int evt_trigger(spdid_t spdid, long extern_evt)
{
struct evt *e;
int ret = 0;
lock_take(&evt_lock);
e = mapping_find(extern_evt);
if (NULL == e) goto err;
ACT_RECORD(ACT_TRIGGER, spdid, e->extern_id, cos_get_thd_id(), 0);
/* Trigger an event being waited for? */
if (0 != (ret = __evt_trigger(e))) {
lock_release(&evt_lock);
ACT_RECORD(ACT_WAKEUP, spdid, e->extern_id, cos_get_thd_id(), ret);
if (sched_wakeup(cos_spd_id(), ret)) BUG();
} else {
lock_release(&evt_lock);
}
return 0;
err:
lock_release(&evt_lock);
return -1;
}
/* Wait for a specific event */
int evt_wait(spdid_t spdid, long extern_evt)
{
struct evt *e;
while (1) {
int ret;
lock_take(&evt_lock);
e = mapping_find(extern_evt);
if (NULL == e) goto err;
if (0 > (ret = __evt_read(e))) goto err;
ACT_RECORD(ACT_WAIT, spdid, e->extern_id, cos_get_thd_id(), 0);
lock_release(&evt_lock);
if (1 == ret) {
assert(extern_evt == e->extern_id);
return 0;
} else {
ACT_RECORD(ACT_SLEEP, spdid, e->extern_id, cos_get_thd_id(), 0);
if (0 > sched_block(cos_spd_id(), 0)) BUG();
}
}
err:
lock_release(&evt_lock);
return -1;
}
/* Wait on a group of events (like epoll) */
long evt_grp_wait(spdid_t spdid)
{
struct evt_grp *g;
struct evt *e = NULL;
long extern_evt;
while (1) {
lock_take(&evt_lock);
g = evt_grp_find(cos_get_thd_id());
ACT_RECORD(ACT_WAIT_GRP, spdid, e ? e->extern_id : 0, cos_get_thd_id(), 0);
if (NULL == g) goto err;
if (__evt_grp_read(g, &e)) goto err;
if (NULL != e) {
extern_evt = e->extern_id;
lock_release(&evt_lock);
return extern_evt;
} else {
lock_release(&evt_lock);
ACT_RECORD(ACT_SLEEP, spdid, 0, cos_get_thd_id(), 0);
if (0 > sched_block(cos_spd_id(), 0)) BUG();
}
}
err:
lock_release(&evt_lock);
return -1;
}
int __evt_wait(spdid_t spdid, long extern_evt, int n)
{
struct evt *e;
while (1) {
int ret;
lock_take(&evt_lock);
e = mapping_find(extern_evt);
if (NULL == e) goto err;
if (0 > (ret = __evt_read(e))) goto err;
ACT_RECORD(ACT_WAIT, spdid, e->extern_id, cos_get_thd_id(), 0);
e->n_wait = n;
e->core_id = cos_cpuid();
if (ret == 1) e->n_received = 0;
lock_release(&evt_lock);
if (1 == ret) {
assert(extern_evt == e->extern_id);
return 0;
} else {
ACT_RECORD(ACT_SLEEP, spdid, e->extern_id, cos_get_thd_id(), 0);
/* We can use acaps to block / wakeup, which
* can avoid calling scheduler. But it's like
* a hack. */
if (0 > sched_block(cos_spd_id(), 0)) BUG();
}
}
err:
lock_release(&evt_lock);
return -1;
}
/* As above, but return more than one event notifications */
int evt_grp_mult_wait(spdid_t spdid, struct cos_array *data)
{
struct evt_grp *g;
struct evt *e = NULL;
int evt_gathered = 0, evt_max;
if (!cos_argreg_arr_intern(data)) return -EINVAL;
evt_max = data->sz / sizeof(long);
while (1) {
lock_take(&evt_lock);
g = evt_grp_find(cos_get_thd_id());
ACT_RECORD(ACT_WAIT_GRP, spdid, e ? e->extern_id : 0, cos_get_thd_id(), 0);
if (NULL == g) goto err;
/* gather multiple events */
do {
if (__evt_grp_read_noblock(g, &e)) goto err;
if (NULL != e) {
((long*)data->mem)[evt_gathered] = e->extern_id;
evt_gathered++;
}
} while (e && evt_gathered < evt_max);
/* return them if they were gathered */
if (evt_gathered > 0) {
lock_release(&evt_lock);
return evt_gathered;
}
/*
* otherwise sleep till there is an event (first we
* need to call evt_grp_read to set the blocked
* status)
*/
if (__evt_grp_read(g, &e)) goto err;
assert(NULL == e);
lock_release(&evt_lock);
ACT_RECORD(ACT_SLEEP, spdid, 0, cos_get_thd_id(), 0);
if (0 > sched_block(cos_spd_id(), 0)) BUG();
}
err:
lock_release(&evt_lock);
return -1;
}
/*
* The problem being solved here is this: T_1 wishes to take the
* mutex, finds that it is taken by another thread. It calls into
* this function, but is preempted by T_2, the lock holder. The lock
* is released. T_1 is switched back to and it invokes this component
* asking to block till the lock is released. This component has no
* way of knowing that the lock already has been released, so we block
* for no reason in wait for the lock to be "released". Thus what we
* do is have the client call the pretake function checking before and
* after invoking it that the lock is still taken. We record the
* generation number in pretake and make sure that it is consistent in
* take. This signifies that no release has happened in the interim,
* and that we really should sleep.
