--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/parallel/mutableSpace.cpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,257 @@
+/*
+ * Copyright (c) 2001, 2016, 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/parallel/mutableSpace.hpp"
+#include "gc/shared/spaceDecorator.hpp"
+#include "oops/oop.inline.hpp"
+#include "runtime/atomic.hpp"
+#include "runtime/safepoint.hpp"
+#include "runtime/thread.hpp"
+#include "utilities/align.hpp"
+#include "utilities/macros.hpp"
+
+MutableSpace::MutableSpace(size_t alignment): ImmutableSpace(), _top(NULL), _alignment(alignment) {
+  assert(MutableSpace::alignment() % os::vm_page_size() == 0,
+         "Space should be aligned");
+  _mangler = new MutableSpaceMangler(this);
+}
+
+MutableSpace::~MutableSpace() {
+  delete _mangler;
+}
+
+void MutableSpace::numa_setup_pages(MemRegion mr, bool clear_space) {
+  if (!mr.is_empty()) {
+    size_t page_size = UseLargePages ? alignment() : os::vm_page_size();
+    HeapWord *start = align_up(mr.start(), page_size);
+    HeapWord *end =   align_down(mr.end(), page_size);
+    if (end > start) {
+      size_t size = pointer_delta(end, start, sizeof(char));
+      if (clear_space) {
+        // Prefer page reallocation to migration.
+        os::free_memory((char*)start, size, page_size);
+      }
+      os::numa_make_global((char*)start, size);
+    }
+  }
+}
+
+void MutableSpace::pretouch_pages(MemRegion mr) {
+  os::pretouch_memory(mr.start(), mr.end());
+}
+
+void MutableSpace::initialize(MemRegion mr,
+                              bool clear_space,
+                              bool mangle_space,
+                              bool setup_pages) {
+
+  assert(Universe::on_page_boundary(mr.start()) && Universe::on_page_boundary(mr.end()),
+         "invalid space boundaries");
+
+  if (setup_pages && (UseNUMA || AlwaysPreTouch)) {
+    // The space may move left and right or expand/shrink.
+    // We'd like to enforce the desired page placement.
+    MemRegion head, tail;
+    if (last_setup_region().is_empty()) {
+      // If it's the first initialization don't limit the amount of work.
+      head = mr;
+      tail = MemRegion(mr.end(), mr.end());
+    } else {
+      // Is there an intersection with the address space?
+      MemRegion intersection = last_setup_region().intersection(mr);
+      if (intersection.is_empty()) {
+        intersection = MemRegion(mr.end(), mr.end());
+      }
+      // All the sizes below are in words.
+      size_t head_size = 0, tail_size = 0;
+      if (mr.start() <= intersection.start()) {
+        head_size = pointer_delta(intersection.start(), mr.start());
+      }
+      if(intersection.end() <= mr.end()) {
+        tail_size = pointer_delta(mr.end(), intersection.end());
+      }
+      // Limit the amount of page manipulation if necessary.
+      if (NUMASpaceResizeRate > 0 && !AlwaysPreTouch) {
+        const size_t change_size = head_size + tail_size;
+        const float setup_rate_words = NUMASpaceResizeRate >> LogBytesPerWord;
+        head_size = MIN2((size_t)(setup_rate_words * head_size / change_size),
+                         head_size);
+        tail_size = MIN2((size_t)(setup_rate_words * tail_size / change_size),
+                         tail_size);
+      }
+      head = MemRegion(intersection.start() - head_size, intersection.start());
+      tail = MemRegion(intersection.end(), intersection.end() + tail_size);
+    }
+    assert(mr.contains(head) && mr.contains(tail), "Sanity");
+
+    if (UseNUMA) {
+      numa_setup_pages(head, clear_space);
+      numa_setup_pages(tail, clear_space);
+    }
+
+    if (AlwaysPreTouch) {
+      pretouch_pages(head);
+      pretouch_pages(tail);
+    }
+
+    // Remember where we stopped so that we can continue later.
