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cuberite-2a/src/DeadlockDetect.h
2016-02-05 23:50:18 +02:00

69 lines
1.7 KiB
C++

// DeadlockDetect.h
// Declares the cDeadlockDetect class that tries to detect deadlocks and aborts the server when it detects one
/*
This class simply monitors each world's m_WorldAge, which is expected to grow on each tick.
If the world age doesn't grow for several seconds, it's either because the server is super-overloaded,
or because the world tick thread hangs in a deadlock. We presume the latter and therefore kill the server.
Once we learn to write crashdumps programmatically, we should do so just before killing, to enable debugging.
*/
#pragma once
#include "OSSupport/IsThread.h"
class cDeadlockDetect :
public cIsThread
{
typedef cIsThread super;
public:
cDeadlockDetect(void);
/** Starts the detection. Hides cIsThread's Start, because we need some initialization */
bool Start(int a_IntervalSec);
protected:
struct sWorldAge
{
/** Last m_WorldAge that has been detected in this world */
Int64 m_Age;
/** Number of cycles for which the age has been the same */
int m_NumCyclesSame;
} ;
/** Maps world name -> sWorldAge */
typedef std::map<AString, sWorldAge> WorldAges;
WorldAges m_WorldAges;
/** Number of secods for which the ages must be the same for the detection to trigger */
int m_IntervalSec;
// cIsThread overrides:
virtual void Execute(void) override;
/** Sets the initial world age */
void SetWorldAge(const AString & a_WorldName, Int64 a_Age);
/** Checks if the world's age has changed, updates the world's stats; calls DeadlockDetected() if deadlock detected */
void CheckWorldAge(const AString & a_WorldName, Int64 a_Age);
/** Called when a deadlock is detected. Aborts the server. */
NORETURN void DeadlockDetected(void);
} ;