VOOZH about

URL: https://www.phoronix.com/news/Linux-Dropping-Zbud-Z3fold

⇱ Z3fold & Zbud Allocators Likely To Be Removed In Linux 6.15 - Phoronix


👁 Phoronix

Z3fold & Zbud Allocators Likely To Be Removed In Linux 6.15

Written by Michael Larabel in Linux Kernel on 21 February 2025 at 06:42 AM EST. 4 Comments
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.

👁 Removal patches


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.

Michael Larabel is the principal author of Phoronix.com and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via MichaelLarabel.com.