Make {Mutex, Condvar, RwLock}::new() const. by m-ou-se · Pull Request #97791 · rust-lang/rust (original) (raw)
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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 #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: #93740
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This change is insta-stable, so needs a completed FCP to proceed.
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🔔 This is now entering its final comment period, as per the review above. 🔔
The final comment period, with a disposition to merge, as per the review above, is now complete.
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This will be merged soon.
📌 Commit edae495 has been approved by m-ou-se
Status: Waiting on bors to run and complete tests. Bors will change the label on completion.
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Finished benchmarking commit (15fc228): comparison url.
Instruction count
- Primary benchmarks: no relevant changes found
- Secondary benchmarks: 🎉 relevant improvement found
| mean1 | max | count2 | |
|---|---|---|---|
| Regressions 😿 (primary) | N/A | N/A | 0 |
| Regressions 😿 (secondary) | N/A | N/A | 0 |
| Improvements 🎉 (primary) | N/A | N/A | 0 |
| Improvements 🎉 (secondary) | -1.7% | -1.7% | 1 |
| All 😿🎉 (primary) | N/A | N/A | 0 |
Max RSS (memory usage)
Results
- Primary benchmarks: 😿 relevant regression found
- Secondary benchmarks: no relevant changes found
| mean1 | max | count2 | |
|---|---|---|---|
| Regressions 😿 (primary) | 0.0% | 0.0% | 1 |
| Regressions 😿 (secondary) | N/A | N/A | 0 |
| Improvements 🎉 (primary) | N/A | N/A | 0 |
| Improvements 🎉 (secondary) | N/A | N/A | 0 |
| All 😿🎉 (primary) | 0.0% | 0.0% | 1 |
Cycles
Results
- Primary benchmarks: 🎉 relevant improvement found
- Secondary benchmarks: 🎉 relevant improvement found
| mean1 | max | count2 | |
|---|---|---|---|
| Regressions 😿 (primary) | N/A | N/A | 0 |
| Regressions 😿 (secondary) | N/A | N/A | 0 |
| Improvements 🎉 (primary) | -3.3% | -3.3% | 1 |
| Improvements 🎉 (secondary) | -2.3% | -2.3% | 1 |
| All 😿🎉 (primary) | -3.3% | -3.3% | 1 |
If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.
@rustbot label: -perf-regression
Footnotes
japaric added a commit to japaric/cargo-call-stack that referenced this pull request
This was referenced
Jun 22, 2022
bors added a commit to rust-lang-ci/rust that referenced this pull request
make Condvar, Mutex, RwLock const constructors work with the unsupported impl
applying this patch locally to the rust-src component fixes rust-lang#98378
however, the solution seems wrong to me because PR rust-lang#97791 didn't add any rustc_const_stable attribute to underlying implementations like std::sys::unix::futex, so I must be missing something about how const-stability is checked ... maybe the restricted_std feature (gate?) has an effect?
fixes rust-lang#98378 fixes rust-lang#98293 (probably)
It raised my eyebrows when static mutex just worked, that's how I found this page! Holy shit, great work! 💪
bors added a commit to rust-lang-ci/rust that referenced this pull request
…lnay
Make Barrier::new() const
I guess this was just missed in rust-lang#97791?
@rustbot label T-libs-api -T-libs
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Status: Waiting on bors to run and complete tests. Bors will change the label on completion.
Status: PR is in FCP and is awaiting for FCP to complete.
Relevant to the library API team, which will review and decide on the PR/issue.