Merge #18234: refactor: Replace boost::mutex,condition_var,chrono with std equivalents in scheduler

70a6b52 lint-cppcheck: Remove -DHAVE_WORKING_BOOST_SLEEP_FOR (Anthony Towns)
294937b scheduler_tests: re-enable mockforward test (Anthony Towns)
cea19f6 Drop unused reverselock.h (Anthony Towns)
d0ebd93 scheduler: switch from boost to std (Anthony Towns)
b9c4260 sync.h: add REVERSE_LOCK (Anthony Towns)
306f71b scheduler: don't rely on boost interrupt on shutdown (Anthony Towns)

Pull request description:

  Replacing boost functionality with C++11 stuff.

  Motivated by #18227, but should stand alone. Changing from `boost::condition_var` to `std::condition_var` means `threadGroup.interrupt_all` isn't enough to interrupt `serviceQueue` anymore, so that means calling `stop()` before `join_all()` is needed. And the existing reverselock.h code doesn't work with sync.h's DebugLock code (because the reversed lock won't be removed from `g_lockstack` which then leads to incorrect potential deadlock warnings), so I've replaced that with a dedicated class and macro that's aware of our debug lock behaviour.

  Fixes #16027, Fixes #14200, Fixes #18227

ACKs for top commit:
  laanwj:
    ACK 70a6b52

Tree-SHA512: d1da13adeabcf9186d114e2dad9a4fdbe2e440f7afbccde0c13dfbaf464efcd850b69d3371c5bf8b179d7ceb9d81f4af3cc22960b90834e41eaaf6d52ef7d331

Author: laanwj

src/Makefile.am

@@ -178,7 +178,6 @@ BITCOIN_CORE_H = \
   random.h \
   randomenv.h \
   reverse_iterator.h \
-  reverselock.h \
   rpc/blockchain.h \
   rpc/client.h \
   rpc/protocol.h \

src/init.cpp

@@ -206,6 +206,7 @@ void Shutdown(NodeContext& node)
 
     // After everything has been shut down, but before things get flushed, stop the
     // CScheduler/checkqueue threadGroup
+    if (node.scheduler) node.scheduler->stop();
     threadGroup.interrupt_all();
     threadGroup.join_all();
 

src/reverselock.h

@@ -393,7 +393,7 @@ static UniValue mockscheduler(const JSONRPCRequest& request)
     // protect against null pointer dereference
     CHECK_NONFATAL(g_rpc_node);
     CHECK_NONFATAL(g_rpc_node->scheduler);
-    g_rpc_node->scheduler->MockForward(boost::chrono::seconds(delta_seconds));
+    g_rpc_node->scheduler->MockForward(std::chrono::seconds(delta_seconds));
 
     return NullUniValue;
 }

src/rpc/misc.cpp

@@ -5,7 +5,6 @@
 #include <scheduler.h>
 
 #include <random.h>
-#include <reverselock.h>
 
 #include <assert.h>
 #include <utility>
@@ -20,18 +19,9 @@ CScheduler::~CScheduler()
 }
 
 
-#if BOOST_VERSION < 105000
-static boost::system_time toPosixTime(const boost::chrono::system_clock::time_point& t)
-{
-    // Creating the posix_time using from_time_t loses sub-second precision. So rather than exporting the time_point to time_t,
-    // start with a posix_time at the epoch (0) and add the milliseconds that have passed since then.
-    return boost::posix_time::from_time_t(0) + boost::posix_time::milliseconds(boost::chrono::duration_cast<boost::chrono::milliseconds>(t.time_since_epoch()).count());
-}
-#endif
-
 void CScheduler::serviceQueue()
 {
-    boost::unique_lock<boost::mutex> lock(newTaskMutex);
+    WAIT_LOCK(newTaskMutex, lock);
     ++nThreadsServicingQueue;
 
     // newTaskMutex is locked throughout this loop EXCEPT
@@ -40,7 +30,7 @@ void CScheduler::serviceQueue()
     while (!shouldStop()) {
         try {
             if (!shouldStop() && taskQueue.empty()) {
-                reverse_lock<boost::unique_lock<boost::mutex> > rlock(lock);
+                REVERSE_LOCK(lock);
             }
             while (!shouldStop() && taskQueue.empty()) {
                 // Wait until there is something to do.
@@ -50,21 +40,13 @@ void CScheduler::serviceQueue()
             // Wait until either there is a new task, or until
             // the time of the first item on the queue:
 
