In Oracle Linux, physical memory is managed in fixed-size blocks called pages. In the x86_64 architecture, the default size of each page is 4 KB.

The kernel stores virtual to physical address mappings for the pages in a data structure known as the page table. However, page table lookups are resource-intensive, so the most recently used addresses are cached in the CPU’s Translation Lookaside Buffer (TLB) for faster retrieval. When the CPU needs to fulfill a request for an address-mapping, the CPU first searches the TLB cache. A TLB hit describes the CPU finding the address in the TLB cache. A TLB miss describes the CPU unable to find the requested address-mapping in the cache, in which case the system would perform a resource intensive lookup on the page table to retrieve the address information.

The default page size of 4 KB is suitable for most applications. However, for applications that work with large amounts of memory, the number of 4 KB pages required can be large and can lead to a high number of TLB misses and a performance overhead. Oracle Linux provides huge page features so that applications requiring more memory can have their requirements fulfilled with fewer pages.