Merge "Rename nextTransaction to syncTransaction"
diff --git a/cmds/installd/InstalldNativeService.cpp b/cmds/installd/InstalldNativeService.cpp
index 39ef0b5..8d23efc 100644
--- a/cmds/installd/InstalldNativeService.cpp
+++ b/cmds/installd/InstalldNativeService.cpp
@@ -1455,7 +1455,7 @@
 }
 
 binder::Status InstalldNativeService::freeCache(const std::optional<std::string>& uuid,
-        int64_t targetFreeBytes, int64_t cacheReservedBytes, int32_t flags) {
+        int64_t targetFreeBytes, int32_t flags) {
     ENFORCE_UID(AID_SYSTEM);
     CHECK_ARGUMENT_UUID(uuid);
     std::lock_guard<std::recursive_mutex> lock(mLock);
@@ -1558,12 +1558,6 @@
                 break;
             }
 
-            // Only keep clearing when we haven't pushed into reserved area
-            if (cacheReservedBytes > 0 && cleared >= (cacheTotal - cacheReservedBytes)) {
-                LOG(DEBUG) << "Refusing to clear cached data in reserved space";
-                break;
-            }
-
             // Find the best tracker to work with; this might involve swapping
             // if the active tracker is no longer the most over quota
             bool nextBetter = active && !queue.empty()
diff --git a/cmds/installd/InstalldNativeService.h b/cmds/installd/InstalldNativeService.h
index 8cfda01..3fdb01a 100644
--- a/cmds/installd/InstalldNativeService.h
+++ b/cmds/installd/InstalldNativeService.h
@@ -145,7 +145,7 @@
 
     binder::Status rmPackageDir(const std::string& packageDir);
     binder::Status freeCache(const std::optional<std::string>& uuid, int64_t targetFreeBytes,
-            int64_t cacheReservedBytes, int32_t flags);
+            int32_t flags);
     binder::Status linkNativeLibraryDirectory(const std::optional<std::string>& uuid,
             const std::string& packageName, const std::string& nativeLibPath32, int32_t userId);
     binder::Status createOatDir(const std::string& oatDir, const std::string& instructionSet);
diff --git a/cmds/installd/binder/android/os/IInstalld.aidl b/cmds/installd/binder/android/os/IInstalld.aidl
index 637a9f2..9c51ff7 100644
--- a/cmds/installd/binder/android/os/IInstalld.aidl
+++ b/cmds/installd/binder/android/os/IInstalld.aidl
@@ -86,8 +86,7 @@
     void destroyProfileSnapshot(@utf8InCpp String packageName, @utf8InCpp String profileName);
 
     void rmPackageDir(@utf8InCpp String packageDir);
-    void freeCache(@nullable @utf8InCpp String uuid, long targetFreeBytes,
-            long cacheReservedBytes, int flags);
+    void freeCache(@nullable @utf8InCpp String uuid, long targetFreeBytes, int flags);
     void linkNativeLibraryDirectory(@nullable @utf8InCpp String uuid,
             @utf8InCpp String packageName, @utf8InCpp String nativeLibPath32, int userId);
     void createOatDir(@utf8InCpp String oatDir, @utf8InCpp String instructionSet);
diff --git a/cmds/installd/tests/installd_cache_test.cpp b/cmds/installd/tests/installd_cache_test.cpp
index 863cdfe..9a1e17e 100644
--- a/cmds/installd/tests/installd_cache_test.cpp
+++ b/cmds/installd/tests/installd_cache_test.cpp
@@ -145,7 +145,7 @@
     EXPECT_EQ(0, exists("com.example/cache/foo/one"));
     EXPECT_EQ(0, exists("com.example/cache/foo/two"));
 
-    service->freeCache(testUuid, kTbInBytes, 0,
+    service->freeCache(testUuid, kTbInBytes,
             FLAG_FREE_CACHE_V2 | FLAG_FREE_CACHE_V2_DEFY_QUOTA);
 
     EXPECT_EQ(0, exists("com.example/normal"));
@@ -153,6 +153,33 @@
     EXPECT_EQ(-1, exists("com.example/cache/foo/two"));
 }
 
+TEST_F(CacheTest, FreeCache_NonAggressive) {
+    LOG(INFO) << "FreeCache_NonAggressive";
+
+    mkdir("com.example");
+    touch("com.example/normal", 1 * kMbInBytes, 60);
+    mkdir("com.example/cache");
+    mkdir("com.example/cache/foo");
+    touch("com.example/cache/foo/one", 65 * kMbInBytes, 60);
+    touch("com.example/cache/foo/two", 2 * kMbInBytes, 120);
+
+    EXPECT_EQ(0, exists("com.example/normal"));
+    EXPECT_EQ(0, exists("com.example/cache/foo/one"));
+    EXPECT_EQ(0, exists("com.example/cache/foo/two"));
+
+    service->freeCache(testUuid, kTbInBytes, FLAG_FREE_CACHE_V2);
+
+    EXPECT_EQ(0, exists("com.example/normal"));
+    EXPECT_EQ(-1, exists("com.example/cache/foo/one"));
+    EXPECT_EQ(0, exists("com.example/cache/foo/two"));
+
+    service->freeCache(testUuid, kTbInBytes, FLAG_FREE_CACHE_V2);
+
+    EXPECT_EQ(0, exists("com.example/normal"));
+    EXPECT_EQ(-1, exists("com.example/cache/foo/one"));
+    EXPECT_EQ(0, exists("com.example/cache/foo/two"));
+}
+
 TEST_F(CacheTest, FreeCache_Age) {
     LOG(INFO) << "FreeCache_Age";
 
@@ -162,13 +189,13 @@
     touch("com.example/cache/foo/one", kMbInBytes, 60);
     touch("com.example/cache/foo/two", kMbInBytes, 120);
 
-    service->freeCache(testUuid, free() + kKbInBytes, 0,
+    service->freeCache(testUuid, free() + kKbInBytes,
             FLAG_FREE_CACHE_V2 | FLAG_FREE_CACHE_V2_DEFY_QUOTA);
 
     EXPECT_EQ(-1, exists("com.example/cache/foo/one"));
     EXPECT_EQ(0, exists("com.example/cache/foo/two"));
 
-    service->freeCache(testUuid, free() + kKbInBytes, 0,
+    service->freeCache(testUuid, free() + kKbInBytes,
             FLAG_FREE_CACHE_V2 | FLAG_FREE_CACHE_V2_DEFY_QUOTA);
 
     EXPECT_EQ(-1, exists("com.example/cache/foo/one"));
@@ -196,7 +223,7 @@
     EXPECT_EQ(2 * kMbInBytes, size("com.example/cache/bar/bar1"));
     EXPECT_EQ(2 * kMbInBytes, size("com.example/cache/bar/bar2"));
 
-    service->freeCache(testUuid, kTbInBytes, 0,
+    service->freeCache(testUuid, kTbInBytes,
             FLAG_FREE_CACHE_V2 | FLAG_FREE_CACHE_V2_DEFY_QUOTA);
 
     EXPECT_EQ(-1, exists("com.example/cache/foo/foo1"));
@@ -218,7 +245,7 @@
 
     setxattr("com.example/cache/foo", "user.cache_group");
 
-    service->freeCache(testUuid, free() + kKbInBytes, 0,
+    service->freeCache(testUuid, free() + kKbInBytes,
             FLAG_FREE_CACHE_V2 | FLAG_FREE_CACHE_V2_DEFY_QUOTA);
 
     EXPECT_EQ(-1, exists("com.example/cache/foo/foo1"));
@@ -263,7 +290,7 @@
     setxattr("com.example/cache/tomb", "user.cache_tombstone");
     setxattr("com.example/cache/tomb/group", "user.cache_group");
 
-    service->freeCache(testUuid, free() + kKbInBytes, 0,
+    service->freeCache(testUuid, free() + kKbInBytes,
             FLAG_FREE_CACHE_V2 | FLAG_FREE_CACHE_V2_DEFY_QUOTA);
 
     EXPECT_EQ(kMbInBytes, size("com.example/cache/group/file1"));
@@ -284,7 +311,7 @@
     EXPECT_EQ(0, size("com.example/cache/tomb/group/dir/file1"));
     EXPECT_EQ(0, size("com.example/cache/tomb/group/dir/file2"));
 
-    service->freeCache(testUuid, free() + kKbInBytes, 0,
+    service->freeCache(testUuid, free() + kKbInBytes,
             FLAG_FREE_CACHE_V2 | FLAG_FREE_CACHE_V2_DEFY_QUOTA);
 
     EXPECT_EQ(-1, size("com.example/cache/group/file1"));
@@ -305,7 +332,7 @@
     EXPECT_EQ(0, size("com.example/cache/tomb/group/dir/file1"));
     EXPECT_EQ(0, size("com.example/cache/tomb/group/dir/file2"));
 
-    service->freeCache(testUuid, kTbInBytes, 0,
+    service->freeCache(testUuid, kTbInBytes,
             FLAG_FREE_CACHE_V2 | FLAG_FREE_CACHE_V2_DEFY_QUOTA);
 
