--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/jfr/recorder/stringpool/jfrStringPool.cpp	Tue May 15 20:24:34 2018 +0200
@@ -0,0 +1,246 @@
+/*
+ * Copyright (c) 2016, 2018, 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 "classfile/javaClasses.inline.hpp"
+#include "jfr/recorder/checkpoint/types/traceid/jfrTraceIdEpoch.hpp"
+#include "jfr/recorder/service/jfrOptionSet.hpp"
+#include "jfr/recorder/storage/jfrMemorySpace.inline.hpp"
+#include "jfr/recorder/repository/jfrChunkWriter.hpp"
+#include "jfr/recorder/storage/jfrStorageUtils.inline.hpp"
+#include "jfr/recorder/stringpool/jfrStringPool.hpp"
+#include "jfr/recorder/stringpool/jfrStringPoolWriter.hpp"
+#include "jfr/utilities/jfrTypes.hpp"
+#include "logging/log.hpp"
+#include "runtime/atomic.hpp"
+#include "runtime/mutexLocker.hpp"
+#include "runtime/orderAccess.inline.hpp"
+#include "runtime/safepoint.hpp"
+#include "runtime/thread.inline.hpp"
+
+typedef JfrStringPool::Buffer* BufferPtr;
+
+static JfrStringPool* _instance = NULL;
+
+JfrStringPool& JfrStringPool::instance() {
+  return *_instance;
+}
+
+JfrStringPool* JfrStringPool::create(JfrChunkWriter& cw) {
+  assert(_instance == NULL, "invariant");
+  _instance = new JfrStringPool(cw);
+  return _instance;
+}
+
+void JfrStringPool::destroy() {
+  assert(_instance != NULL, "invariant");
+  delete _instance;
+  _instance = NULL;
+}
+
+JfrStringPool::JfrStringPool(JfrChunkWriter& cw) : _free_list_mspace(NULL), _lock(NULL), _chunkwriter(cw) {}
+
+JfrStringPool::~JfrStringPool() {
+  if (_free_list_mspace != NULL) {
+    delete _free_list_mspace;
+  }
+  if (_lock != NULL) {
+    delete _lock;
+  }
+}
+
+static const size_t unlimited_mspace_size = 0;
+static const size_t string_pool_cache_count = 2;
+static const size_t string_pool_buffer_size = 512 * K;
+
+bool JfrStringPool::initialize() {
+  assert(_free_list_mspace == NULL, "invariant");
+  _free_list_mspace = new JfrStringPoolMspace(string_pool_buffer_size, unlimited_mspace_size, string_pool_cache_count, this);
+  if (_free_list_mspace == NULL || !_free_list_mspace->initialize()) {
+    return false;
+  }
+  assert(_lock == NULL, "invariant");
+  _lock = new Mutex(Monitor::leaf - 1, "Checkpoint mutex", Mutex::_allow_vm_block_flag, Monitor::_safepoint_check_never);
+  return _lock != NULL;
+}
+
+/*
+* If the buffer was a "lease" from the global system, release back.
+*
+* The buffer is effectively invalidated for the thread post-return,
+* and the caller should take means to ensure that it is not referenced any longer.
+*/
+static void release(BufferPtr buffer, Thread* thread) {
+  assert(buffer != NULL, "invariant");
+  assert(buffer->lease(), "invariant");
+  assert(buffer->acquired_by_self(), "invariant");
+  buffer->clear_lease();
+  buffer->release();
+}
+
+BufferPtr JfrStringPool::flush(BufferPtr old, size_t used, size_t requested, Thread* thread) {
+  assert(old != NULL, "invariant");
+  assert(old->lease(), "invariant");
+  if (0 == requested) {
+    // indicates a lease is being returned
+    release(old, thread);
+    return NULL;
+  }
+  // migration of in-flight information
+  BufferPtr const new_buffer = lease_buffer(thread, used + requested);
+  if (new_buffer != NULL) {
+    migrate_outstanding_writes(old, new_buffer, used, requested);
+  }
+  release(old, thread);
+  return new_buffer; // might be NULL
+}
+
+static const size_t lease_retry = 10;
+
+BufferPtr JfrStringPool::lease_buffer(Thread* thread, size_t size /* 0 */) {
+  BufferPtr buffer = mspace_get_free_lease_with_retry(size, instance()._free_list_mspace, lease_retry, thread);
+  if (buffer == NULL) {
+    buffer = mspace_allocate_transient_lease_to_free(size,  instance()._free_list_mspace, thread);
+  }
+  assert(buffer->acquired_by_self(), "invariant");
+  assert(buffer->lease(), "invariant");
+  return buffer;
+}
+
+bool JfrStringPool::add(bool epoch, jlong id, jstring string, JavaThread* jt) {
