glibc/htl/pt-exit.c
Wilco Dijkstra 4a07fbb689 Use C11 atomics instead of atomic_decrement_and_test
Replace atomic_decrement_and_test with atomic_fetch_add_relaxed.
These are simple counters which do not protect any shared data from
concurrent accesses. Also remove the unused file cond-perf.c.

Passes regress on AArch64.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-09-23 15:59:56 +01:00

113 lines
3.4 KiB
C

/* Thread termination.
Copyright (C) 2000-2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <assert.h>
#include <errno.h>
#include <pthread.h>
#include <stdlib.h>
#include <pt-internal.h>
#include <pthreadP.h>
#include <atomic.h>
/* Terminate the current thread and make STATUS available to any
thread that might join it. */
void
__pthread_exit (void *status)
{
struct __pthread *self = _pthread_self ();
struct __pthread_cancelation_handler **handlers;
int oldstate;
/* Run any cancelation handlers. According to POSIX, the
cancellation cleanup handlers should be called with cancellation
disabled. */
__pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate);
for (handlers = __pthread_get_cleanup_stack ();
*handlers != NULL;
*handlers = (*handlers)->__next)
(*handlers)->__handler ((*handlers)->__arg);
__pthread_setcancelstate (oldstate, &oldstate);
/* Decrease the number of threads. We use an atomic operation to
make sure that only the last thread calls `exit'. */
if (atomic_fetch_add_relaxed (&__pthread_total, -1) == 1)
/* We are the last thread. */
exit (0);
/* Destroy any thread specific data. */
__pthread_destroy_specific (self);
/* Note that after this point the process can be terminated at any
point if another thread calls `pthread_exit' and happens to be
the last thread. */
__pthread_mutex_lock (&self->state_lock);
if (self->cancel_state == PTHREAD_CANCEL_ENABLE && self->cancel_pending)
status = PTHREAD_CANCELED;
switch (self->state)
{
default:
assert (!"Consistency error: unexpected self->state");
abort ();
break;
case PTHREAD_DETACHED:
__pthread_mutex_unlock (&self->state_lock);
break;
case PTHREAD_JOINABLE:
/* We need to stay around for a while since another thread
might want to join us. */
self->state = PTHREAD_EXITED;
/* We need to remember the exit status. A thread joining us
might ask for it. */
self->status = status;
/* Broadcast the condition. This will wake up threads that are
waiting to join us. */
__pthread_cond_broadcast (&self->state_cond);
__pthread_mutex_unlock (&self->state_lock);
break;
}
/* Destroy any signal state. */
__pthread_sigstate_destroy (self);
/* Self terminating requires TLS, so defer the release of the TCB until
the thread structure is reused. */
/* Release kernel resources, including the kernel thread and the stack,
and drop the self reference. */
__pthread_thread_terminate (self);
/* NOTREACHED */
abort ();
}
weak_alias (__pthread_exit, pthread_exit);