cosmopolitan/libc/thread/pthread_zombies.c
Justine Tunney e522aa3a07
Make more threading improvements
- ASAN memory morgue is now lockless
- Make C11 atomics header more portable
- Rewrote pthread keys support to be lockless
- Simplify Python's unicode table unpacking code
- Make crash report write(2) closer to being atomic
- Make it possible to strace/ftrace a single thread
- ASAN now checks nul-terminated strings fast and properly
- Windows fork() now restores TLS memory of calling thread
2022-11-01 23:28:26 -07:00

83 lines
3.5 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2022 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/intrin/atomic.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/thread/posixthread.internal.h"
#include "libc/thread/spawn.h"
#include "libc/thread/thread.h"
// TODO(jart): track all threads, not just zombies
static struct Zombie {
struct Zombie *next;
struct PosixThread *pt;
} * _pthread_zombies;
void _pthread_zombies_add(struct PosixThread *pt) {
struct Zombie *z;
if ((z = malloc(sizeof(struct Zombie)))) {
z->pt = pt;
z->next = atomic_load(&_pthread_zombies);
for (;;) {
if (atomic_compare_exchange_weak(&_pthread_zombies, &z->next, z)) {
break;
}
}
}
}
static void _pthread_zombies_collect(struct Zombie *z) {
_pthread_wait(z->pt);
_pthread_free(z->pt);
free(z);
}
void _pthread_zombies_decimate(void) {
struct Zombie *z;
while ((z = atomic_load_explicit(&_pthread_zombies, memory_order_relaxed)) &&
atomic_load(&z->pt->status) == kPosixThreadZombie) {
if (atomic_compare_exchange_weak(&_pthread_zombies, &z, z->next)) {
_pthread_zombies_collect(z);
}
}
}
void _pthread_zombies_harvest(void) {
struct Zombie *z;
while ((z = atomic_load_explicit(&_pthread_zombies, memory_order_relaxed))) {
if (atomic_compare_exchange_weak(&_pthread_zombies, &z, z->next)) {
_pthread_zombies_collect(z);
}
}
}
void _pthread_zombies_purge(void) {
struct Zombie *z, *n;
while ((z = atomic_load_explicit(&_pthread_zombies, memory_order_relaxed))) {
_pthread_free(z->pt);
n = z->next;
free(z);
atomic_store_explicit(&_pthread_zombies, n, memory_order_relaxed);
}
}
__attribute__((__constructor__)) static void _pthread_zombies_init(void) {
atexit(_pthread_zombies_harvest);
}