Merge "Make concurrently accessed globals atomic" am: df4629e947 am: 851c97cb39 (ee143f3d) · Commits · e / os / android_frameworks_native-old

libs/binder/IPCThreadState.cpp

+15 −13

Original line number	Diff line number	Diff line
		@@ -33,6 +33,7 @@
		#include <private/binder/binder_module.h>
		#include <private/binder/Static.h>

		#include <atomic>
		#include <errno.h>
		#include <inttypes.h>
		#include <pthread.h>
		@@ -278,14 +279,14 @@ static const void* printCommand(TextOutput& out, const void* _cmd)
		}

		static pthread_mutex_t gTLSMutex = PTHREAD_MUTEX_INITIALIZER;
		static bool gHaveTLS = false;
		static std::atomic<bool> gHaveTLS(false);
		static pthread_key_t gTLS = 0;
		static bool gShutdown = false;
		static bool gDisableBackgroundScheduling = false;
		static std::atomic<bool> gShutdown = false;
		static std::atomic<bool> gDisableBackgroundScheduling = false;

		IPCThreadState* IPCThreadState::self()
		{
		if (gHaveTLS) {
		if (gHaveTLS.load(std::memory_order_acquire)) {
		restart:
		const pthread_key_t k = gTLS;
		IPCThreadState* st = (IPCThreadState*)pthread_getspecific(k);
		@@ -293,13 +294,14 @@ restart:
		return new IPCThreadState;
		}

		if (gShutdown) {
		// Racey, heuristic test for simultaneous shutdown.
		if (gShutdown.load(std::memory_order_relaxed)) {
		ALOGW("Calling IPCThreadState::self() during shutdown is dangerous, expect a crash.\n");
		return nullptr;
		}

		pthread_mutex_lock(&gTLSMutex);
		if (!gHaveTLS) {
		if (!gHaveTLS.load(std::memory_order_relaxed)) {
		int key_create_value = pthread_key_create(&gTLS, threadDestructor);
		if (key_create_value != 0) {
		pthread_mutex_unlock(&gTLSMutex);
		@@ -307,7 +309,7 @@ restart:
		strerror(key_create_value));
		return nullptr;
		}
		gHaveTLS = true;
		gHaveTLS.store(true, std::memory_order_release);
		}
		pthread_mutex_unlock(&gTLSMutex);
		goto restart;
		@@ -315,7 +317,7 @@ restart:

		IPCThreadState* IPCThreadState::selfOrNull()
		{
		if (gHaveTLS) {
		if (gHaveTLS.load(std::memory_order_acquire)) {
		const pthread_key_t k = gTLS;
		IPCThreadState* st = (IPCThreadState*)pthread_getspecific(k);
		return st;
		@@ -325,9 +327,9 @@ IPCThreadState* IPCThreadState::selfOrNull()

		void IPCThreadState::shutdown()
		{
		gShutdown = true;
		gShutdown.store(true, std::memory_order_relaxed);

		if (gHaveTLS) {
		if (gHaveTLS.load(std::memory_order_acquire)) {
		// XXX Need to wait for all thread pool threads to exit!
		IPCThreadState* st = (IPCThreadState*)pthread_getspecific(gTLS);
		if (st) {
		@@ -335,18 +337,18 @@ void IPCThreadState::shutdown()
		pthread_setspecific(gTLS, nullptr);
		}
		pthread_key_delete(gTLS);
		gHaveTLS = false;
		gHaveTLS.store(false, std::memory_order_release);
		}
		}

		void IPCThreadState::disableBackgroundScheduling(bool disable)
		{
		gDisableBackgroundScheduling = disable;
		gDisableBackgroundScheduling.store(disable, std::memory_order_relaxed);
		}

		bool IPCThreadState::backgroundSchedulingDisabled()
		{
		return gDisableBackgroundScheduling;
		return gDisableBackgroundScheduling.load(std::memory_order_relaxed);
		}

		sp<ProcessState> IPCThreadState::process()

libs/binder/include/binder/ProcessState.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -124,6 +124,8 @@ private:
		int64_t mStarvationStartTimeMs;

		mutable Mutex mLock; // protects everything below.
		// TODO: mManagesContexts is often accessed without the lock.
		// Explain why that's safe.

		Vector<handle_entry>mHandleToObject;