*/
int lock_component_pretake(spdid_t spd, unsigned long lock_id, unsigned short int thd)
{
struct meta_lock *ml;
spdid_t spdid = cos_spd_id();
int ret = 0;
ACT_RECORD(ACT_PRELOCK, spd, lock_id, cos_get_thd_id(), thd);
TAKE(spdid);
// lock_print_all();
ml = lock_find(lock_id, spd);
if (NULL == ml) {
ret = -1;
goto done;
}
ml->gen_num = generation;
done:
RELEASE(spdid);
return ret;
}
int lock_component_release(spdid_t spd, unsigned long lock_id)
{
struct meta_lock *ml;
struct blocked_thds *sent, *bt;
spdid_t spdid = cos_spd_id();
ACT_RECORD(ACT_UNLOCK, spd, lock_id, cos_get_thd_id(), 0);
TAKE(spdid);
generation++;
ml = lock_find(lock_id, spd);
if (!ml) goto error;
/* Apparently, lock_take calls haven't been made. */
if (EMPTY_LIST(&ml->b_thds, next, prev)) {
RELEASE(spdid);
return 0;
}
sent = bt = FIRST_LIST(&ml->b_thds, next, prev);
/* Remove all threads from the lock's list */
REM_LIST(&ml->b_thds, next, prev);
/* Unblock all waiting threads */
while (1) {
struct blocked_thds *next;
u16_t tid;
/* This is suboptimal: if we wake a thread with a
* higher priority, it will be switched to. Given we
* are holding the component lock here, we should get
* switched _back_ to so as to wake the rest of the
* components. */
next = FIRST_LIST(bt, next, prev);
REM_LIST(bt, next, prev);
ACT_RECORD(ACT_WAKE, spd, lock_id, cos_get_thd_id(), bt->thd_id);
/* cache locally */
tid = bt->thd_id;
/* Last node in the list? */
if (bt == next) {
/* This is sneaky, so to reiterate: Keep this
* lock till now so that if we wake another
* thread, and it begins execution, the system
* will switch back to this thread so that we
* can wake up the rest of the waiting threads
* (one of which might have the highest
* priority). We release before we wake the
* last as we don't really need the lock
* anymore, an it will avoid quite a few
* invocations.*/
RELEASE(spdid);
}
/* Wakeup the way we were put to sleep */
assert(tid != cos_get_thd_id());
/* printc("CPU %ld: %d waking up %d for lock %d\n", cos_cpuid(), cos_get_thd_id(), tid, lock_id); */
sched_wakeup(spdid, tid);
if (bt == next) break;
bt = next;
}
return 0;
error:
RELEASE(spdid);
return -1;
}
/*
* Dependencies here (thus priority inheritance) will NOT be used if
* you specify a timeout value.
*
* Return 0: lock taken, -1: could not find lock, 1: inconsistency -- retry!
*/
int lock_component_take(spdid_t spd, unsigned long lock_id, unsigned short int thd_id)
{
struct meta_lock *ml;
spdid_t spdid = cos_spd_id();
unsigned short int curr = (unsigned short int)cos_get_thd_id();
struct blocked_thds blocked_desc = {.thd_id = curr};
int ret = -1;
ACT_RECORD(ACT_LOCK, spd, lock_id, cos_get_thd_id(), thd_id);
TAKE(spdid);
ml = lock_find(lock_id, spd);
/* tried to access a lock not yet created */
if (!ml) goto error;
assert(!lock_is_thd_blocked(ml, curr));
/* The calling component needs to retry its user-level lock,
* some preemption has caused the generation count to get off,
* i.e. we don't have the most up-to-date view of the
* lock's state */
if (ml->gen_num != generation) {
ml->gen_num = generation;
ret = 1;
goto error;
}
generation++;
/* Note that we are creating the list of blocked threads from
* memory allocated on the individual thread's stacks. */
INIT_LIST(&blocked_desc, next, prev);
ADD_LIST(&ml->b_thds, &blocked_desc, next, prev);
//ml->owner = thd_id;
RELEASE(spdid);
/* printc("cpu %ld: thd %d going to blk waiting for lock %d\n", cos_cpuid(), cos_get_thd_id(), (int)lock_id); */
if (-1 == sched_block(spdid, thd_id)) {
printc("Deadlock including thdids %d -> %d in spd %d, lock id %d.\n",
cos_get_thd_id(), thd_id, spd, (int)lock_id);
debug_print("BUG: Possible deadlock @ ");
assert(0);
if (-1 == sched_block(spdid, 0)) assert(0);
}
if (!EMPTY_LIST(&blocked_desc, next, prev)) BUG();
/*
* OK, this seems ridiculous but here is the rational: Assume
* we are a middle-prio thread, and were just woken by a low
* priority thread. We will preempt that thread when woken,
* and will continue here. If a high priority thread is also
* waiting on the lock, then we would preempt the low priority
* thread while it should wake the high prio thread. With the
* following crit sect will switch to the low prio thread that
* still holds the component lock. See the comments in
* lock_component_release.
