Small JS code cleanup.

1. `cat /proc/<pid>/cpuset` returns "background" for EJs, which implies
   they'll run on little cores
2. Added some annotations
3. Removed specialized method in favor of generic method.

Bug: 141645789
Bug: 171305774
Test: Android builds
Change-Id: I4b6a5776eddbcec1bc28ebbd0ba38577ba3a93c3

apex/jobscheduler/service/java/com/android/server/job/JobConcurrencyManager.java

@@ -25,6 +25,7 @@ import android.app.ActivityManager;
 import android.app.ActivityManagerInternal;
 import android.app.UserSwitchObserver;
 import android.app.job.JobInfo;
+import android.app.job.JobParameters;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
@@ -469,7 +470,7 @@ class JobConcurrencyManager {
         // Update the priorities of jobs that aren't running, and also count the pending work types.
         // Do this before the following loop to hopefully reduce the cost of
         // shouldStopRunningJobLocked().
-        updateNonRunningPriorities(pendingJobs, true);
+        updateNonRunningPrioritiesLocked(pendingJobs, true);
 
         for (int i = 0; i < MAX_JOB_CONTEXTS_COUNT; i++) {
             final JobServiceContext js = activeServices.get(i);
@@ -585,7 +586,8 @@ class JobConcurrencyManager {
                                 + activeServices.get(i).getRunningJobLocked());
                     }
                     // preferredUid will be set to uid of currently running job.
-                    activeServices.get(i).preemptExecutingJobLocked(preemptReasonForContext[i]);
+                    activeServices.get(i).cancelExecutingJobLocked(
+                            JobParameters.REASON_PREEMPT, preemptReasonForContext[i]);
                     preservePreferredUid = true;
                 } else {
                     final JobStatus pendingJob = contextIdToJobMap[i];
@@ -610,7 +612,8 @@ class JobConcurrencyManager {
                 mWorkCountTracker.getRunningJobCount(WORK_TYPE_TOP));
     }
 
-    private void updateNonRunningPriorities(@NonNull final List<JobStatus> pendingJobs,
+    @GuardedBy("mLock")
+    private void updateNonRunningPrioritiesLocked(@NonNull final List<JobStatus> pendingJobs,
             boolean updateCounter) {
         for (int i = 0; i < pendingJobs.size(); i++) {
             final JobStatus pending = pendingJobs.get(i);
@@ -628,6 +631,7 @@ class JobConcurrencyManager {
         }
     }
 
+    @GuardedBy("mLock")
     private void startJobLocked(@NonNull JobServiceContext worker, @NonNull JobStatus jobStatus,
             @WorkType final int workType) {
         final List<StateController> controllers = mService.mControllers;
@@ -647,6 +651,7 @@ class JobConcurrencyManager {
         }
     }
 
+    @GuardedBy("mLock")
     void onJobCompletedLocked(@NonNull JobServiceContext worker, @NonNull JobStatus jobStatus,
             @WorkType final int workType) {
         mWorkCountTracker.onJobFinished(workType);
@@ -655,7 +660,7 @@ class JobConcurrencyManager {
         if (worker.getPreferredUid() != JobServiceContext.NO_PREFERRED_UID) {
             updateCounterConfigLocked();
             // Preemption case needs special care.
-            updateNonRunningPriorities(pendingJobs, false);
+            updateNonRunningPrioritiesLocked(pendingJobs, false);
 
             JobStatus highestPriorityJob = null;
             int highPriWorkType = workType;
@@ -726,7 +731,7 @@ class JobConcurrencyManager {
             }
         } else if (pendingJobs.size() > 0) {
             updateCounterConfigLocked();
-            updateNonRunningPriorities(pendingJobs, false);
+            updateNonRunningPrioritiesLocked(pendingJobs, false);
 
             // This slot is now free and we have pending jobs. Start the highest priority job we
             // find.
@@ -775,6 +780,7 @@ class JobConcurrencyManager {
      * another job to run, or if system state suggests the job should stop.
      */
     @Nullable
+    @GuardedBy("mLock")
     String shouldStopRunningJobLocked(@NonNull JobServiceContext context) {
         final JobStatus js = context.getRunningJobLocked();
         if (js == null) {
@@ -881,6 +887,7 @@ class JobConcurrencyManager {
         return s.toString();
     }
 
