Add locking to performance hint NDK
This patch adds thread safety to the NDK, locking everything behind a
single mutex to avoid multiple lock acquisitions when operating on
shared state. All calls are asynchronous, except for createSession and
setThreads which don't need to hold the lock during their call, so the
risk of contesting the mutex is low.
Test: atest PerformanceHintNativeTest
Bug: 343817997
Change-Id: Ib08c11d6b7c84c30e83cca6613b15c62bcd8a68f
diff --git a/native/android/performance_hint.cpp b/native/android/performance_hint.cpp
index 83056b2..f64b847 100644
--- a/native/android/performance_hint.cpp
+++ b/native/android/performance_hint.cpp
@@ -51,6 +51,9 @@
constexpr int64_t SEND_HINT_TIMEOUT = std::chrono::nanoseconds(100ms).count();
struct AWorkDuration : public hal::WorkDuration {};
+// Shared lock for the whole PerformanceHintManager and sessions
+static std::mutex sHintMutex = std::mutex{};
+
struct APerformanceHintManager {
public:
static APerformanceHintManager* getInstance();
@@ -192,6 +195,7 @@
}
auto out = new APerformanceHintSession(mHintManager, std::move(session), mPreferredRateNanos,
initialTargetWorkDurationNanos, sessionConfig);
+ std::scoped_lock lock(sHintMutex);
out->traceThreads(tids);
out->traceTargetDuration(initialTargetWorkDurationNanos);
out->tracePowerEfficient(false);
@@ -219,6 +223,7 @@
if (sessionConfig->id > INT32_MAX) {
ALOGE("Session ID too large, must fit 32-bit integer");
}
+ std::scoped_lock lock(sHintMutex);
constexpr int numEnums =
ndk::enum_range<hal::SessionHint>().end() - ndk::enum_range<hal::SessionHint>().begin();
mLastHintSentTimestamp = std::vector<int64_t>(numEnums, 0);
@@ -244,6 +249,7 @@
ret.getMessage());
return EPIPE;
}
+ std::scoped_lock lock(sHintMutex);
mTargetDurationNanos = targetDurationNanos;
/**
* Most of the workload is target_duration dependent, so now clear the cached samples
@@ -267,6 +273,7 @@
}
int APerformanceHintSession::sendHint(SessionHint hint) {
+ std::scoped_lock lock(sHintMutex);
if (hint < 0 || hint >= static_cast<int32_t>(mLastHintSentTimestamp.size())) {
ALOGE("%s: invalid session hint %d", __FUNCTION__, hint);
return EINVAL;
@@ -305,6 +312,7 @@
return EPIPE;
}
+ std::scoped_lock lock(sHintMutex);
traceThreads(tids);
return 0;
@@ -343,6 +351,7 @@
ret.getMessage());
return EPIPE;
}
+ std::scoped_lock lock(sHintMutex);
tracePowerEfficient(enabled);
return OK;
}
@@ -355,6 +364,7 @@
int64_t actualTotalDurationNanos = workDuration->durationNanos;
int64_t now = uptimeNanos();
workDuration->timeStampNanos = now;
+ std::scoped_lock lock(sHintMutex);
traceActualDuration(workDuration->durationNanos);
mActualWorkDurations.push_back(std::move(*workDuration));