63a90efe2f
`min_stack` does not provide any synchronization guarantees to its callers, and only requires atomicity for `MIN` itself, so relaxed memory ordering is sufficient.
19 lines
566 B
Rust
19 lines
566 B
Rust
use crate::env;
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use crate::sync::atomic::{self, Ordering};
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use crate::sys::thread as imp;
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pub fn min_stack() -> usize {
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static MIN: atomic::AtomicUsize = atomic::AtomicUsize::new(0);
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match MIN.load(Ordering::Relaxed) {
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0 => {}
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n => return n - 1,
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}
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let amt = env::var("RUST_MIN_STACK").ok().and_then(|s| s.parse().ok());
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let amt = amt.unwrap_or(imp::DEFAULT_MIN_STACK_SIZE);
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// 0 is our sentinel value, so ensure that we'll never see 0 after
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// initialization has run
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MIN.store(amt + 1, Ordering::Relaxed);
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amt
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}
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