-// wait_until needs boost 1.50 or later; older versions have timed_wait:
-#if BOOST_VERSION < 105000
-            while (!shouldStop() && !taskQueue.empty() &&
-                   newTaskScheduled.timed_wait(lock, toPosixTime(taskQueue.begin()->first))) {
-                // Keep waiting until timeout
-            }
-#else
-            // Some boost versions have a conflicting overload of wait_until that returns void.
-            // Explicitly use a template here to avoid hitting that overload.
             while (!shouldStop() && !taskQueue.empty()) {
-                boost::chrono::system_clock::time_point timeToWaitFor = taskQueue.begin()->first;
-                if (newTaskScheduled.wait_until<>(lock, timeToWaitFor) == boost::cv_status::timeout)
+                std::chrono::system_clock::time_point timeToWaitFor = taskQueue.begin()->first;
+                if (newTaskScheduled.wait_until(lock, timeToWaitFor) == std::cv_status::timeout) {
                     break; // Exit loop after timeout, it means we reached the time of the event
+                }
             }
-#endif
+
             // If there are multiple threads, the queue can empty while we're waiting (another
             // thread may service the task we were waiting on).
             if (shouldStop() || taskQueue.empty())
@@ -76,7 +58,7 @@ void CScheduler::serviceQueue()
             {
                 // Unlock before calling f, so it can reschedule itself or another task
                 // without deadlocking:
-                reverse_lock<boost::unique_lock<boost::mutex> > rlock(lock);
+                REVERSE_LOCK(lock);
                 f();
             }
         } catch (...) {
@@ -91,7 +73,7 @@ void CScheduler::serviceQueue()
 void CScheduler::stop(bool drain)
 {
     {
-        boost::unique_lock<boost::mutex> lock(newTaskMutex);
+        LOCK(newTaskMutex);
         if (drain)
             stopWhenEmpty = true;
         else
@@ -100,29 +82,29 @@ void CScheduler::stop(bool drain)
     newTaskScheduled.notify_all();
 }
 
-void CScheduler::schedule(CScheduler::Function f, boost::chrono::system_clock::time_point t)
+void CScheduler::schedule(CScheduler::Function f, std::chrono::system_clock::time_point t)
 {
     {
-        boost::unique_lock<boost::mutex> lock(newTaskMutex);
+        LOCK(newTaskMutex);
         taskQueue.insert(std::make_pair(t, f));
     }
     newTaskScheduled.notify_one();
 }
 
 void CScheduler::scheduleFromNow(CScheduler::Function f, int64_t deltaMilliSeconds)
 {
-    schedule(f, boost::chrono::system_clock::now() + boost::chrono::milliseconds(deltaMilliSeconds));
+    schedule(f, std::chrono::system_clock::now() + std::chrono::milliseconds(deltaMilliSeconds));
 }
 
-void CScheduler::MockForward(boost::chrono::seconds delta_seconds)
+void CScheduler::MockForward(std::chrono::seconds delta_seconds)
 {
-    assert(delta_seconds.count() > 0 && delta_seconds < boost::chrono::hours{1});
+    assert(delta_seconds.count() > 0 && delta_seconds < std::chrono::hours{1});
 
     {
-        boost::unique_lock<boost::mutex> lock(newTaskMutex);
+        LOCK(newTaskMutex);
 
         // use temp_queue to maintain updated schedule
-        std::multimap<boost::chrono::system_clock::time_point, Function> temp_queue;
+        std::multimap<std::chrono::system_clock::time_point, Function> temp_queue;
 
         for (const auto& element : taskQueue) {
             temp_queue.emplace_hint(temp_queue.cend(), element.first - delta_seconds, element.second);
@@ -147,10 +129,10 @@ void CScheduler::scheduleEvery(CScheduler::Function f, int64_t deltaMilliSeconds
     scheduleFromNow(std::bind(&Repeat, this, f, deltaMilliSeconds), deltaMilliSeconds);
 }
 
