Merge "Don't allow bg traffic to stall urgent traffic"

services/core/java/com/android/server/am/BroadcastConstants.java

@@ -136,14 +136,23 @@ public class BroadcastConstants {
     private static final boolean DEFAULT_MODERN_QUEUE_ENABLED = true;
 
     /**
-     * For {@link BroadcastQueueModernImpl}: Maximum number of process queues to
-     * dispatch broadcasts to simultaneously.
+     * For {@link BroadcastQueueModernImpl}: Maximum dispatch parallelism
+     * that we'll tolerate for ordinary broadcast dispatch.
      */
     public int MAX_RUNNING_PROCESS_QUEUES = DEFAULT_MAX_RUNNING_PROCESS_QUEUES;
     private static final String KEY_MAX_RUNNING_PROCESS_QUEUES = "bcast_max_running_process_queues";
     private static final int DEFAULT_MAX_RUNNING_PROCESS_QUEUES =
             ActivityManager.isLowRamDeviceStatic() ? 2 : 4;
 
+    /**
+     * For {@link BroadcastQueueModernImpl}: Additional running process queue parallelism beyond
+     * {@link #MAX_RUNNING_PROCESS_QUEUES} for dispatch of "urgent" broadcasts.
+     */
+    public int EXTRA_RUNNING_URGENT_PROCESS_QUEUES = DEFAULT_EXTRA_RUNNING_URGENT_PROCESS_QUEUES;
+    private static final String KEY_EXTRA_RUNNING_URGENT_PROCESS_QUEUES =
+            "bcast_extra_running_urgent_process_queues";
+    private static final int DEFAULT_EXTRA_RUNNING_URGENT_PROCESS_QUEUES = 1;
+
     /**
      * For {@link BroadcastQueueModernImpl}: Maximum number of active broadcasts
      * to dispatch to a "running" process queue before we retire them back to
@@ -250,6 +259,10 @@ public class BroadcastConstants {
         updateDeviceConfigConstants();
     }
 
+    public int getMaxRunningQueues() {
+        return MAX_RUNNING_PROCESS_QUEUES + EXTRA_RUNNING_URGENT_PROCESS_QUEUES;
+    }
+
     private void updateSettingsConstants() {
         synchronized (this) {
             try {
@@ -317,6 +330,9 @@ public class BroadcastConstants {
                     DEFAULT_MODERN_QUEUE_ENABLED);
             MAX_RUNNING_PROCESS_QUEUES = getDeviceConfigInt(KEY_MAX_RUNNING_PROCESS_QUEUES,
                     DEFAULT_MAX_RUNNING_PROCESS_QUEUES);
+            EXTRA_RUNNING_URGENT_PROCESS_QUEUES = getDeviceConfigInt(
+                    KEY_EXTRA_RUNNING_URGENT_PROCESS_QUEUES,
+                    DEFAULT_EXTRA_RUNNING_URGENT_PROCESS_QUEUES);
             MAX_RUNNING_ACTIVE_BROADCASTS = getDeviceConfigInt(KEY_MAX_RUNNING_ACTIVE_BROADCASTS,
                     DEFAULT_MAX_RUNNING_ACTIVE_BROADCASTS);
             MAX_PENDING_BROADCASTS = getDeviceConfigInt(KEY_MAX_PENDING_BROADCASTS,

services/core/java/com/android/server/am/BroadcastProcessQueue.java

@@ -583,6 +583,14 @@ class BroadcastProcessQueue {
         return mCountManifest > 0;
     }
 
+    /**
+     * Report whether this queue is currently handling an urgent broadcast.
+     */
+    public boolean isPendingUrgent() {
+        BroadcastRecord next = peekNextBroadcastRecord();
+        return (next != null) ? next.isUrgent() : false;
+    }
+
     /**
      * Quickly determine if this queue has broadcasts that are still waiting to
      * be delivered at some point in the future.

services/core/java/com/android/server/am/BroadcastQueueModernImpl.java

@@ -138,7 +138,7 @@ class BroadcastQueueModernImpl extends BroadcastQueue {
 
         // We configure runnable size only once at boot; it'd be too complex to
         // try resizing dynamically at runtime
-        mRunning = new BroadcastProcessQueue[mConstants.MAX_RUNNING_PROCESS_QUEUES];
+        mRunning = new BroadcastProcessQueue[mConstants.getMaxRunningQueues()];
     }
 
     /**
@@ -292,6 +292,19 @@ class BroadcastQueueModernImpl extends BroadcastQueue {
         return size;
     }
 
+    /**
+     * Return the number of active queues that are delivering "urgent" broadcasts
+     */
+    private int getRunningUrgentCount() {
+        int count = 0;
+        for (int i = 0; i < mRunning.length; i++) {
+            if (mRunning[i] != null && mRunning[i].getActive().isUrgent()) {
+                count++;
+            }
+        }
+        return count;
+    }
+
     /**
      * Return the first index of the given value contained inside
      * {@link #mRunning}, otherwise {@code -1}.
@@ -356,7 +369,15 @@ class BroadcastQueueModernImpl extends BroadcastQueue {
      */
     @GuardedBy("mService")
     private void updateRunningListLocked() {
-        int avail = mRunning.length - getRunningSize();
+        // Allocated size here implicitly includes the extra reservation for urgent
+        // dispatches beyond the MAX_RUNNING_QUEUES soft limit for normal
+        // parallelism.  If we're already dispatching some urgent broadcasts,
+        // count that against the extra first - its role is to permit progress of
+        // urgent broadcast traffic when the normal reservation is fully occupied
+        // with less-urgent dispatches, not to generally expand parallelism.
+        final int usedExtra = Math.min(getRunningUrgentCount(),
+                mConstants.EXTRA_RUNNING_URGENT_PROCESS_QUEUES);
+        int avail = mRunning.length - getRunningSize() - usedExtra;
         if (avail == 0) return;
 
         final int cookie = traceBegin("updateRunningList");
@@ -382,6 +403,15 @@ class BroadcastQueueModernImpl extends BroadcastQueue {
                 continue;
             }
 
+            // If we've hit the soft limit for non-urgent dispatch parallelism,
+            // only consider delivering from queues whose ready broadcast is urgent
+            if (getRunningSize() >= mConstants.MAX_RUNNING_PROCESS_QUEUES) {
+                if (!queue.isPendingUrgent()) {
+                    queue = nextQueue;
+                    continue;
+                }
+            }
+
             // If queues beyond this point aren't ready to run yet, schedule
             // another pass when they'll be runnable
             if (runnableAt > now && !waitingFor) {