void
rw_lock_create_func(
/*================*/
rw_lock_t* lock, /* in: pointer to memory */
char* cfile_name, /* in: file name where created */
ulint cline) /* in: file line where created */
{
/* If this is the very first time a synchronization
object is created, then the following call initializes
the sync system. */
mutex_create(rw_lock_get_mutex(lock));
mutex_set_level(rw_lock_get_mutex(lock), SYNC_NO_ORDER_CHECK);
lock->mutex.cfile_name = cfile_name;
lock->mutex.cline = cline;
rw_lock_set_waiters(lock, 0);
rw_lock_set_writer(lock, RW_LOCK_NOT_LOCKED);
lock->writer_count = 0;
rw_lock_set_reader_count(lock, 0);
lock->writer_is_wait_ex = FALSE;
UT_LIST_INIT(lock->debug_list);
lock->magic_n = RW_LOCK_MAGIC_N;
lock->level = SYNC_LEVEL_NONE;
lock->cfile_name = cfile_name;
lock->cline = cline;
lock->last_s_file_name = "not yet reserved";
lock->last_x_file_name = "not yet reserved";
lock->last_s_line = 0;
lock->last_x_line = 0;
mutex_enter(&rw_lock_list_mutex);
UT_LIST_ADD_FIRST(list, rw_lock_list, lock);
mutex_exit(&rw_lock_list_mutex);
}
void
rw_lock_x_lock_func(
/*================*/
rw_lock_t* lock, /* in: pointer to rw-lock */
ulint pass, /* in: pass value; != 0, if the lock will
be passed to another thread to unlock */
const char* file_name,/* in: file name where lock requested */
ulint line) /* in: line where requested */
{
ulint index; /* index of the reserved wait cell */
ulint state; /* lock state acquired */
ulint i; /* spin round count */
ut_ad(rw_lock_validate(lock));
lock_loop:
/* Acquire the mutex protecting the rw-lock fields */
mutex_enter_fast(&(lock->mutex));
state = rw_lock_x_lock_low(lock, pass, file_name, line);
mutex_exit(&(lock->mutex));
if (state == RW_LOCK_EX) {
return; /* Locking succeeded */
} else if (state == RW_LOCK_NOT_LOCKED) {
/* Spin waiting for the writer field to become free */
i = 0;
while (rw_lock_get_writer(lock) != RW_LOCK_NOT_LOCKED
&& i < SYNC_SPIN_ROUNDS) {
if (srv_spin_wait_delay) {
ut_delay(ut_rnd_interval(0,
srv_spin_wait_delay));
}
i++;
}
if (i == SYNC_SPIN_ROUNDS) {
os_thread_yield();
}
} else if (state == RW_LOCK_WAIT_EX) {
/* Spin waiting for the reader count field to become zero */
i = 0;
while (rw_lock_get_reader_count(lock) != 0
&& i < SYNC_SPIN_ROUNDS) {
if (srv_spin_wait_delay) {
ut_delay(ut_rnd_interval(0,
srv_spin_wait_delay));
}
i++;
}
if (i == SYNC_SPIN_ROUNDS) {
os_thread_yield();
}
} else {
i = 0; /* Eliminate a compiler warning */
ut_error;
}
if (srv_print_latch_waits) {
fprintf(stderr,
"Thread %lu spin wait rw-x-lock at %p"
" cfile %s cline %lu rnds %lu\n",
os_thread_pf(os_thread_get_curr_id()), (void*) lock,
lock->cfile_name, (ulong) lock->cline, (ulong) i);
}
rw_x_spin_wait_count++;
/* We try once again to obtain the lock. Acquire the mutex protecting
the rw-lock fields */
mutex_enter(rw_lock_get_mutex(lock));
state = rw_lock_x_lock_low(lock, pass, file_name, line);
if (state == RW_LOCK_EX) {
mutex_exit(rw_lock_get_mutex(lock));
return; /* Locking succeeded */
}
rw_x_system_call_count++;
sync_array_reserve_cell(sync_primary_wait_array,
lock,
#ifdef __WIN__
/* On windows RW_LOCK_WAIT_EX signifies
that this thread should wait on the
special wait_ex_event. */
(state == RW_LOCK_WAIT_EX)
? RW_LOCK_WAIT_EX :
#endif
RW_LOCK_EX,
file_name, line,
&index);
rw_lock_set_waiters(lock, 1);
mutex_exit(rw_lock_get_mutex(lock));
if (srv_print_latch_waits) {
fprintf(stderr,
"Thread %lu OS wait for rw-x-lock at %p"
" cfile %s cline %lu\n",
os_thread_pf(os_thread_get_curr_id()), (void*) lock,
lock->cfile_name, (ulong) lock->cline);
