--- a/src/hotspot/share/gc/g1/g1ConcurrentMark.cpp	Mon Oct 23 11:46:12 2017 +0200
+++ b/src/hotspot/share/gc/g1/g1ConcurrentMark.cpp	Mon Oct 23 11:46:25 2017 +0200
@@ -2996,11 +2996,11 @@
                          G1PPRL_SUM_MB_FORMAT("code-roots"),
                          bytes_to_mb(_total_capacity_bytes),
                          bytes_to_mb(_total_used_bytes),
-                         perc(_total_used_bytes, _total_capacity_bytes),
+                         percent_of(_total_used_bytes, _total_capacity_bytes),
                          bytes_to_mb(_total_prev_live_bytes),
-                         perc(_total_prev_live_bytes, _total_capacity_bytes),
+                         percent_of(_total_prev_live_bytes, _total_capacity_bytes),
                          bytes_to_mb(_total_next_live_bytes),
-                         perc(_total_next_live_bytes, _total_capacity_bytes),
+                         percent_of(_total_next_live_bytes, _total_capacity_bytes),
                          bytes_to_mb(_total_remset_bytes),
                          bytes_to_mb(_total_strong_code_roots_bytes));
 }

--- a/src/hotspot/share/gc/g1/g1ConcurrentMark.hpp	Mon Oct 23 11:46:12 2017 +0200
+++ b/src/hotspot/share/gc/g1/g1ConcurrentMark.hpp	Mon Oct 23 11:46:25 2017 +0200
@@ -850,14 +850,6 @@
   // Accumulator for strong code roots memory size
   size_t _total_strong_code_roots_bytes;
 
-  static double perc(size_t val, size_t total) {
-    if (total == 0) {
-      return 0.0;
-    } else {
-      return 100.0 * ((double) val / (double) total);
-    }
-  }
-
   static double bytes_to_mb(size_t val) {
     return (double) val / (double) M;
   }

--- a/src/hotspot/share/gc/g1/g1DefaultPolicy.cpp	Mon Oct 23 11:46:12 2017 +0200
+++ b/src/hotspot/share/gc/g1/g1DefaultPolicy.cpp	Mon Oct 23 11:46:25 2017 +0200
@@ -1005,11 +1005,7 @@
 }
 
 double G1DefaultPolicy::reclaimable_bytes_perc(size_t reclaimable_bytes) const {
-  // Returns the given amount of reclaimable bytes (that represents
-  // the amount of reclaimable space still to be collected) as a
-  // percentage of the current heap capacity.
-  size_t capacity_bytes = _g1->capacity();
-  return (double) reclaimable_bytes * 100.0 / (double) capacity_bytes;
+  return percent_of(reclaimable_bytes, _g1->capacity());
 }
 
 void G1DefaultPolicy::maybe_start_marking() {

--- a/src/hotspot/share/gc/g1/g1DefaultPolicy.hpp	Mon Oct 23 11:46:12 2017 +0200
+++ b/src/hotspot/share/gc/g1/g1DefaultPolicy.hpp	Mon Oct 23 11:46:25 2017 +0200
@@ -238,6 +238,9 @@
   uint calc_min_old_cset_length() const;
   uint calc_max_old_cset_length() const;
 
+  // Returns the given amount of reclaimable bytes (that represents
+  // the amount of reclaimable space still to be collected) as a
+  // percentage of the current heap capacity.
   double reclaimable_bytes_perc(size_t reclaimable_bytes) const;
 
   jlong collection_pause_end_millis() { return _collection_pause_end_millis; }

--- a/src/hotspot/share/gc/g1/g1IHOPControl.cpp	Mon Oct 23 11:46:12 2017 +0200
+++ b/src/hotspot/share/gc/g1/g1IHOPControl.cpp	Mon Oct 23 11:46:25 2017 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2017, 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
@@ -57,7 +57,7 @@
   log_debug(gc, ihop)("Basic information (value update), threshold: " SIZE_FORMAT "B (%1.2f), target occupancy: " SIZE_FORMAT "B, current occupancy: " SIZE_FORMAT "B, "
                       "recent allocation size: " SIZE_FORMAT "B, recent allocation duration: %1.2fms, recent old gen allocation rate: %1.2fB/s, recent marking phase length: %1.2fms",
                       cur_conc_mark_start_threshold,
-                      cur_conc_mark_start_threshold * 100.0 / _target_occupancy,
+                      percent_of(cur_conc_mark_start_threshold, _target_occupancy),
                       _target_occupancy,
                       G1CollectedHeap::heap()->used(),
                       _last_allocated_bytes,

