To help you understand this better, we'll show an example via screenshots in this section. Implement the following steps:
- Firstly, ensure you enable the CONFIG_SLUB_DEBUG kernel config (it should be set to y; this is typically the case on distro kernels)
- Next, boot the system while including the kernel command-line slub_debug= directive (this turns on full SLUB debug; or you could pass a finer granularity variant such as slub_debug=FZPU (see the kernel documentation here for an explanation of each field: https://www.kernel.org/doc/Documentation/vm/slub.txt); as a demo, on my Fedora 31 guest VM, I passed the kernel command line as follows - the important thing here, the slub_debug=FZPU is highlighted in bold font:
$ cat /proc/cmdline
BOOT_IMAGE=(hd0,msdos1)/vmlinuz-5.4.0-llkd01 root=/dev/mapper/fedora_localhost--live-root ro resume=/dev/mapper/fedora_localhost--live-swap rd.lvm.lv=fedora_localhost-live...