Run audio at priorities 2 and 3 above kernel 1

Also run the watchdog at same priority as the fast mixer.
requestPriority() originally used only the caller's pid to decide which
cgroup to assign, but in the future it might look at the priority also.
So it's safer to use same priority as the fast mixer to be sure we
run in the same cgroup.

Bug: 6461925
Change-Id: Ia59c93e4b22dacbb6746bfa6ad491be7b72f2b8d

1 files changed, 10 insertions, 6 deletions

diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 0c86e20..e7abc45 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -161,6 +161,10 @@ static const enum {
 static uint32_t gScreenState; // incremented by 2 when screen state changes, bit 0 == 1 means "off"
                               // AudioFlinger::setParameters() updates, other threads read w/o lock
 
+// Priorities for requestPriority
+static const int kPriorityAudioApp = 2;
+static const int kPriorityFastMixer = 3;
+
 // ----------------------------------------------------------------------------
 
 #ifdef ADD_BATTERY_DATA
@@ -1795,10 +1799,10 @@ sp<AudioFlinger::PlaybackThread::Track> AudioFlinger::PlaybackThread::createTrac
         pid_t callingPid = IPCThreadState::self()->getCallingPid();
         // we don't have CAP_SYS_NICE, nor do we want to have it as it's too powerful,
         // so ask activity manager to do this on our behalf
-        int err = requestPriority(callingPid, tid, 1);
+        int err = requestPriority(callingPid, tid, kPriorityAudioApp);
         if (err != 0) {
             ALOGW("Policy SCHED_FIFO priority %d is unavailable for pid %d tid %d; error %d",
-                    1, callingPid, tid, err);
+                    kPriorityAudioApp, callingPid, tid, err);
         }
     }
 
@@ -2281,10 +2285,10 @@ AudioFlinger::MixerThread::MixerThread(const sp<AudioFlinger>& audioFlinger, Aud
         // start the fast mixer
         mFastMixer->run("FastMixer", PRIORITY_URGENT_AUDIO);
         pid_t tid = mFastMixer->getTid();
-        int err = requestPriority(getpid_cached, tid, 2);
+        int err = requestPriority(getpid_cached, tid, kPriorityFastMixer);
         if (err != 0) {
             ALOGW("Policy SCHED_FIFO priority %d is unavailable for pid %d tid %d; error %d",
-                    2, getpid_cached, tid, err);
+                    kPriorityFastMixer, getpid_cached, tid, err);
         }
 
 #ifdef AUDIO_WATCHDOG
@@ -2293,10 +2297,10 @@ AudioFlinger::MixerThread::MixerThread(const sp<AudioFlinger>& audioFlinger, Aud
         mAudioWatchdog->setDump(&mAudioWatchdogDump);
         mAudioWatchdog->run("AudioWatchdog", PRIORITY_URGENT_AUDIO);
         tid = mAudioWatchdog->getTid();
-        err = requestPriority(getpid_cached, tid, 1);
+        err = requestPriority(getpid_cached, tid, kPriorityFastMixer);
         if (err != 0) {
             ALOGW("Policy SCHED_FIFO priority %d is unavailable for pid %d tid %d; error %d",
-                    1, getpid_cached, tid, err);
+                    kPriorityFastMixer, getpid_cached, tid, err);
         }
 #endif