From: Yonghong Song <yhs@fb.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Andrii Nakryiko <andriin@fb.com>, bpf <bpf@vger.kernel.org>,
Martin KaFai Lau <kafai@fb.com>,
Networking <netdev@vger.kernel.org>,
Alexei Starovoitov <ast@fb.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Kernel Team <kernel-team@fb.com>
Subject: Re: [PATCH bpf-next v3 03/21] bpf: support bpf tracing/iter programs for BPF_LINK_CREATE
Date: Fri, 8 May 2020 18:36:10 -0700 [thread overview]
Message-ID: <849a051d-5c42-a61c-91ef-15a2bdb2b509@fb.com> (raw)
In-Reply-To: <CAEf4BzaV6u1eTta4h4+mftQCQVOGPf0Q++B8tZxho+Uq3M1=mA@mail.gmail.com>
On 5/8/20 11:24 AM, Andrii Nakryiko wrote:
> On Wed, May 6, 2020 at 10:41 PM Yonghong Song <yhs@fb.com> wrote:
>>
>> Given a bpf program, the step to create an anonymous bpf iterator is:
>> - create a bpf_iter_link, which combines bpf program and the target.
>> In the future, there could be more information recorded in the link.
>> A link_fd will be returned to the user space.
>> - create an anonymous bpf iterator with the given link_fd.
>>
>> The bpf_iter_link can be pinned to bpffs mount file system to
>> create a file based bpf iterator as well.
>>
>> The benefit to use of bpf_iter_link:
>> - using bpf link simplifies design and implementation as bpf link
>> is used for other tracing bpf programs.
>> - for file based bpf iterator, bpf_iter_link provides a standard
>> way to replace underlying bpf programs.
>> - for both anonymous and free based iterators, bpf link query
>> capability can be leveraged.
>>
>> The patch added support of tracing/iter programs for BPF_LINK_CREATE.
>> A new link type BPF_LINK_TYPE_ITER is added to facilitate link
>> querying. Currently, only prog_id is needed, so there is no
>> additional in-kernel show_fdinfo() and fill_link_info() hook
>> is needed for BPF_LINK_TYPE_ITER link.
>>
>> Acked-by: Andrii Nakryiko <andriin@fb.com>
>> Signed-off-by: Yonghong Song <yhs@fb.com>
>> ---
>
> still looks good, but I realized show_fdinfo and fill_link_info is
> missing, see request for a follow-up below :)
>
>
>> include/linux/bpf.h | 1 +
>> include/linux/bpf_types.h | 1 +
>> include/uapi/linux/bpf.h | 1 +
>> kernel/bpf/bpf_iter.c | 62 ++++++++++++++++++++++++++++++++++
>> kernel/bpf/syscall.c | 14 ++++++++
>> tools/include/uapi/linux/bpf.h | 1 +
>> 6 files changed, 80 insertions(+)
>>
>
> [...]
>
>> +static const struct bpf_link_ops bpf_iter_link_lops = {
>> + .release = bpf_iter_link_release,
>> + .dealloc = bpf_iter_link_dealloc,
>> +};
>
> Link infra supports .show_fdinfo and .fill_link_info methods, there is
> no need to block on this, but it would be great to implement them from
> BPF_LINK_TYPE_ITER as well in the same release as a follow-up. Thanks!
The reason I did not implement is due to we do not have additional
information beyond prog_id to present. The prog_id itself gives all
information about this link. I looked at tracing program
show_fdinfo/fill_link_info, the additional attach_type is printed.
But attach_type is obvious for BPF_LINK_TYPE_ITER which does not
need print.
In the future when we add more stuff to parameterize the bpf_iter,
will need to implement these two callbacks as well as bpftool.
>
>
> [...]