-size_t CScheduler::getQueueInfo(boost::chrono::system_clock::time_point &first,
-                             boost::chrono::system_clock::time_point &last) const
+size_t CScheduler::getQueueInfo(std::chrono::system_clock::time_point &first,
+                             std::chrono::system_clock::time_point &last) const
 {
-    boost::unique_lock<boost::mutex> lock(newTaskMutex);
+    LOCK(newTaskMutex);
     size_t result = taskQueue.size();
     if (!taskQueue.empty()) {
         first = taskQueue.begin()->first;
@@ -160,7 +142,7 @@ size_t CScheduler::getQueueInfo(boost::chrono::system_clock::time_point &first,
 }
 
 bool CScheduler::AreThreadsServicingQueue() const {
-    boost::unique_lock<boost::mutex> lock(newTaskMutex);
+    LOCK(newTaskMutex);
     return nThreadsServicingQueue;
 }
 
@@ -174,7 +156,7 @@ void SingleThreadedSchedulerClient::MaybeScheduleProcessQueue() {
         if (m_are_callbacks_running) return;
         if (m_callbacks_pending.empty()) return;
     }
-    m_pscheduler->schedule(std::bind(&SingleThreadedSchedulerClient::ProcessQueue, this));
+    m_pscheduler->schedule(std::bind(&SingleThreadedSchedulerClient::ProcessQueue, this), std::chrono::system_clock::now());
 }
 
 void SingleThreadedSchedulerClient::ProcessQueue() {

src/scheduler.cpp

@@ -7,11 +7,12 @@
 
 //
 // NOTE:
-// boost::thread / boost::chrono should be ported to std::thread / std::chrono
+// boost::thread should be ported to std::thread
 // when we support C++11.
 //
-#include <boost/chrono/chrono.hpp>
-#include <boost/thread.hpp>
+#include <condition_variable>
+#include <functional>
+#include <list>
 #include <map>
 
 #include <sync.h>
@@ -27,8 +28,8 @@
 // s->scheduleFromNow(std::bind(Class::func, this, argument), 3);
 // boost::thread* t = new boost::thread(std::bind(CScheduler::serviceQueue, s));
 //
-// ... then at program shutdown, clean up the thread running serviceQueue:
-// t->interrupt();
+// ... then at program shutdown, make sure to call stop() to clean up the thread(s) running serviceQueue:
+// s->stop();
 // t->join();
 // delete t;
 // delete s; // Must be done after thread is interrupted/joined.
@@ -43,7 +44,7 @@ class CScheduler
     typedef std::function<void()> Function;
 
     // Call func at/after time t
-    void schedule(Function f, boost::chrono::system_clock::time_point t=boost::chrono::system_clock::now());
+    void schedule(Function f, std::chrono::system_clock::time_point t);
 
     // Convenience method: call f once deltaMilliSeconds from now
     void scheduleFromNow(Function f, int64_t deltaMilliSeconds);
@@ -60,7 +61,7 @@ class CScheduler
      * Iterates through items on taskQueue and reschedules them
      * to be delta_seconds sooner.
      */
-    void MockForward(boost::chrono::seconds delta_seconds);
+    void MockForward(std::chrono::seconds delta_seconds);
 
     // To keep things as simple as possible, there is no unschedule.
 
@@ -75,20 +76,20 @@ class CScheduler
 
     // Returns number of tasks waiting to be serviced,
     // and first and last task times
-    size_t getQueueInfo(boost::chrono::system_clock::time_point &first,
-                        boost::chrono::system_clock::time_point &last) const;
+    size_t getQueueInfo(std::chrono::system_clock::time_point &first,
+                        std::chrono::system_clock::time_point &last) const;
 
     // Returns true if there are threads actively running in serviceQueue()
     bool AreThreadsServicingQueue() const;
 
 private:
-    std::multimap<boost::chrono::system_clock::time_point, Function> taskQueue;
-    boost::condition_variable newTaskScheduled;
-    mutable boost::mutex newTaskMutex;
-    int nThreadsServicingQueue;
-    bool stopRequested;
-    bool stopWhenEmpty;
-    bool shouldStop() const { return stopRequested || (stopWhenEmpty && taskQueue.empty()); }
+    mutable Mutex newTaskMutex;
+    std::condition_variable newTaskScheduled;
+    std::multimap<std::chrono::system_clock::time_point, Function> taskQueue GUARDED_BY(newTaskMutex);
+    int nThreadsServicingQueue GUARDED_BY(newTaskMutex);
+    bool stopRequested GUARDED_BY(newTaskMutex);
+    bool stopWhenEmpty GUARDED_BY(newTaskMutex);
+    bool shouldStop() const EXCLUSIVE_LOCKS_REQUIRED(newTaskMutex) { return stopRequested || (stopWhenEmpty && taskQueue.empty()); }
 };
 
