Scheduling policy service (07b04650) · Commits · e / os / android_frameworks_base

Android.mk

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		@@ -132,6 +132,7 @@ LOCAL_SRC_FILES += \
		core/java/android/os/IPermissionController.aidl \
		core/java/android/os/IPowerManager.aidl \
		core/java/android/os/IRemoteCallback.aidl \
		core/java/android/os/ISchedulingPolicyService.aidl \
		core/java/android/os/IUpdateLock.aidl \
		core/java/android/os/IVibratorService.aidl \
		core/java/android/service/dreams/IDreamManager.aidl \

core/java/android/content/Context.java

+11 −0

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		@@ -1927,6 +1927,17 @@ public abstract class Context {
		*/
		public static final String INPUT_SERVICE = "input";

		/**
		* Use with {@link #getSystemService} to retrieve a
		* {@link android.os.SchedulingPolicyService} for managing scheduling policy.
		*
		* @see #getSystemService
		* @see android.os.SchedulingPolicyService
		*
		* @hide
		*/
		public static final String SCHEDULING_POLICY_SERVICE = "scheduling_policy";

		/**
		* Determine whether the given permission is allowed for a particular
		* process and user ID running in the system.

core/java/android/os/ISchedulingPolicyService.aidl

0 → 100644

+34 −0

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		/*
		* Copyright (C) 2012 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		package android.os;

		/**
		* Initially only provides requestPriority() below, but in longer term
		* other scheduling policy related services will be collected here.
		*
		* @hide
		*/
		interface ISchedulingPolicyService {

		/**
		* Move thread tid into appropriate cgroup and assign it priority prio.
		* The thread group leader of tid must be pid.
		* There may be restrictions on who can call this.
		*/
		int requestPriority(int pid, int tid, int prio);

		}

core/java/android/os/Process.java

+33 −0

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		@@ -299,6 +299,24 @@ public class Process {
		**/
		private static final int THREAD_GROUP_FOREGROUND = 1;

		/**
		* System thread group.
		* @hide
		**/
		public static final int THREAD_GROUP_SYSTEM = 2;

		/**
		* Application audio thread group.
		* @hide
		**/
		public static final int THREAD_GROUP_AUDIO_APP = 3;

		/**
		* System audio thread group.
		* @hide
		**/
		public static final int THREAD_GROUP_AUDIO_SYS = 4;

		public static final int SIGNAL_QUIT = 3;
		public static final int SIGNAL_KILL = 9;
		public static final int SIGNAL_USR1 = 10;
		@@ -657,6 +675,21 @@ public class Process {
		return (int) procStatusValues[0];
		}

		/**
		* Returns the thread group leader id for a currently running thread.
		* @param tid the thread id
		* @return the thread group leader id of the thread, or -1 if the thread is not running.
		* This is same as what getpid(2) would return if called by tid.
		* @hide
		*/
		public static final int getThreadGroupLeader(int tid) {
		String[] procStatusLabels = { "Tgid:" };
		long[] procStatusValues = new long[1];
		procStatusValues[0] = -1;
		Process.readProcLines("/proc/" + tid + "/status", procStatusLabels, procStatusValues);
		return (int) procStatusValues[0];
		}

		/**
		* Set the priority of a thread, based on Linux priorities.
		*

core/java/android/os/SchedulingPolicyService.java

0 → 100644

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		/*
		* Copyright (C) 2012 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		package android.os;

		import android.content.Context;
		import android.content.pm.PackageManager;
		import android.os.Binder;
		import android.os.Process;
		import android.util.Log;

		/**
		* The implementation of the scheduling policy service interface.
		*
		* @hide
		*/
		public class SchedulingPolicyService extends ISchedulingPolicyService.Stub {

		private static final String TAG = "SchedulingPolicyService";

		// Minimum and maximum values allowed for requestPriority parameter prio
		private static final int PRIORITY_MIN = 1;
		private static final int PRIORITY_MAX = 2;

		public SchedulingPolicyService() {
		}

		public int requestPriority(int pid, int tid, int prio) {
		//Log.i(TAG, "requestPriority(pid=" + pid + ", tid=" + tid + ", prio=" + prio + ")");

		// Verify that caller is mediaserver, priority is in range, and that the
		// callback thread specified by app belongs to the app that called mediaserver.
		// Once we've verified that the caller is mediaserver, we can trust the pid but
		// we can't trust the tid. No need to explicitly check for pid == 0 \|\| tid == 0,
		// since if not the case then the getThreadGroupLeader() test will also fail.
		if (Binder.getCallingUid() != Process.MEDIA_UID \|\| prio < PRIORITY_MIN \|\|
		prio > PRIORITY_MAX \|\| Process.getThreadGroupLeader(tid) != pid) {
		return PackageManager.PERMISSION_DENIED;
		}
		try {
		// make good use of our CAP_SYS_NICE capability
		Process.setThreadGroup(tid, Binder.getCallingPid() == pid ?
		Process.THREAD_GROUP_AUDIO_SYS : Process.THREAD_GROUP_AUDIO_APP);
		// must be in this order or it fails the schedulability constraint
		Process.setThreadScheduler(tid, Process.SCHED_FIFO, prio);
		} catch (RuntimeException e) {
		return PackageManager.PERMISSION_DENIED;
		}
		return PackageManager.PERMISSION_GRANTED;
		}

		}