Merge "Start process of next activity with top priority in advance"

15 files changed, 171 insertions, 58 deletions

diff --git a/core/java/android/app/ActivityManagerInternal.java b/core/java/android/app/ActivityManagerInternal.java
index 1725db046a95..9b59ab453acf 100644
--- a/core/java/android/app/ActivityManagerInternal.java
+++ b/core/java/android/app/ActivityManagerInternal.java
@@ -29,7 +29,6 @@ import android.content.pm.UserInfo;
 import android.os.Bundle;
 import android.os.IBinder;
 import android.os.TransactionTooLargeException;
-import android.view.RemoteAnimationAdapter;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -300,7 +299,7 @@ public abstract class ActivityManagerInternal {
 
     /** Starts a given process. */
     public abstract void startProcess(String processName, ApplicationInfo info,
-            boolean knownToBeDead, String hostingType, ComponentName hostingName);
+            boolean knownToBeDead, boolean isTop, String hostingType, ComponentName hostingName);
 
     /** Starts up the starting activity process for debugging if needed.
      * This function needs to be called synchronously from WindowManager context so the caller
diff --git a/core/java/android/os/Process.java b/core/java/android/os/Process.java
index 10b4e5ddcd55..1c0f0f42a5dc 100644
--- a/core/java/android/os/Process.java
+++ b/core/java/android/os/Process.java
@@ -525,6 +525,7 @@ public class Process {
      * @param appDataDir null-ok the data directory of the app.
      * @param invokeWith null-ok the command to invoke with.
      * @param packageName null-ok the name of the package this process belongs to.
+     * @param isTopApp whether the process starts for high priority application.
      * @param disabledCompatChanges null-ok list of disabled compat changes for the process being
      *                             started.
      * @param zygoteArgs Additional arguments to supply to the zygote process.
@@ -545,12 +546,13 @@ public class Process {
                                            @Nullable String appDataDir,
                                            @Nullable String invokeWith,
                                            @Nullable String packageName,
+                                           boolean isTopApp,
                                            @Nullable long[] disabledCompatChanges,
                                            @Nullable String[] zygoteArgs) {
         return ZYGOTE_PROCESS.start(processClass, niceName, uid, gid, gids,
                     runtimeFlags, mountExternal, targetSdkVersion, seInfo,
                     abi, instructionSet, appDataDir, invokeWith, packageName,
-                    /*useUsapPool=*/ true, disabledCompatChanges, zygoteArgs);
+                    /*useUsapPool=*/ true, isTopApp, disabledCompatChanges, zygoteArgs);
     }
 
     /** @hide */
@@ -571,7 +573,7 @@ public class Process {
         return WebViewZygote.getProcess().start(processClass, niceName, uid, gid, gids,
                     runtimeFlags, mountExternal, targetSdkVersion, seInfo,
                     abi, instructionSet, appDataDir, invokeWith, packageName,
-                    /*useUsapPool=*/ false, disabledCompatChanges, zygoteArgs);
+                    /*useUsapPool=*/ false, /*isTopApp=*/ false, disabledCompatChanges, zygoteArgs);
     }
 
     /**
diff --git a/core/java/android/os/ZygoteProcess.java b/core/java/android/os/ZygoteProcess.java
index 016823e1a07d..32df0529a41c 100644
--- a/core/java/android/os/ZygoteProcess.java
+++ b/core/java/android/os/ZygoteProcess.java
@@ -309,6 +309,7 @@ public class ZygoteProcess {
      * @param disabledCompatChanges null-ok list of disabled compat changes for the process being
      *                             started.
      * @param zygoteArgs Additional arguments to supply to the zygote process.
+     * @param isTopApp Whether the process starts for high priority application.
      *
      * @return An object that describes the result of the attempt to start the process.
      * @throws RuntimeException on fatal start failure
@@ -325,6 +326,7 @@ public class ZygoteProcess {
                                                   @Nullable String invokeWith,
                                                   @Nullable String packageName,
                                                   boolean useUsapPool,
+                                                  boolean isTopApp,
                                                   @Nullable long[] disabledCompatChanges,
                                                   @Nullable String[] zygoteArgs) {
         // TODO (chriswailes): Is there a better place to check this value?
@@ -336,7 +338,7 @@ public class ZygoteProcess {
             return startViaZygote(processClass, niceName, uid, gid, gids,
                     runtimeFlags, mountExternal, targetSdkVersion, seInfo,
                     abi, instructionSet, appDataDir, invokeWith, /*startChildZygote=*/ false,
-                    packageName, useUsapPool, disabledCompatChanges, zygoteArgs);
+                    packageName, useUsapPool, isTopApp, disabledCompatChanges, zygoteArgs);
         } catch (ZygoteStartFailedEx ex) {
             Log.e(LOG_TAG,
                     "Starting VM process through Zygote failed");
@@ -537,6 +539,7 @@ public class ZygoteProcess {
      * @param startChildZygote Start a sub-zygote. This creates a new zygote process
      * that has its state cloned from this zygote process.
      * @param packageName null-ok the name of the package this process belongs to.
+     * @param isTopApp Whether the process starts for high priority application.
      * @param disabledCompatChanges a list of disabled compat changes for the process being started.
      * @param extraArgs Additional arguments to supply to the zygote process.
      * @return An object that describes the result of the attempt to start the process.
@@ -556,6 +559,7 @@ public class ZygoteProcess {
                                                       boolean startChildZygote,
                                                       @Nullable String packageName,
                                                       boolean useUsapPool,
+                                                      boolean isTopApp,
                                                       @Nullable long[] disabledCompatChanges,
                                                       @Nullable String[] extraArgs)
                                                       throws ZygoteStartFailedEx {
@@ -628,6 +632,10 @@ public class ZygoteProcess {
             argsForZygote.add("--package-name=" + packageName);
         }
 
