It’s looking like Linux 6.15 will be the kernel that does away with the Z3fold and Zbud allocators.
It shouldn’t be too surprising given that these compressed page allocators were already deprecated and slated for removal. The removal patches are now picked up by Andrew Morton’s “MM” patch flow and thus likely material for Linux 6.15 barring any last minute objections from being raised.
Zbud as a reminder is a special purpose allocator for storing compressed pages. Zbud can achieve storing up to two compressed pages per physical page. Z3fold as a derivative of Zbud is a compressed page allocator that can allow storing up to three compressed pages per physical page.
Zbud and Z3fold have been deprecated though since Linux 6.13 as they are rarely used. Users though should turn to zsmalloc instead. Zsmalloc used to have worse latency than Zbud/Z3fold but that is no longer the case and these deprecated allocators consume much more memory.
This patch drops Z3fold and this patch drops Zbud. Unless any good reasons come up for keeping the roughly two thousand lines of code around, they are expected to be dropped during the Linux 6.15 merge window.
