SF: Cleanup EventControlThread
Primarily the goal was to eliminate the use of RefBase in various forms
from EventControlThread.
1) SurfaceFlinger only needs a std::unique_ptr<> and not an
android::sp<> to own the created instance.
2) Convert from android::Thread to std::thread, along with using
std::mutex and std::condition_variable to keep consistency.
3) The code only needs a reference to a function to call, rather than a
reference to all of SurfaceFlinger. This removes an unnecessary full
dependency.
4) Switch the header to #pragma once.
5) Added Clang thread annotations and enabled the corresponding warning.
6) Simplified the thread function to eliminate unnecessary locals and
indentation.
7) Added proper thread shutdown handling (invoked by dtor).
Bug: None
Test: Verified event control thread still works on Pixel XL
Change-Id: I2d5621b0cbbfb9e0f8c5831ccfc94704c95a4a55
diff --git a/services/surfaceflinger/Android.bp b/services/surfaceflinger/Android.bp
index 9f3189a..4ed4392 100644
--- a/services/surfaceflinger/Android.bp
+++ b/services/surfaceflinger/Android.bp
@@ -4,6 +4,7 @@
"-DLOG_TAG=\"SurfaceFlinger\"",
"-Wall",
"-Werror",
+ "-Wthread-safety",
"-Wunused",
"-Wunreachable-code",
],
diff --git a/services/surfaceflinger/EventControlThread.cpp b/services/surfaceflinger/EventControlThread.cpp
index 6fd4cdf..ac54059 100644
--- a/services/surfaceflinger/EventControlThread.cpp
+++ b/services/surfaceflinger/EventControlThread.cpp
@@ -14,45 +14,57 @@
* limitations under the License.
*/
+#include <pthread.h>
+#include <sched.h>
+#include <sys/resource.h>
+
+#include <cutils/sched_policy.h>
+#include <log/log.h>
+#include <system/thread_defs.h>
+
#include "EventControlThread.h"
-#include "SurfaceFlinger.h"
namespace android {
-EventControlThread::EventControlThread(const sp<SurfaceFlinger>& flinger)
- : mFlinger(flinger), mVsyncEnabled(false) {}
+EventControlThread::EventControlThread(EventControlThread::SetVSyncEnabledFunction function)
+ : mSetVSyncEnabled(function) {
+ pthread_setname_np(mThread.native_handle(), "EventControlThread");
-void EventControlThread::setVsyncEnabled(bool enabled) {
- Mutex::Autolock lock(mMutex);
- mVsyncEnabled = enabled;
- mCond.signal();
+ pid_t tid = pthread_gettid_np(mThread.native_handle());
+ setpriority(PRIO_PROCESS, tid, ANDROID_PRIORITY_URGENT_DISPLAY);
+ set_sched_policy(tid, SP_FOREGROUND);
}
-bool EventControlThread::threadLoop() {
- enum class VsyncState { Unset, On, Off };
- auto currentVsyncState = VsyncState::Unset;
-
- while (true) {
- auto requestedVsyncState = VsyncState::On;
- {
- Mutex::Autolock lock(mMutex);
- requestedVsyncState = mVsyncEnabled ? VsyncState::On : VsyncState::Off;
- while (currentVsyncState == requestedVsyncState) {
- status_t err = mCond.wait(mMutex);
- if (err != NO_ERROR) {
- ALOGE("error waiting for new events: %s (%d)", strerror(-err), err);
- return false;
- }
- requestedVsyncState = mVsyncEnabled ? VsyncState::On : VsyncState::Off;
- }
- }
-
- bool enable = requestedVsyncState == VsyncState::On;
- mFlinger->setVsyncEnabled(HWC_DISPLAY_PRIMARY, enable);
- currentVsyncState = requestedVsyncState;
+EventControlThread::~EventControlThread() {
+ {
+ std::lock_guard<std::mutex> lock(mMutex);
+ mKeepRunning = false;
+ mCondition.notify_all();
}
+ mThread.join();
+}
- return false;
+void EventControlThread::setVsyncEnabled(bool enabled) {
+ std::lock_guard<std::mutex> lock(mMutex);
+ mVsyncEnabled = enabled;
+ mCondition.notify_all();
+}
+
+// Unfortunately std::unique_lock gives warnings with -Wthread-safety
+void EventControlThread::threadMain() NO_THREAD_SAFETY_ANALYSIS {
+ auto keepRunning = true;
+ auto currentVsyncEnabled = false;
+
+ while (keepRunning) {
+ mSetVSyncEnabled(currentVsyncEnabled);
+
+ std::unique_lock<std::mutex> lock(mMutex);
+ mCondition.wait(lock, [this, currentVsyncEnabled, keepRunning]() NO_THREAD_SAFETY_ANALYSIS {
+ return currentVsyncEnabled != mVsyncEnabled || keepRunning != mKeepRunning;
+ });
+ currentVsyncEnabled = mVsyncEnabled;
+ keepRunning = mKeepRunning;
+ }
}
} // namespace android
diff --git a/services/surfaceflinger/EventControlThread.h b/services/surfaceflinger/EventControlThread.h
index 1b1ef75..321fb79 100644
--- a/services/surfaceflinger/EventControlThread.h
+++ b/services/surfaceflinger/EventControlThread.h
@@ -14,35 +14,41 @@
* limitations under the License.
