In order to ensure the detached thread obtain the correct return
value from pthread_join()/pthread_cancel(), the detached thread
will create joininfo to save the detached status after thread
destroyed. If there are too many of detached threads in the
process group, the joininfo will consume too much memory.
This is not friendly to embedded MCU devices.
This commit keep the semantics as #11898 was introduced,
will no longer save joininfo for detached threads to avoid wasting memory.
Signed-off-by: chao an <anchao@lixiang.com>
1. add support to join main task
| static pthread_t self;
|
| static void *join_task(void *arg)
| {
| int ret;
| ret = pthread_join(self, NULL); <--- /* Fix Task could not be joined */
| return NULL;
| }
|
| int main(int argc, char *argv[])
| {
| pthread_t thread;
|
| self = pthread_self();
|
| pthread_create(&thread, NULL, join_task, NULL);
| sleep(1);
|
| pthread_exit(NULL);
| return 0;
| }
2. Detach active thread will not alloc for additional join, just update the task flag.
3. Remove the return value waiting lock logic (data_sem),
the return value will be stored in the waiting tcb.
4. Revise the return value of pthread_join(), consistent with linux
e.g:
Joining a detached and canceled thread should return EINVAL, not ESRCH
https://pubs.opengroup.org/onlinepubs/009695399/functions/pthread_join.html
[EINVAL]
The value specified by thread does not refer to a joinable thread.
NOTE:
This PR will not increase stack usage, but struct tcb_s will increase 32 bytes.
Signed-off-by: chao an <anchao@lixiang.com>
Resolving the issue with the ltp_interfaces_pthread_join_6_2 test case.
In SMP mode, the pthread may still be in the process of exiting when
pthread_join returns, and calling pthread_join again at this time will
result in an error. The error code returned should be ESRCH.
Signed-off-by: zhangyuan21 <zhangyuan21@xiaomi.com>
https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_detach.html
If an implementation detects that the value specified by the thread argument
to pthread_detach() does not refer to a joinable thread, it is recommended
that the function should fail and report an [EINVAL] error.
If an implementation detects use of a thread ID after the end of its lifetime,
it is recommended that the function should fail and report an [ESRCH] error.
Signed-off-by: zhangyuan21 <zhangyuan21@xiaomi.com>
pthread_join need check thread is DETACHED,
Whether to wait according to the result.And,
if a thread is DETACHED,it will not set a new
attr.
Signed-off-by: anjiahao <anjiahao@xiaomi.com>
* Simplify EINTR/ECANCEL error handling
1. Add semaphore uninterruptible wait function
2 .Replace semaphore wait loop with a single uninterruptible wait
3. Replace all sem_xxx to nxsem_xxx
* Unify the void cast usage
1. Remove void cast for function because many place ignore the returned value witout cast
2. Replace void cast for variable with UNUSED macro