+    set_last_setup_region(MemRegion(head.start(), tail.end()));
+  }
+
+  set_bottom(mr.start());
+  set_end(mr.end());
+
+  if (clear_space) {
+    clear(mangle_space);
+  }
+}
+
+void MutableSpace::clear(bool mangle_space) {
+  set_top(bottom());
+  if (ZapUnusedHeapArea && mangle_space) {
+    mangle_unused_area();
+  }
+}
+
+#ifndef PRODUCT
+void MutableSpace::check_mangled_unused_area(HeapWord* limit) {
+  mangler()->check_mangled_unused_area(limit);
+}
+
+void MutableSpace::check_mangled_unused_area_complete() {
+  mangler()->check_mangled_unused_area_complete();
+}
+
+// Mangle only the unused space that has not previously
+// been mangled and that has not been allocated since being
+// mangled.
+void MutableSpace::mangle_unused_area() {
+  mangler()->mangle_unused_area();
+}
+
+void MutableSpace::mangle_unused_area_complete() {
+  mangler()->mangle_unused_area_complete();
+}
+
+void MutableSpace::mangle_region(MemRegion mr) {
+  SpaceMangler::mangle_region(mr);
+}
+
+void MutableSpace::set_top_for_allocations(HeapWord* v) {
+  mangler()->set_top_for_allocations(v);
+}
+
+void MutableSpace::set_top_for_allocations() {
+  mangler()->set_top_for_allocations(top());
+}
+#endif
+
+// This version requires locking. */
+HeapWord* MutableSpace::allocate(size_t size) {
+  assert(Heap_lock->owned_by_self() ||
+         (SafepointSynchronize::is_at_safepoint() &&
+          Thread::current()->is_VM_thread()),
+         "not locked");
+  HeapWord* obj = top();
+  if (pointer_delta(end(), obj) >= size) {
+    HeapWord* new_top = obj + size;
+    set_top(new_top);
+    assert(is_object_aligned(obj) && is_object_aligned(new_top),
+           "checking alignment");
+    return obj;
+  } else {
+    return NULL;
+  }
+}
+
+// This version is lock-free.
+HeapWord* MutableSpace::cas_allocate(size_t size) {
+  do {
+    HeapWord* obj = top();
+    if (pointer_delta(end(), obj) >= size) {
+      HeapWord* new_top = obj + size;
+      HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj);
+      // result can be one of two:
+      //  the old top value: the exchange succeeded
+      //  otherwise: the new value of the top is returned.
+      if (result != obj) {
+        continue; // another thread beat us to the allocation, try again
+      }
+      assert(is_object_aligned(obj) && is_object_aligned(new_top),
+             "checking alignment");
+      return obj;
+    } else {
+      return NULL;
+    }
+  } while (true);
+}
+
+// Try to deallocate previous allocation. Returns true upon success.
+bool MutableSpace::cas_deallocate(HeapWord *obj, size_t size) {
+  HeapWord* expected_top = obj + size;
+  return (HeapWord*)Atomic::cmpxchg_ptr(obj, top_addr(), expected_top) == expected_top;
+}
+
+void MutableSpace::oop_iterate_no_header(OopClosure* cl) {
+  HeapWord* obj_addr = bottom();
+  HeapWord* t = top();
+  // Could call objects iterate, but this is easier.
+  while (obj_addr < t) {
+    obj_addr += oop(obj_addr)->oop_iterate_no_header(cl);
+  }
+}
+
+void MutableSpace::object_iterate(ObjectClosure* cl) {
+  HeapWord* p = bottom();
+  while (p < top()) {
+    cl->do_object(oop(p));
+    p += oop(p)->size();
+  }
+}
+
+void MutableSpace::print_short() const { print_short_on(tty); }
+void MutableSpace::print_short_on( outputStream* st) const {
+  st->print(" space " SIZE_FORMAT "K, %d%% used", capacity_in_bytes() / K,
+            (int) ((double) used_in_bytes() * 100 / capacity_in_bytes()));
+}
+
+void MutableSpace::print() const { print_on(tty); }
+void MutableSpace::print_on(outputStream* st) const {
+  MutableSpace::print_short_on(st);
+  st->print_cr(" [" INTPTR_FORMAT "," INTPTR_FORMAT "," INTPTR_FORMAT ")",
+                 p2i(bottom()), p2i(top()), p2i(end()));
+}
+
+void MutableSpace::verify() {
+  HeapWord* p = bottom();
+  HeapWord* t = top();
+  HeapWord* prev_p = NULL;
+  while (p < t) {
+    oop(p)->verify();
+    prev_p = p;
+    p += oop(p)->size();
+  }
+  guarantee(p == top(), "end of last object must match end of space");
+}