8186248: Allow more flexibility in selecting Heap % of available RAM

Reviewed-by: dholmes, drwhite

hotspot/src/share/vm/runtime/arguments.cpp

@@ -379,6 +379,9 @@ static SpecialFlag const special_jvm_flags[] = {
   { "MaxGCMinorPauseMillis",        JDK_Version::jdk(8), JDK_Version::undefined(), JDK_Version::undefined() },
   { "UseConcMarkSweepGC",           JDK_Version::jdk(9), JDK_Version::undefined(), JDK_Version::undefined() },
   { "MonitorInUseLists",            JDK_Version::jdk(10),JDK_Version::undefined(), JDK_Version::undefined() },
+  { "MaxRAMFraction",               JDK_Version::jdk(10),  JDK_Version::undefined(), JDK_Version::undefined() },
+  { "MinRAMFraction",               JDK_Version::jdk(10),  JDK_Version::undefined(), JDK_Version::undefined() },
+  { "InitialRAMFraction",           JDK_Version::jdk(10),  JDK_Version::undefined(), JDK_Version::undefined() },
 
   // --- Deprecated alias flags (see also aliased_jvm_flags) - sorted by obsolete_in then expired_in:
   { "DefaultMaxRAMFraction",        JDK_Version::jdk(8),  JDK_Version::undefined(), JDK_Version::undefined() },
@@ -2069,20 +2072,33 @@ void Arguments::set_heap_size() {
     }
   }
 
+  // Convert deprecated flags
+  if (FLAG_IS_DEFAULT(MaxRAMPercentage) &&
+      !FLAG_IS_DEFAULT(MaxRAMFraction))
+    MaxRAMPercentage = 100.0 / MaxRAMFraction;
+
+  if (FLAG_IS_DEFAULT(MinRAMPercentage) &&
+      !FLAG_IS_DEFAULT(MinRAMFraction))
+    MinRAMPercentage = 100.0 / MinRAMFraction;
+
+  if (FLAG_IS_DEFAULT(InitialRAMPercentage) &&
+      !FLAG_IS_DEFAULT(InitialRAMFraction))
+    InitialRAMPercentage = 100.0 / InitialRAMFraction;
+
   // If the maximum heap size has not been set with -Xmx,
   // then set it as fraction of the size of physical memory,
   // respecting the maximum and minimum sizes of the heap.
   if (FLAG_IS_DEFAULT(MaxHeapSize)) {
-    julong reasonable_max = phys_mem / MaxRAMFraction;
+    julong reasonable_max = (julong)((phys_mem * MaxRAMPercentage) / 100);
-
+    if (phys_mem <= (julong)((MaxHeapSize * MinRAMPercentage) / 100)) {
-    if (phys_mem <= MaxHeapSize * MinRAMFraction) {
       // Small physical memory, so use a minimum fraction of it for the heap
-      reasonable_max = phys_mem / MinRAMFraction;
+      reasonable_max = (julong)((phys_mem * MinRAMPercentage) / 100);
     } else {
       // Not-small physical memory, so require a heap at least
       // as large as MaxHeapSize
       reasonable_max = MAX2(reasonable_max, (julong)MaxHeapSize);
     }
+
     if (!FLAG_IS_DEFAULT(ErgoHeapSizeLimit) && ErgoHeapSizeLimit != 0) {
       // Limit the heap size to ErgoHeapSizeLimit
       reasonable_max = MIN2(reasonable_max, (julong)ErgoHeapSizeLimit);
@@ -2135,7 +2151,7 @@ void Arguments::set_heap_size() {
     reasonable_minimum = limit_by_allocatable_memory(reasonable_minimum);
 
     if (InitialHeapSize == 0) {
-      julong reasonable_initial = phys_mem / InitialRAMFraction;
+      julong reasonable_initial = (julong)((phys_mem * InitialRAMPercentage) / 100);
 
       reasonable_initial = MAX3(reasonable_initial, reasonable_minimum, (julong)min_heap_size());
       reasonable_initial = MIN2(reasonable_initial, (julong)MaxHeapSize);