+        if (isTopApp) {
+            argsForZygote.add(Zygote.START_AS_TOP_APP_ARG);
+        }
+
         if (disabledCompatChanges != null && disabledCompatChanges.length > 0) {
             final StringBuilder sb = new StringBuilder();
             sb.append("--disabled-compat-changes=");
@@ -1190,7 +1198,7 @@ public class ZygoteProcess {
                     gids, runtimeFlags, 0 /* mountExternal */, 0 /* targetSdkVersion */, seInfo,
                     abi, instructionSet, null /* appDataDir */, null /* invokeWith */,
                     true /* startChildZygote */, null /* packageName */,
-                    false /* useUsapPool */,
+                    false /* useUsapPool */, false /* isTopApp */,
                     null /* disabledCompatChanges */, extraArgs);
         } catch (ZygoteStartFailedEx ex) {
             throw new RuntimeException("Starting child-zygote through Zygote failed", ex);
diff --git a/core/java/com/android/internal/os/Zygote.java b/core/java/com/android/internal/os/Zygote.java
index 5f196a0e4c1c..d047415aacfb 100644
--- a/core/java/com/android/internal/os/Zygote.java
+++ b/core/java/com/android/internal/os/Zygote.java
@@ -164,6 +164,9 @@ public final class Zygote {
     /** Number of bytes sent to the Zygote over USAP pipes or the pool event FD */
     public static final int USAP_MANAGEMENT_MESSAGE_BYTES = 8;
 
+    /** Make the new process have top application priority. */
+    public static final String START_AS_TOP_APP_ARG = "--is-top-app";
+
     /**
      * An extraArg passed when a zygote process is forking a child-zygote, specifying a name
      * in the abstract socket namespace. This socket name is what the new child zygote
@@ -266,18 +269,20 @@ public final class Zygote {
      * new zygote process.
      * @param instructionSet null-ok the instruction set to use.
      * @param appDataDir null-ok the data directory of the app.
+     * @param isTopApp true if the process is for top (high priority) application.
      *
      * @return 0 if this is the child, pid of the child
      * if this is the parent, or -1 on error.
      */
     public static int forkAndSpecialize(int uid, int gid, int[] gids, int runtimeFlags,
             int[][] rlimits, int mountExternal, String seInfo, String niceName, int[] fdsToClose,
-            int[] fdsToIgnore, boolean startChildZygote, String instructionSet, String appDataDir) {
+            int[] fdsToIgnore, boolean startChildZygote, String instructionSet, String appDataDir,
+            boolean isTopApp) {
         ZygoteHooks.preFork();
 
         int pid = nativeForkAndSpecialize(
                 uid, gid, gids, runtimeFlags, rlimits, mountExternal, seInfo, niceName, fdsToClose,
-                fdsToIgnore, startChildZygote, instructionSet, appDataDir);
+                fdsToIgnore, startChildZygote, instructionSet, appDataDir, isTopApp);
         if (pid == 0) {
             // Note that this event ends at the end of handleChildProc,
             Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "PostFork");
@@ -293,7 +298,7 @@ public final class Zygote {
     private static native int nativeForkAndSpecialize(int uid, int gid, int[] gids,
             int runtimeFlags, int[][] rlimits, int mountExternal, String seInfo, String niceName,
             int[] fdsToClose, int[] fdsToIgnore, boolean startChildZygote, String instructionSet,
-            String appDataDir);
+            String appDataDir, boolean isTopApp);
 
