From a6f67b4249525089fb97eb9418c7014f66c2a000 Mon Sep 17 00:00:00 2001
From: lichao <lichao@aiotlink.com>
Date: 星期三, 28 四月 2021 19:29:17 +0800
Subject: [PATCH] use new robust mutex, circurar; rm timeout mutex.
---
src/shm.h | 88 ++++++++++++++++++++++++-------------------
1 files changed, 49 insertions(+), 39 deletions(-)
diff --git a/src/shm.h b/src/shm.h
index 7773ceb..17352fe 100644
--- a/src/shm.h
+++ b/src/shm.h
@@ -19,13 +19,11 @@
#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 <chrono>
#include <thread>
namespace bhome_shm
@@ -35,53 +33,65 @@
typedef managed_shared_memory mshm_t;
-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
+class MutexWithPidCheck
{
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_;
+ 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;
+ }
- 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();
+ void lock()
+ {
+ while (!try_lock()) {
+ std::this_thread::yield();
+ }
+ }
+ void unlock()
+ {
+ auto old = pid_.load();
+ if (old == pid()) {
+ mutex_.unlock();
+ }
+ }
};
-// typedef boost::interprocess::interprocess_mutex Mutex;
-typedef MutexWithTimeLimit Mutex;
-typedef scoped_lock<Mutex> Guard;
-typedef interprocess_condition Cond;
+typedef robust::CasMutex<true> Mutex;
+typedef robust::Guard<Mutex> Guard;
class SharedMemory : public mshm_t
{
--
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