     EXPECT_EQ(-1, size("com.example/cache/group/file1"));
diff --git a/data/etc/Android.bp b/data/etc/Android.bp
index 5fe4ea1..931c5e3 100644
--- a/data/etc/Android.bp
+++ b/data/etc/Android.bp
@@ -89,6 +89,12 @@
 }
 
 prebuilt_etc {
+    name: "android.hardware.fingerprint.prebuilt.xml",
+    src: "android.hardware.fingerprint.xml",
+    defaults: ["frameworks_native_data_etc_defaults"],
+}
+
+prebuilt_etc {
     name: "android.hardware.location.gps.prebuilt.xml",
     src: "android.hardware.location.gps.xml",
     defaults: ["frameworks_native_data_etc_defaults"],
diff --git a/libs/binder/ndk/libbinder_ndk.map.txt b/libs/binder/ndk/libbinder_ndk.map.txt
index d63a8d0..197c0a1 100644
--- a/libs/binder/ndk/libbinder_ndk.map.txt
+++ b/libs/binder/ndk/libbinder_ndk.map.txt
@@ -119,11 +119,11 @@
     AIBinder_setRequestingSid; # apex
     AParcel_markSensitive; # systemapi llndk
     AServiceManager_forEachDeclaredInstance; # apex llndk
-    AServiceManager_forceLazyServicesPersist; # llndk
+    AServiceManager_forceLazyServicesPersist; # apex llndk
     AServiceManager_isDeclared; # apex llndk
     AServiceManager_isUpdatableViaApex; # apex
     AServiceManager_reRegister; # llndk
-    AServiceManager_registerLazyService; # llndk
+    AServiceManager_registerLazyService; # apex llndk
     AServiceManager_setActiveServicesCallback; # llndk
     AServiceManager_tryUnregister; # llndk
     AServiceManager_waitForService; # apex llndk
diff --git a/services/surfaceflinger/Android.bp b/services/surfaceflinger/Android.bp
index 6691575..fb42cc0 100644
--- a/services/surfaceflinger/Android.bp
+++ b/services/surfaceflinger/Android.bp
@@ -201,7 +201,7 @@
         "SurfaceFlinger.cpp",
         "SurfaceFlingerDefaultFactory.cpp",
         "SurfaceInterceptor.cpp",
-        "SurfaceTracing.cpp",
+        "Tracing/LayerTracing.cpp",
         "Tracing/TransactionProtoParser.cpp",
         "TransactionCallbackInvoker.cpp",
         "TunnelModeEnabledReporter.cpp",
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index e606e55..968a49d 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -2005,7 +2005,7 @@
     writeToProtoDrawingState(layerProto, traceFlags, display);
     writeToProtoCommonState(layerProto, LayerVector::StateSet::Drawing, traceFlags);
 
-    if (traceFlags & SurfaceTracing::TRACE_COMPOSITION) {
+    if (traceFlags & LayerTracing::TRACE_COMPOSITION) {
         // Only populate for the primary display.
         if (display) {
             const Hwc2::IComposerClient::Composition compositionType = getCompositionType(*display);
@@ -2023,43 +2023,38 @@
 void Layer::writeToProtoDrawingState(LayerProto* layerInfo, uint32_t traceFlags,
                                      const DisplayDevice* display) {
     const ui::Transform transform = getTransform();
+    auto buffer = getBuffer();
+    if (buffer != nullptr) {
+        LayerProtoHelper::writeToProto(buffer,
+                                       [&]() { return layerInfo->mutable_active_buffer(); });
+        LayerProtoHelper::writeToProtoDeprecated(ui::Transform(getBufferTransform()),
+                                                 layerInfo->mutable_buffer_transform());
+    }
+    layerInfo->set_invalidate(contentDirty);
+    layerInfo->set_is_protected(isProtected());
+    layerInfo->set_dataspace(dataspaceDetails(static_cast<android_dataspace>(getDataSpace())));
+    layerInfo->set_queued_frames(getQueuedFrameCount());
+    layerInfo->set_refresh_pending(isBufferLatched());
+    layerInfo->set_curr_frame(mCurrentFrameNumber);
+    layerInfo->set_effective_scaling_mode(getEffectiveScalingMode());
 
-    if (traceFlags & SurfaceTracing::TRACE_CRITICAL) {
+    layerInfo->set_requested_corner_radius(getDrawingState().cornerRadius);
+    layerInfo->set_corner_radius(getRoundedCornerState().radius);
+    layerInfo->set_background_blur_radius(getBackgroundBlurRadius());
+    layerInfo->set_is_trusted_overlay(isTrustedOverlay());
+    LayerProtoHelper::writeToProtoDeprecated(transform, layerInfo->mutable_transform());
+    LayerProtoHelper::writePositionToProto(transform.tx(), transform.ty(),
+                                           [&]() { return layerInfo->mutable_position(); });
+    LayerProtoHelper::writeToProto(mBounds, [&]() { return layerInfo->mutable_bounds(); });
+    if (traceFlags & LayerTracing::TRACE_COMPOSITION) {
+        LayerProtoHelper::writeToProto(getVisibleRegion(display),
+                                       [&]() { return layerInfo->mutable_visible_region(); });
+    }
+    LayerProtoHelper::writeToProto(surfaceDamageRegion,
+                                   [&]() { return layerInfo->mutable_damage_region(); });
 
-        auto buffer = getBuffer();
-        if (buffer != nullptr) {
-            LayerProtoHelper::writeToProto(buffer,
-                                           [&]() { return layerInfo->mutable_active_buffer(); });
-            LayerProtoHelper::writeToProtoDeprecated(ui::Transform(getBufferTransform()),
-                                                     layerInfo->mutable_buffer_transform());
-        }
-        layerInfo->set_invalidate(contentDirty);
-        layerInfo->set_is_protected(isProtected());
-        layerInfo->set_dataspace(dataspaceDetails(static_cast<android_dataspace>(getDataSpace())));
-        layerInfo->set_queued_frames(getQueuedFrameCount());
-        layerInfo->set_refresh_pending(isBufferLatched());
-        layerInfo->set_curr_frame(mCurrentFrameNumber);
-        layerInfo->set_effective_scaling_mode(getEffectiveScalingMode());
-
-        layerInfo->set_requested_corner_radius(getDrawingState().cornerRadius);
-        layerInfo->set_corner_radius(getRoundedCornerState().radius);
-        layerInfo->set_background_blur_radius(getBackgroundBlurRadius());
-        layerInfo->set_is_trusted_overlay(isTrustedOverlay());
-        LayerProtoHelper::writeToProtoDeprecated(transform, layerInfo->mutable_transform());
-        LayerProtoHelper::writePositionToProto(transform.tx(), transform.ty(),
-                                               [&]() { return layerInfo->mutable_position(); });
-        LayerProtoHelper::writeToProto(mBounds, [&]() { return layerInfo->mutable_bounds(); });
-        if (traceFlags & SurfaceTracing::TRACE_COMPOSITION) {
-            LayerProtoHelper::writeToProto(getVisibleRegion(display),
-                                           [&]() { return layerInfo->mutable_visible_region(); });
-        }
-        LayerProtoHelper::writeToProto(surfaceDamageRegion,
-                                       [&]() { return layerInfo->mutable_damage_region(); });
-
-        if (hasColorTransform()) {
-            LayerProtoHelper::writeToProto(getColorTransform(),
-                                           layerInfo->mutable_color_transform());
-        }
+    if (hasColorTransform()) {
+        LayerProtoHelper::writeToProto(getColorTransform(), layerInfo->mutable_color_transform());
     }
 
     LayerProtoHelper::writeToProto(mSourceBounds,
@@ -2079,70 +2074,66 @@
 
     ui::Transform requestedTransform = state.transform;
 
-    if (traceFlags & SurfaceTracing::TRACE_CRITICAL) {
-        layerInfo->set_id(sequence);
-        layerInfo->set_name(getName().c_str());
-        layerInfo->set_type(getType());
+    layerInfo->set_id(sequence);
+    layerInfo->set_name(getName().c_str());
+    layerInfo->set_type(getType());
 
-        for (const auto& child : children) {
-            layerInfo->add_children(child->sequence);
-        }
-
-        for (const wp<Layer>& weakRelative : state.zOrderRelatives) {
-            sp<Layer> strongRelative = weakRelative.promote();
-            if (strongRelative != nullptr) {
-                layerInfo->add_relatives(strongRelative->sequence);
-            }
-        }
-
-        LayerProtoHelper::writeToProto(state.activeTransparentRegion_legacy,
-                                       [&]() { return layerInfo->mutable_transparent_region(); });
-
-        layerInfo->set_layer_stack(getLayerStack().id);
-        layerInfo->set_z(state.z);
-
-        LayerProtoHelper::writePositionToProto(requestedTransform.tx(), requestedTransform.ty(),
-                                               [&]() {
-                                                   return layerInfo->mutable_requested_position();
-                                               });
-
-        LayerProtoHelper::writeSizeToProto(state.width, state.height,
-                                           [&]() { return layerInfo->mutable_size(); });
-
-        LayerProtoHelper::writeToProto(state.crop, [&]() { return layerInfo->mutable_crop(); });
-
-        layerInfo->set_is_opaque(isOpaque(state));
-
-
-        layerInfo->set_pixel_format(decodePixelFormat(getPixelFormat()));
-        LayerProtoHelper::writeToProto(getColor(), [&]() { return layerInfo->mutable_color(); });
-        LayerProtoHelper::writeToProto(state.color,
-                                       [&]() { return layerInfo->mutable_requested_color(); });
-        layerInfo->set_flags(state.flags);
-
-        LayerProtoHelper::writeToProtoDeprecated(requestedTransform,
-                                                 layerInfo->mutable_requested_transform());
-
-        auto parent = useDrawing ? mDrawingParent.promote() : mCurrentParent.promote();
-        if (parent != nullptr) {
-            layerInfo->set_parent(parent->sequence);
-        } else {
-            layerInfo->set_parent(-1);
-        }
-
-        auto zOrderRelativeOf = state.zOrderRelativeOf.promote();
-        if (zOrderRelativeOf != nullptr) {
-            layerInfo->set_z_order_relative_of(zOrderRelativeOf->sequence);
-        } else {
-            layerInfo->set_z_order_relative_of(-1);
-        }
-
-        layerInfo->set_is_relative_of(state.isRelativeOf);
-
-        layerInfo->set_owner_uid(mOwnerUid);
+    for (const auto& child : children) {
+        layerInfo->add_children(child->sequence);
     }
 