     /**
      * Specialize an unspecialized app process.  The current VM must have been started
@@ -315,12 +320,13 @@ public final class Zygote {
      * new zygote process.
      * @param instructionSet null-ok  The instruction set to use.
      * @param appDataDir null-ok  The data directory of the app.
+     * @param isTopApp  True if the process is for top (high priority) application.
      */
     public static void specializeAppProcess(int uid, int gid, int[] gids, int runtimeFlags,
             int[][] rlimits, int mountExternal, String seInfo, String niceName,
-            boolean startChildZygote, String instructionSet, String appDataDir) {
+            boolean startChildZygote, String instructionSet, String appDataDir, boolean isTopApp) {
         nativeSpecializeAppProcess(uid, gid, gids, runtimeFlags, rlimits, mountExternal, seInfo,
-                niceName, startChildZygote, instructionSet, appDataDir);
+                niceName, startChildZygote, instructionSet, appDataDir, isTopApp);
 
         // Note that this event ends at the end of handleChildProc.
         Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "PostFork");
@@ -339,7 +345,7 @@ public final class Zygote {
 
     private static native void nativeSpecializeAppProcess(int uid, int gid, int[] gids,
             int runtimeFlags, int[][] rlimits, int mountExternal, String seInfo, String niceName,
-            boolean startChildZygote, String instructionSet, String appDataDir);
+            boolean startChildZygote, String instructionSet, String appDataDir, boolean isTopApp);
 
     /**
      * Called to do any initialization before starting an application.
@@ -662,7 +668,7 @@ public final class Zygote {
             specializeAppProcess(args.mUid, args.mGid, args.mGids,
                     args.mRuntimeFlags, rlimits, args.mMountExternal,
                     args.mSeInfo, args.mNiceName, args.mStartChildZygote,
-                    args.mInstructionSet, args.mAppDataDir);
+                    args.mInstructionSet, args.mAppDataDir, args.mIsTopApp);
 
             Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
 
diff --git a/core/java/com/android/internal/os/ZygoteArguments.java b/core/java/com/android/internal/os/ZygoteArguments.java
index 3915ba273dfa..4442cf0c8208 100644
--- a/core/java/com/android/internal/os/ZygoteArguments.java
+++ b/core/java/com/android/internal/os/ZygoteArguments.java
@@ -210,6 +210,11 @@ class ZygoteArguments {
     int mHiddenApiAccessStatslogSampleRate = -1;
 
     /**
+     * @see Zygote#START_AS_TOP_APP_ARG
+     */
+    boolean mIsTopApp;
+
+    /**
      * A set of disabled app compatibility changes for the running app. From
      * --disabled-compat-changes.
      */
@@ -422,6 +427,8 @@ class ZygoteArguments {
                 mUsapPoolStatusSpecified = true;
                 mUsapPoolEnabled = Boolean.parseBoolean(arg.substring(arg.indexOf('=') + 1));
                 expectRuntimeArgs = false;
+            } else if (arg.startsWith(Zygote.START_AS_TOP_APP_ARG)) {
+                mIsTopApp = true;
             } else if (arg.startsWith("--disabled-compat-changes=")) {
                 if (mDisabledCompatChanges != null) {
                     throw new IllegalArgumentException("Duplicate arg specified");
diff --git a/core/java/com/android/internal/os/ZygoteConnection.java b/core/java/com/android/internal/os/ZygoteConnection.java
index 24ea59ae6ac0..8f1f4cc1077c 100644
--- a/core/java/com/android/internal/os/ZygoteConnection.java
+++ b/core/java/com/android/internal/os/ZygoteConnection.java
@@ -257,7 +257,7 @@ class ZygoteConnection {
         pid = Zygote.forkAndSpecialize(parsedArgs.mUid, parsedArgs.mGid, parsedArgs.mGids,
                 parsedArgs.mRuntimeFlags, rlimits, parsedArgs.mMountExternal, parsedArgs.mSeInfo,
                 parsedArgs.mNiceName, fdsToClose, fdsToIgnore, parsedArgs.mStartChildZygote,
-                parsedArgs.mInstructionSet, parsedArgs.mAppDataDir);
+                parsedArgs.mInstructionSet, parsedArgs.mAppDataDir, parsedArgs.mIsTopApp);
 
         try {
             if (pid == 0) {
diff --git a/core/jni/com_android_internal_os_Zygote.cpp b/core/jni/com_android_internal_os_Zygote.cpp
index ea58cbd99179..0ce61de270f8 100644
--- a/core/jni/com_android_internal_os_Zygote.cpp
+++ b/core/jni/com_android_internal_os_Zygote.cpp
@@ -663,11 +663,25 @@ static void SetCapabilities(uint64_t permitted, uint64_t effective, uint64_t inh
   }
 }
 
