Replace Linux Mutex and Condvar with futex based ones. by m-ou-se · Pull Request #95035 · rust-lang/rust (original) (raw)

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m-ou-se added the T-libs

Relevant to the library team, which will review and decide on the PR/issue.

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Mar 17, 2022

1 similar comment

m-ou-se marked this pull request as ready for review

March 23, 2022 14:12

joshtriplett added the relnotes

Marks issues that should be documented in the release notes of the next release.

label

Apr 14, 2022

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Apr 25, 2022

This was referenced

May 26, 2022

bors added a commit to rust-lang-ci/rust that referenced this pull request

Jun 19, 2022

Make {Mutex, Condvar, RwLock}::new() const.

This makes it possible to have static M: Mutex<_> = Mutex::new(..); 🎉

Our implementations on Linux, on Windows, and various BSDs and some tier 3 platforms have already been using a non-allocating const-constructible implementation. As of rust-lang#97647, the remaining platforms (most notably macOS) now have a const-constructible implementation as well. This means we can finally make these functions publicly const.

Tracking issue: rust-lang#93740

nnmm mentioned this pull request

Jul 4, 2022

wip-sync pushed a commit to NetBSD/pkgsrc-wip that referenced this pull request

Jul 12, 2022

yvt mentioned this pull request

Aug 14, 2022

yvt added a commit to r3-os/r3 that referenced this pull request

Aug 14, 2022

This drop call is intended to cut short the borrow 'a maintained by a reference-containing Mutex<&'a mut _>, but actually it's unnecessary because Mutex's contained data (&'a mut _) is not subject to drop check, hence the borrow is allowed to expire before the containing Mutex is dropped.

As for the drop_non_drop lint, I would say it's a false-positive because not every target supported by std has a trivial destructor for Mutex. This lint started to trigger only recently because rust-lang/rust#95035 replaced the Mutex implementation with a futex-based one on Linux.

yorickpeterse added a commit to inko-lang/inko that referenced this pull request

Aug 20, 2022

As of rust-lang/rust#95035, the locking API provided by std::sync is improved on Linux, outperforming parking_lot in various cases. Using the built-in locking APIs means we can remove parking_lot as a dependency, along with its own (indirect) dependencies; removing a total of 10 dependencies.

netbsd-srcmastr pushed a commit to NetBSD/pkgsrc that referenced this pull request

Aug 31, 2022

Pkgsrc changes:

• Bump required GCC to 7 (same as LLVM) to avoid ABI issues Fixes native i386 and powerpc 8.x build w/pkgsrc LLVM 14
• Bump available bootstraps to 1.61.0.
• Also unlimit stacksize
• Sync patches over from wip/rust
• Adjust line number in patches which had non-zero offsets.
• no longer pass -I/usr/pkg/include through via gcc-wrap script when building natively. Attempt at fixing version skew with curl package vs. internal version of curl (may not work...)
• The NetBSD bootstraps now use .xz compression.
• Use mk/atomic64.mk. Still have conditional for libatomic-links.
• Default to using the internal LLVM when cross-building.

Upstream changes:

Version 1.62.1 (2022-07-19)

Rust 1.62.1 addresses a few recent regressions in the compiler and standard library, and also mitigates a CPU vulnerability on Intel SGX.

• The compiler fixed unsound function coercions involving impl Trait return types.
• The compiler fixed an incremental compilation bug with async fn lifetimes.
• Windows added a fallback for overlapped I/O in synchronous reads and writes.
• The x86_64-fortanix-unknown-sgx target added a mitigation for the MMIO stale data vulnerability, advisory INTEL-SA-00615.

Version 1.62.0 (2022-06-30)

Language

• Stabilize #[derive(Default)] on enums with a #[default] variant
• Stop validating some checks in dead code after functions with uninhabited return types
• Fix constants not getting dropped if part of a diverging expression
• Support unit struct/enum variant in destructuring assignment
• Remove mutable_borrow_reservation_conflict lint and allow the code pattern

Compiler

• linker: Stop using whole-archive on dependencies of dylibs
• Make unaligned_references lint deny-by-default This lint is also a future compatibility lint, and is expected to eventually become a hard error.
• Only add codegen backend to dep info if -Zbinary-dep-depinfo is used
• Reject #[thread_local] attribute on non-static items
• Add tier 3 aarch64-pc-windows-gnullvm and x86_64-pc-windows-gnullvm targets*
• Implement a lint to warn about unused macro rules
• Promote x86_64-unknown-none target to Tier 2*

* Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support.

Libraries

• Move CStr to libcore, and CString to liballoc
• Windows: Use a pipe relay for chaining pipes
• Replace Linux Mutex and Condvar with futex based ones.
• Replace RwLock by a futex based one on Linux
• std: directly use pthread in UNIX parker implementation

Stabilized APIs

• bool::then_some
• f32::total_cmp
• f64::total_cmp
• Stdin::lines
• windows::CommandExt::raw_arg
• impl<T: Default> Default for AssertUnwindSafe<T>
• From<Rc<str>> for Rc<[u8]>
• From<Arc<str>> for Arc<[u8]>
• FusedIterator for EncodeWide
• RDM intrinsics on aarch64

Clippy

• Create clippy lint against unexpectedly late drop for temporaries in match scrutinee expressions

Cargo

• Added the cargo add command for adding dependencies to Cargo.toml from the command-line. docs
• Package ID specs now support name@version syntax in addition to the previous name:version to align with the behavior in cargo add and other tools. cargo install and cargo yank also now support this syntax so the version does not need to passed as a separate flag.
• The git and registry directories in Cargo's home directory (usually ~/.cargo) are now marked as cache directories so that they are not included in backups or content indexing (on Windows).
• Added automatic @ argfile support, which will use "response files" if the command-line to rustc exceeds the operating system's limit.

