Type Isolation in Kernel Allocators: Linux SLUB vs XNU Zones
Status: draft in progress Overview This article compares two allocator designs: Linux SLUB, which can merge compatible caches of similar-sized objects. XNU zones, which keep allocation domains separated by zone. The article is not meant to argue that one design is simply better than the other. The goal is to understand the tradeoff. SLUB’s cache merging can reduce memory overhead and allocator complexity. XNU’s zone isolation gives stronger type separation. Both choices make sense in context, and both have security and engineering consequences. ...