42,6 → 42,7 |
#endif |
|
static LIST_INITIALIZE(ready_list); |
static LIST_INITIALIZE(serialized_list); |
static LIST_INITIALIZE(manager_list); |
|
static void psthread_exit(void) __attribute__ ((noinline)); |
48,6 → 49,12 |
static void psthread_main(void); |
|
static atomic_t psthread_futex = FUTEX_INITIALIZER; |
/** Count of real threads that are in async_serialized mode */ |
static int serialized_threads; /* Protected by async_futex */ |
/** Thread-local count of serialization. If >0, we must not preempt */ |
static __thread serialization_count; |
/** Counter of threads residing in async_manager */ |
static int threads_in_manager; |
|
/** Setup PSthread information into TCB structure */ |
psthread_data_t * psthread_setup() |
77,35 → 84,12 |
free(pt); |
} |
|
/** Function to preempt to other pseudo thread without adding |
* currently running pseudo thread to ready_list. |
*/ |
void psthread_exit(void) |
{ |
psthread_data_t *pt; |
|
futex_down(&psthread_futex); |
|
if (!list_empty(&ready_list)) |
pt = list_get_instance(ready_list.next, psthread_data_t, link); |
else if (!list_empty(&manager_list)) |
pt = list_get_instance(manager_list.next, psthread_data_t, link); |
else { |
printf("Cannot find suitable psthread to run.\n"); |
_exit(0); |
} |
list_remove(&pt->link); |
futex_up(&psthread_futex); |
|
context_restore(&pt->ctx); |
/* Never reached */ |
} |
|
/** Function that is called on entry to new uspace thread */ |
void psthread_main(void) |
{ |
psthread_data_t *pt = __tcb_get()->pst_data; |
|
serialization_count = 0; // TODO: WHY HERE? |
pt->retval = pt->func(pt->arg); |
|
pt->finished = 1; |
112,7 → 96,7 |
if (pt->waiter) |
list_append(&pt->waiter->link, &ready_list); |
|
psthread_exit(); |
psthread_schedule_next_adv(PS_FROM_DEAD); |
} |
|
/** Schedule next userspace pseudo thread. |
127,7 → 111,7 |
*/ |
int psthread_schedule_next_adv(pschange_type ctype) |
{ |
psthread_data_t *pt; |
psthread_data_t *srcpt, *dstpt; |
int retval = 0; |
|
futex_down(&psthread_futex); |
135,33 → 119,61 |
if (ctype == PS_PREEMPT && list_empty(&ready_list)) |
goto ret_0; |
|
if (ctype == PS_FROM_MANAGER && list_empty(&ready_list)) { |
if (ctype == PS_FROM_MANAGER) { |
if (list_empty(&ready_list) && list_empty(&serialized_list)) |
goto ret_0; |
/* Do not preempt if there is not sufficient count of thread managers */ |
if (list_empty(&serialized_list) && threads_in_manager <= serialized_threads) { |
goto ret_0; |
} |
} |
/* If we are going to manager and none exists, create it */ |
while (ctype == PS_TO_MANAGER && list_empty(&manager_list)) { |
if (ctype == PS_TO_MANAGER || ctype == PS_FROM_DEAD) { |
while (list_empty(&manager_list)) { |
futex_up(&psthread_futex); |
async_create_manager(); |
futex_down(&psthread_futex); |
} |
} |
|
pt = __tcb_get()->pst_data; |
if (!context_save(&pt->ctx)) |
if (ctype != PS_FROM_DEAD) { |
/* Save current state */ |
srcpt = __tcb_get()->pst_data; |
if (!context_save(&srcpt->ctx)) { |
if (serialization_count) |
srcpt->flags &= ~PSTHREAD_SERIALIZED; |
return 1; // futex_up already done here |
} |
|
/* Save myself to correct run list */ |
if (ctype == PS_PREEMPT) |
list_append(&pt->link, &ready_list); |
else if (ctype == PS_FROM_MANAGER) |
list_append(&pt->link, &manager_list); |
list_append(&srcpt->link, &ready_list); |
else if (ctype == PS_FROM_MANAGER) { |
list_append(&srcpt->link, &manager_list); |
threads_in_manager--; |
} /* If ctype == PS_TO_MANAGER, don't save ourselves to any list, we should |
* already be somewhere, or we will be lost */ |
} |
|
if (ctype == PS_TO_MANAGER) |
pt = list_get_instance(manager_list.next,psthread_data_t, link); |
else |
pt = list_get_instance(ready_list.next, psthread_data_t, link); |
list_remove(&pt->link); |
/* Choose new thread to run */ |
if (ctype == PS_TO_MANAGER || ctype == PS_FROM_DEAD) { |
dstpt = list_get_instance(manager_list.next,psthread_data_t, link); |
if (serialization_count && ctype == PS_TO_MANAGER) { |
serialized_threads++; |
srcpt->flags |= PSTHREAD_SERIALIZED; |
} |
threads_in_manager++; |
} else { |
if (!list_empty(&serialized_list)) { |
dstpt = list_get_instance(serialized_list.next, psthread_data_t, link); |
serialized_threads--; |
} else |
dstpt = list_get_instance(ready_list.next, psthread_data_t, link); |
} |
list_remove(&dstpt->link); |
|
futex_up(&psthread_futex); |
context_restore(&pt->ctx); |
context_restore(&dstpt->ctx); |
|
ret_0: |
futex_up(&psthread_futex); |
182,13 → 194,10 |
/* Handle psthrid = Kernel address -> it is wait for call */ |
pt = (psthread_data_t *) psthrid; |
|
if (!pt->finished) { |
mypt = __tcb_get()->pst_data; |
if (context_save(&((psthread_data_t *) mypt)->ctx)) { |
pt->waiter = (psthread_data_t *) mypt; |
psthread_exit(); |
} |
} |
/* TODO */ |
printf("join unsupported\n"); |
_exit(1); |
|
retval = pt->retval; |
|
free(pt->stack); |
223,6 → 232,7 |
pt->func = func; |
pt->finished = 0; |
pt->waiter = NULL; |
pt->flags = 0; |
|
context_save(&pt->ctx); |
context_set(&pt->ctx, FADDR(psthread_main), pt->stack, PSTHREAD_INITIAL_STACK_PAGES_NO*getpagesize(), |
238,6 → 248,9 |
|
pt = (psthread_data_t *) psthrid; |
futex_down(&psthread_futex); |
if ((pt->flags & PSTHREAD_SERIALIZED)) |
list_append(&pt->link, &serialized_list); |
else |
list_append(&pt->link, &ready_list); |
futex_up(&psthread_futex); |
} |
271,3 → 284,21 |
{ |
return (pstid_t)__tcb_get()->pst_data; |
} |
|
/** Disable preemption |
* |
* If the thread wants to send several message in row and does not want |
* to be preempted, it should start async_serialize_start() in the beginning |
* of communication and async_serialize_end() in the end. If it is a |
* true multithreaded application, it should protect the communication channel |
* by a futex as well. Interrupt messages will can still be preempted. |
*/ |
void psthread_inc_sercount(void) |
{ |
serialization_count++; |
} |
|
void psthread_dec_sercount(void) |
{ |
serialization_count--; |
} |