 /**

src/scheduler.h

@@ -13,7 +13,7 @@
 #include <util/strencodings.h>
 #include <util/threadnames.h>
 
-
+#include <system_error>
 #include <map>
 #include <set>
 
@@ -60,6 +60,11 @@ struct CLockLocation {
             mutexName, sourceFile, itostr(sourceLine), (fTry ? " (TRY)" : ""), m_thread_name);
     }
 
+    std::string Name() const
+    {
+        return mutexName;
+    }
+
 private:
     bool fTry;
     std::string mutexName;
@@ -155,6 +160,18 @@ void EnterCritical(const char* pszName, const char* pszFile, int nLine, void* cs
     push_lock(cs, CLockLocation(pszName, pszFile, nLine, fTry, util::ThreadGetInternalName()));
 }
 
+void CheckLastCritical(void* cs, std::string& lockname, const char* guardname, const char* file, int line)
+{
+    if (!g_lockstack.empty()) {
+        const auto& lastlock = g_lockstack.back();
+        if (lastlock.first == cs) {
+            lockname = lastlock.second.Name();
+            return;
+        }
+    }
+    throw std::system_error(EPERM, std::generic_category(), strprintf("%s:%s %s was not most recent critical section locked", file, line, guardname));
+}
+
 void LeaveCritical()
 {
     pop_lock();

src/sync.cpp

@@ -50,6 +50,7 @@ LEAVE_CRITICAL_SECTION(mutex); // no RAII
 #ifdef DEBUG_LOCKORDER
 void EnterCritical(const char* pszName, const char* pszFile, int nLine, void* cs, bool fTry = false);
 void LeaveCritical();
+void CheckLastCritical(void* cs, std::string& lockname, const char* guardname, const char* file, int line);
 std::string LocksHeld();
 void AssertLockHeldInternal(const char* pszName, const char* pszFile, int nLine, void* cs) ASSERT_EXCLUSIVE_LOCK(cs);
 void AssertLockNotHeldInternal(const char* pszName, const char* pszFile, int nLine, void* cs);
@@ -64,6 +65,7 @@ extern bool g_debug_lockorder_abort;
 #else
 void static inline EnterCritical(const char* pszName, const char* pszFile, int nLine, void* cs, bool fTry = false) {}
 void static inline LeaveCritical() {}
+void static inline CheckLastCritical(void* cs, std::string& lockname, const char* guardname, const char* file, int line) {}
 void static inline AssertLockHeldInternal(const char* pszName, const char* pszFile, int nLine, void* cs) ASSERT_EXCLUSIVE_LOCK(cs) {}
 void static inline AssertLockNotHeldInternal(const char* pszName, const char* pszFile, int nLine, void* cs) {}
 void static inline DeleteLock(void* cs) {}
@@ -171,8 +173,45 @@ class SCOPED_LOCKABLE UniqueLock : public Base
     {
         return Base::owns_lock();
     }
+
+protected:
+    // needed for reverse_lock
+    UniqueLock() { }
+
+public:
+    /**
+     * An RAII-style reverse lock. Unlocks on construction and locks on destruction.
+     */
+    class reverse_lock {
+    public:
+        explicit reverse_lock(UniqueLock& _lock, const char* _guardname, const char* _file, int _line) : lock(_lock), file(_file), line(_line) {
+            CheckLastCritical((void*)lock.mutex(), lockname, _guardname, _file, _line);
+            lock.unlock();
+            LeaveCritical();
+            lock.swap(templock);
+        }
+
+        ~reverse_lock() {
+            templock.swap(lock);
+            EnterCritical(lockname.c_str(), file.c_str(), line, (void*)lock.mutex());
+            lock.lock();
+        }
+
+     private:
+        reverse_lock(reverse_lock const&);
+        reverse_lock& operator=(reverse_lock const&);
+
+        UniqueLock& lock;
+        UniqueLock templock;
+        std::string lockname;
+        const std::string file;
+        const int line;
+     };
+     friend class reverse_lock;
 };
 
+#define REVERSE_LOCK(g) decltype(g)::reverse_lock PASTE2(revlock, __COUNTER__)(g, #g, __FILE__, __LINE__)
+
 template<typename MutexArg>
 using DebugLock = UniqueLock<typename std::remove_reference<typename std::remove_pointer<MutexArg>::type>::type>;