NBLog periodic merging thread

Bug: 35468674
Test: no change in functionality, everything works as before
Change-Id: Id2cea243bc15767ca6803c9505bf23a18411500e
diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 3d1f268..c0918d4 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -129,6 +129,7 @@
 
 AudioFlinger::AudioFlinger()
     : BnAudioFlinger(),
+      mMediaLogNotifier(new AudioFlinger::MediaLogNotifier()),
       mPrimaryHardwareDev(NULL),
       mAudioHwDevs(NULL),
       mHardwareStatus(AUDIO_HW_IDLE),
@@ -163,6 +164,8 @@
     mDevicesFactoryHal = DevicesFactoryHalInterface::create();
     mEffectsFactoryHal = EffectsFactoryHalInterface::create();
 
+    mMediaLogNotifier->run("MediaLogNotifier");
+
 #ifdef TEE_SINK
     char value[PROPERTY_VALUE_MAX];
     (void) property_get("ro.debuggable", value, "0");
@@ -1528,6 +1531,41 @@
     mAudioFlinger->removeNotificationClient(mPid);
 }
 
+// ----------------------------------------------------------------------------
+AudioFlinger::MediaLogNotifier::MediaLogNotifier()
+    : mPendingRequests(false) {}
+
+
+void AudioFlinger::MediaLogNotifier::requestMerge() {
+    AutoMutex _l(mMutex);
+    mPendingRequests = true;
+    mCond.signal();
+}
+
+bool AudioFlinger::MediaLogNotifier::threadLoop() {
+    // Wait until there are pending requests
+    {
+        AutoMutex _l(mMutex);
+        mPendingRequests = false; // to ignore past requests
+        while (!mPendingRequests) {
+            mCond.wait(mMutex);
+            // TODO may also need an exitPending check
+        }
+        mPendingRequests = false;
+    }
+    // Execute the actual MediaLogService binder call and ignore extra requests for a while
+    sp<IBinder> binder = defaultServiceManager()->getService(String16("media.log"));
+    if (binder != 0) {
+        sp<IMediaLogService> mediaLogService(interface_cast<IMediaLogService>(binder));
+        mediaLogService->requestMergeWakeup();
+    }
+    usleep(kPostTriggerSleepPeriod);
+    return true;
+}
+
+void AudioFlinger::requestLogMerge() {
+    mMediaLogNotifier->requestMerge();
+}
 
 // ----------------------------------------------------------------------------
 
diff --git a/services/audioflinger/AudioFlinger.h b/services/audioflinger/AudioFlinger.h
index 44fd512..f9c4ffd 100644
--- a/services/audioflinger/AudioFlinger.h
+++ b/services/audioflinger/AudioFlinger.h
@@ -472,6 +472,38 @@
         const sp<IAudioFlingerClient> mAudioFlingerClient;
     };
 
+    // --- MediaLogNotifier ---
+    // Thread in charge of notifying MediaLogService to start merging.
+    // Receives requests from AudioFlinger's binder activity. It is used to reduce the amount of
+    // binder calls to MediaLogService in case of bursts of AudioFlinger binder calls.
+    class MediaLogNotifier : public Thread {
+    public:
+        MediaLogNotifier();
+
+        // Requests a MediaLogService notification. It's ignored if there has recently been another
+        void requestMerge();
+    private:
+        // Every iteration blocks waiting for a request, then interacts with MediaLogService to
+        // start merging.
+        // As every MediaLogService binder call is expensive, once it gets a request it ignores the
+        // following ones for a period of time.
+        virtual bool threadLoop() override;
+
+        bool mPendingRequests;
+
+        // Mutex and condition variable around mPendingRequests' value
+        Mutex       mMutex;
+        Condition   mCond;
+
+        // Duration of the sleep period after a processed request
+        static const int kPostTriggerSleepPeriod = 1000000;
+    };
+
+    const sp<MediaLogNotifier> mMediaLogNotifier;
+
+    // This is a helper that is called during incoming binder calls.
+    void requestLogMerge();
+
     class TrackHandle;
     class RecordHandle;
     class RecordThread;
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index b10e42c..b247b64 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -2953,6 +2953,10 @@
 #endif
     while (!exitPending())
     {
+        // Log merge requests are performed during AudioFlinger binder transactions, but
+        // that does not cover audio playback. It's requested here for that reason.
+        mAudioFlinger->requestLogMerge();
+
         cpuStats.sample(myName);
 
