fix: use conservative bucket reuse that survives reload#394
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maksymar
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michael-weigelt
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maksymar
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This PR reverts adding `reclaim_memory` method. Reverts several recent commits in a single change: - `6e397bd` fix: use conservative bucket reuse that survives reload #394 - `00468e1` docs: update memory reclamation examples in the docs #392 - `b911479` docs: cleanup documentation #391 - `d1fde89` docs: use reclaim_memory() name and update docs accordingly #388 - `a18917b` docs: add safety documentation and tests for manual bucket release #387 - `73e96e8` feat: add manual bucket release to prevent memory waste #386 This PR restores the codebase to the state before these commits. Done with `git revert -n 6e397bd 00468e1 b911479 d1fde89 a18917b 73e96e8` The reason for reverting this approach was that it can reclaim unused memory in theory but provides little benefit in real-world migrations. All due to the requirement to keep buckets in ascending order in each VM. Example 1: Reuse works ``` A allocates: [0, 4, 5] B allocates: [1, 2, 3] A frees: [0, 4, 5] B grows: can reuse bucket 4 (since 4 > max(B) = 3) B after grow: [1, 2, 3, 4] ``` Example 2: Reuse fails ``` A allocates: [0, 1, 2] B allocates: [4, 5, 6] A frees: [0, 1, 2] B grows: cannot reuse any freed bucket (all < max(B) = 6), so allocates new bucket 7 B after grow: [4, 5, 6, 7] ``` In real life when migrating state A to state B, state B created after state A grown, so it's first bucket ID is already higher than any free bucket in state A virtual memory, therefore can not be reused.
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This PR uses conservative bucket reuse to preserve ordering across reloads.
Problem
Previously, a memory with buckets
[5, 6, 7]could reuse free buckets[0, 1, 2], producing[5, 6, 7, 0, 1, 2]. On reload, the manager reads buckets in ascending order —[0, 1, 2, 5, 6, 7]— corrupting the structure.Fix
When growing a memory, reuse only free buckets with IDs greater than the memory’s current max; otherwise allocate a new bucket. This keeps per-memory bucket IDs strictly ascending across lifetimes.
Guarantees
Result
A conservative reuse algorithm that maintains stable-structure consistency after reloads.