diff options
Diffstat (limited to '')
| -rw-r--r-- | library/std/src/sys/unix/thread_parker/mod.rs | 32 | ||||
| -rw-r--r-- | library/std/src/sys/unix/thread_parker/netbsd.rs | 113 | ||||
| -rw-r--r-- | library/std/src/sys/unix/thread_parking/darwin.rs (renamed from library/std/src/sys/unix/thread_parker/darwin.rs) | 2 | ||||
| -rw-r--r-- | library/std/src/sys/unix/thread_parking/pthread.rs (renamed from library/std/src/sys/unix/thread_parker/pthread.rs) | 12 |
4 files changed, 7 insertions, 152 deletions
diff --git a/library/std/src/sys/unix/thread_parker/mod.rs b/library/std/src/sys/unix/thread_parker/mod.rs deleted file mode 100644 index 35f1e68a8..000000000 --- a/library/std/src/sys/unix/thread_parker/mod.rs +++ /dev/null @@ -1,32 +0,0 @@ -//! Thread parking on systems without futex support. - -#![cfg(not(any( - target_os = "linux", - target_os = "android", - all(target_os = "emscripten", target_feature = "atomics"), - target_os = "freebsd", - target_os = "openbsd", - target_os = "dragonfly", - target_os = "fuchsia", -)))] - -cfg_if::cfg_if! { - if #[cfg(all( - any( - target_os = "macos", - target_os = "ios", - target_os = "watchos", - target_os = "tvos", - ), - not(miri), - ))] { - mod darwin; - pub use darwin::Parker; - } else if #[cfg(target_os = "netbsd")] { - mod netbsd; - pub use netbsd::Parker; - } else { - mod pthread; - pub use pthread::Parker; - } -} diff --git a/library/std/src/sys/unix/thread_parker/netbsd.rs b/library/std/src/sys/unix/thread_parker/netbsd.rs deleted file mode 100644 index 7657605b5..000000000 --- a/library/std/src/sys/unix/thread_parker/netbsd.rs +++ /dev/null @@ -1,113 +0,0 @@ -use crate::ffi::{c_int, c_void}; -use crate::pin::Pin; -use crate::ptr::{null, null_mut}; -use crate::sync::atomic::{ - AtomicU64, - Ordering::{Acquire, Relaxed, Release}, -}; -use crate::time::Duration; -use libc::{_lwp_self, clockid_t, lwpid_t, time_t, timespec, CLOCK_MONOTONIC}; - -extern "C" { - fn ___lwp_park60( - clock_id: clockid_t, - flags: c_int, - ts: *mut timespec, - unpark: lwpid_t, - hint: *const c_void, - unparkhint: *const c_void, - ) -> c_int; - fn _lwp_unpark(lwp: lwpid_t, hint: *const c_void) -> c_int; -} - -/// The thread is not parked and the token is not available. -/// -/// Zero cannot be a valid LWP id, since it is used as empty value for the unpark -/// argument in _lwp_park. -const EMPTY: u64 = 0; -/// The token is available. Do not park anymore. -const NOTIFIED: u64 = u64::MAX; - -pub struct Parker { - /// The parker state. Contains either one of the two state values above or the LWP - /// id of the parked thread. - state: AtomicU64, -} - -impl Parker { - pub unsafe fn new(parker: *mut Parker) { - parker.write(Parker { state: AtomicU64::new(EMPTY) }) - } - - // Does not actually need `unsafe` or `Pin`, but the pthread implementation does. - pub unsafe fn park(self: Pin<&Self>) { - // If the token has already been made available, we can skip - // a bit of work, so check for it here. - if self.state.load(Acquire) != NOTIFIED { - let parked = _lwp_self() as u64; - let hint = self.state.as_mut_ptr().cast(); - if self.state.compare_exchange(EMPTY, parked, Relaxed, Acquire).is_ok() { - // Loop to guard against spurious wakeups. - loop { - ___lwp_park60(0, 0, null_mut(), 0, hint, null()); - if self.state.load(Acquire) == NOTIFIED { - break; - } - } - } - } - - // At this point, the change to NOTIFIED has always been observed with acquire - // ordering, so we can just use a relaxed store here (instead of a swap). - self.state.store(EMPTY, Relaxed); - } - - // Does not actually need `unsafe` or `Pin`, but the pthread implementation does. - pub unsafe fn park_timeout(self: Pin<&Self>, dur: Duration) { - if self.state.load(Acquire) != NOTIFIED { - let parked = _lwp_self() as u64; - let hint = self.state.as_mut_ptr().cast(); - let mut timeout = timespec { - // Saturate so that the operation will definitely time out - // (even if it is after the heat death of the universe). - tv_sec: dur.as_secs().try_into().ok().unwrap_or(time_t::MAX), - tv_nsec: dur.subsec_nanos().into(), - }; - - if self.state.compare_exchange(EMPTY, parked, Relaxed, Acquire).is_ok() { - // Timeout needs to be mutable since it is modified on NetBSD 9.0 and - // above. - ___lwp_park60(CLOCK_MONOTONIC, 0, &mut timeout, 0, hint, null()); - // Use a swap to get acquire ordering even if the token was set after - // the timeout occurred. - self.state.swap(EMPTY, Acquire); - return; - } - } - - self.state.store(EMPTY, Relaxed); - } - - // Does not actually need `Pin`, but the pthread implementation does. - pub fn unpark(self: Pin<&Self>) { - let state = self.state.swap(NOTIFIED, Release); - if !matches!(state, EMPTY | NOTIFIED) { - let lwp = state as lwpid_t; - let hint = self.state.as_mut_ptr().cast(); - - // If the parking thread terminated and did not actually park, this will - // probably return an error, which is OK. In the worst case, another - // thread has received the same LWP id. It will then receive a spurious - // wakeup, but those are allowable per the API contract. The same reasoning - // applies if a timeout occurred before this call, but the state was not - // yet reset. - - // SAFETY: - // The syscall has no invariants to hold. Only unsafe because it is an - // extern function. - unsafe { - _lwp_unpark(lwp, hint); - } - } - } -} diff --git a/library/std/src/sys/unix/thread_parker/darwin.rs b/library/std/src/sys/unix/thread_parking/darwin.rs index 2f5356fe2..b709fada3 100644 --- a/library/std/src/sys/unix/thread_parker/darwin.rs +++ b/library/std/src/sys/unix/thread_parking/darwin.rs @@ -46,7 +46,7 @@ unsafe impl Sync for Parker {} unsafe impl Send for Parker {} impl Parker { - pub unsafe fn new(parker: *mut Parker) { + pub unsafe fn new_in_place(parker: *mut Parker) { let semaphore = dispatch_semaphore_create(0); assert!( !semaphore.is_null(), diff --git a/library/std/src/sys/unix/thread_parker/pthread.rs b/library/std/src/sys/unix/thread_parking/pthread.rs index 3dfc0026e..082d25e68 100644 --- a/library/std/src/sys/unix/thread_parker/pthread.rs +++ b/library/std/src/sys/unix/thread_parking/pthread.rs @@ -6,6 +6,7 @@ use crate::pin::Pin; use crate::ptr::addr_of_mut; use crate::sync::atomic::AtomicUsize; use crate::sync::atomic::Ordering::SeqCst; +use crate::sys::time::TIMESPEC_MAX; use crate::time::Duration; const EMPTY: usize = 0; @@ -32,9 +33,6 @@ unsafe fn wait(cond: *mut libc::pthread_cond_t, lock: *mut libc::pthread_mutex_t debug_assert_eq!(r, 0); } -const TIMESPEC_MAX: libc::timespec = - libc::timespec { tv_sec: <libc::time_t>::MAX, tv_nsec: 1_000_000_000 - 1 }; - unsafe fn wait_timeout( cond: *mut libc::pthread_cond_t, lock: *mut libc::pthread_mutex_t, @@ -46,7 +44,8 @@ unsafe fn wait_timeout( target_os = "macos", target_os = "ios", target_os = "watchos", - target_os = "espidf" + target_os = "espidf", + target_os = "horizon", ))] let (now, dur) = { use crate::cmp::min; @@ -72,7 +71,8 @@ unsafe fn wait_timeout( target_os = "macos", target_os = "ios", target_os = "watchos", - target_os = "espidf" + target_os = "espidf", + target_os = "horizon", )))] let (now, dur) = { use crate::sys::time::Timespec; @@ -99,7 +99,7 @@ impl Parker { /// /// # Safety /// The constructed parker must never be moved. - pub unsafe fn new(parker: *mut Parker) { + pub unsafe fn new_in_place(parker: *mut Parker) { // Use the default mutex implementation to allow for simpler initialization. // This could lead to undefined behaviour when deadlocking. This is avoided // by not deadlocking. Note in particular the unlocking operation before any |