-static void SetSchedulerPolicy(fail_fn_t fail_fn) {
-  errno = -set_sched_policy(0, SP_DEFAULT);
+static void SetSchedulerPolicy(fail_fn_t fail_fn, bool is_top_app) {
+  SchedPolicy policy = is_top_app ? SP_TOP_APP : SP_DEFAULT;
+
+  if (is_top_app && cpusets_enabled()) {
+    errno = -set_cpuset_policy(0, policy);
+    if (errno != 0) {
+      fail_fn(CREATE_ERROR("set_cpuset_policy(0, %d) failed: %s", policy, strerror(errno)));
+    }
+  }
+
+  errno = -set_sched_policy(0, policy);
   if (errno != 0) {
-    fail_fn(CREATE_ERROR("set_sched_policy(0, SP_DEFAULT) failed: %s", strerror(errno)));
+    fail_fn(CREATE_ERROR("set_sched_policy(0, %d) failed: %s", policy, strerror(errno)));
   }
+
+  // We are going to lose the permission to set scheduler policy during the specialization, so make
+  // sure that we don't cache the fd of cgroup path that may cause sepolicy violation by writing
+  // value to the cached fd directly when creating new thread.
+  DropTaskProfilesResourceCaching();
 }
 
 static int UnmountTree(const char* path) {
@@ -1055,7 +1069,7 @@ static void SpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArray gids,
                              jint mount_external, jstring managed_se_info,
                              jstring managed_nice_name, bool is_system_server,
                              bool is_child_zygote, jstring managed_instruction_set,
-                             jstring managed_app_data_dir) {
+                             jstring managed_app_data_dir, bool is_top_app) {
   const char* process_name = is_system_server ? "system_server" : "zygote";
   auto fail_fn = std::bind(ZygoteFailure, env, process_name, managed_nice_name, _1);
   auto extract_fn = std::bind(ExtractJString, env, process_name, managed_nice_name, _1);
@@ -1118,6 +1132,9 @@ static void SpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArray gids,
   // privileged syscalls used below still need to be accessible in app process.
   SetUpSeccompFilter(uid, is_child_zygote);
 
+  // Must be called before losing the permission to set scheduler policy.
+  SetSchedulerPolicy(fail_fn, is_top_app);
+
   if (setresuid(uid, uid, uid) == -1) {
     fail_fn(CREATE_ERROR("setresuid(%d) failed: %s", uid, strerror(errno)));
   }
@@ -1176,8 +1193,6 @@ static void SpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArray gids,
 
   SetCapabilities(permitted_capabilities, effective_capabilities, permitted_capabilities, fail_fn);
 
-  SetSchedulerPolicy(fail_fn);
-
   __android_log_close();
   stats_log_close();
 
@@ -1446,7 +1461,7 @@ static jint com_android_internal_os_Zygote_nativeForkAndSpecialize(
         jint runtime_flags, jobjectArray rlimits,
         jint mount_external, jstring se_info, jstring nice_name,
         jintArray managed_fds_to_close, jintArray managed_fds_to_ignore, jboolean is_child_zygote,
-        jstring instruction_set, jstring app_data_dir) {
+        jstring instruction_set, jstring app_data_dir, jboolean is_top_app) {
     jlong capabilities = CalculateCapabilities(env, uid, gid, gids, is_child_zygote);
 
     if (UNLIKELY(managed_fds_to_close == nullptr)) {
@@ -1482,7 +1497,8 @@ static jint com_android_internal_os_Zygote_nativeForkAndSpecialize(
       SpecializeCommon(env, uid, gid, gids, runtime_flags, rlimits,
                        capabilities, capabilities,
                        mount_external, se_info, nice_name, false,
-                       is_child_zygote == JNI_TRUE, instruction_set, app_data_dir);
+                       is_child_zygote == JNI_TRUE, instruction_set, app_data_dir,
+                       is_top_app == JNI_TRUE);
     }
     return pid;
 }
@@ -1514,7 +1530,7 @@ static jint com_android_internal_os_Zygote_nativeForkSystemServer(
       SpecializeCommon(env, uid, gid, gids, runtime_flags, rlimits,
                        permitted_capabilities, effective_capabilities,
                        MOUNT_EXTERNAL_DEFAULT, nullptr, nullptr, true,
-                       false, nullptr, nullptr);
+                       false, nullptr, nullptr, /* is_top_app= */ false);
   } else if (pid > 0) {
       // The zygote process checks whether the child process has died or not.
       ALOGI("System server process %d has been created", pid);
@@ -1637,18 +1653,20 @@ static void com_android_internal_os_Zygote_nativeInstallSeccompUidGidFilter(
  * @param is_child_zygote  If the process is to become a WebViewZygote
  * @param instruction_set  The instruction set expected/requested by the new application
  * @param app_data_dir  Path to the application's data directory
+ * @param is_top_app  If the process is for top (high priority) application
  */
 static void com_android_internal_os_Zygote_nativeSpecializeAppProcess(
     JNIEnv* env, jclass, jint uid, jint gid, jintArray gids,
     jint runtime_flags, jobjectArray rlimits,
     jint mount_external, jstring se_info, jstring nice_name,
-    jboolean is_child_zygote, jstring instruction_set, jstring app_data_dir) {
+    jboolean is_child_zygote, jstring instruction_set, jstring app_data_dir, jboolean is_top_app) {
   jlong capabilities = CalculateCapabilities(env, uid, gid, gids, is_child_zygote);
 
