Function jemalloc_prefork

app/redis-6.2.6/deps/jemalloc/src/jemalloc.c:3189–3259

#ifndef JEMALLOC_MUTEX_INIT_CB
void
jemalloc_prefork(void)
#else
JEMALLOC_EXPORT void
_malloc_prefork(void)
#endif
{
	tsd_t *tsd;
	unsigned i, j, narenas;
	arena_t *arena;

#ifdef JEMALLOC_MUTEX_INIT_CB
	if (!malloc_initialized()) {
		return;
	}
#endif
	assert(malloc_initialized());

	tsd = tsd_fetch();

	narenas = narenas_total_get();

	witness_prefork(tsd_witness_tsdp_get(tsd));
	/* Acquire all mutexes in a safe order. */
	ctl_prefork(tsd_tsdn(tsd));
	tcache_prefork(tsd_tsdn(tsd));
	malloc_mutex_prefork(tsd_tsdn(tsd), &arenas_lock);
	if (have_background_thread) {
		background_thread_prefork0(tsd_tsdn(tsd));
	}
	prof_prefork0(tsd_tsdn(tsd));
	if (have_background_thread) {
		background_thread_prefork1(tsd_tsdn(tsd));
	}
	/* Break arena prefork into stages to preserve lock order. */
	for (i = 0; i < 8; i++) {
		for (j = 0; j < narenas; j++) {
			if ((arena = arena_get(tsd_tsdn(tsd), j, false)) !=
			    NULL) {
				switch (i) {
				case 0:
					arena_prefork0(tsd_tsdn(tsd), arena);
					break;
				case 1:
					arena_prefork1(tsd_tsdn(tsd), arena);
					break;
				case 2:
					arena_prefork2(tsd_tsdn(tsd), arena);
					break;
				case 3:
					arena_prefork3(tsd_tsdn(tsd), arena);
					break;
				case 4:
					arena_prefork4(tsd_tsdn(tsd), arena);
					break;
				case 5:
					arena_prefork5(tsd_tsdn(tsd), arena);
					break;