Activity Manager changes the scheduling group of processes.

The algorithm for this is currently very simple: all persistent processes are
always in the normal scheduling group, all other processes are normal if their
oom_adj is as good or better than VISIBLE, otherwise they are in the background
group.

Note that this currently results in a fair number of log messages about not
being able to change the group, since the system process does not have
permission to do so.  Once a kernel fix is in, these will go away and the code
will start working.

1 files changed, 12 insertions, 0 deletions

diff --git a/core/java/android/app/ActivityThread.java b/core/java/android/app/ActivityThread.java
index 1e15d14271d3..06e0a453b232 100644
--- a/core/java/android/app/ActivityThread.java
+++ b/core/java/android/app/ActivityThread.java
@@ -1513,6 +1513,18 @@ public final class ActivityThread {
             queueOrSendMessage(H.PROFILER_CONTROL, path, start ? 1 : 0);
         }
 
+        public void setSchedulingGroup(int group) {
+            // Note: do this immediately, since going into the foreground
+            // should happen regardless of what pending work we have to do
+            // and the activity manager will wait for us to report back that
+            // we are done before sending us to the background.
+            try {
+                Process.setProcessGroup(Process.myPid(), group);
+            } catch (Exception e) {
+                Log.w(TAG, "Failed setting process group to " + group, e);
+            }
+        }
+        
         @Override
         protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
             long nativeMax = Debug.getNativeHeapSize() / 1024;