From 72bffb0807925a156b076b71f78c848a08d27b87 Mon Sep 17 00:00:00 2001
From: lichao <lichao@aiotlink.com>
Date: 星期四, 29 四月 2021 10:55:35 +0800
Subject: [PATCH] refactor mutex.
---
src/shm.h | 116 +++++++++++++++++++++++++++++++++++++++++++++++----------
1 files changed, 95 insertions(+), 21 deletions(-)
diff --git a/src/shm.h b/src/shm.h
index 22a975b..515d856 100644
--- a/src/shm.h
+++ b/src/shm.h
@@ -19,12 +19,12 @@
#ifndef SHM_6CHO6D6C
#define SHM_6CHO6D6C
+#include "robust.h"
+#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 <thread>
namespace bhome_shm
{
@@ -32,9 +32,66 @@
using namespace boost::interprocess;
typedef managed_shared_memory mshm_t;
-typedef interprocess_mutex Mutex;
-typedef scoped_lock<Mutex> Guard;
-typedef interprocess_condition Cond;
+
+class MutexWithPidCheck
+{
+ typedef boost::interprocess::interprocess_mutex MutexT;
+ static pid_t pid()
+ {
+ static pid_t val = getpid();
+ return val;
+ }
+ static bool Killed(pid_t pid)
+ {
+ char buf[64] = {0};
+ snprintf(buf, sizeof(buf) - 1, "/proc/%d/stat", pid);
+ return access(buf, F_OK) != 0;
+ }
+ bool PidCas(pid_t exp, pid_t val) { return pid_.compare_exchange_strong(exp, val); }
+ MutexT mutex_;
+ std::atomic<pid_t> pid_;
+
+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(); }
+ MutexWithPidCheck() :
+ pid_(0) {}
+ bool try_lock()
+ {
+ bool r = false;
+ if (mutex_.try_lock()) {
+ auto old = pid_.load();
+ r = PidCas(old, pid());
+ } else {
+ auto old = pid_.load();
+ if (Killed(old)) {
+ r = PidCas(old, pid());
+ if (r) {
+ printf("PidCheck captured pid %d -> %d\n", old, pid());
+ }
+ }
+ }
+ return r;
+ }
+
+ void lock()
+ {
+ while (!try_lock()) {
+ std::this_thread::yield();
+ }
+ }
+ void unlock()
+ {
+ auto old = pid_.load();
+ if (old == pid()) {
+ mutex_.unlock();
+ }
+ }
+};
+
+typedef robust::Mutex Mutex;
+typedef robust::Guard<Mutex> Guard;
class SharedMemory : public mshm_t
{
@@ -55,7 +112,16 @@
~SharedMemory();
std::string name() const { return name_; }
bool Remove() { return Remove(name()); }
-
+ template <class T, class... Params>
+ T *FindOrCreate(const std::string &name, Params &&...params)
+ {
+ return find_or_construct<T>(name.c_str(), std::nothrow)(std::forward<decltype(params)>(params)...);
+ }
+ template <class T, class... Params>
+ T *Create(const std::string &name, Params &&...params)
+ {
+ return construct<T>(name.c_str(), std::nothrow)(std::forward<decltype(params)>(params)...);
+ }
void *Alloc(const size_t size) { return allocate(size, std::nothrow); }
void Dealloc(void *p)
{
@@ -65,7 +131,7 @@
void Dealloc(offset_ptr<T> ptr) { return Dealloc(ptr.get()); }
template <class T, class... Params>
- T *New(Params const &...params) { return construct<T>(anonymous_instance, std::nothrow)(params...); }
+ T *New(Params &&...params) { return construct<T>(anonymous_instance, std::nothrow)(std::forward<decltype(params)>(params)...); }
template <class T>
void Delete(T *p)
{
@@ -90,30 +156,33 @@
{
static std::string ObjName(const std::string &name) { return "obj" + name; }
-protected:
+public:
typedef T Data;
typedef SharedMemory ShmType;
-
-private:
- ShmType &shm_;
- std::string name_;
- Data *pdata_ = nullptr;
-
- bool IsOk() const { return pdata_; }
-
-protected:
ShmType &shm() const { return shm_; }
-public:
template <class... Params>
ShmObject(ShmType &segment, const std::string &name, Params &&...t) :
shm_(segment), name_(name)
{
- pdata_ = shm_.find_or_construct<Data>(ObjName(name_).c_str(), std::nothrow)(t...);
+ pdata_ = shm_.FindOrCreate<Data>(ObjName(name_), std::forward<decltype(t)>(t)...);
if (!IsOk()) {
throw("Error: Not enough memory, can not allocate \"" + name_ + "\"");
}
}
+ template <class... Params>
+ ShmObject(ShmType &segment, const bool create_or_else_find, const std::string &name, Params &&...t) :
+ shm_(segment), name_(name)
+ {
+ if (create_or_else_find) {
+ pdata_ = shm_.Create<Data>(ObjName(name_), std::forward<decltype(t)>(t)...);
+ } else {
+ pdata_ = shm_.Find<Data>(ObjName(name_));
+ }
+ }
+ bool IsOk() const { return pdata_; }
+
+ static bool Remove(SharedMemory &shm, const std::string &name) { return shm.destroy<Data>(ObjName(name).c_str()); }
static Data *Find(SharedMemory &shm, const std::string &name) { return shm.Find<Data>(ObjName(name)); }
Data *Find(const std::string &name) { return Find(shm_, ObjName(name)); }
virtual ~ShmObject() {}
@@ -122,7 +191,12 @@
const Data *data() const { return pdata_; }
Data *operator->() { return data(); }
const Data *operator->() const { return data(); }
- bool Remove() { return shm_.destroy<Data>(ObjName(name_).c_str()); }
+ bool Remove() { return Remove(shm_, name_); }
+
+private:
+ ShmType &shm_;
+ std::string name_;
+ Data *pdata_ = nullptr;
};
} // namespace bhome_shm
--
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