From 1d6c040dcb9a01648edc66d8c0006c8c9294a705 Mon Sep 17 00:00:00 2001
From: lichao <lichao@aiotlink.com>
Date: 星期四, 22 四月 2021 18:28:30 +0800
Subject: [PATCH] add mutex timeout limit; use atomic as refcount.

---
 /dev/null          |   57 -----------
 src/shm.h          |   50 +++++++++
 utest/api_test.cpp |  102 +++++++++++++++++++
 src/bh_util.h      |    6 
 src/msg.h          |   27 +---
 src/shm.cpp        |   26 +++++
 6 files changed, 184 insertions(+), 84 deletions(-)

diff --git a/src/bh_util.h b/src/bh_util.h
index bc48578..e3ab70b 100644
--- a/src/bh_util.h
+++ b/src/bh_util.h
@@ -123,13 +123,13 @@
 	D &operator*() const { return *p_; }
 };
 
-template <class T, class Mutex = std::mutex, class Lock = std::unique_lock<Mutex>>
+template <class T, class TMutex = std::mutex, class Lock = std::unique_lock<TMutex>>
 class Synced
 {
 	typedef T Data;
-	Mutex mutex_;
+	TMutex mutex_;
 	Data data_;
-	typedef SyncedPtr<Data, Mutex, Lock> Ptr;
+	typedef SyncedPtr<Data, TMutex, Lock> Ptr;
 
 public:
 	template <class... P>
diff --git a/src/msg.h b/src/msg.h
index e6b0b34..feab5ec 100644
--- a/src/msg.h
+++ b/src/msg.h
@@ -21,6 +21,7 @@
 #include "bh_util.h"
 #include "proto.h"
 #include "shm.h"
+#include <atomic>
 #include <boost/interprocess/offset_ptr.hpp>
 #include <boost/uuid/uuid_generators.hpp>
 #include <functional>
@@ -38,26 +39,14 @@
 // store ref count, msgs shareing the same data should also hold a pointer of the same RefCount object.
 class RefCount : private boost::noncopyable
 {
-public:
-	int Inc()
-	{
-		Guard lk(mutex_);
-		return ++num_;
-	}
-	int Dec()
-	{
-		Guard lk(mutex_);
-		return --num_;
-	}
-	int Get()
-	{
-		Guard lk(mutex_);
-		return num_;
-	}
+	std::atomic<int> num_;
 
-private:
-	Mutex mutex_;
-	int num_ = 1;
+public:
+	RefCount() :
+	    num_(1) { static_assert(std::is_pod<decltype(num_)>::value); }
+	int Inc() { return ++num_; }
+	int Dec() { return --num_; }
+	int Get() { return num_.load(); }
 };
 
 // message content layout: header_size + header + data_size + data
diff --git a/src/shm.cpp b/src/shm.cpp
index 1658900..d499b16 100644
--- a/src/shm.cpp
+++ b/src/shm.cpp
@@ -21,6 +21,32 @@
 namespace bhome_shm
 {
 
+bool MutexWithTimeLimit::try_lock()
+{
+	if (mutex_.try_lock()) {
+		auto old_time = last_lock_time_.load();
+		if (Now() - old_time > limit_) {
+			return last_lock_time_.compare_exchange_strong(old_time, Now());
+		} else {
+			last_lock_time_.store(Now());
+			return true;
+		}
+	} else {
+		auto old_time = last_lock_time_.load();
+		if (Now() - old_time > limit_) {
+			return last_lock_time_.compare_exchange_strong(old_time, Now());
+		} else {
+			return false;
+		}
+	}
+}
+void MutexWithTimeLimit::lock()
+{
+	while (!try_lock()) {
+		std::this_thread::yield();
+	}
+}
+
 SharedMemory::SharedMemory(const std::string &name, const uint64_t size) :
     mshm_t(open_or_create, name.c_str(), size, 0, AllowAll()),
     name_(name)
diff --git a/src/shm.h b/src/shm.h
index 28745dc..5bf8e41 100644
--- a/src/shm.h
+++ b/src/shm.h
@@ -19,12 +19,15 @@
 #ifndef SHM_6CHO6D6C
 #define SHM_6CHO6D6C
 