-    if (traceFlags & SurfaceTracing::TRACE_INPUT) {
+    for (const wp<Layer>& weakRelative : state.zOrderRelatives) {
+        sp<Layer> strongRelative = weakRelative.promote();
+        if (strongRelative != nullptr) {
+            layerInfo->add_relatives(strongRelative->sequence);
+        }
+    }
+
+    LayerProtoHelper::writeToProto(state.activeTransparentRegion_legacy,
+                                   [&]() { return layerInfo->mutable_transparent_region(); });
+
+    layerInfo->set_layer_stack(getLayerStack().id);
+    layerInfo->set_z(state.z);
+
+    LayerProtoHelper::writePositionToProto(requestedTransform.tx(), requestedTransform.ty(), [&]() {
+        return layerInfo->mutable_requested_position();
+    });
+
+    LayerProtoHelper::writeSizeToProto(state.width, state.height,
+                                       [&]() { return layerInfo->mutable_size(); });
+
+    LayerProtoHelper::writeToProto(state.crop, [&]() { return layerInfo->mutable_crop(); });
+
+    layerInfo->set_is_opaque(isOpaque(state));
+
+    layerInfo->set_pixel_format(decodePixelFormat(getPixelFormat()));
+    LayerProtoHelper::writeToProto(getColor(), [&]() { return layerInfo->mutable_color(); });
+    LayerProtoHelper::writeToProto(state.color,
+                                   [&]() { return layerInfo->mutable_requested_color(); });
+    layerInfo->set_flags(state.flags);
+
+    LayerProtoHelper::writeToProtoDeprecated(requestedTransform,
+                                             layerInfo->mutable_requested_transform());
+
+    auto parent = useDrawing ? mDrawingParent.promote() : mCurrentParent.promote();
+    if (parent != nullptr) {
+        layerInfo->set_parent(parent->sequence);
+    } else {
+        layerInfo->set_parent(-1);
+    }
+
+    auto zOrderRelativeOf = state.zOrderRelativeOf.promote();
+    if (zOrderRelativeOf != nullptr) {
+        layerInfo->set_z_order_relative_of(zOrderRelativeOf->sequence);
+    } else {
+        layerInfo->set_z_order_relative_of(-1);
+    }
+
+    layerInfo->set_is_relative_of(state.isRelativeOf);
+
+    layerInfo->set_owner_uid(mOwnerUid);
+
+    if (traceFlags & LayerTracing::TRACE_INPUT) {
         WindowInfo info;
         if (useDrawing) {
             info = fillInputInfo(ui::Transform(), /* displayIsSecure */ true);
@@ -2154,7 +2145,7 @@
                                        [&]() { return layerInfo->mutable_input_window_info(); });
     }
 
-    if (traceFlags & SurfaceTracing::TRACE_EXTRA) {
+    if (traceFlags & LayerTracing::TRACE_EXTRA) {
         auto protoMap = layerInfo->mutable_metadata();
         for (const auto& entry : state.metadata.mMap) {
             (*protoMap)[entry.first] = std::string(entry.second.cbegin(), entry.second.cend());
diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index 84355ea..bda1c28 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -57,7 +57,7 @@
 #include "Scheduler/LayerInfo.h"
 #include "Scheduler/Seamlessness.h"
 #include "SurfaceFlinger.h"
-#include "SurfaceTracing.h"
+#include "Tracing/LayerTracing.h"
 #include "TransactionCallbackInvoker.h"
 
 using namespace android::surfaceflinger;
@@ -693,7 +693,7 @@
     // external mStateLock. If writing drawing state, this function should be called on the
     // main or tracing thread.
     void writeToProtoCommonState(LayerProto* layerInfo, LayerVector::StateSet,
-                                 uint32_t traceFlags = SurfaceTracing::TRACE_ALL);
+                                 uint32_t traceFlags = LayerTracing::TRACE_ALL);
 
     gui::WindowInfo::Type getWindowType() const { return mWindowType; }
 
diff --git a/services/surfaceflinger/Scheduler/Scheduler.cpp b/services/surfaceflinger/Scheduler/Scheduler.cpp
index eeea25d..f201996 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.cpp
+++ b/services/surfaceflinger/Scheduler/Scheduler.cpp
@@ -117,16 +117,10 @@
     }
 };
 
-Scheduler::Scheduler(const std::shared_ptr<scheduler::RefreshRateConfigs>& configs,
-                     ISchedulerCallback& callback)
-      : Scheduler(configs, callback,
-                  {.useContentDetection = sysprop::use_content_detection_for_refresh_rate(false)}) {
-}
+Scheduler::Scheduler(ISchedulerCallback& callback, Options options)
+      : mOptions(options), mSchedulerCallback(callback) {}
 
-Scheduler::Scheduler(const std::shared_ptr<scheduler::RefreshRateConfigs>& configs,
-                     ISchedulerCallback& callback, Options options)
-      : Scheduler(createVsyncSchedule(configs->supportsKernelIdleTimer()), configs, callback,
-                  createLayerHistory(), options) {
+void Scheduler::startTimers() {
     using namespace sysprop;
 
     if (const int64_t millis = set_touch_timer_ms(0); millis > 0) {
@@ -147,22 +141,6 @@
     }
 }
 
-Scheduler::Scheduler(VsyncSchedule schedule,
-                     const std::shared_ptr<scheduler::RefreshRateConfigs>& configs,
-                     ISchedulerCallback& schedulerCallback,
-                     std::unique_ptr<LayerHistory> layerHistory, Options options)
-      : mOptions(options),
-        mVsyncSchedule(std::move(schedule)),
-        mLayerHistory(std::move(layerHistory)),
-        mSchedulerCallback(schedulerCallback),
-        mPredictedVsyncTracer(
-                base::GetBoolProperty("debug.sf.show_predicted_vsync", false)
-                        ? std::make_unique<PredictedVsyncTracer>(*mVsyncSchedule.dispatch)
-                        : nullptr) {
-    setRefreshRateConfigs(configs);
-    mSchedulerCallback.setVsyncEnabled(false);
-}
-
 Scheduler::~Scheduler() {
     // Ensure the OneShotTimer threads are joined before we start destroying state.
     mDisplayPowerTimer.reset();
@@ -170,7 +148,7 @@
     mRefreshRateConfigs.reset();
 }
 
-Scheduler::VsyncSchedule Scheduler::createVsyncSchedule(bool supportKernelTimer) {
+void Scheduler::createVsyncSchedule(bool supportKernelTimer) {
     auto clock = std::make_unique<scheduler::SystemClock>();
     auto tracker = createVSyncTracker();
     auto dispatch = createVSyncDispatch(*tracker);
@@ -180,11 +158,11 @@
     auto controller =
             std::make_unique<scheduler::VSyncReactor>(std::move(clock), *tracker, pendingFenceLimit,
                                                       supportKernelTimer);
-    return {std::move(controller), std::move(tracker), std::move(dispatch)};
-}
+    mVsyncSchedule = {std::move(controller), std::move(tracker), std::move(dispatch)};
 
-std::unique_ptr<LayerHistory> Scheduler::createLayerHistory() {
-    return std::make_unique<scheduler::LayerHistory>();
+    if (base::GetBoolProperty("debug.sf.show_predicted_vsync", false)) {
+        mPredictedVsyncTracer = std::make_unique<PredictedVsyncTracer>(*mVsyncSchedule.dispatch);
+    }
 }
 
 std::unique_ptr<VSyncSource> Scheduler::makePrimaryDispSyncSource(
@@ -594,11 +572,11 @@
     // If the content detection feature is off, we still keep the layer history,
     // since we use it for other features (like Frame Rate API), so layers
     // still need to be registered.
-    mLayerHistory->registerLayer(layer, voteType);
+    mLayerHistory.registerLayer(layer, voteType);
 }
 
 void Scheduler::deregisterLayer(Layer* layer) {
-    mLayerHistory->deregisterLayer(layer);
+    mLayerHistory.deregisterLayer(layer);
 }
 
 void Scheduler::recordLayerHistory(Layer* layer, nsecs_t presentTime,
@@ -608,11 +586,11 @@
         if (!mRefreshRateConfigs->canSwitch()) return;
     }
 
-    mLayerHistory->record(layer, presentTime, systemTime(), updateType);
+    mLayerHistory.record(layer, presentTime, systemTime(), updateType);
 }
 
 void Scheduler::setModeChangePending(bool pending) {
-    mLayerHistory->setModeChangePending(pending);
+    mLayerHistory.setModeChangePending(pending);
 }
 
 void Scheduler::chooseRefreshRateForContent() {
@@ -625,7 +603,7 @@
 
     const auto refreshRateConfigs = holdRefreshRateConfigs();
     scheduler::LayerHistory::Summary summary =
-            mLayerHistory->summarize(*refreshRateConfigs, systemTime());
+            mLayerHistory.summarize(*refreshRateConfigs, systemTime());
     scheduler::RefreshRateConfigs::GlobalSignals consideredSignals;
     DisplayModePtr newMode;
     bool frameRateChanged;
@@ -686,7 +664,7 @@
 
     // Display Power event will boost the refresh rate to performance.
     // Clear Layer History to get fresh FPS detection
-    mLayerHistory->clear();
+    mLayerHistory.clear();
 }
 
 void Scheduler::kernelIdleTimerCallback(TimerState state) {
@@ -730,7 +708,7 @@
     // NOTE: Instead of checking all the layers, we should be checking the layer
     // that is currently on top. b/142507166 will give us this capability.
     if (handleTimerStateChanged(&mFeatures.touch, touch)) {
-        mLayerHistory->clear();
+        mLayerHistory.clear();
     }
     ATRACE_INT("TouchState", static_cast<int>(touch));
 }
@@ -747,7 +725,7 @@
                   mTouchTimer ? mTouchTimer->dump().c_str() : "off");
     StringAppendF(&result, "+  Content detection: %s %s\n\n",
                   toContentDetectionString(mOptions.useContentDetection),
-                  mLayerHistory ? mLayerHistory->dump().c_str() : "(no layer history)");
+                  mLayerHistory.dump().c_str());
 
     {
         std::lock_guard lock(mFrameRateOverridesLock);
@@ -911,7 +889,7 @@
 }
 
 void Scheduler::onActiveDisplayAreaChanged(uint32_t displayArea) {
-    mLayerHistory->setDisplayArea(displayArea);
+    mLayerHistory.setDisplayArea(displayArea);
 }
 
 void Scheduler::setPreferredRefreshRateForUid(FrameRateOverride frameRateOverride) {
diff --git a/services/surfaceflinger/Scheduler/Scheduler.h b/services/surfaceflinger/Scheduler/Scheduler.h
index 8397738..8204abc 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.h
+++ b/services/surfaceflinger/Scheduler/Scheduler.h
@@ -75,9 +75,17 @@
     using RefreshRate = scheduler::RefreshRateConfigs::RefreshRate;
     using ModeEvent = scheduler::RefreshRateConfigEvent;
 
-    Scheduler(const std::shared_ptr<scheduler::RefreshRateConfigs>&, ISchedulerCallback&);
+    struct Options {
+        // Whether to use content detection at all.
+        bool useContentDetection = false;
+    };
+
+    Scheduler(ISchedulerCallback&, Options);
     ~Scheduler();
 
