From 277f05872f8d5c0dfc0da29d5a67cc01961c8bf2 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= Date: Tue, 5 Apr 2022 10:24:27 +0200 Subject: README: say kernel 4.15 is the minimum recommended After various long discussions (https://lists.freedesktop.org/archives/systemd-devel/2022-March/047587.html, https://lwn.net/Articles/889610/), there is no clear answer what the minimum version should be. Bumping the version above 3.15 doesn't allow us to make any significant simplifications (unless we went *much* higher). In particular, even renameat2() is not fully supported with latest kernel versions, e.g. nfs still doesn't have it. And the bpf stuff is optional anyway. So let's just say that 4.15 is what we recommend, because it provides fairly complete cgroups-v2, but without any removals of compat in the code. --- README | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) (limited to 'README') diff --git a/README b/README index 420276eda8..06c54e04d7 100644 --- a/README +++ b/README @@ -30,14 +30,21 @@ LICENSE: LGPL-2.1-or-later for all code, exceptions noted in LICENSES/README.md REQUIREMENTS: - Linux kernel >= 3.15 - Linux kernel >= 4.2 for unified cgroup hierarchy support - Linux kernel >= 4.10 for cgroup-bpf egress and ingress hooks - Linux kernel >= 4.15 for cgroup-bpf device hook - Linux kernel >= 4.17 for cgroup-bpf socket address hooks - Linux kernel >= 5.3 for bounded-loops in BPF program - Linux kernel >= 5.4 for signed Verity images support - Linux kernel >= 5.7 for BPF links and the BPF LSM hook + Linux kernel ≥ 3.15 + ≥ 4.5 for pids controller in cgroup v2 + ≥ 4.6 for cgroup namespaces + ≥ 4.9 for RENAME_NOREPLACE support in vfat + ≥ 4.10 for cgroup-bpf egress and ingress hooks + ≥ 4.15 for cgroup-bpf device hook and cpu controller in cgroup v2 + ≥ 4.17 for cgroup-bpf socket address hooks + ≥ 5.3 for bounded loops in BPF program + ≥ 5.4 for signed Verity images + ≥ 5.7 for BPF links and the BPF LSM hook + + Kernel versions below 4.15 have significant gaps in functionality and + are not recommended for use with this version of systemd. Taint flag + 'old-kernel' will be set. Systemd will most likely still function, but + upstream support and testing are limited. Kernel Config Options: CONFIG_DEVTMPFS -- cgit v1.2.1