         Vector< sp<EffectChain> > effectChains;
diff --git a/services/medialog/IMediaLogService.cpp b/services/medialog/IMediaLogService.cpp
index bc445ff..0e9b01e 100644
--- a/services/medialog/IMediaLogService.cpp
+++ b/services/medialog/IMediaLogService.cpp
@@ -29,6 +29,7 @@
 enum {
     REGISTER_WRITER = IBinder::FIRST_CALL_TRANSACTION,
     UNREGISTER_WRITER,
+    REQUEST_MERGE_WAKEUP,
 };
 
 class BpMediaLogService : public BpInterface<IMediaLogService>
@@ -57,6 +58,13 @@
         // FIXME ignores status
     }
 
+    virtual void    requestMergeWakeup() {
+        Parcel data, reply;
+        data.writeInterfaceToken(IMediaLogService::getInterfaceDescriptor());
+        status_t status __unused = remote()->transact(REQUEST_MERGE_WAKEUP, data, &reply);
+        // FIXME ignores status
+    }
+
 };
 
 IMPLEMENT_META_INTERFACE(MediaLogService, "android.media.IMediaLogService");
@@ -84,6 +92,12 @@
             return NO_ERROR;
         }
 
+        case REQUEST_MERGE_WAKEUP: {
+            CHECK_INTERFACE(IMediaLogService, data, reply);
+            requestMergeWakeup();
+            return NO_ERROR;
+        }
+
         default:
             return BBinder::onTransact(code, data, reply, flags);
     }
diff --git a/services/medialog/MediaLogService.cpp b/services/medialog/MediaLogService.cpp
index 4c81436..aaf1018 100644
--- a/services/medialog/MediaLogService.cpp
+++ b/services/medialog/MediaLogService.cpp
@@ -27,6 +27,23 @@
 namespace android {
 
 // static const char kDeadlockedString[] = "MediaLogService may be deadlocked\n";
+MediaLogService::MediaLogService() :
+    BnMediaLogService(),
+    mMergerShared((NBLog::Shared*) malloc(NBLog::Timeline::sharedSize(kMergeBufferSize))),
+    mMerger(mMergerShared, kMergeBufferSize),
+    mMergeReader(mMergerShared, kMergeBufferSize, mMerger),
+    mMergeThread(new NBLog::MergeThread(mMerger))
+{
+    mMergeThread->run("MergeThread");
+}
+
+MediaLogService::~MediaLogService()
+{
+    mMergeThread->requestExit();
+    mMergeThread->setTimeoutUs(0);
+    mMergeThread->join();
+    free(mMergerShared);
+}
 
 void MediaLogService::registerWriter(const sp<IMemory>& shared, size_t size, const char *name)
 {
@@ -111,8 +128,7 @@
         mLock.unlock();
     }
 #endif
-
-    mMerger.merge();
+    // FIXME request merge to make sure log is up to date
     mMergeReader.dump(fd);
     return NO_ERROR;
 }
@@ -123,4 +139,8 @@
     return BnMediaLogService::onTransact(code, data, reply, flags);
 }
 
+void MediaLogService::requestMergeWakeup() {
+    mMergeThread->wakeup();
+}
+
 }   // namespace android
diff --git a/services/medialog/MediaLogService.h b/services/medialog/MediaLogService.h
index e934844..c6b99f1 100644
--- a/services/medialog/MediaLogService.h
+++ b/services/medialog/MediaLogService.h
@@ -27,13 +27,8 @@
 {
     friend class BinderService<MediaLogService>;    // for MediaLogService()
 public:
-    MediaLogService() :
-        BnMediaLogService(),
-        mMergerShared((NBLog::Shared*) malloc(NBLog::Timeline::sharedSize(kMergeBufferSize))),
-        mMerger(mMergerShared, kMergeBufferSize),
-        mMergeReader(mMergerShared, kMergeBufferSize, mMerger)
-    {ALOGI("Nico creating MergeReader");}
-    virtual ~MediaLogService() { free(mMergerShared); }
+    MediaLogService();
+    virtual ~MediaLogService() override;
     virtual void onFirstRef() { }
 
     static const char*  getServiceName() { return "media.log"; }
@@ -47,6 +42,8 @@
     virtual status_t    onTransact(uint32_t code, const Parcel& data, Parcel* reply,
                                 uint32_t flags);
 
+    virtual void        requestMergeWakeup() override;
+
 private:
 
     // Internal dump
@@ -58,10 +55,10 @@
     Mutex               mLock;
 
     Vector<NBLog::NamedReader> mNamedReaders;
-
     NBLog::Shared *mMergerShared;
     NBLog::Merger mMerger;
     NBLog::MergeReader mMergeReader;
+    const sp<NBLog::MergeThread> mMergeThread;
 };
 
 }   // namespace android