+    void createVsyncSchedule(bool supportKernelIdleTimer);
+    void startTimers();
+
     using ConnectionHandle = scheduler::ConnectionHandle;
     ConnectionHandle createConnection(const char* connectionName, frametimeline::TokenManager*,
                                       std::chrono::nanoseconds workDuration,
@@ -213,27 +221,12 @@
     enum class TimerState { Reset, Expired };
     enum class TouchState { Inactive, Active };
 
-    struct Options {
-        // Whether to use content detection at all.
-        bool useContentDetection;
-    };
-
     struct VsyncSchedule {
         std::unique_ptr<scheduler::VsyncController> controller;
         std::unique_ptr<scheduler::VSyncTracker> tracker;
         std::unique_ptr<scheduler::VSyncDispatch> dispatch;
     };
 
-    // Unlike the testing constructor, this creates the VsyncSchedule, LayerHistory, and timers.
-    Scheduler(const std::shared_ptr<scheduler::RefreshRateConfigs>&, ISchedulerCallback&, Options);
-
-    // Used by tests to inject mocks.
-    Scheduler(VsyncSchedule, const std::shared_ptr<scheduler::RefreshRateConfigs>&,
-              ISchedulerCallback&, std::unique_ptr<LayerHistory>, Options);
-
-    static VsyncSchedule createVsyncSchedule(bool supportKernelIdleTimer);
-    static std::unique_ptr<LayerHistory> createLayerHistory();
-
     // Create a connection on the given EventThread.
     ConnectionHandle createConnection(std::unique_ptr<EventThread>);
     sp<EventThreadConnection> createConnectionInternal(
@@ -297,7 +290,7 @@
     VsyncSchedule mVsyncSchedule;
 
     // Used to choose refresh rate if content detection is enabled.
-    std::unique_ptr<LayerHistory> mLayerHistory;
+    LayerHistory mLayerHistory;
 
     // Timer used to monitor touch events.
     std::optional<scheduler::OneShotTimer> mTouchTimer;
@@ -338,7 +331,7 @@
             GUARDED_BY(mVsyncTimelineLock);
     static constexpr std::chrono::nanoseconds MAX_VSYNC_APPLIED_TIME = 200ms;
 
-    const std::unique_ptr<PredictedVsyncTracer> mPredictedVsyncTracer;
+    std::unique_ptr<PredictedVsyncTracer> mPredictedVsyncTracer;
 
     // The frame rate override lists need their own mutex as they are being read
     // by SurfaceFlinger, Scheduler and EventThread (as a callback) to prevent deadlocks
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index d05111e..d1e24d9 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1948,7 +1948,7 @@
     }
 
     if (mTracingEnabledChanged) {
-        mTracingEnabled = mTracing.isEnabled();
+        mTracingEnabled = mLayerTracing.isEnabled();
         mTracingEnabledChanged = false;
     }
 
@@ -1962,12 +1962,6 @@
     // Composite if transactions were committed, or if requested by HWC.
     bool mustComposite = mMustComposite.exchange(false);
     {
-        mTracePostComposition = mTracing.flagIsSet(SurfaceTracing::TRACE_COMPOSITION) ||
-                mTracing.flagIsSet(SurfaceTracing::TRACE_SYNC) ||
-                mTracing.flagIsSet(SurfaceTracing::TRACE_BUFFERS);
-        const bool tracePreComposition = mTracingEnabled && !mTracePostComposition;
-        ConditionalLockGuard<std::mutex> lock(mTracingLock, tracePreComposition);
-
         mFrameTimeline->setSfWakeUp(vsyncId, frameTime, Fps::fromPeriodNsecs(stats.vsyncPeriod));
 
         bool needsTraversal = false;
@@ -1999,12 +1993,6 @@
         }
 
         updateLayerGeometry();
-
-        if (tracePreComposition) {
-            if (mVisibleRegionsDirty) {
-                mTracing.notifyLocked("visibleRegionsDirty");
-            }
-        }
     }
 
     // Layers need to get updated (in the previous line) before we can use them for
@@ -2109,12 +2097,12 @@
     modulateVsync(&VsyncModulator::onDisplayRefresh, usedGpuComposition);
 
     mLayersWithQueuedFrames.clear();
-    if (mTracingEnabled && mTracePostComposition) {
-        // This may block if SurfaceTracing is running in sync mode.
+    if (mTracingEnabled) {
+        // This will block and should only be used for debugging.
         if (mVisibleRegionsDirty) {
-            mTracing.notify("visibleRegionsDirty");
-        } else if (mTracing.flagIsSet(SurfaceTracing::TRACE_BUFFERS)) {
-            mTracing.notify("bufferLatched");
+            mLayerTracing.notify("visibleRegionsDirty");
+        } else if (mLayerTracing.flagIsSet(LayerTracing::TRACE_BUFFERS)) {
+            mLayerTracing.notify("bufferLatched");
         }
     }
 
@@ -3137,8 +3125,19 @@
     mVsyncConfiguration = getFactory().createVsyncConfiguration(currRefreshRate);
     mVsyncModulator = sp<VsyncModulator>::make(mVsyncConfiguration->getCurrentConfigs());
 
-    // start the EventThread
-    mScheduler = getFactory().createScheduler(display->holdRefreshRateConfigs(), *this);
+    const Scheduler::Options options = {
+            .useContentDetection = sysprop::use_content_detection_for_refresh_rate(false)};
+
+    mScheduler = std::make_unique<Scheduler>(static_cast<ISchedulerCallback&>(*this), options);
+    {
+        auto configs = display->holdRefreshRateConfigs();
+        mScheduler->createVsyncSchedule(configs->supportsKernelIdleTimer());
+        mScheduler->setRefreshRateConfigs(std::move(configs));
+    }
+
+    setVsyncEnabled(false);
+    mScheduler->startTimers();
+
     const auto configs = mVsyncConfiguration->getCurrentConfigs();
     const nsecs_t vsyncPeriod = currRefreshRate.getPeriodNsecs();
     mAppConnectionHandle =
@@ -4639,7 +4638,7 @@
         }
 
         if (dumpLayers) {
-            LayersTraceFileProto traceFileProto = SurfaceTracing::createLayersTraceFileProto();
+            LayersTraceFileProto traceFileProto = mLayerTracing.createTraceFileProto();
             LayersTraceProto* layersTrace = traceFileProto.add_entry();
             LayersProto layersProto = dumpProtoFromMainThread();
             layersTrace->mutable_layers()->Swap(&layersProto);
@@ -4661,8 +4660,8 @@
 }
 
 status_t SurfaceFlinger::dumpCritical(int fd, const DumpArgs&, bool asProto) {
-    if (asProto && mTracing.isEnabled()) {
-        mTracing.writeToFile();
+    if (asProto && mLayerTracing.isEnabled()) {
+        mLayerTracing.writeToFile();
     }
 
     return doDump(fd, DumpArgs(), asProto);
@@ -5058,7 +5057,7 @@
     /*
      * Tracing state
      */
-    mTracing.dump(result);
+    mLayerTracing.dump(result);
     result.append("\n");
 
     /*
@@ -5485,20 +5484,20 @@
                 bool tracingEnabledChanged;
                 if (n) {
                     ALOGD("LayerTracing enabled");
-                    tracingEnabledChanged = mTracing.enable();
+                    tracingEnabledChanged = mLayerTracing.enable();
                     if (tracingEnabledChanged) {
-                        schedule([&]() MAIN_THREAD { mTracing.notify("start"); }).wait();
+                        schedule([&]() MAIN_THREAD { mLayerTracing.notify("start"); }).wait();
                     }
                 } else {
                     ALOGD("LayerTracing disabled");
-                    tracingEnabledChanged = mTracing.disable();
+                    tracingEnabledChanged = mLayerTracing.disable();
                 }
                 mTracingEnabledChanged = tracingEnabledChanged;
                 reply->writeInt32(NO_ERROR);
                 return NO_ERROR;
             }
             case 1026: { // Get layer tracing status
-                reply->writeBool(mTracing.isEnabled());
+                reply->writeBool(mLayerTracing.isEnabled());
                 return NO_ERROR;
             }
             // Is a DisplayColorSetting supported?
@@ -5539,7 +5538,7 @@
                 }
 
                 ALOGD("Updating trace buffer to %d KB", n);
-                mTracing.setBufferSize(n * 1024);
+                mLayerTracing.setBufferSize(n * 1024);
                 reply->writeInt32(NO_ERROR);
                 return NO_ERROR;
             }
@@ -5584,7 +5583,7 @@
             case 1033: {
                 n = data.readUint32();
                 ALOGD("Updating trace flags to 0x%x", n);
-                mTracing.setTraceFlags(n);
+                mLayerTracing.setTraceFlags(n);
                 reply->writeInt32(NO_ERROR);
                 return NO_ERROR;
             }
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index f896c50..8897858 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -62,8 +62,8 @@
 #include "Scheduler/Scheduler.h"
 #include "Scheduler/VsyncModulator.h"
 #include "SurfaceFlingerFactory.h"
-#include "SurfaceTracing.h"
 #include "TracedOrdinal.h"
+#include "Tracing/LayerTracing.h"
 #include "TransactionCallbackInvoker.h"
 #include "TransactionState.h"
 
@@ -353,7 +353,7 @@
     friend class MonitoredProducer;
     friend class RefreshRateOverlay;
     friend class RegionSamplingThread;
-    friend class SurfaceTracing;
+    friend class LayerTracing;
 
     // For unit tests
     friend class TestableSurfaceFlinger;
@@ -1039,12 +1039,12 @@
     void dumpWideColorInfo(std::string& result) const REQUIRES(mStateLock);
     LayersProto dumpDrawingStateProto(uint32_t traceFlags) const;
     void dumpOffscreenLayersProto(LayersProto& layersProto,
-                                  uint32_t traceFlags = SurfaceTracing::TRACE_ALL) const;
+                                  uint32_t traceFlags = LayerTracing::TRACE_ALL) const;
     void dumpDisplayProto(LayersTraceProto& layersTraceProto) const;
 
