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Get rid of kmalloc()

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This changes *NSYNC to allocate waiters on the stack so our locks don't
need to depend on dynamic memory. This make our runtiem simpler, and it
also fixes bugs with thread cancellation support.
This commit is contained in:
Justine Tunney 2023-09-11 21:34:53 -07:00
parent 77a7873057
commit a359de7893
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GPG key ID: BE714B4575D6E328
57 changed files with 405 additions and 472 deletions
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35
libc/calls/tkill.c
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@ -98,16 +98,43 @@ static dontinline textwindows int __tkill_nt(int tid, int sig,
}
}
static int __tkill_m1(int tid, int sig, struct CosmoTib *tib) {
struct PosixThread *pt = (struct PosixThread *)__get_tls()->tib_pthread;
return __syslib->pthread_kill(pt->next, sig);
static int __tkill_posix(int tid, int sig, struct CosmoTib *tib) {
// avoid lock when killing self
int me;
struct PosixThread *pt;
pt = (struct PosixThread *)__get_tls()->tib_pthread;
me = atomic_load_explicit(&__get_tls()->tib_tid, memory_order_relaxed);
if (tid == me && (!tib || tib == __get_tls())) {
return __syslib->pthread_kill(pt->next, sig);
}
// otherwise look for matching thread
struct Dll *e;
pthread_spin_lock(&_pthread_lock);
for (e = dll_first(_pthread_list); e; e = dll_next(_pthread_list, e)) {
enum PosixThreadStatus status;
struct PosixThread *pt = POSIXTHREAD_CONTAINER(e);
int rhs = atomic_load_explicit(&pt->tib->tib_tid, memory_order_acquire);
if (rhs <= 0 || tid != rhs) continue;
if (tib && tib != pt->tib) continue;
status = atomic_load_explicit(&pt->status, memory_order_acquire);
pthread_spin_unlock(&_pthread_lock);
if (status < kPosixThreadTerminated) {
return __syslib->pthread_kill(pt->next, sig);
} else {
return 0;
}
}
pthread_spin_unlock(&_pthread_lock);
return esrch();
}
// OpenBSD has an optional `tib` parameter for extra safety.
int __tkill(int tid, int sig, void *tib) {
int rc;
if (IsXnuSilicon()) {
return __tkill_m1(tid, sig, tib);
return __tkill_posix(tid, sig, tib);
} else if (IsLinux() || IsXnu() || IsFreebsd() || IsOpenbsd() || IsNetbsd()) {
rc = sys_tkill(tid, sig, tib);
} else if (IsWindows()) {