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| author | John Kåre Alsaker <john.kare.alsaker@gmail.com> | 2023-05-28 15:54:52 +0200 |
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| committer | John Kåre Alsaker <john.kare.alsaker@gmail.com> | 2023-05-28 15:54:52 +0200 |
| commit | 8abafd085aab9b703711b49d02b66910c8c2d739 (patch) | |
| tree | d9e497e6a05d1d94668c14fa3693a685208ff486 | |
| parent | 5843858c015614c92515f317ce93796c885ca2cf (diff) | |
| download | rust-8abafd085aab9b703711b49d02b66910c8c2d739.tar.gz rust-8abafd085aab9b703711b49d02b66910c8c2d739.zip | |
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| -rw-r--r-- | compiler/rustc_data_structures/src/sharded.rs | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/compiler/rustc_data_structures/src/sharded.rs b/compiler/rustc_data_structures/src/sharded.rs index 9f5c97ae798..40cbf14958e 100644 --- a/compiler/rustc_data_structures/src/sharded.rs +++ b/compiler/rustc_data_structures/src/sharded.rs @@ -20,6 +20,9 @@ pub const SHARDS: usize = 1 << SHARD_BITS; /// An array of cache-line aligned inner locked structures with convenience methods. pub struct Sharded<T> { + /// This mask is used to ensure that accesses are inbounds of `shards`. + /// When dynamic thread safety is off, this field is set to 0 causing only + /// a single shard to be used for greater cache efficiency. #[cfg(parallel_compiler)] mask: usize, shards: [CacheAligned<Lock<T>>; SHARDS], @@ -56,6 +59,7 @@ impl<T> Sharded<T> { #[inline(always)] fn count(&self) -> usize { + // `self.mask` is always one below the used shard count self.mask() + 1 } |