diff options
Diffstat (limited to 'library/core/src/sync')
| -rw-r--r-- | library/core/src/sync/atomic.rs | 54 | ||||
| -rw-r--r-- | library/core/src/sync/exclusive.rs | 9 |
2 files changed, 48 insertions, 15 deletions
diff --git a/library/core/src/sync/atomic.rs b/library/core/src/sync/atomic.rs index 3c96290fc..edc68d6fa 100644 --- a/library/core/src/sync/atomic.rs +++ b/library/core/src/sync/atomic.rs @@ -294,7 +294,7 @@ impl AtomicBool { /// ``` /// use std::sync::atomic::AtomicBool; /// - /// let atomic_true = AtomicBool::new(true); + /// let atomic_true = AtomicBool::new(true); /// let atomic_false = AtomicBool::new(false); /// ``` #[inline] @@ -955,6 +955,14 @@ impl AtomicBool { /// **Note:** This method is only available on platforms that support atomic /// operations on `u8`. /// + /// # Considerations + /// + /// This method is not magic; it is not provided by the hardware. + /// It is implemented in terms of [`AtomicBool::compare_exchange_weak`], and suffers from the same drawbacks. + /// In particular, this method will not circumvent the [ABA Problem]. + /// + /// [ABA Problem]: https://en.wikipedia.org/wiki/ABA_problem + /// /// # Examples /// /// ```rust @@ -1171,7 +1179,7 @@ impl<T> AtomicPtr<T> { /// use std::sync::atomic::{AtomicPtr, Ordering}; /// /// let ptr = &mut 5; - /// let some_ptr = AtomicPtr::new(ptr); + /// let some_ptr = AtomicPtr::new(ptr); /// /// let value = some_ptr.load(Ordering::Relaxed); /// ``` @@ -1198,7 +1206,7 @@ impl<T> AtomicPtr<T> { /// use std::sync::atomic::{AtomicPtr, Ordering}; /// /// let ptr = &mut 5; - /// let some_ptr = AtomicPtr::new(ptr); + /// let some_ptr = AtomicPtr::new(ptr); /// /// let other_ptr = &mut 10; /// @@ -1230,7 +1238,7 @@ impl<T> AtomicPtr<T> { /// use std::sync::atomic::{AtomicPtr, Ordering}; /// /// let ptr = &mut 5; - /// let some_ptr = AtomicPtr::new(ptr); + /// let some_ptr = AtomicPtr::new(ptr); /// /// let other_ptr = &mut 10; /// @@ -1282,9 +1290,9 @@ impl<T> AtomicPtr<T> { /// use std::sync::atomic::{AtomicPtr, Ordering}; /// /// let ptr = &mut 5; - /// let some_ptr = AtomicPtr::new(ptr); + /// let some_ptr = AtomicPtr::new(ptr); /// - /// let other_ptr = &mut 10; + /// let other_ptr = &mut 10; /// /// let value = some_ptr.compare_and_swap(ptr, other_ptr, Ordering::Relaxed); /// ``` @@ -1325,9 +1333,9 @@ impl<T> AtomicPtr<T> { /// use std::sync::atomic::{AtomicPtr, Ordering}; /// /// let ptr = &mut 5; - /// let some_ptr = AtomicPtr::new(ptr); + /// let some_ptr = AtomicPtr::new(ptr); /// - /// let other_ptr = &mut 10; + /// let other_ptr = &mut 10; /// /// let value = some_ptr.compare_exchange(ptr, other_ptr, /// Ordering::SeqCst, Ordering::Relaxed); @@ -1422,6 +1430,14 @@ impl<T> AtomicPtr<T> { /// **Note:** This method is only available on platforms that support atomic /// operations on pointers. /// + /// # Considerations + /// + /// This method is not magic; it is not provided by the hardware. + /// It is implemented in terms of [`AtomicPtr::compare_exchange_weak`], and suffers from the same drawbacks. + /// In particular, this method will not circumvent the [ABA Problem]. + /// + /// [ABA Problem]: https://en.wikipedia.org/wiki/ABA_problem + /// /// # Examples /// /// ```rust @@ -1626,8 +1642,8 @@ impl<T> AtomicPtr<T> { /// and the argument `val`, and stores a pointer with provenance of the /// current pointer and the resulting address. /// - /// This is equivalent equivalent to using [`map_addr`] to atomically - /// perform `ptr = ptr.map_addr(|a| a | val)`. This can be used in tagged + /// This is equivalent to using [`map_addr`] to atomically perform + /// `ptr = ptr.map_addr(|a| a | val)`. This can be used in tagged /// pointer schemes to atomically set tag bits. /// /// **Caveat**: This operation returns the previous value. To compute the @@ -1677,8 +1693,8 @@ impl<T> AtomicPtr<T> { /// pointer, and the argument `val`, and stores a pointer with provenance of /// the current pointer and the resulting address. /// - /// This is equivalent equivalent to using [`map_addr`] to atomically - /// perform `ptr = ptr.map_addr(|a| a & val)`. This can be