}
rw_x_system_call_count++;
rw_x_os_wait_count++;
sync_array_wait_event(sync_primary_wait_array, index);
goto lock_loop;
}
void
rw_lock_s_lock_spin(
/*================*/
rw_lock_t* lock, /* in: pointer to rw-lock */
ulint pass, /* in: pass value; != 0, if the lock
will be passed to another thread to unlock */
const char* file_name, /* in: file name where lock requested */
ulint line) /* in: line where requested */
{
ulint index; /* index of the reserved wait cell */
ulint i; /* spin round count */
ut_ad(rw_lock_validate(lock));
lock_loop:
rw_s_spin_wait_count++;
/* Spin waiting for the writer field to become free */
i = 0;
while (rw_lock_get_writer(lock) != RW_LOCK_NOT_LOCKED
&& i < SYNC_SPIN_ROUNDS) {
if (srv_spin_wait_delay) {
ut_delay(ut_rnd_interval(0, srv_spin_wait_delay));
}
i++;
}
if (i == SYNC_SPIN_ROUNDS) {
os_thread_yield();
}
if (srv_print_latch_waits) {
fprintf(stderr,
"Thread %lu spin wait rw-s-lock at %p"
" cfile %s cline %lu rnds %lu\n",
(ulong) os_thread_pf(os_thread_get_curr_id()),
(void*) lock,
lock->cfile_name, (ulong) lock->cline, (ulong) i);
}
mutex_enter(rw_lock_get_mutex(lock));
/* We try once again to obtain the lock */
if (TRUE == rw_lock_s_lock_low(lock, pass, file_name, line)) {
mutex_exit(rw_lock_get_mutex(lock));
return; /* Success */
} else {
/* If we get here, locking did not succeed, we may
suspend the thread to wait in the wait array */
rw_s_system_call_count++;
sync_array_reserve_cell(sync_primary_wait_array,
lock, RW_LOCK_SHARED,
file_name, line,
&index);
rw_lock_set_waiters(lock, 1);
mutex_exit(rw_lock_get_mutex(lock));
if (srv_print_latch_waits) {
fprintf(stderr,
"Thread %lu OS wait rw-s-lock at %p"
" cfile %s cline %lu\n",
os_thread_pf(os_thread_get_curr_id()),
(void*) lock, lock->cfile_name,
(ulong) lock->cline);
}
rw_s_system_call_count++;
rw_s_os_wait_count++;
sync_array_wait_event(sync_primary_wait_array, index);
goto lock_loop;
}
}
void
rw_lock_create_func(
/*================*/
rw_lock_t* lock, /* in: pointer to memory */
#ifdef UNIV_DEBUG
# ifdef UNIV_SYNC_DEBUG
ulint level, /* in: level */
# endif /* UNIV_SYNC_DEBUG */
const char* cmutex_name, /* in: mutex name */
#endif /* UNIV_DEBUG */
const char* cfile_name, /* in: file name where created */
ulint cline) /* in: file line where created */
{
/* If this is the very first time a synchronization object is
created, then the following call initializes the sync system. */
mutex_create(rw_lock_get_mutex(lock), SYNC_NO_ORDER_CHECK);
lock->mutex.cfile_name = cfile_name;
lock->mutex.cline = cline;
#if defined UNIV_DEBUG && !defined UNIV_HOTBACKUP
lock->mutex.cmutex_name = cmutex_name;
lock->mutex.mutex_type = 1;
#endif /* UNIV_DEBUG && !UNIV_HOTBACKUP */
rw_lock_set_waiters(lock, 0);
rw_lock_set_writer(lock, RW_LOCK_NOT_LOCKED);
lock->writer_count = 0;
rw_lock_set_reader_count(lock, 0);
lock->writer_is_wait_ex = FALSE;
#ifdef UNIV_SYNC_DEBUG
UT_LIST_INIT(lock->debug_list);
lock->level = level;
#endif /* UNIV_SYNC_DEBUG */
lock->magic_n = RW_LOCK_MAGIC_N;
lock->cfile_name = cfile_name;
lock->cline = (unsigned int) cline;
lock->last_s_file_name = "not yet reserved";
lock->last_x_file_name = "not yet reserved";
lock->last_s_line = 0;
lock->last_x_line = 0;
lock->event = os_event_create(NULL);
#ifdef __WIN__
lock->wait_ex_event = os_event_create(NULL);
#endif
mutex_enter(&rw_lock_list_mutex);
if (UT_LIST_GET_LEN(rw_lock_list) > 0) {
ut_a(UT_LIST_GET_FIRST(rw_lock_list)->magic_n
== RW_LOCK_MAGIC_N);
}
UT_LIST_ADD_FIRST(list, rw_lock_list, lock);
mutex_exit(&rw_lock_list_mutex);
}