   SpecializeCommon(env, uid, gid, gids, runtime_flags, rlimits,
                    capabilities, capabilities,
                    mount_external, se_info, nice_name, false,
-                   is_child_zygote == JNI_TRUE, instruction_set, app_data_dir);
+                   is_child_zygote == JNI_TRUE, instruction_set, app_data_dir,
+                   is_top_app == JNI_TRUE);
 }
 
 /**
@@ -1845,7 +1863,7 @@ static jint com_android_internal_os_Zygote_nativeParseSigChld(JNIEnv* env, jclas
 
 static const JNINativeMethod gMethods[] = {
     { "nativeForkAndSpecialize",
-      "(II[II[[IILjava/lang/String;Ljava/lang/String;[I[IZLjava/lang/String;Ljava/lang/String;)I",
+      "(II[II[[IILjava/lang/String;Ljava/lang/String;[I[IZLjava/lang/String;Ljava/lang/String;Z)I",
       (void *) com_android_internal_os_Zygote_nativeForkAndSpecialize },
     { "nativeForkSystemServer", "(II[II[[IJJ)I",
       (void *) com_android_internal_os_Zygote_nativeForkSystemServer },
@@ -1858,7 +1876,7 @@ static const JNINativeMethod gMethods[] = {
     { "nativeForkUsap", "(II[IZ)I",
       (void *) com_android_internal_os_Zygote_nativeForkUsap },
     { "nativeSpecializeAppProcess",
-      "(II[II[[IILjava/lang/String;Ljava/lang/String;ZLjava/lang/String;Ljava/lang/String;)V",
+      "(II[II[[IILjava/lang/String;Ljava/lang/String;ZLjava/lang/String;Ljava/lang/String;Z)V",
       (void *) com_android_internal_os_Zygote_nativeSpecializeAppProcess },
     { "nativeInitNativeState", "(Z)V",
       (void *) com_android_internal_os_Zygote_nativeInitNativeState },
diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 53d23842ec79..f19dc7a11eaa 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -4875,7 +4875,7 @@ public class ActivityManagerService extends IActivityManager.Stub
         EventLog.writeEvent(EventLogTags.AM_PROC_BOUND, app.userId, app.pid, app.processName);
 
         app.curAdj = app.setAdj = app.verifiedAdj = ProcessList.INVALID_ADJ;
-        app.setCurrentSchedulingGroup(app.setSchedGroup = ProcessList.SCHED_GROUP_DEFAULT);
+        mOomAdjuster.setAttachingSchedGroupLocked(app);
         app.forcingToImportant = null;
         updateProcessForegroundLocked(app, false, 0, false);
         app.hasShownUi = false;
@@ -18473,16 +18473,19 @@ public class ActivityManagerService extends IActivityManager.Stub
         }
 
         @Override
-        public void startProcess(String processName, ApplicationInfo info,
-                boolean knownToBeDead, String hostingType, ComponentName hostingName) {
+        public void startProcess(String processName, ApplicationInfo info, boolean knownToBeDead,
+                boolean isTop, String hostingType, ComponentName hostingName) {
             try {
                 if (Trace.isTagEnabled(Trace.TRACE_TAG_ACTIVITY_MANAGER)) {
                     Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "startProcess:"
                             + processName);
                 }
                 synchronized (ActivityManagerService.this) {
+                    // If the process is known as top app, set a hint so when the process is
+                    // started, the top priority can be applied immediately to avoid cpu being
+                    // preempted by other processes before attaching the process of top app.
                     startProcessLocked(processName, info, knownToBeDead, 0 /* intentFlags */,
-                            new HostingRecord(hostingType, hostingName),
+                            new HostingRecord(hostingType, hostingName, isTop),
                             false /* allowWhileBooting */, false /* isolated */,
                             true /* keepIfLarge */);
                 }
diff --git a/services/core/java/com/android/server/am/HostingRecord.java b/services/core/java/com/android/server/am/HostingRecord.java
index 784dde1e98df..6bb5def26b9d 100644
--- a/services/core/java/com/android/server/am/HostingRecord.java
+++ b/services/core/java/com/android/server/am/HostingRecord.java
@@ -41,6 +41,8 @@ import android.content.ComponentName;
  * {@link android.content.Context#BIND_EXTERNAL_SERVICE} service. In that case, the packageName
  * and uid in the ApplicationInfo will be set to those of the caller, not of the defining package.
  *
+ * {@code mIsTopApp} will be passed to {@link android.os.Process#start}. So Zygote will initialize
+ * the process with high priority.
  */
 
 public final class HostingRecord {
@@ -53,15 +55,22 @@ public final class HostingRecord {
     private final int mHostingZygote;
     private final String mDefiningPackageName;
     private final int mDefiningUid;
+    private final boolean mIsTopApp;
 
     public HostingRecord(String hostingType) {
-        this(hostingType, null, REGULAR_ZYGOTE, null, -1);
+        this(hostingType, null /* hostingName */, REGULAR_ZYGOTE, null /* definingPackageName */,
+                -1 /* mDefiningUid */, false /* isTopApp */);
     }
 
     public HostingRecord(String hostingType, ComponentName hostingName) {
         this(hostingType, hostingName, REGULAR_ZYGOTE);
     }
 
