Michał Chojnowski 7f9152babc utils/lsa/chunked_managed_vector: fix the calculation of max_chunk_capacity() ...

`chunked_managed_vector` is a vector-like container which splits
its contents into multiple contiguous allocations if necessary,
in order to fit within LSA's max preferred contiguous allocation
limits.

Each limited-size chunk is stored in a `managed_vector`.
`managed_vector` is unaware of LSA's size limits.
It's up to the user of `managed_vector` to pick a size which
is small enough.

This happens in `chunked_managed_vector::max_chunk_capacity()`.
But the calculation is wrong, because it doesn't account for
the fact that `managed_vector` has to place some metadata
(the backreference pointer) inside the allocation.
In effect, the chunks allocated by `chunked_managed_vector`
are just a tiny bit larger than the limit, and the limit is violated.

Fix this by accounting for the metadata.

Also, before the patch `chunked_managed_vector::max_contiguous_allocation`,
repeats the definition of logalloc::max_managed_object_size.
This is begging for a bug if `logalloc::max_managed_object_size`
changes one day. Adjust it so that `chunked_managed_vector` looks
directly at `logalloc::max_managed_object_size`, as it means to.

2025-04-28 12:30:13 +02:00

7.5 KiB

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