129 lines
3.6 KiB
C++
129 lines
3.6 KiB
C++
// Copyright (c) 2011-2012 The Bitcoin developers
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// Distributed under the MIT/X11 software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#include "sync.h"
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#include "util.h"
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#include <boost/foreach.hpp>
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#ifdef DEBUG_LOCKCONTENTION
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void PrintLockContention(const char* pszName, const char* pszFile, int nLine)
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{
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printf("LOCKCONTENTION: %s\n", pszName);
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printf("Locker: %s:%d\n", pszFile, nLine);
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}
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#endif /* DEBUG_LOCKCONTENTION */
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#ifdef DEBUG_LOCKORDER
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//
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// Early deadlock detection.
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// Problem being solved:
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// Thread 1 locks A, then B, then C
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// Thread 2 locks D, then C, then A
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// --> may result in deadlock between the two threads, depending on when they run.
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// Solution implemented here:
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// Keep track of pairs of locks: (A before B), (A before C), etc.
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// Complain if any thread tries to lock in a different order.
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//
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struct CLockLocation
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{
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CLockLocation(const char* pszName, const char* pszFile, int nLine)
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{
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mutexName = pszName;
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sourceFile = pszFile;
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sourceLine = nLine;
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}
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std::string ToString() const
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{
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return mutexName+" "+sourceFile+":"+itostr(sourceLine);
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}
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private:
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std::string mutexName;
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std::string sourceFile;
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int sourceLine;
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};
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typedef std::vector< std::pair<void*, CLockLocation> > LockStack;
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static boost::mutex dd_mutex;
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static std::map<std::pair<void*, void*>, LockStack> lockorders;
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static boost::thread_specific_ptr<LockStack> lockstack;
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static void potential_deadlock_detected(const std::pair<void*, void*>& mismatch, const LockStack& s1, const LockStack& s2)
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{
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printf("POTENTIAL DEADLOCK DETECTED\n");
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printf("Previous lock order was:\n");
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BOOST_FOREACH(const PAIRTYPE(void*, CLockLocation)& i, s2)
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{
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if (i.first == mismatch.first) printf(" (1)");
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if (i.first == mismatch.second) printf(" (2)");
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printf(" %s\n", i.second.ToString().c_str());
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}
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printf("Current lock order is:\n");
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BOOST_FOREACH(const PAIRTYPE(void*, CLockLocation)& i, s1)
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{
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if (i.first == mismatch.first) printf(" (1)");
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if (i.first == mismatch.second) printf(" (2)");
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printf(" %s\n", i.second.ToString().c_str());
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}
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}
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static void push_lock(void* c, const CLockLocation& locklocation, bool fTry)
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{
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if (lockstack.get() == NULL)
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lockstack.reset(new LockStack);
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if (fDebug) printf("Locking: %s\n", locklocation.ToString().c_str());
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dd_mutex.lock();
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(*lockstack).push_back(std::make_pair(c, locklocation));
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if (!fTry) {
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BOOST_FOREACH(const PAIRTYPE(void*, CLockLocation)& i, (*lockstack)) {
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if (i.first == c) break;
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std::pair<void*, void*> p1 = std::make_pair(i.first, c);
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if (lockorders.count(p1))
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continue;
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lockorders[p1] = (*lockstack);
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std::pair<void*, void*> p2 = std::make_pair(c, i.first);
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if (lockorders.count(p2))
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{
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potential_deadlock_detected(p1, lockorders[p2], lockorders[p1]);
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break;
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}
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}
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}
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dd_mutex.unlock();
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}
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static void pop_lock()
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{
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if (fDebug)
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{
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const CLockLocation& locklocation = (*lockstack).rbegin()->second;
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printf("Unlocked: %s\n", locklocation.ToString().c_str());
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}
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dd_mutex.lock();
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(*lockstack).pop_back();
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dd_mutex.unlock();
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}
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void EnterCritical(const char* pszName, const char* pszFile, int nLine, void* cs, bool fTry)
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{
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push_lock(cs, CLockLocation(pszName, pszFile, nLine), fTry);
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}
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void LeaveCritical()
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{
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pop_lock();
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}
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#endif /* DEBUG_LOCKORDER */
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