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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Jiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andriin@fb.com>,
	"Steven Rostedt (VMware)" <rostedt@goodmis.org>,
	Network Development <netdev@vger.kernel.org>,
	bpf <bpf@vger.kernel.org>, Martin KaFai Lau <kafai@fb.com>,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>, Daniel Xu <dxu@dxuuu.xyz>,
	Viktor Malik <vmalik@redhat.com>
Subject: Re: [PATCH 13/19] bpf: Add support to link multi func tracing program
Date: Tue, 8 Jun 2021 08:42:32 -0700	[thread overview]
Message-ID: <CAADnVQJV+0SjqUrTw+3Y02tFedcAaPKJS-W8sQHw5YT4XUW0hQ@mail.gmail.com> (raw)
In-Reply-To: <20210605111034.1810858-14-jolsa@kernel.org>

On Sat, Jun 5, 2021 at 4:11 AM Jiri Olsa <jolsa@kernel.org> wrote:
>
> Adding support to attach multiple functions to tracing program
> by using the link_create/link_update interface.
>
> Adding multi_btf_ids/multi_btf_ids_cnt pair to link_create struct
> API, that define array of functions btf ids that will be attached
> to prog_fd.
>
> The prog_fd needs to be multi prog tracing program (BPF_F_MULTI_FUNC).
>
> The new link_create interface creates new BPF_LINK_TYPE_TRACING_MULTI
> link type, which creates separate bpf_trampoline and registers it
> as direct function for all specified btf ids.
>
> The new bpf_trampoline is out of scope (bpf_trampoline_lookup) of
> standard trampolines, so all registered functions need to be free
> of direct functions, otherwise the link fails.

Overall the api makes sense to me.
The restriction of multi vs non-multi is too severe though.
The multi trampoline can serve normal fentry/fexit too.
If ip is moved to the end (instead of start) the trampoline
will be able to call into multi and normal fentry/fexit progs. Right?

  parent reply	other threads:[~2021-06-08 15:43 UTC|newest]