hotspot/src/share/vm/runtime/globals.hpp

@@ -2037,7 +2037,7 @@ public:
                                                                             \
   product(size_t, ErgoHeapSizeLimit, 0,                                     \
           "Maximum ergonomically set heap size (in bytes); zero means use " \
-          "MaxRAM / MaxRAMFraction")                                        \
+          "MaxRAM * MaxRAMPercentage / 100")                                \
           range(0, max_uintx)                                               \
                                                                             \
   experimental(bool, UseCGroupMemoryLimitForHeap, false,                    \
@@ -2046,18 +2046,34 @@ public:
                                                                             \
   product(uintx, MaxRAMFraction, 4,                                         \
           "Maximum fraction (1/n) of real memory used for maximum heap "    \
-          "size")                                                           \
+          "size. "                                                          \
+          "Deprecated, use MaxRAMPercentage instead")                       \
           range(1, max_uintx)                                               \
                                                                             \
   product(uintx, MinRAMFraction, 2,                                         \
           "Minimum fraction (1/n) of real memory used for maximum heap "    \
-          "size on systems with small physical memory size")                \
+          "size on systems with small physical memory size. "               \
+          "Deprecated, use MinRAMPercentage instead")                       \
           range(1, max_uintx)                                               \
                                                                             \
   product(uintx, InitialRAMFraction, 64,                                    \
-          "Fraction (1/n) of real memory used for initial heap size")       \
+          "Fraction (1/n) of real memory used for initial heap size. "      \
+          "Deprecated, use InitialRAMPercentage instead")                   \
           range(1, max_uintx)                                               \
                                                                             \
+  product(double, MaxRAMPercentage, 25.0,                                   \
+          "Maximum percentage of real memory used for maximum heap size")   \
+          range(0.0, 100.0)                                                 \
+                                                                            \
+  product(double, MinRAMPercentage, 50.0,                                   \
+          "Minimum percentage of real memory used for maximum heap"         \
+          "size on systems with small physical memory size")                \
+          range(0.0, 100.0)                                                 \
+                                                                            \
+  product(double, InitialRAMPercentage, 1.5625,                             \
+          "Percentage of real memory used for initial heap size")           \
+          range(0.0, 100.0)                                                 \
+                                                                            \
   develop(uintx, MaxVirtMemFraction, 2,                                     \
           "Maximum fraction (1/n) of virtual memory used for ergonomically "\
           "determining maximum heap size")                                  \

hotspot/test/Makefile

@@ -70,8 +70,8 @@ else ifeq ($(shell expr $(CONCURRENCY) \> 12), 1)
   CONCURRENCY := 12
 endif
 
-# Make sure MaxRAMFraction is high enough to not cause OOM or swapping since we may end up with a lot of JVM's
+# Make sure MaxRAMPercentage is high enough to not cause OOM or swapping since we may end up with a lot of JVM's
-JTREG_BASIC_OPTIONS += -vmoption:-XX:MaxRAMFraction=$(shell expr $(CONCURRENCY) \* 4)
+JTREG_BASIC_OPTIONS += -vmoption:-XX:MaxRAMPercentage=$(shell expr 25 / $(CONCURRENCY))
 
 # Include the common base file with most of the logic
 include ../../test/TestCommon.gmk

hotspot/test/runtime/CommandLine/FlagWithInvalidValue.java

@@ -36,10 +36,10 @@ import jdk.test.lib.process.OutputAnalyzer;
 public class FlagWithInvalidValue {
   public static void main(String[] args) throws Exception {
     ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
-        "-XX:MaxRAMFraction=v", "-version");
+        "-XX:MaxRAMPercentage=v", "-version");
 
     OutputAnalyzer output = new OutputAnalyzer(pb.start());
-    output.shouldContain("Improperly specified VM option 'MaxRAMFraction=v'");
+    output.shouldContain("Improperly specified VM option 'MaxRAMPercentage=v'");
     output.shouldHaveExitValue(1);
   }
 }

hotspot/test/runtime/CommandLine/NonBooleanFlagWithInvalidBooleanPrefix.java

@@ -36,17 +36,17 @@ import jdk.test.lib.process.OutputAnalyzer;
 public class NonBooleanFlagWithInvalidBooleanPrefix {
   public static void main(String[] args) throws Exception {
     ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
-        "-XX:-MaxRAMFraction=16", "-version");
+        "-XX:-MaxRAMPercentage=1", "-version");
 
     OutputAnalyzer output = new OutputAnalyzer(pb.start());
-    output.shouldContain("Unexpected +/- setting in VM option 'MaxRAMFraction=16'");
+    output.shouldContain("Unexpected +/- setting in VM option 'MaxRAMPercentage=1'");
     output.shouldHaveExitValue(1);
 
     pb = ProcessTools.createJavaProcessBuilder(
-        "-XX:+MaxRAMFraction=16", "-version");
+        "-XX:+MaxRAMPercentage=1", "-version");
 
     output = new OutputAnalyzer(pb.start());
-    output.shouldContain("Unexpected +/- setting in VM option 'MaxRAMFraction=16'");
+    output.shouldContain("Unexpected +/- setting in VM option 'MaxRAMPercentage=1'");
     output.shouldHaveExitValue(1);
 
   }

hotspot/test/runtime/CommandLine/VMDeprecatedOptions.java

@@ -43,6 +43,9 @@ public class VMDeprecatedOptions {
         {"MaxGCMinorPauseMillis",     "1032"},
         {"MustCallLoadClassInternal", "false"},
         {"UnsyncloadClass",           "false"},
+        {"MaxRAMFraction",            "8"},
+        {"MinRAMFraction",            "2"},
+        {"InitialRAMFraction",        "64"},
 
         // deprecated alias flags (see also aliased_jvm_flags):
         {"DefaultMaxRAMFraction", "4"},