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Fix race condition.

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Change a counter (s_next_delayed_call_id) in Worker from class static to
class member to avoid race conditions on the variable.
This commit is contained in:
Niclas Antti
2018-09-25 15:47:41 +03:00
parent 25038432bb
commit 5132339b7b
2 changed files with 23 additions and 19 deletions
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38
maxutils/maxbase/include/maxbase/worker.hh
View File

@ -573,10 +573,9 @@ public:
* case the return value is ignored and the function will not * case the return value is ignored and the function will not
* be called again. * be called again.
*/ */
uint32_t delayed_call(int32_t delay, uint32_t delayed_call(int32_t delay, bool (* pFunction)(Worker::Call::action_t action))
bool (* pFunction)(Worker::Call::action_t action))
{ {
return add_delayed_call(new DelayedCallFunctionVoid(delay, pFunction)); return add_delayed_call(new DelayedCallFunctionVoid(delay, next_delayed_call_id(), pFunction));
} }
/** /**
@ -604,7 +603,7 @@ public:
bool (* pFunction)(Worker::Call::action_t action, D data), bool (* pFunction)(Worker::Call::action_t action, D data),
D data) D data)
{ {
return add_delayed_call(new DelayedCallFunction<D>(delay, pFunction, data)); return add_delayed_call(new DelayedCallFunction<D>(delay, next_delayed_call_id(), pFunction, data));
} }
/** /**
@ -631,7 +630,7 @@ public:
bool (T::* pMethod)(Worker::Call::action_t action), bool (T::* pMethod)(Worker::Call::action_t action),
T* pT) T* pT)
{ {
return add_delayed_call(new DelayedCallMethodVoid<T>(delay, pMethod, pT)); return add_delayed_call(new DelayedCallMethodVoid<T>(delay, next_delayed_call_id(), pMethod, pT));
} }
/** /**
@ -660,7 +659,11 @@ public:
T* pT, T* pT,
D data) D data)
{ {
return add_delayed_call(new DelayedCallMethod<T, D>(delay, pMethod, pT, data)); return add_delayed_call(new DelayedCallMethod<T, D>(delay,
next_delayed_call_id(),
pMethod,
pT,
data));
} }
/** /**
@ -734,12 +737,12 @@ private:
class DelayedCall; class DelayedCall;
friend class DelayedCall; friend class DelayedCall;
static uint32_t next_delayed_call_id() uint32_t next_delayed_call_id()
{ {
// Called in single-thread context. Wrapping does not matter // Called in single-thread context. Wrapping does not matter
// as it is unlikely there would be 4 billion pending delayed // as it is unlikely there would be 4 billion pending delayed
// calls. // calls.
return ++s_next_delayed_call_id; return ++m_next_delayed_call_id;
} }
class DelayedCall class DelayedCall
@ -779,8 +782,8 @@ private:
} }
protected: protected:
DelayedCall(int32_t delay) DelayedCall(int32_t delay, int32_t id)
: m_id(Worker::next_delayed_call_id()) : m_id(id)
, m_delay(delay) , m_delay(delay)
, m_at(get_at(delay)) , m_at(get_at(delay))
{ {
@ -815,9 +818,10 @@ private:
public: public:
DelayedCallFunction(int32_t delay, DelayedCallFunction(int32_t delay,
int32_t id,
bool (*pFunction)(Worker::Call::action_t action, D data), bool (*pFunction)(Worker::Call::action_t action, D data),
D data) D data)
: DelayedCall(delay) : DelayedCall(delay, id)
, m_pFunction(pFunction) , m_pFunction(pFunction)
, m_data(data) , m_data(data)
{ {
@ -842,8 +846,9 @@ private:
public: public:
DelayedCallFunctionVoid(int32_t delay, DelayedCallFunctionVoid(int32_t delay,
int32_t id,
bool (*pFunction)(Worker::Call::action_t action)) bool (*pFunction)(Worker::Call::action_t action))
: DelayedCall(delay) : DelayedCall(delay, id)
, m_pFunction(pFunction) , m_pFunction(pFunction)
{ {
} }
@ -866,10 +871,11 @@ private:
public: public:
DelayedCallMethod(int32_t delay, DelayedCallMethod(int32_t delay,
int32_t id,
bool (T::* pMethod)(Worker::Call::action_t action, D data), bool (T::* pMethod)(Worker::Call::action_t action, D data),
T* pT, T* pT,
D data) D data)
: DelayedCall(delay) : DelayedCall(delay, id)
, m_pMethod(pMethod) , m_pMethod(pMethod)
, m_pT(pT) , m_pT(pT)
, m_data(data) , m_data(data)
@ -896,9 +902,10 @@ private:
public: public:
DelayedCallMethodVoid(int32_t delay, DelayedCallMethodVoid(int32_t delay,
int32_t id,
bool (T::* pMethod)(Worker::Call::action_t), bool (T::* pMethod)(Worker::Call::action_t),
T* pT) T* pT)
: DelayedCall(delay) : DelayedCall(delay, id)
, m_pMethod(pMethod) , m_pMethod(pMethod)
, m_pT(pT) , m_pT(pT)
{ {
@ -925,7 +932,6 @@ private:
void poll_waitevents(); void poll_waitevents();
void tick(); void tick();
private: private:
class LaterAt : public std::binary_function<const DelayedCall*, const DelayedCall*, bool> class LaterAt : public std::binary_function<const DelayedCall*, const DelayedCall*, bool>
{ {
@ -956,6 +962,6 @@ private:
DelayedCallsByTime m_sorted_calls; /*< Current delayed calls sorted by time. */ DelayedCallsByTime m_sorted_calls; /*< Current delayed calls sorted by time. */
DelayedCallsById m_calls; /*< Current delayed calls indexed by id. */ DelayedCallsById m_calls; /*< Current delayed calls indexed by id. */
static uint32_t s_next_delayed_call_id; /*< The next delayed call id. */ int32_t m_next_delayed_call_id; /*< The next delayed call id. */
}; };
} }

4
maxutils/maxbase/src/worker.cc
View File

@ -278,9 +278,6 @@ int create_epoll_instance()
} }
} }
// static
uint32_t Worker::s_next_delayed_call_id = 1;
Worker::Worker(int max_events) Worker::Worker(int max_events)
: m_epoll_fd(create_epoll_instance()) : m_epoll_fd(create_epoll_instance())
, m_state(STOPPED) , m_state(STOPPED)
@ -292,6 +289,7 @@ Worker::Worker(int max_events)
, m_nCurrent_descriptors(0) , m_nCurrent_descriptors(0)
, m_nTotal_descriptors(0) , m_nTotal_descriptors(0)
, m_pTimer(new PrivateTimer(this, this, &Worker::tick)) , m_pTimer(new PrivateTimer(this, this, &Worker::tick))
, m_next_delayed_call_id{1}
{ {
mxb_assert(max_events > 0); mxb_assert(max_events > 0);