Memory Calculation Headroom

This change adds a configuration option that allocates empty overhead in the memory calculation. This configuration defaults to zero, but would be used in cases where the memory calculator cannot accurately allocate memory regions (e.g. 10G heap sizes). [resolves cloudfoundry#583]
mateuszrzeszutek · May 3, 2018 · 1977b77 · 1977b77
1 parent 33b33f6
commit 1977b77
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Showing 11 changed files with 91 additions and 44 deletions.
diff --git a/config/open_jdk_jre.yml b/config/open_jdk_jre.yml
@@ -26,4 +26,5 @@ memory_calculator:
   version: 3.+
   repository_root: "{default.repository.root}/memory-calculator/{platform}/{architecture}"
   class_count: 
+  headroom: 
   stack_threads: 250
diff --git a/config/oracle_jre.yml b/config/oracle_jre.yml
@@ -29,4 +29,5 @@ memory_calculator:
   version: 3.+
   repository_root: "{default.repository.root}/memory-calculator/{platform}/{architecture}"
   class_count: 
+  headroom: 
   stack_threads: 250
diff --git a/config/sap_machine_jre.yml b/config/sap_machine_jre.yml
@@ -25,5 +25,6 @@ jvmkill_agent:
 memory_calculator:
   version: 3.+
   repository_root: "{default.repository.root}/memory-calculator/{platform}/{architecture}"
-  class_count:
+  class_count: 
+  headroom: 
   stack_threads: 250
diff --git a/config/zulu_jre.yml b/config/zulu_jre.yml
@@ -29,4 +29,5 @@ memory_calculator:
   version: 3.+
   repository_root: "{default.repository.root}/memory-calculator/{platform}/{architecture}"
   class_count: 
+  headroom: 
   stack_threads: 250
diff --git a/docs/jre-open_jdk_jre.md b/docs/jre-open_jdk_jre.md
@@ -91,6 +91,19 @@ The user can change the container's total memory available to influence the JRE
 Unless the user specifies the heap size Java option (`-Xmx`), increasing or decreasing the total memory
 available results in the heap size setting increasing or decreasing by a corresponding amount.
 
+#### Loaded Classes
+
+The amount of memory that is allocated to metaspace and compressed class space (or, on Java 7, the permanent generation) is calculated from an estimate of the number of classes that will be loaded. The default behaviour is to estimate the number of loaded classes as a fraction of the number of class files in the application.
+If a specific number of loaded classes should be used for calculations, then it should be specified as in the following example:
+
+```yaml
+class_count: 500
+```
+
+#### Headroom
+
+A percentage of the total memory allocated to the container to be left as headroom and excluded from the memory calculation.
+
 #### Stack Threads
 
 The amount of memory that should be allocated to stacks is given as an amount of memory per
@@ -102,15 +115,6 @@ the following example:
 stack_threads: 500
 ```
 
-#### Loaded Classes
-
-The amount of memory that is allocated to metaspace and compressed class space (or, on Java 7, the permanent generation) is calculated from an estimate of the number of classes that will be loaded. The default behaviour is to estimate the number of loaded classes as a fraction of the number of class files in the application.
-If a specific number of loaded classes should be used for calculations, then it should be specified as in the following example:
-
-```yaml
-class_count: 500
-```
-
 #### Java Options
 
 If the JRE memory settings need to be fine-tuned, the user can set one or more Java memory options to

diff --git a/docs/jre-oracle_jre.md b/docs/jre-oracle_jre.md
@@ -107,6 +107,19 @@ The user can change the container's total memory available to influence the JRE
 Unless the user specifies the heap size Java option (`-Xmx`), increasing or decreasing the total memory
 available results in the heap size setting increasing or decreasing by a corresponding amount.
 
+#### Loaded Classes
+
+The amount of memory that is allocated to metaspace and compressed class space (or, on Java 7, the permanent generation) is calculated from an estimate of the number of classes that will be loaded. The default behaviour is to estimate the number of loaded classes as a fraction of the number of class files in the application.
+If a specific number of loaded classes should be used for calculations, then it should be specified as in the following example:
+
+```yaml
+class_count: 500
+```
+
+#### Headroom
+
+A percentage of the total memory allocated to the container to be left as headroom and excluded from the memory calculation.
+
 #### Stack Threads
 
 The amount of memory that should be allocated to stacks is given as an amount of memory per
@@ -118,15 +131,6 @@ the following example:
 stack_threads: 500
 ```
 
-#### Loaded Classes
-
-The amount of memory that is allocated to metaspace and compressed class space (or, on Java 7, the permanent generation) is calculated from an estimate of the number of classes that will be loaded. The default behaviour is to estimate the number of loaded classes as a fraction of the number of class files in the application.
-If a specific number of loaded classes should be used for calculations, then it should be specified as in the following example:
-
-```yaml
-class_count: 500
-```
-
 #### Java Options
 
 If the JRE memory settings need to be fine-tuned, the user can set one or more Java memory options to

diff --git a/docs/jre-sap_machine_jre.md b/docs/jre-sap_machine_jre.md
@@ -94,6 +94,19 @@ The user can change the container's total memory available to influence the JRE
 Unless the user specifies the heap size Java option (`-Xmx`), increasing or decreasing the total memory
 available results in the heap size setting increasing or decreasing by a corresponding amount.
 
