--- /dev/null	2017-04-17 13:03:13.666114673 -0700
+++ new/src/share/vm/runtime/heapMonitoring.hpp	2017-04-18 10:46:14.166543150 -0700
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2017, Google 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_RUNTIME_HEAPMONITORING_HPP
+#define SHARE_VM_RUNTIME_HEAPMONITORING_HPP
+
+#include "gc/shared/referenceProcessor.hpp"
+#include "runtime/sharedRuntime.hpp"
+
+// Support class for sampling heap allocations across the VM.
+class HeapMonitoring {
+ private:
+  // Cheap random number generator
+  static uint64_t _rnd;
+  static bool _initialized;
+  static jint _monitoring_period;
+
+  // Statics for the fast log
+  static const int kFastlogNumBits = 10;
+  static const int kFastlogMask = (1 << kFastlogNumBits) - 1;
+  static double _log_table[1<<kFastlogNumBits];  // Constant
+
+  static void pick_next_sample(JavaThread *t);
+
+  // TODO(jcbeyler): is this algorithm acceptable in open source?
+  // Returns the next prng value.
+  // pRNG is: aX+b mod c with a = 0x5DEECE66D, b =  0xB, c = 1<<48
+  // This is the lrand64 generator.
+  static inline uint64_t next_random(uint64_t rnd) {
+    const uint64_t prng_mult = 0x5DEECE66DLL;
+    const uint64_t prng_add = 0xB;
+    const uint64_t prng_mod_power = 48;
+    const uint64_t prng_mod_mask =
+        ~((~static_cast<uint64_t>(0)) << prng_mod_power);
+    return (prng_mult * rnd + prng_add) & prng_mod_mask;
+  }
+
+  // TODO(jcbeyler): is this algorithm acceptable in open source?
+  // Adapted from //util/math/fastmath.[h|cc] by Noam Shazeer
+  // This mimics the VeryFastLog2 code in those files
+  static inline double fast_log2(const double & d) {
+    assert(d>0, "bad value passed to assert");
+    uint64_t x = 0;
+    memcpy(&x, &d, sizeof(uint64_t));
+    const uint32_t x_high = x >> 32;
+    const uint32_t y = x_high >> (20 - kFastlogNumBits) & kFastlogMask;
+    const int32_t exponent = ((x_high >> 20) & 0x7FF) - 1023;
+    return exponent + _log_table[y];
+  }
+
+ public:
+  static void get_live_traces(jvmtiStackTraceData** stack_traces, jint* num_traces);
+  static void initialize_profiling(jint monitoring_period);
+
+  // Called when o is allocated, called by interpreter and C1.
+  static void object_alloc_unsized(oopDesc* o);
+  static void object_alloc(oopDesc* o, intx byte_size);
+
+  // Called when o is allocated from C2 directly,
+  // we know the thread, and we have done the sampling.
+  static void object_alloc_do_sample(Thread *t, oopDesc *o, intx size_in_bytes);
+};
+
+#endif // SHARE_VM_RUNTIME_HEAPMONITORING_HPP