*/
//TAKE(spdid);
//RELEASE(spdid);
ACT_RECORD(ACT_WAKEUP, spd, lock_id, cos_get_thd_id(), 0);
ret = 0;
done:
return ret;
error:
RELEASE(spdid);
goto done;
}
/*
* Dependencies here (thus priority inheritance) will NOT be used if
* you specify a timeout value.
*/
int lock_component_take(spdid_t spd, unsigned long lock_id, unsigned short int thd_id, unsigned int microsec)
{
struct meta_lock *ml;
spdid_t spdid = cos_spd_id();
unsigned short int curr = (unsigned short int)cos_get_thd_id();
struct blocked_thds blocked_desc = {.thd_id = curr};
int ret = 0;
// print("thread %d from spd %d locking for %d micrseconds.", curr, spdid, microsec);
ACT_RECORD(ACT_LOCK, spd, lock_id, cos_get_thd_id(), thd_id);
TAKE(spdid);
if (0 == microsec) {
ret = TIMER_EXPIRED;
goto error;
}
ml = lock_find(lock_id, spd);
/* tried to access a lock not yet created */
if (!ml) {
ret = -1;
//print("take wtf%d%d%d", 0,0,0);
goto error;
}
if (lock_is_thd_blocked(ml, curr)) {
prints("lock: lock_is_thd_blocked failed in lock_component_take\n");
goto error;
}
/* The calling component needs to retry its user-level lock,
* some preemption has caused the generation count to get off,
* i.e. we don't have the most up-to-date view of the
* lock's state */
if (ml->gen_num != generation) {
ml->gen_num = generation;
ret = 0;
goto error;
}
generation++;
/* Note that we are creating the list of blocked threads from
* memory allocated on the individual thread's stacks. */
INIT_LIST(&blocked_desc, next, prev);
ADD_LIST(&ml->b_thds, &blocked_desc, next, prev);
blocked_desc.timed = (TIMER_EVENT_INF != microsec);
//ml->owner = thd_id;
RELEASE(spdid);
/* Bypass calling the timed every component if there is an infinite wait */
// assert(TIMER_EVENT_INF == microsec);
// assert(!blocked_desc.timed);
if (TIMER_EVENT_INF == microsec) {
if (-1 == sched_block(spdid, thd_id)) BUG();
if (!EMPTY_LIST(&blocked_desc, next, prev)) BUG();
/*
* OK, this seems ridiculous but here is the rational: Assume
* we are a middle-prio thread, and were just woken by a low
* priority thread. We will preempt that thread when woken,
* and will continue here. If a high priority thread is also
* waiting on the lock, then we would preempt the low priority
* thread while it should wake the high prio thread. With the
* following crit sect will switch to the low prio thread that
* still holds the component lock. See the comments in
* lock_component_release.
*/
//TAKE(spdid);
//RELEASE(spdid);
ACT_RECORD(ACT_WAKEUP, spd, lock_id, cos_get_thd_id(), 0);
ret = 0;
} else {
assert(0);
#ifdef NIL
/* ret here will fall through. We do NOT use the
* dependency here as I can't think through the
* repercussions */
if (-1 == (ret = timed_event_block(spdid, microsec))) return ret;
/*
* We might have woken from a timeout, which means
* that we need to remove this thread from the waiting
* list for the lock.
*/
TAKE(spdid);
ml = lock_find(lock_id, spd);
if (!ml) {
ret = -1;
goto error;
}
REM_LIST(&blocked_desc, next, prev);
RELEASE(spdid);
ACT_RECORD(ACT_WAKEUP, spd, lock_id, cos_get_thd_id(), 0);
/* ret is set to the amnt of time we blocked */
#endif
}
return ret;
error:
RELEASE(spdid);
return ret;
}