     // Dumps state from HW Composer
     void dumpHwc(std::string& result) const;
-    LayersProto dumpProtoFromMainThread(uint32_t traceFlags = SurfaceTracing::TRACE_ALL)
+    LayersProto dumpProtoFromMainThread(uint32_t traceFlags = LayerTracing::TRACE_ALL)
             EXCLUDES(mStateLock);
     void dumpOffscreenLayers(std::string& result) EXCLUDES(mStateLock);
     void dumpPlannerInfo(const DumpArgs& args, std::string& result) const REQUIRES(mStateLock);
@@ -1187,10 +1187,9 @@
     bool mPropagateBackpressureClientComposition = false;
     sp<SurfaceInterceptor> mInterceptor;
 
-    SurfaceTracing mTracing{*this};
+    LayerTracing mLayerTracing{*this};
     std::mutex mTracingLock;
     bool mTracingEnabled = false;
-    bool mTracePostComposition = false;
     std::atomic<bool> mTracingEnabledChanged = false;
 
     const std::shared_ptr<TimeStats> mTimeStats;
diff --git a/services/surfaceflinger/SurfaceFlingerDefaultFactory.cpp b/services/surfaceflinger/SurfaceFlingerDefaultFactory.cpp
index 9a2f910..ae21fcc 100644
--- a/services/surfaceflinger/SurfaceFlingerDefaultFactory.cpp
+++ b/services/surfaceflinger/SurfaceFlingerDefaultFactory.cpp
@@ -64,12 +64,6 @@
     }
 }
 
-std::unique_ptr<Scheduler> DefaultFactory::createScheduler(
-        const std::shared_ptr<scheduler::RefreshRateConfigs>& refreshRateConfigs,
-        ISchedulerCallback& callback) {
-    return std::make_unique<Scheduler>(std::move(refreshRateConfigs), callback);
-}
-
 sp<SurfaceInterceptor> DefaultFactory::createSurfaceInterceptor() {
     return new android::impl::SurfaceInterceptor();
 }
diff --git a/services/surfaceflinger/SurfaceFlingerDefaultFactory.h b/services/surfaceflinger/SurfaceFlingerDefaultFactory.h
index 2be09ee..4f70979 100644
--- a/services/surfaceflinger/SurfaceFlingerDefaultFactory.h
+++ b/services/surfaceflinger/SurfaceFlingerDefaultFactory.h
@@ -30,8 +30,6 @@
     std::unique_ptr<MessageQueue> createMessageQueue(ICompositor&) override;
     std::unique_ptr<scheduler::VsyncConfiguration> createVsyncConfiguration(
             Fps currentRefreshRate) override;
-    std::unique_ptr<Scheduler> createScheduler(
-            const std::shared_ptr<scheduler::RefreshRateConfigs>&, ISchedulerCallback&) override;
     sp<SurfaceInterceptor> createSurfaceInterceptor() override;
     sp<StartPropertySetThread> createStartPropertySetThread(bool timestampPropertyValue) override;
     sp<DisplayDevice> createDisplayDevice(DisplayDeviceCreationArgs&) override;
diff --git a/services/surfaceflinger/SurfaceFlingerFactory.h b/services/surfaceflinger/SurfaceFlingerFactory.h
index bca533b..a1bf9fe 100644
--- a/services/surfaceflinger/SurfaceFlingerFactory.h
+++ b/services/surfaceflinger/SurfaceFlingerFactory.h
@@ -80,8 +80,6 @@
     virtual std::unique_ptr<MessageQueue> createMessageQueue(ICompositor&) = 0;
     virtual std::unique_ptr<scheduler::VsyncConfiguration> createVsyncConfiguration(
             Fps currentRefreshRate) = 0;
-    virtual std::unique_ptr<Scheduler> createScheduler(
-            const std::shared_ptr<scheduler::RefreshRateConfigs>&, ISchedulerCallback&) = 0;
     virtual sp<SurfaceInterceptor> createSurfaceInterceptor() = 0;
 
