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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:03:36 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:03:36 +0000
commit17d40c6057c88f4c432b0d7bac88e1b84cb7e67f (patch)
tree3f66c4a5918660bb8a758ab6cda5ff8ee4f6cdcd /src/tools/clippy/src/docs/missing_spin_loop.txt
parentAdding upstream version 1.64.0+dfsg1. (diff)
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Adding upstream version 1.65.0+dfsg1.upstream/1.65.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+### What it does
+Check for empty spin loops
+
+### Why is this bad?
+The loop body should have something like `thread::park()` or at least
+`std::hint::spin_loop()` to avoid needlessly burning cycles and conserve
+energy. Perhaps even better use an actual lock, if possible.
+
+### Known problems
+This lint doesn't currently trigger on `while let` or
+`loop { match .. { .. } }` loops, which would be considered idiomatic in
+combination with e.g. `AtomicBool::compare_exchange_weak`.
+
+### Example
+
+```
+use core::sync::atomic::{AtomicBool, Ordering};
+let b = AtomicBool::new(true);
+// give a ref to `b` to another thread,wait for it to become false
+while b.load(Ordering::Acquire) {};
+```
+Use instead:
+```
+while b.load(Ordering::Acquire) {
+ std::hint::spin_loop()
+}
+``` \ No newline at end of file