--- a/src/hotspot/share/gc/g1/g1StringDedupStat.cpp	Mon Oct 23 11:46:12 2017 +0200
+++ b/src/hotspot/share/gc/g1/g1StringDedupStat.cpp	Mon Oct 23 11:46:25 2017 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2017, 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
@@ -82,7 +82,7 @@
 
   if (total_stat._new_bytes > 0) {
     // Avoid division by zero
-    total_deduped_bytes_percent = (double)total_stat._deduped_bytes / (double)total_stat._new_bytes * 100.0;
+    total_deduped_bytes_percent = percent_of(total_stat._deduped_bytes, total_stat._new_bytes);
   }
 
   log_info(gc, stringdedup)(
@@ -100,48 +100,16 @@
 }
 
 void G1StringDedupStat::print_statistics(const G1StringDedupStat& stat, bool total) {
-  double young_percent               = 0.0;
-  double old_percent                 = 0.0;
-  double skipped_percent             = 0.0;
-  double hashed_percent              = 0.0;
-  double known_percent               = 0.0;
-  double new_percent                 = 0.0;
-  double deduped_percent             = 0.0;
-  double deduped_bytes_percent       = 0.0;
-  double deduped_young_percent       = 0.0;
-  double deduped_young_bytes_percent = 0.0;
-  double deduped_old_percent         = 0.0;
-  double deduped_old_bytes_percent   = 0.0;
-
-  if (stat._inspected > 0) {
-    // Avoid division by zero
-    skipped_percent = (double)stat._skipped / (double)stat._inspected * 100.0;
-    hashed_percent  = (double)stat._hashed / (double)stat._inspected * 100.0;
-    known_percent   = (double)stat._known / (double)stat._inspected * 100.0;
-    new_percent     = (double)stat._new / (double)stat._inspected * 100.0;
-  }
-
-  if (stat._new > 0) {
-    // Avoid division by zero
-    deduped_percent = (double)stat._deduped / (double)stat._new * 100.0;
-  }
-
-  if (stat._deduped > 0) {
-    // Avoid division by zero
-    deduped_young_percent = (double)stat._deduped_young / (double)stat._deduped * 100.0;
-    deduped_old_percent   = (double)stat._deduped_old / (double)stat._deduped * 100.0;
-  }
-
-  if (stat._new_bytes > 0) {
-    // Avoid division by zero
-    deduped_bytes_percent = (double)stat._deduped_bytes / (double)stat._new_bytes * 100.0;
-  }
-
-  if (stat._deduped_bytes > 0) {
-    // Avoid division by zero
-    deduped_young_bytes_percent = (double)stat._deduped_young_bytes / (double)stat._deduped_bytes * 100.0;
-    deduped_old_bytes_percent   = (double)stat._deduped_old_bytes / (double)stat._deduped_bytes * 100.0;
-  }
+  double skipped_percent             = percent_of(stat._skipped, stat._inspected);
+  double hashed_percent              = percent_of(stat._hashed, stat._inspected);
+  double known_percent               = percent_of(stat._known, stat._inspected);
+  double new_percent                 = percent_of(stat._new, stat._inspected);
+  double deduped_percent             = percent_of(stat._deduped, stat._new);
+  double deduped_bytes_percent       = percent_of(stat._deduped_bytes, stat._new_bytes);
+  double deduped_young_percent       = percent_of(stat._deduped_young, stat._deduped);
+  double deduped_young_bytes_percent = percent_of(stat._deduped_young_bytes, stat._deduped_bytes);
+  double deduped_old_percent         = percent_of(stat._deduped_old, stat._deduped);
+  double deduped_old_bytes_percent   = percent_of(stat._deduped_old_bytes, stat._deduped_bytes);
 
   if (total) {
     log_debug(gc, stringdedup)(

--- a/src/hotspot/share/gc/g1/g1StringDedupTable.cpp	Mon Oct 23 11:46:12 2017 +0200
+++ b/src/hotspot/share/gc/g1/g1StringDedupTable.cpp	Mon Oct 23 11:46:25 2017 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2017, 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
@@ -616,7 +616,7 @@
             G1_STRDEDUP_BYTES_PARAM(_table->_size * sizeof(G1StringDedupEntry*) + (_table->_entries + _entry_cache->size()) * sizeof(G1StringDedupEntry)));
   log.debug("    Size: " SIZE_FORMAT ", Min: " SIZE_FORMAT ", Max: " SIZE_FORMAT, _table->_size, _min_size, _max_size);
   log.debug("    Entries: " UINTX_FORMAT ", Load: " G1_STRDEDUP_PERCENT_FORMAT_NS ", Cached: " UINTX_FORMAT ", Added: " UINTX_FORMAT ", Removed: " UINTX_FORMAT,
-            _table->_entries, (double)_table->_entries / (double)_table->_size * 100.0, _entry_cache->size(), _entries_added, _entries_removed);
+            _table->_entries, percent_of(_table->_entries, _table->_size), _entry_cache->size(), _entries_added, _entries_removed);
   log.debug("    Resize Count: " UINTX_FORMAT ", Shrink Threshold: " UINTX_FORMAT "(" G1_STRDEDUP_PERCENT_FORMAT_NS "), Grow Threshold: " UINTX_FORMAT "(" G1_STRDEDUP_PERCENT_FORMAT_NS ")",
             _resize_count, _table->_shrink_threshold, _shrink_load_factor * 100.0, _table->_grow_threshold, _grow_load_factor * 100.0);
   log.debug("    Rehash Count: " UINTX_FORMAT ", Rehash Threshold: " UINTX_FORMAT ", Hash Seed: 0x%x", _rehash_count, _rehash_threshold, _table->_hash_seed);