     virtual sp<StartPropertySetThread> createStartPropertySetThread(
diff --git a/services/surfaceflinger/SurfaceTracing.cpp b/services/surfaceflinger/SurfaceTracing.cpp
deleted file mode 100644
index 5963737..0000000
--- a/services/surfaceflinger/SurfaceTracing.cpp
+++ /dev/null
@@ -1,264 +0,0 @@
-/*
- * Copyright 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#undef LOG_TAG
-#define LOG_TAG "SurfaceTracing"
-#define ATRACE_TAG ATRACE_TAG_GRAPHICS
-
-#include "SurfaceTracing.h"
-#include <SurfaceFlinger.h>
-
-#include <android-base/file.h>
-#include <android-base/stringprintf.h>
-#include <log/log.h>
-#include <utils/SystemClock.h>
-#include <utils/Trace.h>
-
-namespace android {
-
-SurfaceTracing::SurfaceTracing(SurfaceFlinger& flinger) : mFlinger(flinger) {}
-
-bool SurfaceTracing::enable() {
-    std::scoped_lock lock(mTraceLock);
-    if (mEnabled) {
-        return false;
-    }
-
-    if (flagIsSet(TRACE_SYNC)) {
-        runner = std::make_unique<SurfaceTracing::Runner>(mFlinger, mConfig);
-    } else {
-        runner = std::make_unique<SurfaceTracing::AsyncRunner>(mFlinger, mConfig,
-                                                               mFlinger.mTracingLock);
-    }
-    mEnabled = true;
-    return true;
-}
-
-bool SurfaceTracing::disable() {
-    std::scoped_lock lock(mTraceLock);
-    if (!mEnabled) {
-        return false;
-    }
-    mEnabled = false;
-    runner->stop();
-    return true;
-}
-
-bool SurfaceTracing::isEnabled() const {
-    std::scoped_lock lock(mTraceLock);
-    return mEnabled;
-}
-
-status_t SurfaceTracing::writeToFile() {
-    std::scoped_lock lock(mTraceLock);
-    if (!mEnabled) {
-        return STATUS_OK;
-    }
-    return runner->writeToFile();
-}
-
-void SurfaceTracing::notify(const char* where) {
-    std::scoped_lock lock(mTraceLock);
-    if (mEnabled) {
-        runner->notify(where);
-    }
-}
-
-void SurfaceTracing::notifyLocked(const char* where) {
-    std::scoped_lock lock(mTraceLock);
-    if (mEnabled) {
-        runner->notifyLocked(where);
-    }
-}
-
-void SurfaceTracing::dump(std::string& result) const {
-    std::scoped_lock lock(mTraceLock);
-    base::StringAppendF(&result, "Tracing state: %s\n", mEnabled ? "enabled" : "disabled");
-    if (mEnabled) {
-        runner->dump(result);
-    }
-}
-
-void SurfaceTracing::LayersTraceBuffer::reset(size_t newSize) {
-    // use the swap trick to make sure memory is released
-    std::queue<LayersTraceProto>().swap(mStorage);
-    mSizeInBytes = newSize;
-    mUsedInBytes = 0U;
-}
-
-void SurfaceTracing::LayersTraceBuffer::emplace(LayersTraceProto&& proto) {
-    size_t protoSize = static_cast<size_t>(proto.ByteSize());
-    while (mUsedInBytes + protoSize > mSizeInBytes) {
-        if (mStorage.empty()) {
-            return;
-        }
-        mUsedInBytes -= static_cast<size_t>(mStorage.front().ByteSize());
-        mStorage.pop();
-    }
-    mUsedInBytes += protoSize;
-    mStorage.emplace();
-    mStorage.back().Swap(&proto);
-}
-
-void SurfaceTracing::LayersTraceBuffer::flush(LayersTraceFileProto* fileProto) {
-    fileProto->mutable_entry()->Reserve(static_cast<int>(mStorage.size()));
-
-    while (!mStorage.empty()) {
-        auto entry = fileProto->add_entry();
-        entry->Swap(&mStorage.front());
-        mStorage.pop();
-    }
-}
-
-SurfaceTracing::Runner::Runner(SurfaceFlinger& flinger, SurfaceTracing::Config& config)
-      : mFlinger(flinger), mConfig(config) {
-    mBuffer.setSize(mConfig.bufferSize);
-}
-
-void SurfaceTracing::Runner::notify(const char* where) {
-    LayersTraceProto entry = traceLayers(where);
-    mBuffer.emplace(std::move(entry));
-}
-
-status_t SurfaceTracing::Runner::stop() {
-    return writeToFile();
-}
-
-LayersTraceFileProto SurfaceTracing::createLayersTraceFileProto() {
-    LayersTraceFileProto fileProto;
-    fileProto.set_magic_number(uint64_t(LayersTraceFileProto_MagicNumber_MAGIC_NUMBER_H) << 32 |
-                               LayersTraceFileProto_MagicNumber_MAGIC_NUMBER_L);
-    return fileProto;
-}
-
-status_t SurfaceTracing::Runner::writeToFile() {
-    ATRACE_CALL();
-
-    LayersTraceFileProto fileProto = createLayersTraceFileProto();
-    std::string output;
-
-    mBuffer.flush(&fileProto);
-    mBuffer.reset(mConfig.bufferSize);
-
-    if (!fileProto.SerializeToString(&output)) {
-        ALOGE("Could not save the proto file! Permission denied");
-        return PERMISSION_DENIED;
-    }
-
-    // -rw-r--r--
-    const mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
-    if (!android::base::WriteStringToFile(output, DEFAULT_FILE_NAME, mode, getuid(), getgid(),
-                                          true)) {
-        ALOGE("Could not save the proto file! There are missing fields");
-        return PERMISSION_DENIED;
-    }
-
-    return NO_ERROR;
-}
-
-LayersTraceProto SurfaceTracing::Runner::traceLayers(const char* where) {
-    ATRACE_CALL();
-
-    LayersTraceProto entry;
-    entry.set_elapsed_realtime_nanos(elapsedRealtimeNano());
-    entry.set_where(where);
-    LayersProto layers(mFlinger.dumpDrawingStateProto(mConfig.flags));
-
-    if (flagIsSet(SurfaceTracing::TRACE_EXTRA)) {
-        mFlinger.dumpOffscreenLayersProto(layers);
-    }
-    entry.mutable_layers()->Swap(&layers);
-
-    if (flagIsSet(SurfaceTracing::TRACE_HWC)) {
-        std::string hwcDump;
-        mFlinger.dumpHwc(hwcDump);
-        entry.set_hwc_blob(hwcDump);
-    }
-    if (!flagIsSet(SurfaceTracing::TRACE_COMPOSITION)) {
-        entry.set_excludes_composition_state(true);
-    }
-    entry.set_missed_entries(mMissedTraceEntries);
-    mFlinger.dumpDisplayProto(entry);
-    return entry;
-}
-
-void SurfaceTracing::Runner::dump(std::string& result) const {
-    base::StringAppendF(&result, "  number of entries: %zu (%.2fMB / %.2fMB)\n",
-                        mBuffer.frameCount(), float(mBuffer.used()) / float(1_MB),
-                        float(mBuffer.size()) / float(1_MB));
-}
-
-SurfaceTracing::AsyncRunner::AsyncRunner(SurfaceFlinger& flinger, SurfaceTracing::Config& config,
-                                         std::mutex& sfLock)
-      : SurfaceTracing::Runner(flinger, config), mSfLock(sfLock) {
-    mEnabled = true;
-    mThread = std::thread(&AsyncRunner::loop, this);
-}
-
-void SurfaceTracing::AsyncRunner::loop() {
-    while (mEnabled) {
-        LayersTraceProto entry;
-        bool entryAdded = traceWhenNotified(&entry);
-        if (entryAdded) {
-            mBuffer.emplace(std::move(entry));
-        }
-        if (mWriteToFile) {
-            Runner::writeToFile();
-            mWriteToFile = false;
-        }
-    }
-}
-
-bool SurfaceTracing::AsyncRunner::traceWhenNotified(LayersTraceProto* outProto) {
-    std::unique_lock<std::mutex> lock(mSfLock);
-    mCanStartTrace.wait(lock);
-    if (!mAddEntry) {
-        return false;
-    }
-    *outProto = traceLayers(mWhere);
-    mAddEntry = false;
-    mMissedTraceEntries = 0;
-    return true;
-}
-
-void SurfaceTracing::AsyncRunner::notify(const char* where) {
-    std::scoped_lock lock(mSfLock);
-    notifyLocked(where);
-}
-
-void SurfaceTracing::AsyncRunner::notifyLocked(const char* where) {
-    mWhere = where;
-    if (mAddEntry) {
-        mMissedTraceEntries++;
-    }
-    mAddEntry = true;
-    mCanStartTrace.notify_one();
-}
-
-status_t SurfaceTracing::AsyncRunner::writeToFile() {
-    mWriteToFile = true;
-    mCanStartTrace.notify_one();
-    return STATUS_OK;
-}
-
-status_t SurfaceTracing::AsyncRunner::stop() {
-    mEnabled = false;
-    mCanStartTrace.notify_one();
-    mThread.join();
-    return Runner::writeToFile();
-}
-
-} // namespace android
diff --git a/services/surfaceflinger/SurfaceTracing.h b/services/surfaceflinger/SurfaceTracing.h
deleted file mode 100644
index 97adb20..0000000
--- a/services/surfaceflinger/SurfaceTracing.h
+++ /dev/null
@@ -1,164 +0,0 @@
-/*
- * Copyright 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#pragma once
-
-#include <android-base/thread_annotations.h>
-#include <layerproto/LayerProtoHeader.h>
-#include <utils/Errors.h>
-#include <utils/StrongPointer.h>
-
-#include <condition_variable>
-#include <memory>
-#include <mutex>
-#include <queue>
-#include <thread>
-
-using namespace android::surfaceflinger;
-
-namespace android {
-
-class SurfaceFlinger;
-constexpr auto operator""_MB(unsigned long long const num) {
-    return num * 1024 * 1024;
-}
-/*
- * SurfaceTracing records layer states during surface flinging. Manages tracing state and
- * configuration.
- */
-class SurfaceTracing {
-public:
-    SurfaceTracing(SurfaceFlinger& flinger);
-    bool enable();
-    bool disable();
-    status_t writeToFile();
-    bool isEnabled() const;
-    /*
-     * Adds a trace entry, must be called from the drawing thread or while holding the
-     * SurfaceFlinger tracing lock.
-     */
-    void notify(const char* where);
-    /*
-     * Adds a trace entry, called while holding the SurfaceFlinger tracing lock.
-     */
-    void notifyLocked(const char* where) /* REQUIRES(mSfLock) */;
-
-    void setBufferSize(size_t bufferSizeInBytes) { mConfig.bufferSize = bufferSizeInBytes; }
-    void dump(std::string& result) const;
-
-    enum : uint32_t {
-        TRACE_CRITICAL = 1 << 0,
-        TRACE_INPUT = 1 << 1,
-        TRACE_COMPOSITION = 1 << 2,
-        TRACE_EXTRA = 1 << 3,
-        TRACE_HWC = 1 << 4,
-        // Add non-geometry composition changes to the trace.
-        TRACE_BUFFERS = 1 << 5,
-        // Add entries from the drawing thread post composition.
-        TRACE_SYNC = 1 << 6,
-        TRACE_ALL = TRACE_CRITICAL | TRACE_INPUT | TRACE_COMPOSITION | TRACE_EXTRA,
-    };
-    void setTraceFlags(uint32_t flags) { mConfig.flags = flags; }
-    bool flagIsSet(uint32_t flags) { return (mConfig.flags & flags) == flags; }
-    static LayersTraceFileProto createLayersTraceFileProto();
-
-private:
-    class Runner;
-    static constexpr auto DEFAULT_BUFFER_SIZE = 20_MB;
-    static constexpr auto DEFAULT_FILE_NAME = "/data/misc/wmtrace/layers_trace.winscope";
-
-    SurfaceFlinger& mFlinger;
-    mutable std::mutex mTraceLock;
-    bool mEnabled GUARDED_BY(mTraceLock) = false;
-    std::unique_ptr<Runner> runner GUARDED_BY(mTraceLock);
-
-    struct Config {
-        uint32_t flags = TRACE_CRITICAL | TRACE_INPUT | TRACE_SYNC;
-        size_t bufferSize = DEFAULT_BUFFER_SIZE;
-    } mConfig;
-
-    /*
-     * ring buffer.
-     */
-    class LayersTraceBuffer {
-    public:
-        size_t size() const { return mSizeInBytes; }
-        size_t used() const { return mUsedInBytes; }
-        size_t frameCount() const { return mStorage.size(); }
-
-        void setSize(size_t newSize) { mSizeInBytes = newSize; }
-        void reset(size_t newSize);
-        void emplace(LayersTraceProto&& proto);
-        void flush(LayersTraceFileProto* fileProto);
-
-    private:
-        size_t mUsedInBytes = 0U;
-        size_t mSizeInBytes = DEFAULT_BUFFER_SIZE;
-        std::queue<LayersTraceProto> mStorage;
-    };
-
-    /*
-     * Implements a synchronous way of adding trace entries. This must be called
-     * from the drawing thread.
-     */
-    class Runner {
-    public:
-        Runner(SurfaceFlinger& flinger, SurfaceTracing::Config& config);
-        virtual ~Runner() = default;
-        virtual status_t stop();
