From 235268ea8bff5fd012632720baa38abae98c38fa Mon Sep 17 00:00:00 2001
From: Rick Yiu <rickyiu@google.com>
Date: Fri, 28 Aug 2020 05:10:29 +0000
Subject: [PATCH] Revert "Use async approach to change sched policy"

This reverts commit 98e231640833cf88331e6c91e1db760f8cb24ff5.

Reason for revert: may have problem under race condition

Change-Id: I2ced8b1a78e107f107b63468c5d8e4d62faa143c
---
 core/jni/android_util_Process.cpp | 52 +++----------------------------
 1 file changed, 5 insertions(+), 47 deletions(-)

diff --git a/core/jni/android_util_Process.cpp b/core/jni/android_util_Process.cpp
index cbcbe7f113903..891d6352a4a9a 100644
--- a/core/jni/android_util_Process.cpp
+++ b/core/jni/android_util_Process.cpp
@@ -19,18 +19,16 @@
 
 // To make sure cpu_set_t is included from sched.h
 #define _GNU_SOURCE 1
-#include <android-base/properties.h>
-#include <android-base/unique_fd.h>
-#include <binder/ActivityManager.h>
+#include <utils/Log.h>
 #include <binder/IPCThreadState.h>
 #include <binder/IServiceManager.h>
+#include <utils/String8.h>
+#include <utils/Vector.h>
 #include <meminfo/procmeminfo.h>
 #include <meminfo/sysmeminfo.h>
 #include <processgroup/processgroup.h>
 #include <processgroup/sched_policy.h>
-#include <utils/Log.h>
-#include <utils/String8.h>
-#include <utils/Vector.h>
+#include <android-base/unique_fd.h>
 
 #include <algorithm>
 #include <array>
@@ -86,8 +84,6 @@ Mutex gKeyCreateMutex;
 static pthread_key_t gBgKey = -1;
 #endif
 
-static bool boot_completed = false;
-
 // For both of these, err should be in the errno range (positive), not a status_t (negative)
 static void signalExceptionForError(JNIEnv* env, int err, int tid) {
     switch (err) {
@@ -600,20 +596,7 @@ void android_os_Process_setThreadPriority(JNIEnv* env, jobject clazz,
     }
 #endif
 
-    SchedPolicy policy;
-    bool policy_changed = false;
-    int rc = 0, curr_pri = getpriority(PRIO_PROCESS, pid);
-
-    if (pri == curr_pri) {
-        return;
-    }
-
-    if (!boot_completed) {
-        boot_completed = android::base::GetBoolProperty("sys.boot_completed", false);
-    }
-
-    // Do not change sched policy cgroup after boot complete.
-    rc = androidSetThreadPriorityAndPolicy(pid, pri, !boot_completed);
+    int rc = androidSetThreadPriority(pid, pri);
     if (rc != 0) {
         if (rc == INVALID_OPERATION) {
             signalExceptionForPriorityError(env, errno, pid);
@@ -622,31 +605,6 @@ void android_os_Process_setThreadPriority(JNIEnv* env, jobject clazz,
         }
     }
 
-    // Only use async approach after boot complete.
-    if (!boot_completed) {
-        return;
-    }
-
-    // Change to background sched policy for the thread if setting to low priority.
-    if (pri >= ANDROID_PRIORITY_BACKGROUND) {
-        policy = SP_BACKGROUND;
-        policy_changed = true;
-        // Change to sched policy of the process if thread priority is raising from low priority.
-    } else if (curr_pri >= ANDROID_PRIORITY_BACKGROUND) {
-        // If we cannot get sched policy of the process, use SP_FOREGROUND as default.
-        policy = SP_FOREGROUND;
-        get_sched_policy(getpid(), &policy);
-        policy_changed = true;
-    }
-
-    // Sched policy will only change in above 2 cases.
-    if (policy_changed) {
-        ActivityManager am;
-        if (!am.setSchedPolicyCgroup(pid, policy)) {
-            ALOGE("am.setThreadPriority failed: tid=%d priority=%d policy=%d", pid, pri, policy);
-        }
-    }
-
     //ALOGI("Setting priority of %" PRId32 ": %" PRId32 ", getpriority returns %d\n",
     //     pid, pri, getpriority(PRIO_PROCESS, pid));
 }