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Commit 72b16f0a authored by Roland Levillain's avatar Roland Levillain
Browse files

Replace generic GC type flag with a specific Generational CC flag. 

The "gctype" device configuration flag (from the "runtime_native_boot"
namespace) was a string passed verbatim as an argument to the runtime
option "-Xgc". It was too generic, conveyed no typing information, and
was error-prone (there was no control over what was passed from the
server to the zygote, and then to the runtime).

This change replaces "gctype" with a specific, Boolean
"enable_generational_cc" flag. This new flag better reflects the
nature of the experiment to be conducted (either enable or disable
generational garbage collection in ART's concurrent copying
collector).

Test: core/jni/runtime_native_boot-flags-test.sh
Bug: 72446017
Bug: 120794191
Bug: 123754583
Change-Id: I30a73171c0dc3c7bc891c4f164eed0ba42b0f420
parent a331a7bd

core/jni/AndroidRuntime.cpp

+24 −13
Original line number Diff line number Diff line
@@ -232,8 +232,15 @@ extern int register_com_android_internal_util_VirtualRefBasePtr(JNIEnv *env); 


// Namespace for Android Runtime flags applied during boot time.

static const char* RUNTIME_NATIVE_BOOT_NAMESPACE = "runtime_native_boot";

// Feature flag name for Garbage Collector type.

static const char* GCTYPE = "gctype";

// Feature flag name to enable/disable generational garbage collection in ART's

// Concurrent Copying (CC) garbage collector.

static const char* ENABLE_GENERATIONAL_CC = "enable_generational_cc";

// Runtime option enabling generational garbage collection in ART's Concurrent

// Copying (CC) garbage collector.

static const char* kGenerationalCCRuntimeOption = "-Xgc:generational_cc";

// Runtime option disabling generational garbage collection in ART's Concurrent

// Copying (CC) garbage collector.

static const char* kNoGenerationalCCRuntimeOption = "-Xgc:nogenerational_cc";



static AndroidRuntime* gCurRuntime = NULL;
@@ -785,17 +792,21 @@ int AndroidRuntime::startVm(JavaVM** pJavaVM, JNIEnv** pEnv, bool zygote) 
      addOption("-XX:LowMemoryMode");

    }



    std::string gc_type_override =

    /*

     * Garbage-collection related options.

     */

    parseRuntimeOption("dalvik.vm.gctype", gctypeOptsBuf, "-Xgc:");



    // If it set, honor the "enable_generational_cc" device configuration;

    // otherwise, let the runtime use its default behavior.

    std::string enable_generational_cc =

        server_configurable_flags::GetServerConfigurableFlag(RUNTIME_NATIVE_BOOT_NAMESPACE,

                                                                 GCTYPE,

                                                             ENABLE_GENERATIONAL_CC,

                                                             /*default_value=*/ "");

    std::string gc_type_override_temp;

    if (gc_type_override.empty()) {

        parseRuntimeOption("dalvik.vm.gctype", gctypeOptsBuf, "-Xgc:");

    } else {

        // Copy the string so it doesn't go out of scope since addOption does not make a copy.

        gc_type_override_temp = "-Xgc:" + gc_type_override;

        addOption(gc_type_override_temp.c_str());

    if (enable_generational_cc == "true") {

        addOption(kGenerationalCCRuntimeOption);

    } else if (enable_generational_cc == "false") {

        addOption(kNoGenerationalCCRuntimeOption);

    }



    parseRuntimeOption("dalvik.vm.backgroundgctype", backgroundgcOptsBuf, "-XX:BackgroundGC=");

core/jni/runtime_native_boot-flags-test.sh

+12 −10
Original line number Diff line number Diff line
@@ -172,12 +172,14 @@ function check_no_zygote_gc_runtime_option { 
  done

}



# test_android_runtime_flag FLAG VALUE

# ------------------------------------

# Test device configuration FLAG with VALUE.

# test_android_runtime_flag FLAG VALUE GC_RUNTIME_OPTION

# ------------------------------------------------------

# Test device configuration FLAG with VALUE. Check that GC_RUNTIME_OPTION is

# passed as GC Runtime option by the zygote.

function test_android_runtime_flag {

  local flag=$1

  local value=$2

  local gc_runtime_option=$3



  # Persistent system property (set after a reboot) associated with the device

  # configuration flag.
@@ -196,21 +198,21 @@ function test_android_runtime_flag { 
  local context="Flag set, before reboot"

  check_device_config_flag "$context" "$flag" "$value"

  check_system_property "$context" "$prop" "$value"

  check_no_zygote_gc_runtime_option "$context" "$value"

  check_no_zygote_gc_runtime_option "$context" "$gc_runtime_option"



  # Reboot device for the flag value to take effect.

  reboot_and_wait_for_device

  context="Flag set, after 1st reboot"

  check_device_config_flag "$context" "$flag" "$value"

  check_system_property "$context" "$prop" "$value"

  check_zygote_gc_runtime_option "$context" "$value"

  check_zygote_gc_runtime_option "$context" "$gc_runtime_option"



  # Reboot device a second time and check that the state has persisted.

  reboot_and_wait_for_device

  context="Flag set, after 2nd reboot"

  check_device_config_flag "$context" "$flag" "$value"

  check_system_property "$context" "$prop" "$value"

  check_zygote_gc_runtime_option "$context" "$value"

  check_zygote_gc_runtime_option "$context" "$gc_runtime_option"



  say "Unsetting device configuration flag..."

  adb shell device_config delete "$namespace" "$flag" >/dev/null
@@ -222,7 +224,7 @@ function test_android_runtime_flag { 
  context="Flag unset, after 3rd reboot"

  check_no_device_config_flag "$context" "$flag"

  check_no_system_property "$context" "$prop"

  check_no_zygote_gc_runtime_option "$context" "$value"

  check_no_zygote_gc_runtime_option "$context" "$gc_runtime_option"

}



# Enumerate Zygote processes.
@@ -232,9 +234,9 @@ case $(adb shell getprop ro.zygote) in 
  (zygote32_64|zygote64_32) zygotes="zygote zygote64";;

esac



# Test "gctype" flag values.

test_android_runtime_flag gctype nogenerational_cc

test_android_runtime_flag gctype generational_cc

# Test "enable_generational_cc" flag values.

test_android_runtime_flag enable_generational_cc false nogenerational_cc

test_android_runtime_flag enable_generational_cc true generational_cc



if [[ "$exit_status" -eq 0 ]]; then

  banner "All tests passed."