>
next prev parent reply other threads:[~2020-05-09 1:36 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-07 5:39 [PATCH bpf-next v3 00/21] bpf: implement bpf iterator for kernel data Yonghong Song
2020-05-07 5:39 ` [PATCH bpf-next v3 01/21] bpf: implement an interface to register bpf_iter targets Yonghong Song
2020-05-08 18:18 ` Andrii Nakryiko
2020-05-07 5:39 ` [PATCH bpf-next v3 02/21] bpf: allow loading of a bpf_iter program Yonghong Song
2020-05-08 18:20 ` Andrii Nakryiko
2020-05-07 5:39 ` [PATCH bpf-next v3 03/21] bpf: support bpf tracing/iter programs for BPF_LINK_CREATE Yonghong Song
2020-05-08 18:24 ` Andrii Nakryiko
2020-05-09 1:36 ` Yonghong Song [this message]
2020-05-12 3:15 ` Andrii Nakryiko
2020-05-13 16:57 ` Yonghong Song
2020-05-07 5:39 ` [PATCH bpf-next v3 04/21] bpf: support bpf tracing/iter programs for BPF_LINK_UPDATE Yonghong Song
2020-05-07 5:39 ` [PATCH bpf-next v3 05/21] bpf: implement bpf_seq_read() for bpf iterator Yonghong Song
2020-05-08 18:52 ` Andrii Nakryiko
2020-05-09 1:41 ` Yonghong Song
2020-05-07 5:39 ` [PATCH bpf-next v3 06/21] bpf: create anonymous " Yonghong Song
2020-05-08 18:57 ` Andrii Nakryiko
2020-05-07 5:39 ` [PATCH bpf-next v3 07/21] bpf: create file " Yonghong Song
2020-05-07 5:39 ` [PATCH bpf-next v3 08/21] bpf: implement common macros/helpers for target iterators Yonghong Song
2020-05-08 19:07 ` Andrii Nakryiko
2020-05-09 3:18 ` Yonghong Song
2020-05-12 3:16 ` Andrii Nakryiko
2020-05-07 5:39 ` [PATCH bpf-next v3 09/21] bpf: add bpf_map iterator Yonghong Song
2020-05-07 5:39 ` [PATCH bpf-next v3 10/21] net: bpf: add netlink and ipv6_route bpf_iter targets Yonghong Song
2020-05-08 19:17 ` Andrii Nakryiko
2020-05-07 5:39 ` [PATCH bpf-next v3 11/21] bpf: add task and task/file iterator targets Yonghong Song
2020-05-08 19:36 ` Andrii Nakryiko
2020-05-07 5:39 ` [PATCH bpf-next v3 12/21] bpf: add PTR_TO_BTF_ID_OR_NULL support Yonghong Song
2020-05-07 5:39 ` [PATCH bpf-next v3 13/21] bpf: add bpf_seq_printf and bpf_seq_write helpers Yonghong Song
2020-05-08 19:44 ` Andrii Nakryiko
2020-05-09 4:18 ` Yonghong Song
2020-05-09 5:30 ` Alexei Starovoitov
2020-05-09 6:04 ` Yonghong Song
2020-05-07 5:39 ` [PATCH bpf-next v3 14/21] bpf: handle spilled PTR_TO_BTF_ID properly when checking stack_boundary Yonghong Song
2020-05-07 5:39 ` [PATCH bpf-next v3 15/21] bpf: support variable length array in tracing programs Yonghong Song
2020-05-07 5:39 ` [PATCH bpf-next v3 16/21] tools/libbpf: add bpf_iter support Yonghong Song
2020-05-08 19:46 ` Andrii Nakryiko
2020-05-07 5:39 ` [PATCH bpf-next v3 17/21] tools/libpf: add offsetof/container_of macro in bpf_helpers.h Yonghong Song
2020-05-08 19:48 ` Andrii Nakryiko
2020-05-07 5:39 ` [PATCH bpf-next v3 18/21] tools/bpftool: add bpf_iter support for bptool Yonghong Song
2020-05-08 19:51 ` Andrii Nakryiko
2020-05-09 5:26 ` Yonghong Song
2020-05-07 5:39 ` [PATCH bpf-next v3 19/21] tools/bpf: selftests: add iterator programs for ipv6_route and netlink Yonghong Song
2020-05-07 5:39 ` [PATCH bpf-next v3 20/21] tools/bpf: selftests: add iter progs for bpf_map/task/task_file Yonghong Song
2020-05-07 5:39 ` [PATCH bpf-next v3 21/21] tools/bpf: selftests: add bpf_iter selftests Yonghong Song
2020-05-08 19:57 ` Andrii Nakryiko
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