--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc/g1/ptrQueue.hpp Wed May 13 15:16:06 2015 +0200
@@ -0,0 +1,319 @@
+/*
+ * 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_PTRQUEUE_HPP
+#define SHARE_VM_GC_G1_PTRQUEUE_HPP
+
+#include "memory/allocation.hpp"
+#include "utilities/sizes.hpp"
+
+// There are various techniques that require threads to be able to log
+// addresses. For example, a generational write barrier might log
+// the addresses of modified old-generation objects. This type supports
+// this operation.
+
+// The definition of placement operator new(size_t, void*) in the <new>.
+#include <new>
+
+class PtrQueueSet;
+class PtrQueue VALUE_OBJ_CLASS_SPEC {
+ friend class VMStructs;
+
+protected:
+ // The ptr queue set to which this queue belongs.
+ PtrQueueSet* _qset;
+
+ // Whether updates should be logged.
+ bool _active;
+
+ // The buffer.
+ void** _buf;
+ // The index at which an object was last enqueued. Starts at "_sz"
+ // (indicating an empty buffer) and goes towards zero.
+ size_t _index;
+
+ // The size of the buffer.
+ size_t _sz;
+
+ // If true, the queue is permanent, and doesn't need to deallocate
+ // its buffer in the destructor (since that obtains a lock which may not
+ // be legally locked by then.
+ bool _perm;
+
+ // If there is a lock associated with this buffer, this is that lock.
+ Mutex* _lock;
+
+ PtrQueueSet* qset() { return _qset; }
+ bool is_permanent() const { return _perm; }
+
+ // Process queue entries and release resources, if not permanent.
+ void flush_impl();
+
+public:
+ // Initialize this queue to contain a null buffer, and be part of the
+ // given PtrQueueSet.
+ PtrQueue(PtrQueueSet* qset, bool perm = false, bool active = false);
+
+ // Requires queue flushed or permanent.
+ ~PtrQueue();
+
+ // Associate a lock with a ptr queue.
+ void set_lock(Mutex* lock) { _lock = lock; }
+
+ void reset() { if (_buf != NULL) _index = _sz; }
+
+ void enqueue(volatile void* ptr) {
+ enqueue((void*)(ptr));
+ }
+
+ // Enqueues the given "obj".
+ void enqueue(void* ptr) {
+ if (!_active) return;
+ else enqueue_known_active(ptr);
+ }
+
+ // This method is called when we're doing the zero index handling
+ // and gives a chance to the queues to do any pre-enqueueing
+ // processing they might want to do on the buffer. It should return
+ // true if the buffer should be enqueued, or false if enough
+ // entries were cleared from it so that it can be re-used. It should
+ // not return false if the buffer is still full (otherwise we can
+ // get into an infinite loop).
+ virtual bool should_enqueue_buffer() { return true; }
+ void handle_zero_index();
+ void locking_enqueue_completed_buffer(void** buf);
+
+ void enqueue_known_active(void* ptr);
+
+ size_t size() {
+ assert(_sz >= _index, "Invariant.");
+ return _buf == NULL ? 0 : _sz - _index;
+ }
+
+ bool is_empty() {
+ return _buf == NULL || _sz == _index;
+ }
+
+ // Set the "active" property of the queue to "b". An enqueue to an
+ // inactive thread is a no-op. Setting a queue to inactive resets its
+ // log to the empty state.
+ void set_active(bool b) {
+ _active = b;
+ if (!b && _buf != NULL) {
+ _index = _sz;
+ } else if (b && _buf != NULL) {
+ assert(_index == _sz, "invariant: queues are empty when activated.");
+ }
+ }
+
+ bool is_active() { return _active; }
+
+ static int byte_index_to_index(int ind) {
+ assert((ind % oopSize) == 0, "Invariant.");
+ return ind / oopSize;
+ }
+
+ static int index_to_byte_index(int byte_ind) {
+ return byte_ind * oopSize;
+ }
+
+ // To support compiler.
+ static ByteSize byte_offset_of_index() {
+ return byte_offset_of(PtrQueue, _index);
+ }
+ static ByteSize byte_width_of_index() { return in_ByteSize(sizeof(size_t)); }
+
+ static ByteSize byte_offset_of_buf() {
+ return byte_offset_of(PtrQueue, _buf);
+ }
+ static ByteSize byte_width_of_buf() { return in_ByteSize(sizeof(void*)); }
+
+ static ByteSize byte_offset_of_active() {
+ return byte_offset_of(PtrQueue, _active);
+ }
+ static ByteSize byte_width_of_active() { return in_ByteSize(sizeof(bool)); }
+
+};
+
+class BufferNode {
+ size_t _index;
+ BufferNode* _next;
+public:
+ BufferNode() : _index(0), _next(NULL) { }
+ BufferNode* next() const { return _next; }
+ void set_next(BufferNode* n) { _next = n; }
+ size_t index() const { return _index; }
+ void set_index(size_t i) { _index = i; }
+
+ // Align the size of the structure to the size of the pointer
+ static size_t aligned_size() {
+ static const size_t alignment = round_to(sizeof(BufferNode), sizeof(void*));
+ return alignment;
+ }
+
+ // BufferNode is allocated before the buffer.
+ // The chunk of memory that holds both of them is a block.
+
+ // Produce a new BufferNode given a buffer.
