diff options
Diffstat (limited to 'sql/my_apc.cc')
| -rw-r--r-- | sql/my_apc.cc | 56 |
1 files changed, 45 insertions, 11 deletions
diff --git a/sql/my_apc.cc b/sql/my_apc.cc index 91559483b1f..58290ece56b 100644 --- a/sql/my_apc.cc +++ b/sql/my_apc.cc @@ -24,6 +24,14 @@ */ +/* + Initialize the target. + + @note + Initialization must be done prior to enabling/disabling the target, or making + any call requests to it. + Initial state after initialization is 'disabled'. +*/ void Apc_target::init() { // todo: should use my_pthread_... functions instead? @@ -36,6 +44,9 @@ void Apc_target::init() } +/* + Destroy the target. The target must be disabled when this call is made. +*/ void Apc_target::destroy() { DBUG_ASSERT(!enabled); @@ -43,6 +54,9 @@ void Apc_target::destroy() } +/* + Enter ther state where the target is available for serving APC requests +*/ void Apc_target::enable() { pthread_mutex_lock(&LOCK_apc_queue); @@ -51,6 +65,13 @@ void Apc_target::enable() } +/* + Make the target unavailable for serving APC requests. + + @note + This call will serve all requests that were already enqueued +*/ + void Apc_target::disable() { bool process= FALSE; @@ -62,6 +83,9 @@ void Apc_target::disable() process_apc_requests(); } + +/* (internal) Put request into the request list */ + void Apc_target::enqueue_request(Call_request *qe) { //call_queue_size++; @@ -81,6 +105,13 @@ void Apc_target::enqueue_request(Call_request *qe) } } + +/* + (internal) Remove given request from the request queue. + + The request is not necessarily first in the queue. +*/ + void Apc_target::dequeue_request(Call_request *qe) { //call_queue_size--; @@ -99,8 +130,10 @@ void Apc_target::dequeue_request(Call_request *qe) /* - Make an apc call in another thread. The caller is responsible so - that we're not calling to ourselves. + Make an APC (Async Procedure Call) in another thread. + + The caller is responsible for making sure he's not calling an Apc_target + that is serviced by the same thread it is called from. psergey-todo: Should waits here be KILLable? (it seems one needs to use thd->enter_cond() calls to be killable) @@ -119,7 +152,7 @@ bool Apc_target::make_apc_call(apc_func_t func, void *func_arg, Call_request apc_request; apc_request.func= func; apc_request.func_arg= func_arg; - apc_request.done= FALSE; + apc_request.processed= FALSE; (void)pthread_cond_init(&apc_request.COND_request, NULL); (void)pthread_mutex_init(&apc_request.LOCK_request, MY_MUTEX_INIT_SLOW); pthread_mutex_lock(&apc_request.LOCK_request); @@ -133,19 +166,19 @@ bool Apc_target::make_apc_call(apc_func_t func, void *func_arg, int wait_res= 0; /* todo: how about processing other errors here? */ - while (!apc_request.done && (wait_res != ETIMEDOUT)) + while (!apc_request.processed && (wait_res != ETIMEDOUT)) { wait_res= pthread_cond_timedwait(&apc_request.COND_request, &apc_request.LOCK_request, &abstime); } - if (!apc_request.done) + if (!apc_request.processed) { - /* We timed out */ - apc_request.done= TRUE; + /* The wait has timed out. Remove the request from the queue */ + apc_request.processed= TRUE; *timed_out= TRUE; pthread_mutex_unlock(&apc_request.LOCK_request); - + //psergey-todo: "Whoa rare event" refers to this part, right? put a comment. pthread_mutex_lock(&LOCK_apc_queue); dequeue_request(&apc_request); pthread_mutex_unlock(&LOCK_apc_queue); @@ -171,7 +204,8 @@ bool Apc_target::make_apc_call(apc_func_t func, void *func_arg, /* - Process all APC requests + Process all APC requests. + This should be called periodically by the APC target thread. */ void Apc_target::process_apc_requests() @@ -190,7 +224,7 @@ void Apc_target::process_apc_requests() request->what="seen by process_apc_requests"; pthread_mutex_lock(&request->LOCK_request); - if (request->done) + if (request->processed) { /* We can get here when @@ -214,7 +248,7 @@ void Apc_target::process_apc_requests() */ request->what="dequeued by process_apc_requests"; dequeue_request(request); - request->done= TRUE; + request->processed= TRUE; pthread_mutex_unlock(&LOCK_apc_queue); |