Changes of root storage space unmounting time on Zygote Process
Zygote process forks every child process for launch the SystemServer and other
applications. When child process is forked, unmount storage inherited
from Zygote process is executed before it gains its own root storage
space.
If Zygote have no storage spaces, unmount operations not needed to
get relevant permission storage space.
Thus unmount is executed only once shortly before the SystemServer is forked.
And the child processes do not unmount its inherited root storage space.
Change-Id: I311ca7ea2c93085f42579f8cf8bdc7ef1d570a04
diff --git a/core/java/com/android/internal/os/Zygote.java b/core/java/com/android/internal/os/Zygote.java
index d23f26d..4b52d90 100644
--- a/core/java/com/android/internal/os/Zygote.java
+++ b/core/java/com/android/internal/os/Zygote.java
@@ -145,6 +145,12 @@
native private static int nativeForkSystemServer(int uid, int gid, int[] gids, int debugFlags,
int[][] rlimits, long permittedCapabilities, long effectiveCapabilities);
+ /**
+ * Zygote unmount storage space on initializing.
+ * This method is called once.
+ */
+ native protected static void nativeUnmountStorageOnInit();
+
private static void callPostForkChildHooks(int debugFlags, boolean isSystemServer,
String instructionSet) {
VM_HOOKS.postForkChild(debugFlags, isSystemServer, instructionSet);
diff --git a/core/java/com/android/internal/os/ZygoteInit.java b/core/java/com/android/internal/os/ZygoteInit.java
index 67ed85a..172fdf6 100644
--- a/core/java/com/android/internal/os/ZygoteInit.java
+++ b/core/java/com/android/internal/os/ZygoteInit.java
@@ -621,6 +621,9 @@
// Zygote.
Trace.setTracingEnabled(false);
+ // Zygote process unmounts root storage spaces.
+ Zygote.nativeUnmountStorageOnInit();
+
if (startSystemServer) {
startSystemServer(abiList, socketName);
}
diff --git a/core/jni/com_android_internal_os_Zygote.cpp b/core/jni/com_android_internal_os_Zygote.cpp
index 4194aa4..ce56853 100644
--- a/core/jni/com_android_internal_os_Zygote.cpp
+++ b/core/jni/com_android_internal_os_Zygote.cpp
@@ -302,9 +302,6 @@
return false;
}
- // Unmount storage provided by root namespace and mount requested view
- UnmountTree("/storage");
-
String8 storageSource;
if (mount_mode == MOUNT_EXTERNAL_DEFAULT) {
storageSource = "/mnt/runtime/default";
@@ -663,12 +660,24 @@
return pid;
}
+static void com_android_internal_os_Zygote_nativeUnmountStorageOnInit(JNIEnv* env, jclass) {
+ // Zygote process unmount root storage space initially before every child processes are forked.
+ // Every forked child processes (include SystemServer) only mount their own root storage space
+ // And no need unmount storage operation in MountEmulatedStorage method.
+ // Zygote process does not utilize root storage spaces and unshared its mount namespace from the ART.
+
+ UnmountTree("/storage");
+ return;
+}
+
static const JNINativeMethod gMethods[] = {
{ "nativeForkAndSpecialize",
"(II[II[[IILjava/lang/String;Ljava/lang/String;[ILjava/lang/String;Ljava/lang/String;)I",
(void *) com_android_internal_os_Zygote_nativeForkAndSpecialize },
{ "nativeForkSystemServer", "(II[II[[IJJ)I",
- (void *) com_android_internal_os_Zygote_nativeForkSystemServer }
+ (void *) com_android_internal_os_Zygote_nativeForkSystemServer },
+ { "nativeUnmountStorageOnInit", "()V",
+ (void *) com_android_internal_os_Zygote_nativeUnmountStorageOnInit }
};
int register_com_android_internal_os_Zygote(JNIEnv* env) {