+#include <atomic>
 #include <boost/interprocess/managed_shared_memory.hpp>
 #include <boost/interprocess/sync/interprocess_condition.hpp>
 #include <boost/interprocess/sync/interprocess_mutex.hpp>
 #include <boost/interprocess/sync/scoped_lock.hpp>
 #include <boost/noncopyable.hpp>
 #include <boost/uuid/uuid.hpp>
+#include <chrono>
+#include <thread>
 
 namespace bhome_shm
 {
@@ -32,7 +35,52 @@
 using namespace boost::interprocess;
 
 typedef managed_shared_memory mshm_t;
-typedef interprocess_mutex Mutex;
+
+class CasMutex
+{
+	std::atomic<bool> flag_;
+	bool cas(bool expected, bool new_val) { return flag_.compare_exchange_strong(expected, new_val); }
+
+public:
+	CasMutex() :
+	    flag_(false) {}
+	bool try_lock() { return cas(false, true); }
+	void lock()
+	{
+		while (!try_lock()) { std::this_thread::yield(); }
+	}
+	void unlock() { cas(true, false); }
+};
+
+class MutexWithTimeLimit
+{
+	typedef boost::interprocess::interprocess_mutex MutexT;
+	// typedef CasMutex MutexT;
+	typedef std::chrono::steady_clock Clock;
+	typedef Clock::duration Duration;
+	static Duration Now() { return Clock::now().time_since_epoch(); }
+
+	const Duration limit_;
+	std::atomic<Duration> last_lock_time_;
+	MutexT mutex_;
+
+public:
+	typedef MutexT::internal_mutex_type internal_mutex_type;
+	const internal_mutex_type &internal_mutex() const { return mutex_.internal_mutex(); }
+	internal_mutex_type &internal_mutex() { return mutex_.internal_mutex(); }
+
+	explicit MutexWithTimeLimit(Duration limit) :
+	    limit_(limit) {}
+	MutexWithTimeLimit() :
+	    MutexWithTimeLimit(std::chrono::seconds(1)) {}
+	~MutexWithTimeLimit() { static_assert(std::is_pod<Duration>::value); }
+	bool try_lock();
+	void lock();
+	void unlock() { mutex_.unlock(); }
+};
+
+// typedef boost::interprocess::interprocess_mutex Mutex;
+typedef MutexWithTimeLimit Mutex;
 typedef scoped_lock<Mutex> Guard;
 typedef interprocess_condition Cond;
 
diff --git a/utest/api_test.cpp b/utest/api_test.cpp
index 7981a2c..a91db43 100644
--- a/utest/api_test.cpp
+++ b/utest/api_test.cpp
@@ -96,6 +96,63 @@
 	// printf("client Recv reply : %s\n", reply.data().c_str());
 }
 
+class TLMutex
+{
+	// typedef boost::interprocess::interprocess_mutex MutexT;
+	typedef CasMutex MutexT;
+	// typedef std::mutex MutexT;
+	typedef std::chrono::steady_clock Clock;
+	typedef Clock::duration Duration;
+	static Duration Now() { return Clock::now().time_since_epoch(); }
+
+	const Duration limit_;
+	std::atomic<Duration> last_lock_time_;
+	MutexT mutex_;
+
+public:
+	struct Status {
+		int64_t nlock_ = 0;
+		int64_t nupdate_time_fail = 0;
+		int64_t nfail = 0;
+		int64_t nexcept = 0;
+	};
+	Status st_;
+
+	explicit TLMutex(Duration limit) :
+	    limit_(limit) {}
+	TLMutex() :
+	    TLMutex(std::chrono::seconds(1)) {}
+	~TLMutex() { static_assert(std::is_pod<Duration>::value); }
+	bool try_lock()
+	{
+		if (mutex_.try_lock()) {
+			auto old_time = last_lock_time_.load();
+			if (Now() - old_time > limit_) {
+				return last_lock_time_.compare_exchange_strong(old_time, Now());
+			} else {
+				last_lock_time_.store(Now());
+				return true;
+			}
+		} else {
+			auto old_time = last_lock_time_.load();
+			if (Now() - old_time > limit_) {
+				return last_lock_time_.compare_exchange_strong(old_time, Now());
+			} else {
+				return false;
+			}
+		}
+	}
+	void lock()
+	{
+		int n = 0;
+		while (!try_lock()) {
+			n++;
+			std::this_thread::yield();
+		}
+		st_.nlock_ += n;
+	}
+	void unlock() { mutex_.unlock(); }
+};
 BOOST_AUTO_TEST_CASE(MutexTest)
 {
 	const std::string shm_name("ShmMutex");
@@ -104,12 +161,42 @@
 
