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
diff --git a/core/jni/AndroidRuntime.cpp b/core/jni/AndroidRuntime.cpp
index c45900c..ce2e353 100644
--- a/core/jni/AndroidRuntime.cpp
+++ b/core/jni/AndroidRuntime.cpp
@@ -232,8 +232,15 @@
// 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 @@
addOption("-XX:LowMemoryMode");
}
- std::string gc_type_override =
- server_configurable_flags::GetServerConfigurableFlag(RUNTIME_NATIVE_BOOT_NAMESPACE,
- GCTYPE,
- /*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());
+ /*
+ * 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,
+ ENABLE_GENERATIONAL_CC,
+ /*default_value=*/ "");
+ if (enable_generational_cc == "true") {
+ addOption(kGenerationalCCRuntimeOption);
+ } else if (enable_generational_cc == "false") {
+ addOption(kNoGenerationalCCRuntimeOption);
}
parseRuntimeOption("dalvik.vm.backgroundgctype", backgroundgcOptsBuf, "-XX:BackgroundGC=");
diff --git a/core/jni/runtime_native_boot-flags-test.sh b/core/jni/runtime_native_boot-flags-test.sh
index 66e18bb..01f37f0 100755
--- a/core/jni/runtime_native_boot-flags-test.sh
+++ b/core/jni/runtime_native_boot-flags-test.sh
@@ -172,12 +172,14 @@
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=$3
# Persistent system property (set after a reboot) associated with the device
# configuration flag.
@@ -196,21 +198,21 @@
local context="Flag set, before reboot"
check_device_config_flag "$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" "$flag" >/dev/null
@@ -222,7 +224,7 @@
context="Flag unset, after 3rd reboot"
check_no_device_config_flag "$context" "$flag"
check_no_system_property "$context" "$prop"
- check_no_zygote_gc_runtime_option "$context" "$value"
+ check_no_zygote_gc_runtime_option "$context" "$gc_runtime_option"
}
# Enumerate Zygote processes.
@@ -232,9 +234,9 @@
(zygote32_64|zygote64_32) zygotes="zygote zygote64";;
esac
-# Test "gctype" flag values.
-test_android_runtime_flag gctype nogenerational_cc
-test_android_runtime_flag gctype generational_cc
+# Test "enable_generational_cc" flag values.
+test_android_runtime_flag enable_generational_cc false nogenerational_cc
+test_android_runtime_flag enable_generational_cc true generational_cc
if [[ "$exit_status" -eq 0 ]]; then
banner "All tests passed."