+    public HostingRecord(String hostingType, ComponentName hostingName, boolean isTopApp) {
+        this(hostingType, hostingName.toShortString(), REGULAR_ZYGOTE,
+                null /* definingPackageName */, -1 /* mDefiningUid */, isTopApp /* isTopApp */);
+    }
+
     public HostingRecord(String hostingType, String hostingName) {
         this(hostingType, hostingName, REGULAR_ZYGOTE);
     }
@@ -71,16 +80,18 @@ public final class HostingRecord {
     }
 
     private HostingRecord(String hostingType, String hostingName, int hostingZygote) {
-        this(hostingType, hostingName, hostingZygote, null, -1);
+        this(hostingType, hostingName, hostingZygote, null /* definingPackageName */,
+                -1 /* mDefiningUid */, false /* isTopApp */);
     }
 
     private HostingRecord(String hostingType, String hostingName, int hostingZygote,
-            String definingPackageName, int definingUid) {
+            String definingPackageName, int definingUid, boolean isTopApp) {
         mHostingType = hostingType;
         mHostingName = hostingName;
         mHostingZygote = hostingZygote;
         mDefiningPackageName = definingPackageName;
         mDefiningUid = definingUid;
+        mIsTopApp = isTopApp;
     }
 
     public String getType() {
@@ -91,6 +102,10 @@ public final class HostingRecord {
         return mHostingName;
     }
 
+    public boolean isTopApp() {
+        return mIsTopApp;
+    }
+
     /**
      * Returns the UID of the package defining the component we want to start. Only valid
      * when {@link #usesAppZygote()} returns true.
@@ -130,7 +145,7 @@ public final class HostingRecord {
     public static HostingRecord byAppZygote(ComponentName hostingName, String definingPackageName,
             int definingUid) {
         return new HostingRecord("", hostingName.toShortString(), APP_ZYGOTE,
-                definingPackageName, definingUid);
+                definingPackageName, definingUid, false /* isTopApp */);
     }
 
     /**
diff --git a/services/core/java/com/android/server/am/OomAdjuster.java b/services/core/java/com/android/server/am/OomAdjuster.java
index dbf8acf74dbd..80e22e529ba9 100644
--- a/services/core/java/com/android/server/am/OomAdjuster.java
+++ b/services/core/java/com/android/server/am/OomAdjuster.java
@@ -178,9 +178,12 @@ public final class OomAdjuster {
         adjusterThread.start();
         Process.setThreadGroupAndCpuset(adjusterThread.getThreadId(), THREAD_GROUP_TOP_APP);
         mProcessGroupHandler = new Handler(adjusterThread.getLooper(), msg -> {
-            Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "setProcessGroup");
             final int pid = msg.arg1;
             final int group = msg.arg2;
+            if (Trace.isTagEnabled(Trace.TRACE_TAG_ACTIVITY_MANAGER)) {
+                Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "setProcessGroup "
+                        + msg.obj + " to " + group);
+            }
             try {
                 setProcessGroup(pid, group);
             } catch (Exception e) {
@@ -1758,7 +1761,7 @@ public final class OomAdjuster {
                         break;
                 }
                 mProcessGroupHandler.sendMessage(mProcessGroupHandler.obtainMessage(
-                        0 /* unused */, app.pid, processGroup));
+                        0 /* unused */, app.pid, processGroup, app.processName));
                 try {
                     if (curSchedGroup == ProcessList.SCHED_GROUP_TOP_APP) {
                         // do nothing if we already switched to RT
@@ -1949,6 +1952,38 @@ public final class OomAdjuster {
         return success;
     }
 