+ static BufferNode* new_from_buffer(void** buf) {
+ return new (make_block_from_buffer(buf)) BufferNode;
+ }
+
+ // The following are the required conversion routines:
+ static BufferNode* make_node_from_buffer(void** buf) {
+ return (BufferNode*)make_block_from_buffer(buf);
+ }
+ static void** make_buffer_from_node(BufferNode *node) {
+ return make_buffer_from_block(node);
+ }
+ static void* make_block_from_node(BufferNode *node) {
+ return (void*)node;
+ }
+ static void** make_buffer_from_block(void* p) {
+ return (void**)((char*)p + aligned_size());
+ }
+ static void* make_block_from_buffer(void** p) {
+ return (void*)((char*)p - aligned_size());
+ }
+};
+
+// A PtrQueueSet represents resources common to a set of pointer queues.
+// In particular, the individual queues allocate buffers from this shared
+// set, and return completed buffers to the set.
+// All these variables are are protected by the TLOQ_CBL_mon. XXX ???
+class PtrQueueSet VALUE_OBJ_CLASS_SPEC {
+protected:
+ Monitor* _cbl_mon; // Protects the fields below.
+ BufferNode* _completed_buffers_head;
+ BufferNode* _completed_buffers_tail;
+ int _n_completed_buffers;
+ int _process_completed_threshold;
+ volatile bool _process_completed;
+
+ // This (and the interpretation of the first element as a "next"
+ // pointer) are protected by the TLOQ_FL_lock.
+ Mutex* _fl_lock;
+ BufferNode* _buf_free_list;
+ size_t _buf_free_list_sz;
+ // Queue set can share a freelist. The _fl_owner variable
+ // specifies the owner. It is set to "this" by default.
+ PtrQueueSet* _fl_owner;
+
+ // The size of all buffers in the set.
+ size_t _sz;
+
+ bool _all_active;
+
+ // If true, notify_all on _cbl_mon when the threshold is reached.
+ bool _notify_when_complete;
+
+ // Maximum number of elements allowed on completed queue: after that,
+ // enqueuer does the work itself. Zero indicates no maximum.
+ int _max_completed_queue;
+ int _completed_queue_padding;
+
+ int completed_buffers_list_length();
+ void assert_completed_buffer_list_len_correct_locked();
+ void assert_completed_buffer_list_len_correct();
+
+protected:
+ // A mutator thread does the the work of processing a buffer.
+ // Returns "true" iff the work is complete (and the buffer may be
+ // deallocated).
+ virtual bool mut_process_buffer(void** buf) {
+ ShouldNotReachHere();
+ return false;
+ }
+
+public:
+ // Create an empty ptr queue set.
+ PtrQueueSet(bool notify_when_complete = false);
+
+ // Because of init-order concerns, we can't pass these as constructor
+ // arguments.
+ void initialize(Monitor* cbl_mon, Mutex* fl_lock,
+ int process_completed_threshold,
+ int max_completed_queue,
+ PtrQueueSet *fl_owner = NULL) {
+ _max_completed_queue = max_completed_queue;
+ _process_completed_threshold = process_completed_threshold;
+ _completed_queue_padding = 0;
+ assert(cbl_mon != NULL && fl_lock != NULL, "Init order issue?");
+ _cbl_mon = cbl_mon;
+ _fl_lock = fl_lock;
+ _fl_owner = (fl_owner != NULL) ? fl_owner : this;
+ }
+
+ // Return an empty oop array of size _sz (required to be non-zero).
+ void** allocate_buffer();
+
+ // Return an empty buffer to the free list. The "buf" argument is
+ // required to be a pointer to the head of an array of length "_sz".
+ void deallocate_buffer(void** buf);
+
+ // Declares that "buf" is a complete buffer.
+ void enqueue_complete_buffer(void** buf, size_t index = 0);
+
+ // To be invoked by the mutator.
+ bool process_or_enqueue_complete_buffer(void** buf);
+
+ bool completed_buffers_exist_dirty() {
+ return _n_completed_buffers > 0;
+ }
+
+ bool process_completed_buffers() { return _process_completed; }
+ void set_process_completed(bool x) { _process_completed = x; }
+
+ bool is_active() { return _all_active; }
+
+ // Set the buffer size. Should be called before any "enqueue" operation
+ // can be called. And should only be called once.
+ void set_buffer_size(size_t sz);
+
+ // Get the buffer size.
+ size_t buffer_size() { return _sz; }
+
+ // Get/Set the number of completed buffers that triggers log processing.
+ void set_process_completed_threshold(int sz) { _process_completed_threshold = sz; }
+ int process_completed_threshold() const { return _process_completed_threshold; }
+
+ // Must only be called at a safe point. Indicates that the buffer free
+ // list size may be reduced, if that is deemed desirable.
+ void reduce_free_list();
+
+ int completed_buffers_num() { return _n_completed_buffers; }
+
+ void merge_bufferlists(PtrQueueSet* src);
+
+ void set_max_completed_queue(int m) { _max_completed_queue = m; }
+ int max_completed_queue() { return _max_completed_queue; }
+
+ void set_completed_queue_padding(int padding) { _completed_queue_padding = padding; }
+ int completed_queue_padding() { return _completed_queue_padding; }
+
+ // Notify the consumer if the number of buffers crossed the threshold
+ void notify_if_necessary();
+};
+
+#endif // SHARE_VM_GC_G1_PTRQUEUE_HPP