+#### Loaded Classes
+
+The amount of memory that is allocated to metaspace and compressed class space (or, on Java 7, the permanent generation) is calculated from an estimate of the number of classes that will be loaded. The default behaviour is to estimate the number of loaded classes as a fraction of the number of class files in the application.
+If a specific number of loaded classes should be used for calculations, then it should be specified as in the following example:
+
+```yaml
+class_count: 500
+```
+
+#### Headroom
+
+A percentage of the total memory allocated to the container to be left as headroom and excluded from the memory calculation.
+
 #### Stack Threads
 
 The amount of memory that should be allocated to stacks is given as an amount of memory per
@@ -105,15 +118,6 @@ the following example:
 stack_threads: 500
 ```
 
-#### Loaded Classes
-
-The amount of memory that is allocated to metaspace and compressed class space (or, on Java 7, the permanent generation) is calculated from an estimate of the number of classes that will be loaded. The default behaviour is to estimate the number of loaded classes as a fraction of the number of class files in the application.
-If a specific number of loaded classes should be used for calculations, then it should be specified as in the following example:
-
-```yaml
-class_count: 500
-```
-
 #### Java Options
 
 If the JRE memory settings need to be fine-tuned, the user can set one or more Java memory options to

diff --git a/docs/jre-zulu_jre.md b/docs/jre-zulu_jre.md
@@ -98,6 +98,19 @@ The user can change the container's total memory available to influence the JRE
 Unless the user specifies the heap size Java option (`-Xmx`), increasing or decreasing the total memory
 available results in the heap size setting increasing or decreasing by a corresponding amount.
 
+#### Loaded Classes
+
+The amount of memory that is allocated to metaspace and compressed class space (or, on Java 7, the permanent generation) is calculated from an estimate of the number of classes that will be loaded. The default behaviour is to estimate the number of loaded classes as a fraction of the number of class files in the application.
+If a specific number of loaded classes should be used for calculations, then it should be specified as in the following example:
+
+```yaml
+class_count: 500
+```
+
+#### Headroom
+
+A percentage of the total memory allocated to the container to be left as headroom and excluded from the memory calculation.
+
 #### Stack Threads
 
 The amount of memory that should be allocated to stacks is given as an amount of memory per
@@ -109,15 +122,6 @@ the following example:
 stack_threads: 500
 ```
 
-#### Loaded Classes
-
-The amount of memory that is allocated to metaspace and compressed class space (or, on Java 7, the permanent generation) is calculated from an estimate of the number of classes that will be loaded. The default behaviour is to estimate the number of loaded classes as a fraction of the number of class files in the application.
-If a specific number of loaded classes should be used for calculations, then it should be specified as in the following example:
-
-```yaml
-class_count: 500
-```
-
 #### Java Options
 
 If the JRE memory settings need to be fine-tuned, the user can set one or more Java memory options to

diff --git a/lib/java_buildpack/jre/open_jdk_like_memory_calculator.rb b/lib/java_buildpack/jre/open_jdk_like_memory_calculator.rb
@@ -89,6 +89,10 @@ def class_count(configuration)
         configuration['class_count'] || (0.35 * actual_class_count(root)).ceil
       end
 
+      def headroom(configuration)
+        configuration['headroom']
+      end
+
       def memory_calculator
         @droplet.sandbox + "bin/java-buildpack-memory-calculator-#{@version}"
       end
@@ -101,9 +105,13 @@ def memory_calculator_tar
       def memory_calculation_string(relative_path)
         memory_calculation_string = [qualify_path(memory_calculator, relative_path)]
         memory_calculation_string << '-totMemory=$MEMORY_LIMIT'
-        memory_calculation_string << "-stackThreads=#{stack_threads @configuration}"
+
+        headroom = headroom(@configuration)
+        memory_calculation_string << "-headRoom=#{headroom}" if headroom
+
         memory_calculation_string << "-loadedClasses=#{class_count @configuration}"
         memory_calculation_string << "-poolType=#{pool_type}"
+        memory_calculation_string << "-stackThreads=#{stack_threads @configuration}"
         memory_calculation_string << '-vmOptions="$JAVA_OPTS"'
 
         memory_calculation_string.join(' ')