used in tagged + /// This is equivalent to using [`map_addr`] to atomically perform + /// `ptr = ptr.map_addr(|a| a & val)`. This can be used in tagged /// pointer schemes to atomically unset tag bits. /// /// **Caveat**: This operation returns the previous value. To compute the @@ -1727,8 +1743,8 @@ impl<T> AtomicPtr<T> { /// pointer, and the argument `val`, and stores a pointer with provenance of /// the current pointer and the resulting address. /// - /// This is equivalent equivalent to using [`map_addr`] to atomically - /// perform `ptr = ptr.map_addr(|a| a ^ val)`. This can be used in tagged + /// This is equivalent to using [`map_addr`] to atomically perform + /// `ptr = ptr.map_addr(|a| a ^ val)`. This can be used in tagged /// pointer schemes to atomically toggle tag bits. /// /// **Caveat**: This operation returns the previous value. To compute the @@ -2510,6 +2526,16 @@ macro_rules! atomic_int { /// **Note**: This method is only available on platforms that support atomic operations on #[doc = concat!("[`", $s_int_type, "`].")] /// + /// # Considerations + /// + /// This method is not magic; it is not provided by the hardware. + /// It is implemented in terms of + #[doc = concat!("[`", stringify!($atomic_type), "::compare_exchange_weak`],")] + /// and suffers from the same drawbacks. + /// In particular, this method will not circumvent the [ABA Problem]. + /// + /// [ABA Problem]: https://en.wikipedia.org/wiki/ABA_problem + /// /// # Examples /// /// ```rust diff --git a/library/core/src/sync/exclusive.rs b/library/core/src/sync/exclusive.rs index a7519ab5a..c65c27500 100644 --- a/library/core/src/sync/exclusive.rs +++ b/library/core/src/sync/exclusive.rs @@ -100,6 +100,7 @@ impl<T: Sized> Exclusive<T> { /// Wrap a value in an `Exclusive` #[unstable(feature = "exclusive_wrapper", issue = "98407")] #[must_use] + #[inline] pub const fn new(t: T) -> Self { Self { inner: t } } @@ -107,6 +108,7 @@ impl<T: Sized> Exclusive<T> { /// Unwrap the value contained in the `Exclusive` #[unstable(feature = "exclusive_wrapper", issue = "98407")] #[must_use] + #[inline] pub const fn into_inner(self) -> T { self.inner } @@ -116,6 +118,7 @@ impl<T: ?Sized> Exclusive<T> { /// Get exclusive access to the underlying value. #[unstable(feature = "exclusive_wrapper", issue = "98407")] #[must_use] + #[inline] pub const fn get_mut(&mut self) -> &mut T { &mut self.inner } @@ -128,6 +131,7 @@ impl<T: ?Sized> Exclusive<T> { /// produce _pinned_ access to the underlying value. #[unstable(feature = "exclusive_wrapper", issue = "98407")] #[must_use] + #[inline] pub const fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut T> { // SAFETY: `Exclusive` can only produce `&mut T` if itself is unpinned // `Pin::map_unchecked_mut` is not const, so we do this conversion manually @@ -139,6 +143,7 @@ impl<T: ?Sized> Exclusive<T> { /// building an `Exclusive` with [`Exclusive::new`]. #[unstable(feature = "exclusive_wrapper", issue = "98407")] #[must_use] + #[inline] pub const fn from_mut(r: &'_ mut T) -> &'_ mut Exclusive<T> { // SAFETY: repr is ≥ C, so refs have the same layout; and `Exclusive` properties are `&mut`-agnostic unsafe { &mut *(r as *mut T as *mut Exclusive<T>) } @@ -149,6 +154,7 @@ impl<T: ?Sized> Exclusive<T> { /// building an `Exclusive` with [`Exclusive::new`]. #[unstable(feature = "exclusive_wrapper", issue = "98407")] #[must_use] + #[inline] pub const fn from_pin_mut(r: Pin<&'_ mut T>) -> Pin<&'_ mut Exclusive<T>> { // SAFETY: `Exclusive` can only produce `&mut T` if itself is unpinned // `Pin::map_unchecked_mut` is not const, so we do this conversion manually @@ -158,6 +164,7 @@ impl<T: ?Sized> Exclusive<T> { #[unstable(feature = "exclusive_wrapper", issue = "98407")] impl<T> From<T> for Exclusive<T> { + #[inline] fn from(t: T) -> Self { Self::new(t) } @@ -166,7 +173,7 @@ impl<T> From<T> for Exclusive<T> { #[unstable(feature = "exclusive_wrapper", issue = "98407")] impl<T: Future + ?Sized> Future for Exclusive<T> { type Output = T::Output; - + #[inline] fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { self.get_pin_mut().poll(cx) } |