-        virtual status_t writeToFile();
-        virtual void notify(const char* where);
-        /* Cannot be called with a synchronous runner. */
-        virtual void notifyLocked(const char* /* where */) {}
-        void dump(std::string& result) const;
-
-    protected:
-        bool flagIsSet(uint32_t flags) { return (mConfig.flags & flags) == flags; }
-        SurfaceFlinger& mFlinger;
-        SurfaceTracing::Config mConfig;
-        SurfaceTracing::LayersTraceBuffer mBuffer;
-        uint32_t mMissedTraceEntries = 0;
-        LayersTraceProto traceLayers(const char* where);
-    };
-
-    /*
-     * Implements asynchronous way to add trace entries called from a separate thread while holding
-     * the SurfaceFlinger tracing lock. Trace entries may be missed if the tracing thread is not
-     * scheduled in time.
-     */
-    class AsyncRunner : public Runner {
-    public:
-        AsyncRunner(SurfaceFlinger& flinger, SurfaceTracing::Config& config, std::mutex& sfLock);
-        virtual ~AsyncRunner() = default;
-        status_t stop() override;
-        status_t writeToFile() override;
-        void notify(const char* where) override;
-        void notifyLocked(const char* where);
-
-    private:
-        std::mutex& mSfLock;
-        std::condition_variable mCanStartTrace;
-        std::thread mThread;
-        const char* mWhere = "";
-        bool mWriteToFile = false;
-        bool mEnabled = false;
-        bool mAddEntry = false;
-        void loop();
-        bool traceWhenNotified(LayersTraceProto* outProto);
-    };
-};
-
-} // namespace android
diff --git a/services/surfaceflinger/Tracing/LayerTracing.cpp b/services/surfaceflinger/Tracing/LayerTracing.cpp
new file mode 100644
index 0000000..84890ee
--- /dev/null
+++ b/services/surfaceflinger/Tracing/LayerTracing.cpp
@@ -0,0 +1,130 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#undef LOG_TAG
+#define LOG_TAG "LayerTracing"
+#define ATRACE_TAG ATRACE_TAG_GRAPHICS
+
+#include <SurfaceFlinger.h>
+#include <android-base/stringprintf.h>
+#include <log/log.h>
+#include <utils/SystemClock.h>
+#include <utils/Trace.h>
+
+#include "LayerTracing.h"
+#include "RingBuffer.h"
+
+namespace android {
+
+LayerTracing::LayerTracing(SurfaceFlinger& flinger) : mFlinger(flinger) {
+    mBuffer = std::make_unique<RingBuffer<LayersTraceFileProto, LayersTraceProto>>();
+}
+
+LayerTracing::~LayerTracing() = default;
+
+bool LayerTracing::enable() {
+    std::scoped_lock lock(mTraceLock);
+    if (mEnabled) {
+        return false;
+    }
+    mBuffer->setSize(mBufferSizeInBytes);
+    mEnabled = true;
+    return true;
+}
+
+bool LayerTracing::disable() {
+    std::scoped_lock lock(mTraceLock);
+    if (!mEnabled) {
+        return false;
+    }
+    mEnabled = false;
+    LayersTraceFileProto fileProto = createTraceFileProto();
+    mBuffer->writeToFile(fileProto, FILE_NAME);
+    return true;
+}
+
+bool LayerTracing::isEnabled() const {
+    std::scoped_lock lock(mTraceLock);
+    return mEnabled;
+}
+
+status_t LayerTracing::writeToFile() {
+    std::scoped_lock lock(mTraceLock);
+    if (!mEnabled) {
+        return STATUS_OK;
+    }
+    LayersTraceFileProto fileProto = createTraceFileProto();
+    return mBuffer->writeToFile(fileProto, FILE_NAME);
+}
+
+void LayerTracing::setTraceFlags(uint32_t flags) {
+    std::scoped_lock lock(mTraceLock);
+    mFlags = flags;
+}
+
+void LayerTracing::setBufferSize(size_t bufferSizeInBytes) {
+    std::scoped_lock lock(mTraceLock);
+    mBufferSizeInBytes = bufferSizeInBytes;
+}
+
+bool LayerTracing::flagIsSet(uint32_t flags) const {
+    return (mFlags & flags) == flags;
+}
+
+LayersTraceFileProto LayerTracing::createTraceFileProto() const {
+    LayersTraceFileProto fileProto;
+    fileProto.set_magic_number(uint64_t(LayersTraceFileProto_MagicNumber_MAGIC_NUMBER_H) << 32 |
+                               LayersTraceFileProto_MagicNumber_MAGIC_NUMBER_L);
+    return fileProto;
+}
+
+void LayerTracing::dump(std::string& result) const {
+    std::scoped_lock lock(mTraceLock);
+    base::StringAppendF(&result, "Tracing state: %s\n", mEnabled ? "enabled" : "disabled");
+    mBuffer->dump(result);
+}
+
+void LayerTracing::notify(const char* where) {
+    ATRACE_CALL();
+    std::scoped_lock lock(mTraceLock);
+    if (!mEnabled) {
+        return;
+    }
+
+    ATRACE_CALL();
+    LayersTraceProto entry;
+    entry.set_elapsed_realtime_nanos(elapsedRealtimeNano());
+    entry.set_where(where);
+    LayersProto layers(mFlinger.dumpDrawingStateProto(mFlags));
+
+    if (flagIsSet(LayerTracing::TRACE_EXTRA)) {
+        mFlinger.dumpOffscreenLayersProto(layers);
+    }
+    entry.mutable_layers()->Swap(&layers);
+
+    if (flagIsSet(LayerTracing::TRACE_HWC)) {
+        std::string hwcDump;
+        mFlinger.dumpHwc(hwcDump);
+        entry.set_hwc_blob(hwcDump);
+    }
+    if (!flagIsSet(LayerTracing::TRACE_COMPOSITION)) {
+        entry.set_excludes_composition_state(true);
+    }
+    mFlinger.dumpDisplayProto(entry);
+    mBuffer->emplace(std::move(entry));
+}
+
+} // namespace android
diff --git a/services/surfaceflinger/Tracing/LayerTracing.h b/services/surfaceflinger/Tracing/LayerTracing.h
new file mode 100644
index 0000000..8ca3587
--- /dev/null
+++ b/services/surfaceflinger/Tracing/LayerTracing.h
@@ -0,0 +1,77 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <android-base/thread_annotations.h>
+#include <layerproto/LayerProtoHeader.h>
+#include <utils/Errors.h>
+#include <utils/StrongPointer.h>
+#include <utils/Timers.h>
+
+#include <memory>
+#include <mutex>
+
+using namespace android::surfaceflinger;
+
+namespace android {
+
+template <typename FileProto, typename EntryProto>
+class RingBuffer;
+
+class SurfaceFlinger;
+
+/*
+ * LayerTracing records layer states during surface flinging. Manages tracing state and
+ * configuration.
+ */
+class LayerTracing {
+public:
+    LayerTracing(SurfaceFlinger& flinger);
+    ~LayerTracing();
+    bool enable();
+    bool disable();
+    bool isEnabled() const;
+    status_t writeToFile();
+    LayersTraceFileProto createTraceFileProto() const;
+    void notify(const char* where);
+
+    enum : uint32_t {
+        TRACE_INPUT = 1 << 1,
+        TRACE_COMPOSITION = 1 << 2,
+        TRACE_EXTRA = 1 << 3,
+        TRACE_HWC = 1 << 4,
+        TRACE_BUFFERS = 1 << 5,
+        TRACE_ALL = TRACE_INPUT | TRACE_COMPOSITION | TRACE_EXTRA,
+    };
+    void setTraceFlags(uint32_t flags);
+    bool flagIsSet(uint32_t flags) const;
+    void setBufferSize(size_t bufferSizeInBytes);
+    void dump(std::string&) const;
+
+private:
+    static constexpr auto FILE_NAME = "/data/misc/wmtrace/layers_trace.winscope";
+
+    SurfaceFlinger& mFlinger;
+    uint32_t mFlags = TRACE_INPUT;
+    mutable std::mutex mTraceLock;
+    bool mEnabled GUARDED_BY(mTraceLock) = false;
+    std::unique_ptr<RingBuffer<LayersTraceFileProto, LayersTraceProto>> mBuffer
+            GUARDED_BY(mTraceLock);
+    size_t mBufferSizeInBytes GUARDED_BY(mTraceLock) = 20 * 1024 * 1024;
+};
+
+} // namespace android
diff --git a/services/surfaceflinger/Tracing/RingBuffer.h b/services/surfaceflinger/Tracing/RingBuffer.h
new file mode 100644
index 0000000..d0fb3f2
--- /dev/null
+++ b/services/surfaceflinger/Tracing/RingBuffer.h
@@ -0,0 +1,112 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <android-base/file.h>
+#include <android-base/stringprintf.h>
+
+#include <log/log.h>
+#include <utils/Errors.h>
+#include <utils/SystemClock.h>
+#include <utils/Trace.h>
+#include <queue>
+
+namespace android {
+
+class SurfaceFlinger;
+
+template <typename FileProto, typename EntryProto>
+class RingBuffer {
+public:
+    size_t size() const { return mSizeInBytes; }
+    size_t used() const { return mUsedInBytes; }
+    size_t frameCount() const { return mStorage.size(); }
+    void setSize(size_t newSize) { mSizeInBytes = newSize; }
+    EntryProto& front() { return mStorage.front(); }
+    const EntryProto& front() const { return mStorage.front(); }
+
+    void reset(size_t newSize) {
+        // use the swap trick to make sure memory is released
+        std::queue<EntryProto>().swap(mStorage);
+        mSizeInBytes = newSize;
+        mUsedInBytes = 0U;
+    }
+    void flush(FileProto& fileProto) {
+        fileProto.mutable_entry()->Reserve(static_cast<int>(mStorage.size()));
+        while (!mStorage.empty()) {
+            auto entry = fileProto.add_entry();
+            entry->Swap(&mStorage.front());
+            mStorage.pop();
+        }
+    }
+
+    status_t writeToFile(FileProto& fileProto, std::string filename) {
+        ATRACE_CALL();
+        std::string output;
+        flush(fileProto);
+        reset(mSizeInBytes);
+        if (!fileProto.SerializeToString(&output)) {
+            ALOGE("Could not serialize proto.");
+            return UNKNOWN_ERROR;
+        }
+
+        // -rw-r--r--
+        const mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
+        if (!android::base::WriteStringToFile(output, filename, mode, getuid(), getgid(), true)) {
+            ALOGE("Could not save the proto file.");
+            return PERMISSION_DENIED;
+        }
+        return NO_ERROR;
+    }
+
+    std::vector<EntryProto> emplace(EntryProto&& proto) {
+        std::vector<EntryProto> replacedEntries;
+        size_t protoSize = static_cast<size_t>(proto.ByteSize());
+        while (mUsedInBytes + protoSize > mSizeInBytes) {
+            if (mStorage.empty()) {
+                return {};
+            }
+            mUsedInBytes -= static_cast<size_t>(mStorage.front().ByteSize());
+            replacedEntries.emplace_back(mStorage.front());
+            mStorage.pop();
+        }
+        mUsedInBytes += protoSize;
+        mStorage.emplace();
+        mStorage.back().Swap(&proto);
+        return replacedEntries;
+    }
+
+    void dump(std::string& result) const {
+        std::chrono::milliseconds duration(0);
+        if (frameCount() > 0) {
+            duration = std::chrono::duration_cast<std::chrono::milliseconds>(
+                    std::chrono::nanoseconds(systemTime() - front().elapsed_realtime_nanos()));
+        }
+        const int64_t durationCount = duration.count();
+        base::StringAppendF(&result,
+                            "  number of entries: %zu (%.2fMB / %.2fMB) duration: %" PRIi64 "ms\n",
+                            frameCount(), float(used()) / 1024.f * 1024.f,
+                            float(size()) / 1024.f * 1024.f, durationCount);
+    }
+
+private:
+    size_t mUsedInBytes = 0U;
+    size_t mSizeInBytes = 0U;
+    std::queue<EntryProto> mStorage;
+};
+
+} // namespace android
diff --git a/services/surfaceflinger/tests/unittests/CompositionTest.cpp b/services/surfaceflinger/tests/unittests/CompositionTest.cpp
index 52d8c35..dffc6c6 100644
--- a/services/surfaceflinger/tests/unittests/CompositionTest.cpp
+++ b/services/surfaceflinger/tests/unittests/CompositionTest.cpp
@@ -145,9 +145,6 @@
         mFlinger.setupScheduler(std::move(vsyncController), std::move(vsyncTracker),
                                 std::move(eventThread), std::move(sfEventThread), kCallback,
                                 kHasMultipleConfigs);
-
-        // Layer history should be created if there are multiple configs.
-        ASSERT_TRUE(mFlinger.scheduler()->hasLayerHistory());
     }
 