+    @GuardedBy("mService")
+    void setAttachingSchedGroupLocked(ProcessRecord app) {
+        int initialSchedGroup = ProcessList.SCHED_GROUP_DEFAULT;
+        // If the process has been marked as foreground via Zygote.START_FLAG_USE_TOP_APP_PRIORITY,
+        // then verify that the top priority is actually is applied.
+        if (app.hasForegroundActivities()) {
+            String fallbackReason = null;
+            try {
+                // The priority must be the same as how does {@link #applyOomAdjLocked} set for
+                // {@link ProcessList.SCHED_GROUP_TOP_APP}. We don't check render thread because it
+                // is not ready when attaching.
+                if (Process.getProcessGroup(app.pid) == THREAD_GROUP_TOP_APP) {
+                    app.getWindowProcessController().onTopProcChanged();
+                    setThreadPriority(app.pid, TOP_APP_PRIORITY_BOOST);
+                } else {
+                    fallbackReason = "not expected top priority";
+                }
+            } catch (Exception e) {
+                fallbackReason = e.toString();
+            }
+            if (fallbackReason == null) {
+                initialSchedGroup = ProcessList.SCHED_GROUP_TOP_APP;
+            } else {
+                // The real scheduling group will depend on if there is any component of the process
+                // did something during attaching.
+                Slog.w(TAG, "Fallback pre-set sched group to default: " + fallbackReason);
+            }
+        }
+
+        app.setCurrentSchedulingGroup(app.setSchedGroup = initialSchedGroup);
+    }
+
     // ONLY used for unit testing in OomAdjusterTests.java
     @VisibleForTesting
     void maybeUpdateUsageStats(ProcessRecord app, long nowElapsed) {
diff --git a/services/core/java/com/android/server/am/ProcessList.java b/services/core/java/com/android/server/am/ProcessList.java
index 8520cb7c30b8..3996ae2172b4 100644
--- a/services/core/java/com/android/server/am/ProcessList.java
+++ b/services/core/java/com/android/server/am/ProcessList.java
@@ -51,7 +51,6 @@ import android.app.ActivityThread;
 import android.app.AppGlobals;
 import android.app.AppProtoEnums;
 import android.app.IApplicationThread;
-import android.app.IUidObserver;
 import android.compat.annotation.ChangeId;
 import android.compat.annotation.EnabledAfter;
 import android.content.ComponentName;
@@ -1899,6 +1898,14 @@ public final class ProcessList {
             Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "Start proc: " +
                     app.processName);
             checkSlow(startTime, "startProcess: asking zygote to start proc");
+            final boolean isTopApp = hostingRecord.isTopApp();
+            if (isTopApp) {
+                // Use has-foreground-activities as a temporary hint so the current scheduling
+                // group won't be lost when the process is attaching. The actual state will be
+                // refreshed when computing oom-adj.
+                app.setHasForegroundActivities(true);
+            }
+
             final Process.ProcessStartResult startResult;
             if (hostingRecord.usesWebviewZygote()) {
                 startResult = startWebView(entryPoint,
@@ -1913,13 +1920,13 @@ public final class ProcessList {
                         app.processName, uid, uid, gids, runtimeFlags, mountExternal,
                         app.info.targetSdkVersion, seInfo, requiredAbi, instructionSet,
                         app.info.dataDir, null, app.info.packageName,
-                        /*useUsapPool=*/ false, app.mDisabledCompatChanges,
+                        /*useUsapPool=*/ false, isTopApp, app.mDisabledCompatChanges,
                         new String[]{PROC_START_SEQ_IDENT + app.startSeq});
             } else {
                 startResult = Process.start(entryPoint,
                         app.processName, uid, uid, gids, runtimeFlags, mountExternal,
                         app.info.targetSdkVersion, seInfo, requiredAbi, instructionSet,
-                        app.info.dataDir, invokeWith, app.info.packageName,
+                        app.info.dataDir, invokeWith, app.info.packageName, isTopApp,
                         app.mDisabledCompatChanges,
                         new String[]{PROC_START_SEQ_IDENT + app.startSeq});
             }
diff --git a/services/core/java/com/android/server/wm/ActivityRecord.java b/services/core/java/com/android/server/wm/ActivityRecord.java
index 1d8f059a7e75..500cc38f8b66 100644
--- a/services/core/java/com/android/server/wm/ActivityRecord.java
+++ b/services/core/java/com/android/server/wm/ActivityRecord.java
@@ -3551,7 +3551,7 @@ final class ActivityRecord extends ConfigurationContainer {
         mStackSupervisor.scheduleRestartTimeout(this);
     }
 
-    private boolean isProcessRunning() {
+    boolean isProcessRunning() {
         WindowProcessController proc = app;
         if (proc == null) {
             proc = mAtmService.mProcessNames.get(processName, info.applicationInfo.uid);
diff --git a/services/core/java/com/android/server/wm/ActivityStack.java b/services/core/java/com/android/server/wm/ActivityStack.java
index 242139cd2da7..848971d3b044 100644
--- a/services/core/java/com/android/server/wm/ActivityStack.java
+++ b/services/core/java/com/android/server/wm/ActivityStack.java
@@ -2743,7 +2743,7 @@ class ActivityStack extends ConfigurationContainer {
         final boolean resumeWhilePausing = (next.info.flags & FLAG_RESUME_WHILE_PAUSING) != 0
                 && !lastResumedCanPip;
 
