commit dddb7556b50d79d8db9baea18b936e93bd934cc5
author Austin Borger <borgera@google.com> Thu Mar 30 17:53:01 2023 -0700
committer Austin Borger <borgera@google.com> Thu Apr 27 17:12:45 2023 -0700
tree aff5d5e13e73ddb353923b63957c56cb261749cf
parent 95d65e209dbc738bc9a2da1393fc70750fd2ccf6

UidObserver / Camera: Track the OOM adj of a uid via UidObserver.

Previously, onUidProcAdjChanged merely signaled that the OOM adj of a
uid changed, but did not provide the actual OOM adj score. Having this
information allows the camera service to cut out redundant calls to
onCameraAccessPrioritiesChanged and avoid overwhelming apps.

The number of calls to onCameraAccessPrioritiesChanged is reduced by
only signaling when it's likely the uid owning a camera would lose
access to it if another uid tried to open that camera. This is opposed
to the status quo, which signals every time a watched uid changes its
OOM adj, which is highly inefficient.

Bug: 274486653
Test: -- on physical device:
      -- testCamera2AccessCallbackInSplitMode x10
      -- ActivityManagerServiceTest
      -- ActivityManagerProcessStateTest
      -- ActivityManagerFgsBgStartTest
      -- UidObserverControllerTest
      -- Alternate focus in split screen between Camera2 + GCA x20
Change-Id: I3e00490b835aefb74443c047e02c47d784e45f67

services/camera/libcameraservice/CameraService.h

diff --git a/services/camera/libcameraservice/CameraService.h b/services/camera/libcameraservice/CameraService.h
index ecec15f..8c57d26 100644
--- a/services/camera/libcameraservice/CameraService.h
+++ b/services/camera/libcameraservice/CameraService.h
@@ -233,6 +233,7 @@
 
     // Monitored UIDs availability notification
     void                notifyMonitoredUids();
+    void                notifyMonitoredUids(const std::unordered_set<uid_t> &notifyUidSet);
 
     // Stores current open session device info in temp file.
     void cacheDump();
@@ -763,13 +764,13 @@
         void onUidIdle(uid_t uid, bool disabled) override;
         void onUidStateChanged(uid_t uid, int32_t procState, int64_t procStateSeq,
                 int32_t capability) override;
-        void onUidProcAdjChanged(uid_t uid) override;
+        void onUidProcAdjChanged(uid_t uid, int adj) override;
 
         void addOverrideUid(uid_t uid, String16 callingPackage, bool active);
         void removeOverrideUid(uid_t uid, String16 callingPackage);
 
-        void registerMonitorUid(uid_t uid);
-        void unregisterMonitorUid(uid_t uid);
+        void registerMonitorUid(uid_t uid, bool openCamera);
+        void unregisterMonitorUid(uid_t uid, bool closeCamera);
 
         // Implementation of IServiceManager::LocalRegistrationCallback
         virtual void onServiceRegistration(const String16& name,
@@ -784,6 +785,8 @@
 
         struct MonitoredUid {
             int32_t procState;
+            int32_t procAdj;
+            bool hasCamera;
             size_t refCount;
         };