*/
-#ifndef ANDROID_EVENTCONTROLTHREAD_H
-#define ANDROID_EVENTCONTROLTHREAD_H
+#pragma once
-#include <stddef.h>
+#include <cstddef>
+#include <condition_variable>
+#include <functional>
+#include <mutex>
+#include <thread>
-#include <utils/Mutex.h>
-#include <utils/Thread.h>
+#include <android-base/thread_annotations.h>
namespace android {
class SurfaceFlinger;
-class EventControlThread: public Thread {
+class EventControlThread {
public:
+ using SetVSyncEnabledFunction = std::function<void(bool)>;
- explicit EventControlThread(const sp<SurfaceFlinger>& flinger);
- virtual ~EventControlThread() {}
+ explicit EventControlThread(SetVSyncEnabledFunction function);
+ ~EventControlThread();
void setVsyncEnabled(bool enabled);
- virtual bool threadLoop();
private:
- sp<SurfaceFlinger> mFlinger;
- bool mVsyncEnabled;
+ void threadMain();
- Mutex mMutex;
- Condition mCond;
+ std::mutex mMutex;
+ std::condition_variable mCondition;
+
+ const SetVSyncEnabledFunction mSetVSyncEnabled;
+ bool mVsyncEnabled GUARDED_BY(mMutex) = false;
+ bool mKeepRunning GUARDED_BY(mMutex) = true;
+
+ // Must be last so that everything is initialized before the thread starts.
+ std::thread mThread{&EventControlThread::threadMain, this};
};
-}
-
-#endif // ANDROID_EVENTCONTROLTHREAD_H
+} // namespace android
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index d8740d9..70a282d 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -636,8 +636,9 @@
}
}
- mEventControlThread = new EventControlThread(this);
- mEventControlThread->run("EventControl", PRIORITY_URGENT_DISPLAY);
+ mEventControlThread = std::make_unique<EventControlThread>([this](bool enabled) {
+ setVsyncEnabled(HWC_DISPLAY_PRIMARY, enabled);
+ });
// initialize our drawing state
mDrawingState = mCurrentState;
@@ -1101,7 +1102,8 @@
return NO_ERROR;
}
-status_t SurfaceFlinger::getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) const {
+status_t SurfaceFlinger::getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) const
+ NO_THREAD_SAFETY_ANALYSIS {
IPCThreadState* ipc = IPCThreadState::self();
const int pid = ipc->getCallingPid();
const int uid = ipc->getCallingUid();
@@ -3567,7 +3569,8 @@
// ---------------------------------------------------------------------------
-status_t SurfaceFlinger::doDump(int fd, const Vector<String16>& args, bool asProto) {
+status_t SurfaceFlinger::doDump(int fd, const Vector<String16>& args, bool asProto)
+ NO_THREAD_SAFETY_ANALYSIS {
String8 result;
IPCThreadState* ipc = IPCThreadState::self();
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index bde1a8e..89f3930 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -723,7 +723,7 @@
sp<EventThread> mSFEventThread;
sp<EventThread> mInjectorEventThread;
sp<InjectVSyncSource> mVSyncInjector;
- sp<EventControlThread> mEventControlThread;
+ std::unique_ptr<EventControlThread> mEventControlThread;
sp<IBinder> mBuiltinDisplays[DisplayDevice::NUM_BUILTIN_DISPLAY_TYPES];
// Can only accessed from the main thread, these members