3.9. Handling Edge Cases

3.9.1. Allocations exceeding claims

When an allocation exceeds the domain’s claims, the allocator must check whether unclaimed memory can satisfy the remainder of the request before rejecting the allocation.

Previously, if a domain’s remaining claim did not fully cover a request, the allocator rejected the allocation even when enough unclaimed memory existed to satisfy it.

This forced the meminit API to fall back from 1G pages to 2M and eventually to 4K pages, reducing performance due to higher TLB pressure and increased page bookkeeping.

Supporting the use of unclaimed memory to satisfy the remainder of the request in such cases lets builders continue to use large pages when the combination of claims and unclaimed memory allows it, possibly improving runtime performance in such scenarios.