--- /dev/null	2020-09-04 12:37:41.765504620 +0200
+++ new/src/hotspot/share/memory/metaspace/msCommon.cpp	2020-09-04 13:57:50.005348677 +0200
@@ -0,0 +1,203 @@
+/*
+ * Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2020 SAP SE. 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 "memory/metaspace/msCommon.hpp"
+#include "memory/metaspace/msAllocationGuard.hpp"
+#include "memory/metaspace/msFreeBlocks.hpp"
+#include "memory/metaspace/msSettings.hpp"
+#include "memory/metaspace/msVirtualSpaceNode.hpp"
+#include "utilities/align.hpp"
+#include "utilities/debug.hpp"
+#include "utilities/globalDefinitions.hpp"
+#include "utilities/ostream.hpp"
+
+namespace metaspace {
+
+// Print a size, in words, scaled.
+void print_scaled_words(outputStream* st, size_t word_size, size_t scale, int width) {
+  print_human_readable_size(st, word_size * sizeof(MetaWord), scale, width);
+}
+
+// Convenience helper: prints a size value and a percentage.
+void print_scaled_words_and_percentage(outputStream* st, size_t word_size, size_t compare_word_size, size_t scale, int width) {
+  print_scaled_words(st, word_size, scale, width);
+  st->print(" (");
+  print_percentage(st, compare_word_size, word_size);
+  st->print(")");
+}
+
+static const char* display_unit_for_scale(size_t scale) {
+  const char* s = NULL;
+  switch(scale) {
+    case 1: s = "bytes"; break;
+    case BytesPerWord: s = "words"; break;
+    case K: s = "KB"; break;
+    case M: s = "MB"; break;
+    case G: s = "GB"; break;
+    default:
+      ShouldNotReachHere();
+  }
+  return s;
+}
+
+// Print a human readable size.
+// byte_size: size, in bytes, to be printed.
+// scale: one of 1 (byte-wise printing), sizeof(word) (word-size printing), K, M, G (scaled by KB, MB, GB respectively,
+//         or 0, which means the best scale is choosen dynamically.
+// width: printing width.
+void print_human_readable_size(outputStream* st, size_t byte_size, size_t scale, int width)  {
+  if (scale == 0) {
+    // Dynamic mode. Choose scale for this value.
+    if (byte_size == 0) {
+      // Zero values are printed as bytes.
+      scale = 1;
+    } else {
+      if (byte_size >= G) {
+        scale = G;
+      } else if (byte_size >= M) {
+        scale = M;
+      } else if (byte_size >= K) {
+        scale = K;
+      } else {
+        scale = 1;
+      }
+    }
+    return print_human_readable_size(st, byte_size, scale, width);
+  }
+
+#ifdef ASSERT
+  assert(scale == 1 || scale == BytesPerWord ||
+         scale == K || scale == M || scale == G, "Invalid scale");
+  // Special case: printing wordsize should only be done with word-sized values
+  if (scale == BytesPerWord) {
+    assert(byte_size % BytesPerWord == 0, "not word sized");
+  }
+#endif
+
+  if (width == -1) {
+    if (scale == 1) {
+      st->print(SIZE_FORMAT " bytes", byte_size);
+    } else if (scale == BytesPerWord) {
+      st->print(SIZE_FORMAT " words", byte_size / BytesPerWord);
+    } else {
+      const char* display_unit = display_unit_for_scale(scale);
+      float display_value = (float) byte_size / scale;
+      // Prevent very small but non-null values showing up as 0.00.
+      if (byte_size > 0 && display_value < 0.01f) {
+        st->print("<0.01 %s", display_unit);
+      } else {
+        st->print("%.2f %s", display_value, display_unit);
+      }
+    }
+  } else {
+    if (scale == 1) {
+      st->print("%*" PRIuPTR " bytes", width, byte_size);
+    } else if (scale == BytesPerWord) {
+      st->print("%*" PRIuPTR " words", width, byte_size / BytesPerWord);
+    } else {
+      const char* display_unit = display_unit_for_scale(scale);
+      float display_value = (float) byte_size / scale;
+      // Since we use width to display a number with two trailing digits, increase it a bit.
+      width += 3;
+      // Prevent very small but non-null values showing up as 0.00.
+      if (byte_size > 0 && display_value < 0.01f) {
+        st->print("%*s %s", width, "<0.01", display_unit);
+      } else {
+        st->print("%*.2f %s", width, display_value, display_unit);
+      }
+    }
+  }
+}
+
+// Prints a percentage value. Values smaller than 1% but not 0 are displayed as "<1%", values
+// larger than 99% but not 100% are displayed as ">100%".
+void print_percentage(outputStream* st, size_t total, size_t part) {
+  if (total == 0) {
+    st->print("  ?%%");
+  } else if (part == 0) {
+    st->print("  0%%");
+  } else if (part == total) {
+    st->print("100%%");
+  } else {
+    // Note: clearly print very-small-but-not-0% and very-large-but-not-100% percentages.
+    float p = ((float)part / total) * 100.0f;
+    if (p < 1.0f) {
+      st->print(" <1%%");
+    } else if (p > 99.0f){
+      st->print(">99%%");
+    } else {
+      st->print("%3.0f%%", p);
+    }
+  }
+}
+
+const char* loaders_plural(uintx num) {
+  return num == 1 ? "loader" : "loaders";
+}
+
+const char* classes_plural(uintx num) {
+  return num == 1 ? "class" : "classes";
+}
+
+void print_number_of_classes(outputStream* out, uintx classes, uintx classes_shared) {
+  out->print(UINTX_FORMAT " %s", classes, classes_plural(classes));
+  if (classes_shared > 0) {
+    out->print(" (" UINTX_FORMAT " shared)", classes_shared);
+  }
+}
+
+// Given a net allocation word size, return the raw word size we actually allocate.
+// Note: externally visible for gtests.
+//static
+size_t get_raw_word_size_for_requested_word_size(size_t word_size) {
+
+  size_t byte_size = word_size * BytesPerWord;
+
+  // Deallocated metablocks are kept in a binlist which limits their minimal
+  //  size to at least the size of a binlist item (2 words).
+  byte_size = MAX2(byte_size, FreeBlocks::MinWordSize * BytesPerWord);
+
+  // Metaspace allocations are aligned to word size.
+  byte_size = align_up(byte_size, AllocationAlignmentByteSize);
+
+  // If we guard allocations, we need additional space for a prefix.
+#ifdef ASSERT
+  if (Settings::use_allocation_guard()) {
+    byte_size += align_up(prefix_size(), AllocationAlignmentByteSize);
+  }
+#endif
+
+  size_t raw_word_size = byte_size / BytesPerWord;
+
+  assert(raw_word_size * BytesPerWord == byte_size, "Sanity");
+
+  return raw_word_size;
+
+}
+
+} // namespace metaspace
+