     void setupForceGeometryDirty() {
@@ -844,7 +841,7 @@
         sp<L> layer = factory();
 
         // Layer should be registered with scheduler.
-        EXPECT_EQ(1, test->mFlinger.scheduler()->layerHistorySize());
+        EXPECT_EQ(1u, test->mFlinger.scheduler()->layerHistorySize());
 
         Mock::VerifyAndClear(test->mComposer);
         Mock::VerifyAndClear(test->mRenderEngine);
@@ -889,7 +886,7 @@
 
         // Layer should be unregistered with scheduler.
         test->mFlinger.commit();
-        EXPECT_EQ(0, test->mFlinger.scheduler()->layerHistorySize());
+        EXPECT_EQ(0u, test->mFlinger.scheduler()->layerHistorySize());
     }
 };
 
diff --git a/services/surfaceflinger/tests/unittests/LayerHistoryTest.cpp b/services/surfaceflinger/tests/unittests/LayerHistoryTest.cpp
index e8795fe..4993a2d 100644
--- a/services/surfaceflinger/tests/unittests/LayerHistoryTest.cpp
+++ b/services/surfaceflinger/tests/unittests/LayerHistoryTest.cpp
@@ -59,10 +59,8 @@
 
     LayerHistoryTest() { mFlinger.resetScheduler(mScheduler); }
 
-    void SetUp() override { ASSERT_TRUE(mScheduler->hasLayerHistory()); }
-
-    LayerHistory& history() { return *mScheduler->mutableLayerHistory(); }
-    const LayerHistory& history() const { return *mScheduler->mutableLayerHistory(); }
+    LayerHistory& history() { return mScheduler->mutableLayerHistory(); }
+    const LayerHistory& history() const { return mScheduler->mutableLayerHistory(); }
 
     LayerHistory::Summary summarizeLayerHistory(nsecs_t now) {
         return history().summarize(*mScheduler->refreshRateConfigs(), now);
diff --git a/services/surfaceflinger/tests/unittests/SchedulerTest.cpp b/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
index 599b235..e558f3b 100644
--- a/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
+++ b/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
@@ -68,14 +68,6 @@
             std::make_shared<scheduler::RefreshRateConfigs>(DisplayModes{mode60}, mode60->getId());
 
     mock::SchedulerCallback mSchedulerCallback;
-
-    // The scheduler should initially disable VSYNC.
-    struct ExpectDisableVsync {
-        ExpectDisableVsync(mock::SchedulerCallback& callback) {
-            EXPECT_CALL(callback, setVsyncEnabled(false)).Times(1);
-        }
-    } mExpectDisableVsync{mSchedulerCallback};
-
     TestableScheduler* mScheduler = new TestableScheduler{mConfigs, mSchedulerCallback};
 
     Scheduler::ConnectionHandle mConnectionHandle;
@@ -166,9 +158,9 @@
     sp<mock::MockLayer> layer = sp<mock::MockLayer>::make(mFlinger.flinger());
 
     // recordLayerHistory should be a noop
-    ASSERT_EQ(static_cast<size_t>(0), mScheduler->getNumActiveLayers());
+    ASSERT_EQ(0u, mScheduler->getNumActiveLayers());
     mScheduler->recordLayerHistory(layer.get(), 0, LayerHistory::LayerUpdateType::Buffer);
-    ASSERT_EQ(static_cast<size_t>(0), mScheduler->getNumActiveLayers());
+    ASSERT_EQ(0u, mScheduler->getNumActiveLayers());
 
     constexpr bool kPowerStateNormal = true;
     mScheduler->setDisplayPowerState(kPowerStateNormal);
@@ -181,17 +173,17 @@
 }
 
 TEST_F(SchedulerTest, updateDisplayModes) {
-    ASSERT_EQ(static_cast<size_t>(0), mScheduler->layerHistorySize());
+    ASSERT_EQ(0u, mScheduler->layerHistorySize());
     sp<mock::MockLayer> layer = sp<mock::MockLayer>::make(mFlinger.flinger());
-    ASSERT_EQ(static_cast<size_t>(1), mScheduler->layerHistorySize());
+    ASSERT_EQ(1u, mScheduler->layerHistorySize());
 
     mScheduler->setRefreshRateConfigs(
             std::make_shared<scheduler::RefreshRateConfigs>(DisplayModes{mode60, mode120},
                                                             mode60->getId()));
 
-    ASSERT_EQ(static_cast<size_t>(0), mScheduler->getNumActiveLayers());
+    ASSERT_EQ(0u, mScheduler->getNumActiveLayers());
     mScheduler->recordLayerHistory(layer.get(), 0, LayerHistory::LayerUpdateType::Buffer);
-    ASSERT_EQ(static_cast<size_t>(1), mScheduler->getNumActiveLayers());
+    ASSERT_EQ(1u, mScheduler->getNumActiveLayers());
 }
 
 TEST_F(SchedulerTest, testDispatchCachedReportedMode) {
diff --git a/services/surfaceflinger/tests/unittests/SetFrameRateTest.cpp b/services/surfaceflinger/tests/unittests/SetFrameRateTest.cpp
index 360f9c6..84c845d 100644
--- a/services/surfaceflinger/tests/unittests/SetFrameRateTest.cpp
+++ b/services/surfaceflinger/tests/unittests/SetFrameRateTest.cpp
@@ -454,20 +454,16 @@
     parent->setFrameRate(FRAME_RATE_VOTE1);
     commitTransaction();
 
-    mFlinger.mutableScheduler()
-            .mutableLayerHistory()
-            ->record(parent.get(), 0, 0, LayerHistory::LayerUpdateType::Buffer);
-    mFlinger.mutableScheduler()
-            .mutableLayerHistory()
-            ->record(child.get(), 0, 0, LayerHistory::LayerUpdateType::Buffer);
+    auto& history = mFlinger.mutableScheduler().mutableLayerHistory();
+    history.record(parent.get(), 0, 0, LayerHistory::LayerUpdateType::Buffer);
+    history.record(child.get(), 0, 0, LayerHistory::LayerUpdateType::Buffer);
 
-    const auto layerHistorySummary =
-            mFlinger.mutableScheduler()
-                    .mutableLayerHistory()
-                    ->summarize(*mFlinger.mutableScheduler().refreshRateConfigs(), 0);
-    ASSERT_EQ(2u, layerHistorySummary.size());
-    EXPECT_EQ(FRAME_RATE_VOTE1.rate, layerHistorySummary[0].desiredRefreshRate);
-    EXPECT_EQ(FRAME_RATE_VOTE1.rate, layerHistorySummary[1].desiredRefreshRate);
+    const auto configs = mFlinger.mutableScheduler().refreshRateConfigs();
+    const auto summary = history.summarize(*configs, 0);
+
+    ASSERT_EQ(2u, summary.size());
+    EXPECT_EQ(FRAME_RATE_VOTE1.rate, summary[0].desiredRefreshRate);
+    EXPECT_EQ(FRAME_RATE_VOTE1.rate, summary[1].desiredRefreshRate);
 }
 
 TEST_P(SetFrameRateTest, addChildForParentWithTreeVote) {
diff --git a/services/surfaceflinger/tests/unittests/TestableScheduler.h b/services/surfaceflinger/tests/unittests/TestableScheduler.h
index 1d21bd4..1b850fc 100644
--- a/services/surfaceflinger/tests/unittests/TestableScheduler.h
+++ b/services/surfaceflinger/tests/unittests/TestableScheduler.h
@@ -32,19 +32,20 @@
 
 class TestableScheduler : public Scheduler {
 public:
-    TestableScheduler(const std::shared_ptr<scheduler::RefreshRateConfigs>& refreshRateConfigs,
+    TestableScheduler(std::shared_ptr<scheduler::RefreshRateConfigs> configs,
                       ISchedulerCallback& callback)
           : TestableScheduler(std::make_unique<mock::VsyncController>(),
-                              std::make_unique<mock::VSyncTracker>(), refreshRateConfigs,
+                              std::make_unique<mock::VSyncTracker>(), std::move(configs),
                               callback) {}
 
     TestableScheduler(std::unique_ptr<scheduler::VsyncController> vsyncController,
                       std::unique_ptr<scheduler::VSyncTracker> vsyncTracker,
-                      const std::shared_ptr<scheduler::RefreshRateConfigs>& refreshRateConfigs,
+                      std::shared_ptr<scheduler::RefreshRateConfigs> configs,
                       ISchedulerCallback& callback)
-          : Scheduler({std::move(vsyncController), std::move(vsyncTracker), nullptr},
-                      refreshRateConfigs, callback, createLayerHistory(),
-                      {.useContentDetection = true}) {}
+          : Scheduler(callback, {.useContentDetection = true}) {
+        mVsyncSchedule = {std::move(vsyncController), std::move(vsyncTracker), nullptr};
+        setRefreshRateConfigs(std::move(configs));
+    }
 
     // Used to inject mock event thread.
     ConnectionHandle createConnection(std::unique_ptr<EventThread> eventThread) {
@@ -58,22 +59,13 @@
     auto& mutablePrimaryHWVsyncEnabled() { return mPrimaryHWVsyncEnabled; }
     auto& mutableHWVsyncAvailable() { return mHWVsyncAvailable; }
 
-    bool hasLayerHistory() const { return static_cast<bool>(mLayerHistory); }
+    auto& mutableLayerHistory() { return mLayerHistory; }
 
-    auto* mutableLayerHistory() { return mLayerHistory.get(); }
-
-    size_t layerHistorySize() NO_THREAD_SAFETY_ANALYSIS {
-        if (!mLayerHistory) return 0;
-        return mutableLayerHistory()->mLayerInfos.size();
-    }
+    size_t layerHistorySize() NO_THREAD_SAFETY_ANALYSIS { return mLayerHistory.mLayerInfos.size(); }
+    size_t getNumActiveLayers() NO_THREAD_SAFETY_ANALYSIS { return mLayerHistory.mActiveLayersEnd; }
 
     auto refreshRateConfigs() { return holdRefreshRateConfigs(); }
 
-    size_t getNumActiveLayers() NO_THREAD_SAFETY_ANALYSIS {
-        if (!mLayerHistory) return 0;
-        return mutableLayerHistory()->mActiveLayersEnd;
-    }
-
     void replaceTouchTimer(int64_t millis) {
         if (mTouchTimer) {
             mTouchTimer.reset();
diff --git a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
index 8cca6af..c2c4a54 100644
--- a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
+++ b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
@@ -82,11 +82,6 @@
         return std::make_unique<scheduler::FakePhaseOffsets>();
     }
 
-    std::unique_ptr<Scheduler> createScheduler(
-            const std::shared_ptr<scheduler::RefreshRateConfigs>&, ISchedulerCallback&) override {
-        return nullptr;
-    }
-
     sp<SurfaceInterceptor> createSurfaceInterceptor() override {
         return new android::impl::SurfaceInterceptor();
     }