diff --git a/spec/java_buildpack/jre/open_jdk_like_memory_calculator_spec.rb b/spec/java_buildpack/jre/open_jdk_like_memory_calculator_spec.rb
@@ -91,8 +91,8 @@
     command = component.memory_calculation_command
 
     expect(command).to eq('CALCULATED_MEMORY=$($PWD/.java-buildpack/open_jdk_like_memory_calculator/bin/' \
-                            'java-buildpack-memory-calculator-0.0.0 -totMemory=$MEMORY_LIMIT -stackThreads=200 ' \
-                            '-loadedClasses=2 -poolType=metaspace -vmOptions="$JAVA_OPTS") && echo JVM Memory ' \
+                            'java-buildpack-memory-calculator-0.0.0 -totMemory=$MEMORY_LIMIT -loadedClasses=2 ' \
+                            '-poolType=metaspace -stackThreads=200 -vmOptions="$JAVA_OPTS") && echo JVM Memory ' \
                             'Configuration: $CALCULATED_MEMORY && JAVA_OPTS="$JAVA_OPTS $CALCULATED_MEMORY"')
   end
 
@@ -111,6 +111,25 @@
     expect(environment_variables).to include('MALLOC_ARENA_MAX=2')
   end
 
+  context 'with headroom' do
+
+    let(:configuration) { { 'headroom' => '11', 'stack_threads' => '200' } }
+
+    it 'creates memory calculation command with headroom',
+       app_fixture: 'jre_memory_calculator_application' do
+
+      java_home.version = version_8
+
+      command = component.memory_calculation_command
+
+      expect(command).to eq('CALCULATED_MEMORY=$($PWD/.java-buildpack/open_jdk_like_memory_calculator/bin/' \
+                            'java-buildpack-memory-calculator-0.0.0 -totMemory=$MEMORY_LIMIT -headRoom=11 ' \
+                            '-loadedClasses=2 -poolType=metaspace -stackThreads=200 -vmOptions="$JAVA_OPTS") && echo ' \
+                            'JVM Memory Configuration: $CALCULATED_MEMORY && JAVA_OPTS="$JAVA_OPTS $CALCULATED_MEMORY"')
+    end
+
+  end
+
   context 'when java 9' do
 
     it 'creates memory calculation command',
@@ -121,8 +140,8 @@
       command = component.memory_calculation_command
 
       expect(command).to eq('CALCULATED_MEMORY=$($PWD/.java-buildpack/open_jdk_like_memory_calculator/bin/' \
-                            'java-buildpack-memory-calculator-0.0.0 -totMemory=$MEMORY_LIMIT -stackThreads=200 ' \
-                            '-loadedClasses=14777 -poolType=metaspace -vmOptions="$JAVA_OPTS") && echo JVM Memory ' \
+                            'java-buildpack-memory-calculator-0.0.0 -totMemory=$MEMORY_LIMIT -loadedClasses=14777 ' \
+                            '-poolType=metaspace -stackThreads=200 -vmOptions="$JAVA_OPTS") && echo JVM Memory ' \
                             'Configuration: $CALCULATED_MEMORY && JAVA_OPTS="$JAVA_OPTS $CALCULATED_MEMORY"')
     end
 

diff --git a/spec/java_buildpack/jre/open_jdk_like_spec.rb b/spec/java_buildpack/jre/open_jdk_like_spec.rb
@@ -70,7 +70,7 @@
     java_home.version = version_7
     expect(component.command).to eq('CALCULATED_MEMORY=$($PWD/.java-buildpack/open_jdk_like/bin/' \
                                     'java-buildpack-memory-calculator-0.0.0 -totMemory=$MEMORY_LIMIT' \
-                                    ' -stackThreads=200 -loadedClasses=0 -poolType=permgen -vmOptions="$JAVA_OPTS")' \
+                                    ' -loadedClasses=0 -poolType=permgen -stackThreads=200 -vmOptions="$JAVA_OPTS")' \
                                     ' && echo JVM Memory Configuration: $CALCULATED_MEMORY && ' \
                                     'JAVA_OPTS="$JAVA_OPTS $CALCULATED_MEMORY"')
 
@@ -80,7 +80,7 @@
     java_home.version = version_8
     expect(component.command).to eq('CALCULATED_MEMORY=$($PWD/.java-buildpack/open_jdk_like/bin/' \
                                     'java-buildpack-memory-calculator-0.0.0 -totMemory=$MEMORY_LIMIT' \
-                                    ' -stackThreads=200 -loadedClasses=0 -poolType=metaspace -vmOptions="$JAVA_OPTS")' \
+                                    ' -loadedClasses=0 -poolType=metaspace -stackThreads=200 -vmOptions="$JAVA_OPTS")' \
                                     ' && echo JVM Memory Configuration: $CALCULATED_MEMORY && ' \
                                     'JAVA_OPTS="$JAVA_OPTS $CALCULATED_MEMORY"')