Adds code and documentation to rectify potential memory leaks in LinkedListAllocator #1182
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seewishnew
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I am not sure if this was a design decision to keep things simple for the sake of the blog post implementation of the
LinkedListAllocator, but the currentalloc_from_regionmethod can fail to keep track of free unused heap areas that are created due to misalignment between the freeregionand the layout request.In x86_64, this can only happen if the layout request was for an alignment of 16 bytes and the
regionhappened to start in the middle of this alignment, at some address16*n + 8. The current behavior would "leak" the 8 bytes between16*n + 8and16*(n+1)and never attempt to reclaim those regions even upon deallocation.It seemed simple enough to ensure that we leave enough room in the beginning for at least another
ListNode, following a similar approach in thelinked_list_allocatorcrate.This PR also adds a pretty simple test case to ensure we are not "leaking" these excess bytes on either end.