/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-â
âvi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :viâ
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â Copyright 2022 Justine Alexandra Roberts Tunney                              â
â                                                                              â
â Permission to use, copy, modify, and/or distribute this software for         â
â any purpose with or without fee is hereby granted, provided that the         â
â above copyright notice and this permission notice appear in all copies.      â
â                                                                              â
â THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                â
â WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                â
â WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             â
â AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         â
â DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        â
â PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               â
â TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             â
â PERFORMANCE OF THIS SOFTWARE.                                                â
ââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââââ*/
#include "libc/intrin/atomic.h"
#include "libc/runtime/runtime.h"
#include "libc/thread/posixthread.internal.h"
#include "libc/thread/thread.h"
#include "libc/thread/tls.h"
#include "third_party/nsync/dll.h"

/**
 * Releases memory of detached threads that have terminated.
 */
void pthread_decimate_np(void) {
  nsync_dll_element_ *e;
  struct PosixThread *pt;
  enum PosixThreadStatus status;
StartOver:
  pthread_spin_lock(&_pthread_lock);
  for (e = nsync_dll_first_(_pthread_list); e;
       e = nsync_dll_next_(_pthread_list, e)) {
    pt = (struct PosixThread *)e->container;
    if (pt->tib == __get_tls()) continue;
    status = atomic_load_explicit(&pt->status, memory_order_acquire);
    if (status != kPosixThreadZombie) break;
    if (!atomic_load_explicit(&pt->tib->tib_tid, memory_order_acquire)) {
      _pthread_list = nsync_dll_remove_(_pthread_list, e);
      pthread_spin_unlock(&_pthread_lock);
      _pthread_free(pt);
      goto StartOver;
    }
  }
  pthread_spin_unlock(&_pthread_lock);
}