+  assert(jt != NULL, "invariant");
+  const bool current_epoch = JfrTraceIdEpoch::epoch();
+  if (current_epoch == epoch) {
+    JfrStringPoolWriter writer(jt);
+    writer.write(id);
+    writer.write(string);
+    writer.inc_nof_strings();
+  }
+  return current_epoch;
+}
+
+class StringPoolWriteOp  {
+ public:
+  typedef JfrStringPoolBuffer Type;
+ private:
+  UnBufferedWriteToChunk<Type> _writer;
+  Thread* _thread;
+  size_t _strings_processed;
+ public:
+  StringPoolWriteOp(JfrChunkWriter& writer, Thread* thread) : _writer(writer), _thread(thread), _strings_processed(0) {}
+  bool write(Type* buffer, const u1* data, size_t size) {
+    buffer->acquire(_thread); // blocking
+    const u4 nof_strings_used = (const u4)buffer->string_count();
+    assert(nof_strings_used > 0, "invariant");
+    buffer->set_string_top(buffer->string_top() + nof_strings_used);
+    // "size processed" for string pool buffers is the number of processed string elements
+    _strings_processed += nof_strings_used;
+    const bool ret = _writer.write(buffer, data, size);
+    buffer->release();
+    return ret;
+  }
+  size_t processed() { return _strings_processed; }
+};
+
+typedef StringPoolWriteOp WriteOperation;
+typedef ConcurrentWriteOp<WriteOperation> ConcurrentWriteOperation;
+
+size_t JfrStringPool::write() {
+  Thread* const thread = Thread::current();
+  WriteOperation wo(_chunkwriter, thread);
+  ConcurrentWriteOperation cwo(wo);
+  assert(_free_list_mspace->is_full_empty(), "invariant");
+  process_free_list(cwo, _free_list_mspace);
+  return wo.processed();
+}
+
+typedef MutexedWriteOp<WriteOperation> MutexedWriteOperation;
+typedef ReleaseOp<JfrStringPoolMspace> StringPoolReleaseOperation;
+typedef CompositeOperation<MutexedWriteOperation, StringPoolReleaseOperation> StringPoolWriteOperation;
+
+size_t JfrStringPool::write_at_safepoint() {
+  assert(SafepointSynchronize::is_at_safepoint(), "invariant");
+  Thread* const thread = Thread::current();
+  WriteOperation wo(_chunkwriter, thread);
+  MutexedWriteOperation mwo(wo);
+  StringPoolReleaseOperation spro(_free_list_mspace, thread, false);
+  StringPoolWriteOperation spwo(&mwo, &spro);
+  assert(_free_list_mspace->is_full_empty(), "invariant");
+  process_free_list(spwo, _free_list_mspace);
+  return wo.processed();
+}
+
+class StringPoolBufferDiscarder {
+ private:
+  Thread* _thread;
+  size_t _processed;
+ public:
+  typedef JfrStringPoolBuffer Type;
+  StringPoolBufferDiscarder() : _thread(Thread::current()), _processed(0) {}
+  bool process(Type* buffer) {
+    buffer->acquire(_thread); // serialized access
+    const u1* const current_top = buffer->top();
+    const size_t unflushed_size = buffer->pos() - current_top;
+    if (unflushed_size == 0) {
+      assert(buffer->string_count() == 0, "invariant");
+      buffer->release();
+      return true;
+    }
+    buffer->set_top(current_top + unflushed_size);
+    const u4 nof_strings_used = buffer->string_count();
+    buffer->set_string_top(buffer->string_top() + nof_strings_used);
+    // "size processed" for string pool buffers is the number of string elements
+    _processed += nof_strings_used;
+    buffer->release();
+    return true;
+  }
+  size_t processed() const { return _processed; }
+};
+
+size_t JfrStringPool::clear() {
+  StringPoolBufferDiscarder discard_operation;
+  assert(_free_list_mspace->is_full_empty(), "invariant");
+  process_free_list(discard_operation, _free_list_mspace);
+  return discard_operation.processed();
+}
+
+void JfrStringPool::register_full(BufferPtr t, Thread* thread) {
+  // nothing here at the moment
+  assert(t->retired(), "invariant");
+}
+
+void JfrStringPool::lock() {
+  assert(!_lock->owned_by_self(), "invariant");
+  _lock->lock_without_safepoint_check();
+}
+
+void JfrStringPool::unlock() {
+  _lock->unlock();
+}
+
+#ifdef ASSERT
+bool JfrStringPool::is_locked() const {
+  return _lock->owned_by_self();
+}
+#endif