+    @GuardedBy("mLock")
     void updateConfigLocked() {
         DeviceConfig.Properties properties =
                 DeviceConfig.getProperties(DeviceConfig.NAMESPACE_JOB_SCHEDULER);

apex/jobscheduler/service/java/com/android/server/job/JobServiceContext.java

@@ -269,8 +269,6 @@ public final class JobServiceContext implements ServiceConnection {
             try {
                 final int bindFlags;
                 if (job.shouldTreatAsExpeditedJob()) {
-                    // TODO(171305774): The job should run on the little cores. We'll probably need
-                    // another binding flag for that.
                     bindFlags = Context.BIND_AUTO_CREATE | Context.BIND_NOT_FOREGROUND
                             | Context.BIND_ALMOST_PERCEPTIBLE
                             | Context.BIND_ALLOW_NETWORK_ACCESS;
@@ -353,15 +351,10 @@ public final class JobServiceContext implements ServiceConnection {
 
     /** Called externally when a job that was scheduled for execution should be cancelled. */
     @GuardedBy("mLock")
-    void cancelExecutingJobLocked(int reason, String debugReason) {
+    void cancelExecutingJobLocked(int reason, @NonNull String debugReason) {
         doCancelLocked(reason, debugReason);
     }
 
-    @GuardedBy("mLock")
-    void preemptExecutingJobLocked(@NonNull String reason) {
-        doCancelLocked(JobParameters.REASON_PREEMPT, reason);
-    }
-
     int getPreferredUid() {
         return mPreferredUid;
     }
@@ -618,7 +611,7 @@ public final class JobServiceContext implements ServiceConnection {
     }
 
     @GuardedBy("mLock")
-    private void doCancelLocked(int stopReasonCode, String debugReason) {
+    private void doCancelLocked(int stopReasonCode, @Nullable String debugReason) {
         if (mVerb == VERB_FINISHED) {
             if (DEBUG) {
                 Slog.d(TAG,
@@ -731,7 +724,7 @@ public final class JobServiceContext implements ServiceConnection {
      *     _ENDING     -> No point in doing anything here, so we ignore.
      */
     @GuardedBy("mLock")
-    private void handleCancelLocked(String reason) {
+    private void handleCancelLocked(@Nullable String reason) {
         if (JobSchedulerService.DEBUG) {
             Slog.d(TAG, "Handling cancel for: " + mRunningJob.getJobId() + " "
                     + VERB_STRINGS[mVerb]);
@@ -815,7 +808,7 @@ public final class JobServiceContext implements ServiceConnection {
      * VERB_STOPPING.
      */
     @GuardedBy("mLock")
-    private void sendStopMessageLocked(String reason) {
+    private void sendStopMessageLocked(@Nullable String reason) {
         removeOpTimeOutLocked();
         if (mVerb != VERB_EXECUTING) {
             Slog.e(TAG, "Sending onStopJob for a job that isn't started. " + mRunningJob);
@@ -841,7 +834,7 @@ public final class JobServiceContext implements ServiceConnection {
      * we want to clean up internally.
      */
     @GuardedBy("mLock")
-    private void closeAndCleanupJobLocked(boolean reschedule, String reason) {
+    private void closeAndCleanupJobLocked(boolean reschedule, @Nullable String reason) {
         final JobStatus completedJob;
         if (mVerb == VERB_FINISHED) {
             return;
@@ -886,7 +879,7 @@ public final class JobServiceContext implements ServiceConnection {
         mJobConcurrencyManager.onJobCompletedLocked(this, completedJob, workType);
     }
 
-    private void applyStoppedReasonLocked(String reason) {
+    private void applyStoppedReasonLocked(@Nullable String reason) {
         if (reason != null && mStoppedReason == null) {
             mStoppedReason = reason;
             mStoppedTime = sElapsedRealtimeClock.millis();