--- a/src/hotspot/share/gc/shared/threadLocalAllocBuffer.cpp	Mon Oct 23 11:46:12 2017 +0200
+++ b/src/hotspot/share/gc/shared/threadLocalAllocBuffer.cpp	Mon Oct 23 11:46:25 2017 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2017, 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
@@ -275,8 +275,7 @@
   Thread* thrd = myThread();
   size_t waste = _gc_waste + _slow_refill_waste + _fast_refill_waste;
   size_t alloc = _number_of_refills * _desired_size;
-  double waste_percent = alloc == 0 ? 0.0 :
-                      100.0 * waste / alloc;
+  double waste_percent = percent_of(waste, alloc);
   size_t tlab_used  = Universe::heap()->tlab_used(thrd);
   log.trace("TLAB: %s thread: " INTPTR_FORMAT " [id: %2d]"
             " desired_size: " SIZE_FORMAT "KB"
@@ -416,8 +415,7 @@
   }
 
   size_t waste = _total_gc_waste + _total_slow_refill_waste + _total_fast_refill_waste;
-  double waste_percent = _total_allocation == 0 ? 0.0 :
-                         100.0 * waste / _total_allocation;
+  double waste_percent = percent_of(waste, _total_allocation);
   log.debug("TLAB totals: thrds: %d  refills: %d max: %d"
             " slow allocs: %d max %d waste: %4.1f%%"
             " gc: " SIZE_FORMAT "B max: " SIZE_FORMAT "B"

--- a/src/hotspot/share/memory/metaspaceShared.cpp	Mon Oct 23 11:46:12 2017 +0200
+++ b/src/hotspot/share/memory/metaspaceShared.cpp	Mon Oct 23 11:46:25 2017 +0200
@@ -157,16 +157,9 @@
     return !is_packed() && _base != NULL;
   }
 
-  double perc(size_t used, size_t total) const {
-    if (total == 0) {
-      total = 1;
-    }
-    return used / double(total) * 100.0;
-  }
-
   void print(size_t total_bytes) const {
     tty->print_cr("%-3s space: " SIZE_FORMAT_W(9) " [ %4.1f%% of total] out of " SIZE_FORMAT_W(9) " bytes [%5.1f%% used] at " INTPTR_FORMAT,
-                  _name, used(), perc(used(), total_bytes), reserved(), perc(used(), reserved()), p2i(_base));
+                  _name, used(), percent_of(used(), total_bytes), reserved(), percent_of(used(), reserved()), p2i(_base));
   }
   void print_out_of_space_msg(const char* failing_region, size_t needed_bytes) {
     tty->print("[%-8s] " PTR_FORMAT " - " PTR_FORMAT " capacity =%9d, allocated =%9d",
@@ -906,9 +899,9 @@
     int count = ro_count + rw_count;
     int bytes = ro_bytes + rw_bytes;
 
-    double ro_perc = 100.0 * double(ro_bytes) / double(ro_all);
-    double rw_perc = 100.0 * double(rw_bytes) / double(rw_all);
-    double perc    = 100.0 * double(bytes)    / double(ro_all + rw_all);
+    double ro_perc = percent_of(ro_bytes, ro_all);
+    double rw_perc = percent_of(rw_bytes, rw_all);
+    double perc    = percent_of(bytes, ro_all + rw_all);
 
     info_stream.print_cr(fmt_stats, name,
                          ro_count, ro_bytes, ro_perc,
@@ -924,9 +917,9 @@
   int all_count = all_ro_count + all_rw_count;
   int all_bytes = all_ro_bytes + all_rw_bytes;
 
-  double all_ro_perc = 100.0 * double(all_ro_bytes) / double(ro_all);
-  double all_rw_perc = 100.0 * double(all_rw_bytes) / double(rw_all);
-  double all_perc    = 100.0 * double(all_bytes)    / double(ro_all + rw_all);
+  double all_ro_perc = percent_of(all_ro_bytes, ro_all);
+  double all_rw_perc = percent_of(all_rw_bytes, rw_all);
+  double all_perc    = percent_of(all_bytes, ro_all + rw_all);
 
   info_stream.print_cr("%s", sep);
   info_stream.print_cr(fmt_stats, "Total",
@@ -1427,7 +1420,7 @@
                              _od_region.used()  +
                              _total_string_region_size +
                              _total_open_archive_region_size;
-  const double total_u_perc = total_bytes / double(total_reserved) * 100.0;
+  const double total_u_perc = percent_of(total_bytes, total_reserved);
 
   _mc_region.print(total_reserved);
   _rw_region.print(total_reserved);