-        boolean pausing = getDisplay().pauseBackStacks(userLeaving, next, false);
+        boolean pausing = display.pauseBackStacks(userLeaving, next, false);
         if (mResumedActivity != null) {
             if (DEBUG_STATES) Slog.d(TAG_STATES,
                     "resumeTopActivityLocked: Pausing " + mResumedActivity);
@@ -2759,6 +2759,13 @@ class ActivityStack extends ConfigurationContainer {
             if (next.attachedToProcess()) {
                 next.app.updateProcessInfo(false /* updateServiceConnectionActivities */,
                         true /* activityChange */, false /* updateOomAdj */);
+            } else if (!next.isProcessRunning()) {
+                // Since the start-process is asynchronous, if we already know the process of next
+                // activity isn't running, we can start the process earlier to save the time to wait
+                // for the current activity to be paused.
+                final boolean isTop = this == display.getFocusedStack();
+                mService.startProcessAsync(next, false /* knownToBeDead */, isTop,
+                        isTop ? "pre-top-activity" : "pre-activity");
             }
             if (lastResumed != null) {
                 lastResumed.setWillCloseOrEnterPip(true);
@@ -2827,7 +2834,7 @@ class ActivityStack extends ConfigurationContainer {
         // that the previous one will be hidden soon.  This way it can know
         // to ignore it when computing the desired screen orientation.
         boolean anim = true;
-        final DisplayContent dc = getDisplay().mDisplayContent;
+        final DisplayContent dc = display.mDisplayContent;
         if (prev != null) {
             if (prev.finishing) {
                 if (DEBUG_TRANSITION) Slog.v(TAG_TRANSITION,
@@ -2984,7 +2991,7 @@ class ActivityStack extends ConfigurationContainer {
                 next.clearOptionsLocked();
                 transaction.setLifecycleStateRequest(
                         ResumeActivityItem.obtain(next.app.getReportedProcState(),
-                                getDisplay().mDisplayContent.isNextTransitionForward()));
+                                dc.isNextTransitionForward()));
                 mService.getLifecycleManager().scheduleTransaction(transaction);
 
                 if (DEBUG_STATES) Slog.d(TAG_STATES, "resumeTopActivityLocked: Resumed "
diff --git a/services/core/java/com/android/server/wm/ActivityStackSupervisor.java b/services/core/java/com/android/server/wm/ActivityStackSupervisor.java
index 8f573c0e7234..69bd84b1267b 100644
--- a/services/core/java/com/android/server/wm/ActivityStackSupervisor.java
+++ b/services/core/java/com/android/server/wm/ActivityStackSupervisor.java
@@ -995,20 +995,8 @@ public class ActivityStackSupervisor implements RecentTasks.Callbacks {
             r.notifyUnknownVisibilityLaunched();
         }
 
-        try {
-            if (Trace.isTagEnabled(TRACE_TAG_ACTIVITY_MANAGER)) {
-                Trace.traceBegin(TRACE_TAG_ACTIVITY_MANAGER, "dispatchingStartProcess:"
-                        + r.processName);
-            }
-            // Post message to start process to avoid possible deadlock of calling into AMS with the
-            // ATMS lock held.
-            final Message msg = PooledLambda.obtainMessage(
-                    ActivityManagerInternal::startProcess, mService.mAmInternal, r.processName,
-                    r.info.applicationInfo, knownToBeDead, "activity", r.intent.getComponent());
-            mService.mH.sendMessage(msg);
-        } finally {
-            Trace.traceEnd(TRACE_TAG_ACTIVITY_MANAGER);
-        }
+        final boolean isTop = andResume && r.isTopRunningActivity();
+        mService.startProcessAsync(r, knownToBeDead, isTop, isTop ? "top-activity" : "activity");
     }
 
     boolean checkStartAnyActivityPermission(Intent intent, ActivityInfo aInfo, String resultWho,
diff --git a/services/core/java/com/android/server/wm/ActivityTaskManagerService.java b/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
index 223205377bb9..c0fd24c39908 100644
--- a/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
+++ b/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
@@ -5653,6 +5653,24 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub {
         mH.sendMessage(m);
     }
 
+    void startProcessAsync(ActivityRecord activity, boolean knownToBeDead, boolean isTop,
+            String hostingType) {
+        try {
+            if (Trace.isTagEnabled(TRACE_TAG_ACTIVITY_MANAGER)) {
+                Trace.traceBegin(TRACE_TAG_ACTIVITY_MANAGER, "dispatchingStartProcess:"
+                        + activity.processName);
+            }
+            // Post message to start process to avoid possible deadlock of calling into AMS with the
+            // ATMS lock held.
+            final Message m = PooledLambda.obtainMessage(ActivityManagerInternal::startProcess,
+                    mAmInternal, activity.processName, activity.info.applicationInfo, knownToBeDead,
+                    isTop, hostingType, activity.intent.getComponent());
+            mH.sendMessage(m);
+        } finally {
+            Trace.traceEnd(TRACE_TAG_ACTIVITY_MANAGER);
+        }
+    }
+
     void setBooting(boolean booting) {
         mAmInternal.setBooting(booting);
     }