 	const std::string mtx_name("test_mutex");
 	const std::string int_name("test_int");
-	auto mtx = shm.find_or_construct<Mutex>(mtx_name.c_str())();
+	auto mtx = shm.find_or_construct<Mutex>(mtx_name.c_str())(3s);
+
 	auto pi = shm.find_or_construct<int>(int_name.c_str())(100);
+	typedef std::chrono::steady_clock Clock;
+	auto Now = []() { return Clock::now().time_since_epoch(); };
 	if (pi) {
 		auto old = *pi;
 		printf("int : %d, add1: %d\n", old, ++*pi);
 	}
+
+	{
+		boost::timer::auto_cpu_timer timer;
+		printf("test time: ");
+		TLMutex mutex;
+		// CasMutex mutex;
+		auto Lock = [&]() {
+			for (int i = 0; i < 1000 * 100; ++i) {
+				mutex.lock();
+				mutex.unlock();
+			}
+		};
+		std::thread t1(Lock), t2(Lock);
+		t1.join();
+		t2.join();
+		printf("mutex nlock: %ld, update time error: %ld, normal fail: %ld, error wait: %ld\n",
+		       mutex.st_.nlock_,
+		       mutex.st_.nupdate_time_fail,
+		       mutex.st_.nfail,
+		       mutex.st_.nexcept);
+	}
+
+	auto MSFromNow = [](const int ms) {
+		using namespace boost::posix_time;
+		ptime cur = boost::posix_time::microsec_clock::universal_time();
+		return cur + millisec(ms);
+	};
 
 	auto TryLock = [&]() {
 		if (mtx->try_lock()) {
@@ -128,10 +215,17 @@
 	if (mtx) {
 		printf("mtx exists\n");
 		if (TryLock()) {
-			if (TryLock()) {
-				Unlock();
-			}
+			auto op = [&]() {
+				if (TryLock()) {
+					Unlock();
+				}
+			};
+			op();
+			std::thread t(op);
+			t.join();
 			// Unlock();
+		} else {
+			// mtx->unlock();
 		}
 	} else {
 		printf("mtx not exists\n");
diff --git a/utest/lock_free_queue.cpp b/utest/lock_free_queue.cpp
deleted file mode 100644
index a05a454..0000000
--- a/utest/lock_free_queue.cpp
+++ /dev/null
@@ -1,29 +0,0 @@
-/*
- * =====================================================================================
- *
- *       Filename:  lock_free_queue.cpp
- *
- *    Description:  
- *
- *        Version:  1.0
- *        Created:  2021骞�04鏈�21鏃� 13鏃�57鍒�02绉�
- *       Revision:  none
- *       Compiler:  gcc
- *
- *         Author:  Li Chao (), lichao@aiotlink.com
- *   Organization:  
- *
- * =====================================================================================
- */
-#include "lock_free_queue.h"
-#include "defs.h"
-#include "util.h"
-
-BOOST_AUTO_TEST_CASE(LockFreeTest)
-{
-	LockFreeQueue q(BHomeShm());
-	for (int i = 0; i < 15; ++i) {
-		int r = q.Write(i);
-		printf("write %d %s\n", i, (r ? "ok" : "failed"));
-	}
-}
\ No newline at end of file
diff --git a/utest/lock_free_queue.h b/utest/lock_free_queue.h
deleted file mode 100644
index 968f796..0000000
--- a/utest/lock_free_queue.h
+++ /dev/null
@@ -1,57 +0,0 @@
-/*
- * =====================================================================================
- *
- *       Filename:  lock_free_queue.h
- *
- *    Description:  
- *
- *        Version:  1.0
- *        Created:  2021骞�04鏈�21鏃� 14鏃�03鍒�27绉�
- *       Revision:  none
- *       Compiler:  gcc
- *
- *         Author:  Li Chao (), lichao@aiotlink.com
- *   Organization:  
- *
- * =====================================================================================
- */
-
-#ifndef LOCK_FREE_QUEUE_KQWP70HT
-#define LOCK_FREE_QUEUE_KQWP70HT
-
-#include "shm.h"
-#include <boost/interprocess/offset_ptr.hpp>
-#include <boost/lockfree/queue.hpp>
-
-using namespace bhome_shm;
-
-typedef int64_t Data;
-const int kQLen = 10;
-class LockFreeQueue : private boost::lockfree::queue<Data,
-                                                     boost::lockfree::allocator<Allocator<Data>>,
-                                                     boost::lockfree::capacity<kQLen>>,
-                      private boost::noncopyable
-{
-	typedef boost::lockfree::queue<Data,
-	                               boost::lockfree::allocator<Allocator<Data>>,
-	                               boost::lockfree::capacity<kQLen>>
-	    Queue;
-
-public:
-	LockFreeQueue(SharedMemory &shm) :
-	    Queue(shm.get_segment_manager()) {}
-	bool Read(Data &d) { return pop(d); }
-	bool Write(Data const &d) { return push(d); }
-	template <class Func>
-	bool Write(Data const &d, Func onWrite)
-	{
-		if (Write(d)) {
-			onWrite(d);
-			return true;
-		} else {
-			return false;
-		}
-	}
-};
-
-#endif // end of include guard: LOCK_FREE_QUEUE_KQWP70HT

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