Fix undetected pinned element in advance_hot #96
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ihtefyw
changed the title
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Thanks for the PR. We probably want to think of a cheaper way, as building a hashset on that code path is very costly. I'll give this a think |
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Superseded by #98 |
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In
advance_hot, if an element is concurrently marked as pinned right after theis_pinnedfunction return false (line 738), the function will loop forever if every element is pinned as unpinned cannot decrement, i.e. the function doesn't detect that the element was pinned in the meantime.This can happen if the element pinning logic is independent of the cache data structure.
This PR fixes this by storing which key is marked as unpinned, and clearing it if it gets pinned in the meantime.