/*
* __wt_log_slot_new --
* Find a free slot and switch it as the new active slot.
* Must be called holding the slot lock.
*/
int
__wt_log_slot_new(WT_SESSION_IMPL *session)
{
WT_CONNECTION_IMPL *conn;
WT_LOG *log;
WT_LOGSLOT *slot;
int32_t i;
WT_ASSERT(session, F_ISSET(session, WT_SESSION_LOCKED_SLOT));
conn = S2C(session);
log = conn->log;
/*
* Although this function is single threaded, multiple threads could
* be trying to set a new active slot sequentially. If we find an
* active slot that is valid, return.
*/
if ((slot = log->active_slot) != NULL &&
WT_LOG_SLOT_OPEN(slot->slot_state))
return (0);
/*
* Keep trying until we can find a free slot.
*/
for (;;) {
/*
* For now just restart at 0. We could use log->pool_index
* if that is inefficient.
*/
for (i = 0; i < WT_SLOT_POOL; i++) {
slot = &log->slot_pool[i];
if (slot->slot_state == WT_LOG_SLOT_FREE) {
/*
* Acquire our starting position in the
* log file. Assume the full buffer size.
*/
WT_RET(__wt_log_acquire(session,
log->slot_buf_size, slot));
/*
* We have a new, initialized slot to use.
* Set it as the active slot.
*/
WT_STAT_FAST_CONN_INCR(session,
log_slot_transitions);
log->active_slot = slot;
return (0);
}
}
/*
* If we didn't find any free slots signal the worker thread.
*/
(void)__wt_cond_signal(session, conn->log_wrlsn_cond);
__wt_yield();
}
/* NOTREACHED */
}
/*
* __log_slot_new --
* Find a free slot and switch it as the new active slot.
* Must be called holding the slot lock.
*/
static int
__log_slot_new(WT_SESSION_IMPL *session)
{
WT_CONNECTION_IMPL *conn;
WT_LOG *log;
WT_LOGSLOT *slot;
int32_t i, pool_i;
#ifdef HAVE_DIAGNOSTIC
uint64_t time_start, time_stop;
int count;
#endif
WT_ASSERT(session, F_ISSET(session, WT_SESSION_LOCKED_SLOT));
conn = S2C(session);
log = conn->log;
/*
* Although this function is single threaded, multiple threads could
* be trying to set a new active slot sequentially. If we find an
* active slot that is valid, return.
*/
if ((slot = log->active_slot) != NULL &&
WT_LOG_SLOT_OPEN(slot->slot_state))
return (0);
#ifdef HAVE_DIAGNOSTIC
count = 0;
time_start = __wt_clock(session);
#endif
/*
* Keep trying until we can find a free slot.
*/
for (;;) {
/*
* Rotate among the slots to lessen collisions.
*/
WT_RET(WT_SESSION_CHECK_PANIC(session));
for (i = 0, pool_i = log->pool_index; i < WT_SLOT_POOL;
i++, pool_i++) {
if (pool_i >= WT_SLOT_POOL)
pool_i = 0;
slot = &log->slot_pool[pool_i];
if (slot->slot_state == WT_LOG_SLOT_FREE) {
/*
* Acquire our starting position in the
* log file. Assume the full buffer size.
*/
WT_RET(__wt_log_acquire(session,
log->slot_buf_size, slot));
/*
* We have a new, initialized slot to use.
* Set it as the active slot.
*/
log->active_slot = slot;
log->pool_index = pool_i;
return (0);
}
}
/*
* If we didn't find any free slots signal the worker thread.
*/
WT_STAT_CONN_INCR(session, log_slot_no_free_slots);
__wt_cond_signal(session, conn->log_wrlsn_cond);
__wt_yield();
#ifdef HAVE_DIAGNOSTIC
++count;
if (count > WT_MILLION) {
time_stop = __wt_clock(session);
if (WT_CLOCKDIFF_SEC(time_stop, time_start) > 10) {
__wt_errx(session,
"SLOT_NEW: Timeout free slot");
__log_slot_dump(session);
__wt_abort(session);
}
count = 0;
}
#endif
}
/* NOTREACHED */
}
