From 4f84c00fdd7936563ca0c0c6967f20079da222ce Mon Sep 17 00:00:00 2001
From: Rick Yiu <rickyiu@google.com>
Date: Fri, 28 Aug 2020 05:10:45 +0000
Subject: [PATCH] Revert "Add setSchedPolicyCgroup to AM service"

This reverts commit d2b8105f032a67c9fbd4d96aaa636e8d412588a5.

Reason for revert: may have problem under race condition

Change-Id: I170bef11948e6d079ce04f5520088ee97a18a133
---
 core/java/android/app/IActivityManager.aidl   |  1 -
 .../server/am/ActivityManagerService.java     | 47 -------------------
 2 files changed, 48 deletions(-)

diff --git a/core/java/android/app/IActivityManager.aidl b/core/java/android/app/IActivityManager.aidl
index 0a47248e3b704..ec46fd8e07030 100644
--- a/core/java/android/app/IActivityManager.aidl
+++ b/core/java/android/app/IActivityManager.aidl
@@ -99,7 +99,6 @@ interface IActivityManager {
     void unregisterUidObserver(in IUidObserver observer);
     boolean isUidActive(int uid, String callingPackage);
     int getUidProcessState(int uid, in String callingPackage);
-    boolean setSchedPolicyCgroup(int tid, int group);
     // =============== End of transactions used on native side as well ============================
 
     // Special low-level communication with activity manager.
diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 44258d1a69e8e..05e9fbd52cfc1 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -7318,53 +7318,6 @@ public class ActivityManagerService extends IActivityManager.Stub
         return uidRecord != null && !uidRecord.setIdle;
     }
 
-    /**
-     * Change the sched policy cgroup of a thread.
-     *
-     * <p>It is intended to be used in jni call of {@link Process#setThreadPriority(int, int)}.
-     * When a process is changing the priority of its threads, the sched policy of that
-     * thread may need to be changed accordingly - if the priority is changed to below
-     * or equal to {@link android.os.Process#THREAD_PRIORITY_BACKGROUND} or raising from it.
-     * However, because of the limitation of sepolicy, the thread priority change will
-     * fail for some processes. To solve it, we add this binder call in Activity Manager,
-     * so that the jni call of {@link Process#setThreadPriority(int, int)} could use it.
-     *
-     * @param tid tid of the thread to be changed.
-     * @param group The sched policy group to be changed to.
-     *
-     * @throws IllegalArgumentException if group is invalid.
-     * @throws SecurityException if no permission.
-     *
-     * @return Returns {@code true} if the sched policy is changed successfully;
-     *         {@code false} otherwise.
-     */
-    @Override
-    public boolean setSchedPolicyCgroup(final int tid, final int group) {
-        final int pid = Binder.getCallingPid();
-        final int tgid = Process.getThreadGroupLeader(tid);
-        final int pgroup = Process.getProcessGroup(pid);
-
-        // tid is not in the thread group of caller
-        if (pid != tgid) {
-            return false;
-        }
-
-        // sched group is higher than its main process
-        if (group > pgroup) {
-            return false;
-        }
-
-        try {
-            Process.setThreadGroup(tid, group);
-            return true;
-        } catch (IllegalArgumentException e) {
-            Slog.w(TAG, "Failed to set thread group, argument invalid:\n" + e);
-        } catch (SecurityException e) {
-            Slog.w(TAG, "Failed to set thread group, no permission:\n" + e);
-        }
-        return false;
-    }
-
     @Override
     public void setPersistentVrThread(int tid) {
         mActivityTaskManager.setPersistentVrThread(tid);