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Reconcile binder JNI with earlier changes, removing lock.

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Change Idbacb6ad14c43aff8030d70b5e17427b86e92d6e introduced
synchronization of the sProxyMap in Java, removing the need
for serialization (and having a native lock). But for some
reason, we did not remove it in AOSP.

Bug: 132922399
Test: builds
Change-Id: Ib2dc64a7716a1e4798b998e54fac298eb40a7c1d
Merged-In: I4e06b3f93e30ed1c7868ec9e018709a7e796e441
This commit is contained in:
Martijn Coenen
2019-06-06 11:15:15 +02:00
parent 2bba8e7b60
commit 6ccf33b00c
1 changed files with 17 additions and 33 deletions
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50
core/jni/android_util_Binder.cpp
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@@ -156,9 +156,8 @@ static struct thread_dispatch_offsets_t
static constexpr int32_t PROXY_WARN_INTERVAL = 5000;
static constexpr uint32_t GC_INTERVAL = 1000;
// Protected by gProxyLock. We warn if this gets too large.
static int32_t gNumProxies = 0;
static int32_t gProxiesWarned = 0;
static std::atomic<uint32_t> gNumProxies(0);
static std::atomic<uint32_t> gProxiesWarned(0);
// Number of GlobalRefs held by JavaBBinders.
static std::atomic<uint32_t> gNumLocalRefsCreated(0);
@@ -660,12 +659,6 @@ BinderProxyNativeData* getBPNativeData(JNIEnv* env, jobject obj) {
return (BinderProxyNativeData *) env->GetLongField(obj, gBinderProxyOffsets.mNativeData);
}
static Mutex gProxyLock;
// We may cache a single BinderProxyNativeData node to avoid repeat allocation.
// All fields are null. Protected by gProxyLock.
static BinderProxyNativeData *gNativeDataCache;
// If the argument is a JavaBBinder, return the Java object that was used to create it.
// Otherwise return a BinderProxy for the IBinder. If a previous call was passed the
// same IBinder, and the original BinderProxy is still alive, return the same BinderProxy.
@@ -680,36 +673,31 @@ jobject javaObjectForIBinder(JNIEnv* env, const sp<IBinder>& val)
return object;
}
// For the rest of the function we will hold this lock, to serialize
// looking/creation/destruction of Java proxies for native Binder proxies.
AutoMutex _l(gProxyLock);
BinderProxyNativeData* nativeData = new BinderProxyNativeData();
nativeData->mOrgue = new DeathRecipientList;
nativeData->mObject = val;
BinderProxyNativeData* nativeData = gNativeDataCache;
if (nativeData == nullptr) {
nativeData = new BinderProxyNativeData();
}
// gNativeDataCache is now logically empty.
jobject object = env->CallStaticObjectMethod(gBinderProxyOffsets.mClass,
gBinderProxyOffsets.mGetInstance, (jlong) nativeData, (jlong) val.get());
if (env->ExceptionCheck()) {
// In the exception case, getInstance still took ownership of nativeData.
gNativeDataCache = nullptr;
return NULL;
}
BinderProxyNativeData* actualNativeData = getBPNativeData(env, object);
if (actualNativeData == nativeData) {
// New BinderProxy; we still have exclusive access.
nativeData->mOrgue = new DeathRecipientList;
nativeData->mObject = val;
gNativeDataCache = nullptr;
++gNumProxies;
if (gNumProxies >= gProxiesWarned + PROXY_WARN_INTERVAL) {
ALOGW("Unexpectedly many live BinderProxies: %d\n", gNumProxies);
gProxiesWarned = gNumProxies;
// Created a new Proxy
uint32_t numProxies = gNumProxies.fetch_add(1, std::memory_order_relaxed);
uint32_t numLastWarned = gProxiesWarned.load(std::memory_order_relaxed);
if (numProxies >= numLastWarned + PROXY_WARN_INTERVAL) {
// Multiple threads can get here, make sure only one of them gets to
// update the warn counter.
if (gProxiesWarned.compare_exchange_strong(numLastWarned,
numLastWarned + PROXY_WARN_INTERVAL, std::memory_order_relaxed)) {
ALOGW("Unexpectedly many live BinderProxies: %d\n", numProxies);
}
}
} else {
// nativeData wasn't used. Reuse it the next time.
gNativeDataCache = nativeData;
delete nativeData;
}
return object;
@@ -989,8 +977,7 @@ jint android_os_Debug_getLocalObjectCount(JNIEnv* env, jobject clazz)
jint android_os_Debug_getProxyObjectCount(JNIEnv* env, jobject clazz)
{
AutoMutex _l(gProxyLock);
return gNumProxies;
return gNumProxies.load();
}
jint android_os_Debug_getDeathObjectCount(JNIEnv* env, jobject clazz)
@@ -1385,9 +1372,6 @@ static jboolean android_os_BinderProxy_unlinkToDeath(JNIEnv* env, jobject obj,
static void BinderProxy_destroy(void* rawNativeData)
{
// Don't race with construction/initialization
AutoMutex _l(gProxyLock);
BinderProxyNativeData * nativeData = (BinderProxyNativeData *) rawNativeData;
LOGDEATH("Destroying BinderProxy: binder=%p drl=%p\n",
nativeData->mObject.get(), nativeData->mOrgue.get());