Compatibility Notes

• cargo test now passes --target to rustdoc if the specified target is the same as the host target. #10594
• rustdoc: Remove .woff font files
• Enforce Copy bounds for repeat elements while considering lifetimes

Internal Changes

• Unify ReentrantMutex implementations across all platforms

These changes provide no direct user facing benefits, but represent significant improvements to the internals and overall performance of rustc and related tools.

Version 1.61.0 (2022-05-19)

Language

• const fn signatures can now include generic trait bounds
• const fn signatures can now use impl Trait in argument and return position
• Function pointers can now be created, cast, and passed around in a const fn
• Recursive calls can now set the value of a function's opaque impl Trait return type

Compiler

• Linking modifier syntax in #[link] attributes and on the command line, as well as the whole-archive modifier specifically, are now supported
• The char type is now described as UTF-32 in debuginfo
• The #[target_feature] attribute can now be used with aarch64 features
• X86 #[target_feature = "adx"] is now stable

Libraries

• ManuallyDrop<T> is now documented to have the same layout as T
• #[ignore = "#"] messages are printed when running tests
• Consistently show absent stdio handles on Windows as NULL handles
• Make std::io::stdio::lock() return 'static handles. Previously, the creation of locked handles to stdin/stdout/stderr would borrow the handles being locked, which prevented writing let out = std::io::stdout().lock(); because out would outlive the return value of stdout(). Such code now works, eliminating a common pitfall that affected many Rust users.
• Vec::from_raw_parts is now less restrictive about its inputs
• std::thread::available_parallelism now takes cgroup quotas into account. Since available_parallelism is often used to create a thread pool for parallel computation, which may be CPU-bound for performance, available_parallelism will return a value consistent with the ability to use that many threads continuously, if possible. For instance, in a container with 8 virtual CPUs but quotas only allowing for 50% usage, available_parallelism will return 4.

Stabilized APIs

• Pin::static_mut
• Pin::static_ref
• Vec::retain_mut
• VecDeque::retain_mut
• Write for Cursor<[u8; N]>
• std::os::unix:🥅:SocketAddr::from_pathname
• std::process::ExitCode and std::process::Termination. The stabilization of these two API s now makes it possible for programs to return errors from main with custom exit codes.
• std::thread::JoinHandle::is_finished

These APIs are now usable in const contexts:

• <*const T>::offset and <*mut T>::offset
• [<*const T>::wrapping_offset and <*mut T>::wrapping_offset] ptr-wrapping_offset
• <*const T>::add and <*mut T>::add
• <*const T>::sub and <*mut T>::sub
• <*const T>::wrapping_add and <*mut T>::wrapping_add
• <*const T>::wrapping_sub and <*mut T>::wrapping_sub
• <[T]>::as_mut_ptr
• <[T]>::as_ptr_range
• <[T]>::as_mut_ptr_range

Cargo

No feature changes, but see compatibility notes.

Compatibility Notes

• Previously native static libraries were linked as whole-archive in some cases, but now rustc tries not to use whole-archive unless explicitly requested. This change may result in linking errors in some cases. To fix such errors, native libraries linked from the command line, build scripts, or #[link] attributes need to
  • (more common) either be reordered to respect dependencies between them (if a depends on b then a should go first and b second)
  • (less common) or be updated to use the +whole-archive modifier.
• Catching a second unwind from FFI code while cleaning up from a Rust panic now causes the process to abort
• Proc macros no longer see ident matchers wrapped in groups
• The number of # in r# raw string literals is now required to be less than 256
• When checking that a dyn type satisfies a trait bound, supertrait bounds are now enforced
• [cargo vendor now only accepts one value for each --sync flag] cargo/10448
• cfg predicates in all() and any() are always evaluated to detect errors, instead of short-circuiting. The compatibility considerations here arise in nightly-only code that used the short-circuiting behavior of all to write something like cfg(all(feature = "nightly", syntax-requiring-nightly)), which will now fail to compile. Instead, use either cfg_attr(feature = "nightly", ...) or nested uses of cfg.
• bootstrap: static-libstdcpp is now enabled by default, and can now be disabled when llvm-tools is enabled

Internal Changes

These changes provide no direct user facing benefits, but represent significant improvements to the internals and overall performance of rustc and related tools.

• debuginfo: Refactor debuginfo generation for types
• Remove the everybody loops pass

workingjubilee pushed a commit to tcdi/postgrestd that referenced this pull request

Sep 15, 2022

Make {Mutex, Condvar, RwLock}::new() const.

This makes it possible to have static M: Mutex<_> = Mutex::new(..); 🎉

Our implementations on Linux, on Windows, and various BSDs and some tier 3 platforms have already been using a non-allocating const-constructible implementation. As of rust-lang/rust#97647, the remaining platforms (most notably macOS) now have a const-constructible implementation as well. This means we can finally make these functions publicly const.

Tracking issue: rust-lang/rust#93740

Tpt mentioned this pull request

Sep 22, 2022

gz mentioned this pull request

Jun 24, 2024