SF: Extract utils::OnceFuture
Make `mRenderEnginePrimeCacheFuture` thread-safe and release its shared
state after the wait.
Bug: 328459745
Test: presubmit
Change-Id: I2bf3029823109a8c97e599d20c15e46ac1e4aeb9
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 30b8953..78e14ae 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -565,14 +565,11 @@
initializeDisplays();
}));
- std::lock_guard lock(mInitBootPropsFutureMutex);
- if (!mInitBootPropsFuture.valid()) {
- mInitBootPropsFuture =
- std::async(std::launch::async, &SurfaceFlinger::initBootProperties, this);
- }
+ mInitBootPropsFuture.callOnce([this] {
+ return std::async(std::launch::async, &SurfaceFlinger::initBootProperties, this);
+ });
mInitBootPropsFuture.wait();
- mInitBootPropsFuture = {};
}
void SurfaceFlinger::run() {
@@ -729,13 +726,8 @@
mBootFinished = true;
FlagManager::getMutableInstance().markBootCompleted();
- if (std::lock_guard lock(mInitBootPropsFutureMutex); mInitBootPropsFuture.valid()) {
- mInitBootPropsFuture.wait();
- mInitBootPropsFuture = {};
- }
- if (mRenderEnginePrimeCacheFuture.valid()) {
- mRenderEnginePrimeCacheFuture.wait();
- }
+ mInitBootPropsFuture.wait();
+ mRenderEnginePrimeCacheFuture.wait();
const nsecs_t now = systemTime();
const nsecs_t duration = now - mBootTime;
@@ -925,9 +917,11 @@
ALOGW("Can't set SCHED_OTHER for primeCache");
}
- bool shouldPrimeUltraHDR =
- base::GetBoolProperty("ro.surface_flinger.prime_shader_cache.ultrahdr"s, false);
- mRenderEnginePrimeCacheFuture = getRenderEngine().primeCache(shouldPrimeUltraHDR);
+ mRenderEnginePrimeCacheFuture.callOnce([this] {
+ const bool shouldPrimeUltraHDR =
+ base::GetBoolProperty("ro.surface_flinger.prime_shader_cache.ultrahdr"s, false);
+ return getRenderEngine().primeCache(shouldPrimeUltraHDR);
+ });
if (setSchedFifo(true) != NO_ERROR) {
ALOGW("Can't set SCHED_FIFO after primeCache");
@@ -935,10 +929,9 @@
}
// Avoid blocking the main thread on `init` to set properties.
- if (std::lock_guard lock(mInitBootPropsFutureMutex); !mInitBootPropsFuture.valid()) {
- mInitBootPropsFuture =
- std::async(std::launch::async, &SurfaceFlinger::initBootProperties, this);
- }
+ mInitBootPropsFuture.callOnce([this] {
+ return std::async(std::launch::async, &SurfaceFlinger::initBootProperties, this);
+ });
initTransactionTraceWriter();
ALOGV("Done initializing");
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index b9ea0c3..0cc8fbb 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -89,6 +89,7 @@
#include "Tracing/TransactionTracing.h"
#include "TransactionCallbackInvoker.h"
#include "TransactionState.h"
+#include "Utils/OnceFuture.h"
#include <atomic>
#include <cstdint>
@@ -1189,10 +1190,9 @@
pid_t mPid;
// TODO: b/328459745 - Encapsulate in a SystemProperties object.
- std::mutex mInitBootPropsFutureMutex;
- std::future<void> mInitBootPropsFuture GUARDED_BY(mInitBootPropsFutureMutex);
+ utils::OnceFuture mInitBootPropsFuture;
- std::future<void> mRenderEnginePrimeCacheFuture;
+ utils::OnceFuture mRenderEnginePrimeCacheFuture;
// mStateLock has conventions related to the current thread, because only
// the main thread should modify variables protected by mStateLock.
diff --git a/services/surfaceflinger/Utils/OnceFuture.h b/services/surfaceflinger/Utils/OnceFuture.h
new file mode 100644
index 0000000..412038c
--- /dev/null
+++ b/services/surfaceflinger/Utils/OnceFuture.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright 2024 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 <future>
+#include <mutex>
+
+#include <android-base/thread_annotations.h>
+
+namespace android::utils {
+
+// Allows a thread to `wait` for a future produced by a different thread. The future is returned by
+// the first call to a function `F` that multiple threads may `callOnce`. If no `callOnce` happens,
+// then `wait` does nothing. Otherwise, it blocks on the future, then destroys it, which resets the
+// `OnceFuture`.
+class OnceFuture {
+public:
+ template <typename F>
+ void callOnce(F f) {
+ std::lock_guard lock(mMutex);
+ if (!mFuture.valid()) {
+ mFuture = f();
+ }
+ }
+
+ void wait() {
+ std::lock_guard lock(mMutex);
+ if (mFuture.valid()) {
+ mFuture.wait();
+ mFuture = {};
+ }
+ }
+
+private:
+ std::mutex mMutex;
+ std::future<void> mFuture GUARDED_BY(mMutex);
+};
+
+} // namespace android::utils