Thread overview: 76+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-05 11:10 [RFCv3 00/19] x86/ftrace/bpf: Add batch support for direct/tracing attach Jiri Olsa
2021-06-05 11:10 ` [PATCH 01/19] x86/ftrace: Remove extra orig rax move Jiri Olsa
2021-06-05 11:10 ` [PATCH 02/19] x86/ftrace: Remove fault protection code in prepare_ftrace_return Jiri Olsa
2021-06-05 11:10 ` [PATCH 03/19] x86/ftrace: Make function graph use ftrace directly Jiri Olsa
2021-06-08 18:35   ` Andrii Nakryiko
2021-06-08 18:51     ` Jiri Olsa
2021-06-08 19:11       ` Steven Rostedt
2021-06-05 11:10 ` [PATCH 04/19] tracing: Add trampoline/graph selftest Jiri Olsa
2021-06-05 11:10 ` [PATCH 05/19] ftrace: Add ftrace_add_rec_direct function Jiri Olsa
2021-06-05 11:10 ` [PATCH 06/19] ftrace: Add multi direct register/unregister interface Jiri Olsa
2021-06-05 11:10 ` [PATCH 07/19] ftrace: Add multi direct modify interface Jiri Olsa
2021-06-05 11:10 ` [PATCH 08/19] ftrace/samples: Add multi direct interface test module Jiri Olsa
2021-06-05 11:10 ` [PATCH 09/19] bpf, x64: Allow to use caller address from stack Jiri Olsa
2021-06-07  3:07   ` Yonghong Song
2021-06-07 18:13     ` Jiri Olsa
2021-06-05 11:10 ` [PATCH 10/19] bpf: Allow to store caller's ip as argument Jiri Olsa
2021-06-07  3:21   ` Yonghong Song
2021-06-07 18:15     ` Jiri Olsa
2021-06-08 18:49   ` Andrii Nakryiko
2021-06-08 20:58     ` Jiri Olsa
2021-06-08 21:02       ` Andrii Nakryiko
2021-06-08 21:11         ` Jiri Olsa
2021-06-05 11:10 ` [PATCH 11/19] bpf: Add support to load multi func tracing program Jiri Olsa
2021-06-07  3:56   ` Yonghong Song
2021-06-07 18:18     ` Jiri Olsa
2021-06-07 19:35       ` Yonghong Song
2021-06-05 11:10 ` [PATCH 12/19] bpf: Add bpf_trampoline_alloc function Jiri Olsa
2021-06-05 11:10 ` [PATCH 13/19] bpf: Add support to link multi func tracing program Jiri Olsa
2021-06-07  5:36   ` Yonghong Song
2021-06-07 18:25     ` Jiri Olsa
2021-06-07 19:39       ` Yonghong Song
2021-06-08 15:42   ` Alexei Starovoitov [this message]
2021-06-08 18:17     ` Jiri Olsa
2021-06-08 18:49       ` Alexei Starovoitov
2021-06-08 21:07         ` Jiri Olsa
2021-06-08 23:05           ` Alexei Starovoitov
2021-06-09  5:08             ` Andrii Nakryiko
2021-06-09 13:42               ` Jiri Olsa
2021-06-09 13:33             ` Jiri Olsa
2021-06-09  5:18   ` Andrii Nakryiko
2021-06-09 13:53     ` Jiri Olsa
2021-06-05 11:10 ` [PATCH 14/19] libbpf: Add btf__find_by_pattern_kind function Jiri Olsa
2021-06-09  5:29   ` Andrii Nakryiko
2021-06-09 13:59     ` Jiri Olsa
2021-06-09 14:19       ` Jiri Olsa
2021-06-05 11:10 ` [PATCH 15/19] libbpf: Add support to link multi func tracing program Jiri Olsa
2021-06-07  5:49   ` Yonghong Song
2021-06-07 18:28     ` Jiri Olsa
2021-06-07 19:42       ` Yonghong Song
2021-06-07 20:11         ` Jiri Olsa
2021-06-09  5:34   ` Andrii Nakryiko
2021-06-09 14:17     ` Jiri Olsa
2021-06-10 17:05       ` Andrii Nakryiko
2021-06-10 20:35         ` Jiri Olsa
2021-06-05 11:10 ` [PATCH 16/19] selftests/bpf: Add fentry multi func test Jiri Olsa
2021-06-07  6:06   ` Yonghong Song
2021-06-07 18:42     ` Jiri Olsa
2021-06-09  5:40   ` Andrii Nakryiko
2021-06-09 14:29     ` Jiri Olsa
2021-06-10 17:00       ` Andrii Nakryiko
2021-06-10 20:28         ` Jiri Olsa
2021-06-05 11:10 ` [PATCH 17/19] selftests/bpf: Add fexit " Jiri Olsa
2021-06-05 11:10 ` [PATCH 18/19] selftests/bpf: Add fentry/fexit " Jiri Olsa
2021-06-09  5:41   ` Andrii Nakryiko
2021-06-09 14:29     ` Jiri Olsa
2021-06-05 11:10 ` [PATCH 19/19] selftests/bpf: Temporary fix for fentry_fexit_multi_test Jiri Olsa
2021-06-17 20:29 ` [RFCv3 00/19] x86/ftrace/bpf: Add batch support for direct/tracing attach Andrii Nakryiko
2021-06-19  8:33   ` Jiri Olsa
2021-06-19 16:19     ` Yonghong Song
2021-06-19 17:09       ` Jiri Olsa
2021-06-20 16:56         ` Yonghong Song
2021-06-20 17:47           ` Alexei Starovoitov
2021-06-21  6:46             ` Andrii Nakryiko
2021-06-21  6:50     ` Andrii Nakryiko
2021-07-06 20:26       ` Andrii Nakryiko
2021-07-07 15:19         ` Jiri Olsa

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