Messages in this thread | | | Subject | Re: [PATCH v2 net-next 4/4] bpftool: implement cgroup bpf operations | From | David Ahern <> | Date | Fri, 8 Dec 2017 09:52:16 -0700 |
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On 12/8/17 8:39 AM, Quentin Monnet wrote: > I don't believe compatibility is an issue here, since the program and > its documentation come together (so they should stay in sync) and are > part of the kernel tree (so the tool should be compatible with the > kernel sources it comes with). My concern is that there is no way to > guess from the current description what the values for ATTACH_FLAG or > ATTACH_TYPE can be, without reading the source code of the program—which > is not exactly user-friendly. >
The tool should be backward and forward compatible across kernel versions. Running a newer command on an older kernel should fail in a deterministic. While the tool is in the kernel tree for ease of development, that should not be confused with having a direct tie to any kernel version.
I believe man pages do include kernel version descriptions in flags (e.g., man 7 socket -- flags are denoted with "since Linux x.y") which is one way to handle it with the usual caveat that vendors might have backported support to earlier kernels.
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