protected: - ~SATBBufferClosure() { } - -public: - // Process the SATB entries in the designated buffer range. - virtual void do_buffer(void** buffer, size_t size) = 0; -}; - -// A ptrQueue whose elements are "oops", pointers to object heads. -class ObjPtrQueue: public PtrQueue { - friend class SATBMarkQueueSet; - -private: - // Filter out unwanted entries from the buffer. - void filter(); - -public: - ObjPtrQueue(SATBMarkQueueSet* qset, bool permanent = false); - - // Process queue entries and free resources. - void flush(); - - // Apply cl to the active part of the buffer. - // Prerequisite: Must be at a safepoint. - void apply_closure_and_empty(SATBBufferClosure* cl); - - // Overrides PtrQueue::should_enqueue_buffer(). See the method's - // definition for more information. - virtual bool should_enqueue_buffer(); - -#ifndef PRODUCT - // Helpful for debugging - void print(const char* name); - static void print(const char* name, void** buf, size_t index, size_t sz); -#endif // PRODUCT -}; - -class SATBMarkQueueSet: public PtrQueueSet { - ObjPtrQueue _shared_satb_queue; - -#ifdef ASSERT - void dump_active_states(bool expected_active); - void verify_active_states(bool expected_active); -#endif // ASSERT - -public: - SATBMarkQueueSet(); - - void initialize(Monitor* cbl_mon, Mutex* fl_lock, - int process_completed_threshold, - Mutex* lock); - - static void handle_zero_index_for_thread(JavaThread* t); - - // Apply "set_active(active)" to all SATB queues in the set. It should be - // called only with the world stopped. The method will assert that the - // SATB queues of all threads it visits, as well as the SATB queue - // set itself, has an active value same as expected_active. - void set_active_all_threads(bool active, bool expected_active); - - // Filter all the currently-active SATB buffers. - void filter_thread_buffers(); - - // If there exists some completed buffer, pop and process it, and - // return true. Otherwise return false. Processing a buffer - // consists of applying the closure to the buffer range starting - // with the first non-NULL entry to the end of the buffer; the - // leading entries may be NULL due to filtering. - bool apply_closure_to_completed_buffer(SATBBufferClosure* cl); - -#ifndef PRODUCT - // Helpful for debugging - void print_all(const char* msg); -#endif // PRODUCT - - ObjPtrQueue* shared_satb_queue() { return &_shared_satb_queue; } - - // If a marking is being abandoned, reset any unprocessed log buffers. - void abandon_partial_marking(); -}; - -#endif // SHARE_VM_GC_G1_SATBQUEUE_HPP diff -r 229ed95d8958 -r 2bae5bf9e431 hotspot/src/share/vm/precompiled/precompiled.hpp --- a/hotspot/src/share/vm/precompiled/precompiled.hpp Mon Nov 09 11:35:45 2015 +0000 +++ b/hotspot/src/share/vm/precompiled/precompiled.hpp Fri Nov 06 16:30:40 2015 -0500 @@ -304,7 +304,7 @@ # include "gc/g1/g1OopClosures.hpp" # include "gc/g1/g1_globals.hpp" # include "gc/g1/ptrQueue.hpp" -# include "gc/g1/satbQueue.hpp" +# include "gc/g1/satbMarkQueue.hpp" # include "gc/parallel/gcAdaptivePolicyCounters.hpp" # include "gc/parallel/objectStartArray.hpp" # include "gc/parallel/parMarkBitMap.hpp" diff -r 229ed95d8958 -r 2bae5bf9e431 hotspot/src/share/vm/runtime/thread.cpp --- a/hotspot/src/share/vm/runtime/thread.cpp Mon Nov 09 11:35:45 2015 +0000 +++ b/hotspot/src/share/vm/runtime/thread.cpp Fri Nov 06 16:30:40 2015 -0500 @@ -1938,7 +1938,7 @@ assert(!SafepointSynchronize::is_at_safepoint(), "we should not be at a safepoint"); - ObjPtrQueue& satb_queue = satb_mark_queue(); + SATBMarkQueue& satb_queue = satb_mark_queue(); SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); // The SATB queue should have been constructed with its active // field set to false. diff -r 229ed95d8958 -r 2bae5bf9e431 hotspot/src/share/vm/runtime/thread.hpp --- a/hotspot/src/share/vm/runtime/thread.hpp Mon Nov 09 11:35:45 2015 +0000 +++ b/hotspot/src/share/vm/runtime/thread.hpp Fri Nov 06 16:30:40 2015 -0500 @@ -49,7 +49,7 @@ #include "utilities/top.hpp" #if INCLUDE_ALL_GCS #include "gc/g1/dirtyCardQueue.hpp" -#include "gc/g1/satbQueue.hpp" +#include "gc/g1/satbMarkQueue.hpp" #endif // INCLUDE_ALL_GCS #ifdef TARGET_ARCH_zero # include "stack_zero.hpp" @@ -992,7 +992,7 @@ #if INCLUDE_ALL_GCS // Support for G1 barriers - ObjPtrQueue _satb_mark_queue; // Thread-local log for SATB barrier. + SATBMarkQueue _satb_mark_queue; // Thread-local log for SATB barrier. // Set of all such queues. static SATBMarkQueueSet _satb_mark_queue_set; @@ -1727,7 +1727,7 @@ #if INCLUDE_ALL_GCS // SATB marking queue support - ObjPtrQueue& satb_mark_queue() { return _satb_mark_queue; } + SATBMarkQueue& satb_mark_queue() { return _satb_mark_queue; } static SATBMarkQueueSet& satb_mark_queue_set() { return _satb_mark_queue_set; } diff -r 229ed95d8958 -r 2bae5bf9e431 hotspot/src/share/vm/runtime/vmStructs.cpp --- a/hotspot/src/share/vm/runtime/vmStructs.cpp Mon Nov 09 11:35:45 2015 +0000 +++ b/hotspot/src/share/vm/runtime/vmStructs.cpp Fri Nov 06 16:30:40 2015 -0500 @@ -1030,7 +1030,7 @@ nonstatic_field(JavaThread, _stack_size, size_t) \ nonstatic_field(JavaThread, _vframe_array_head, vframeArray*) \ nonstatic_field(JavaThread, _vframe_array_last, vframeArray*) \ - nonstatic_field(JavaThread, _satb_mark_queue, ObjPtrQueue) \ + nonstatic_field(JavaThread, _satb_mark_queue, SATBMarkQueue) \ nonstatic_field(JavaThread, _dirty_card_queue, DirtyCardQueue) \ nonstatic_field(Thread, _resource_area, ResourceArea*) \ nonstatic_field(CompilerThread, _env, ciEnv*) \ @@ -1622,7 +1622,7 @@ declare_toplevel_type(MemRegion) \ declare_toplevel_type(ThreadLocalAllocBuffer) \ declare_toplevel_type(VirtualSpace) \ - declare_toplevel_type(ObjPtrQueue) \ + declare_toplevel_type(SATBMarkQueue) \ declare_toplevel_type(DirtyCardQueue) \ \ /* Pointers to Garbage Collection types */ \