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From: Jiri Olsa <jolsa@redhat.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Networking <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>
Subject: Re: [PATCH bpf-next 09/29] bpf: Add support to load multi func tracing program
Date: Sun, 28 Nov 2021 18:41:15 +0100	[thread overview]
Message-ID: <YaO/O4bNeg2JRrbU@krava> (raw)
In-Reply-To: <CAEf4Bzad=O3PgZ9Z55HpuiobQTkhA57GHFEV2M6JveG_nzP40A@mail.gmail.com>

On Wed, Nov 24, 2021 at 01:51:36PM -0800, Andrii Nakryiko wrote:
> On Mon, Nov 22, 2021 at 12:15 PM Jiri Olsa <jolsa@redhat.com> wrote:
> >
> > On Thu, Nov 18, 2021 at 08:11:59PM -0800, Alexei Starovoitov wrote:
> > > On Thu, Nov 18, 2021 at 12:24:35PM +0100, Jiri Olsa wrote:
> > > > +
> > > > +DEFINE_BPF_MULTI_FUNC(unsigned long a1, unsigned long a2,
> > > > +                 unsigned long a3, unsigned long a4,
> > > > +                 unsigned long a5, unsigned long a6)
> > >
> > > This is probably a bit too x86 specific. May be make add all 12 args?
> > > Or other places would need to be tweaked?
> >
> > I think si, I'll check
> >
> > >
> > > > +BTF_ID_LIST_SINGLE(bpf_multi_func_btf_id, func, bpf_multi_func)
> > > ...
> > > > -   prog->aux->attach_btf_id = attr->attach_btf_id;
> > > > +   prog->aux->attach_btf_id = multi_func ? bpf_multi_func_btf_id[0] : attr->attach_btf_id;
> > >
> > > Just ignoring that was passed in uattr?
> > > Maybe instead of ignoring dopr BPF_F_MULTI_FUNC and make libbpf
> > > point to that btf_id instead?
> > > Then multi or not can be checked with if (attr->attach_btf_id == bpf_multi_func_btf_id[0]).
> > >
> >
> > nice idea, it might fit better than the flag
> 
> Instead of a flag we can also use a different expected_attach_type
> (FENTRY vs FENTRY_MULTI, etc).

right, you already asked for that - https://lore.kernel.org/bpf/YS9k26rRcUJVS%2Fvx@krava/

I still think it'd mean more code while this way we just use
current fentry/fexit code paths with few special handling
for multi programs

> As for attach_btf_id, why can't we just
> enforce it as 0?

there's prog->aux->attach_func_proto that needs to be set based
on attach_btf_id, and is checked later in btf_ctx_access

jirka

> 
> >
> > thanks,
> > jirka
> >
> 


  reply	other threads:[~2021-11-28 17:43 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-18 11:24 [RFC bpf-next v5 00/29] bpf: Add batch support for attaching trampolines Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 01/29] ftrace: Use direct_ops hash in unregister_ftrace_direct Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 02/29] ftrace: Add cleanup to unregister_ftrace_direct_multi Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 03/29] ftrace: Add ftrace_set_filter_ips function Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 04/29] bpf: Factor bpf_check_attach_target function Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 05/29] bpf: Add bpf_check_attach_model function Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 06/29] bpf: Add bpf_arg/bpf_ret_value helpers for tracing programs Jiri Olsa
2021-11-24 21:43   ` Andrii Nakryiko
2021-11-25 16:14     ` Alexei Starovoitov
2021-11-28 18:07       ` Jiri Olsa
2021-11-28 18:06     ` Jiri Olsa
2021-12-01  7:13       ` Andrii Nakryiko
2021-12-01 17:37         ` Alexei Starovoitov
2021-12-01 17:59           ` Andrii Nakryiko
2021-12-01 20:36             ` Alexei Starovoitov
2021-12-01 21:16             ` Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 07/29] bpf, x64: Allow to use caller address from stack Jiri Olsa
2021-11-19  4:14   ` Alexei Starovoitov
2021-11-19 21:46     ` Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 08/29] bpf: Keep active attached trampoline in bpf_prog Jiri Olsa
2021-11-24 21:48   ` Andrii Nakryiko
2021-11-28 17:24     ` Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 09/29] bpf: Add support to load multi func tracing program Jiri Olsa
2021-11-19  4:11   ` Alexei Starovoitov
2021-11-22 20:15     ` Jiri Olsa
2021-11-24 21:51       ` Andrii Nakryiko
2021-11-28 17:41         ` Jiri Olsa [this message]
2021-12-01  7:17           ` Andrii Nakryiko
2021-12-01 21:20             ` Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 10/29] bpf: Add bpf_trampoline_id object Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 11/29] bpf: Add addr to " Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 12/29] bpf: Add struct bpf_tramp_node layer Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 13/29] bpf: Add bpf_tramp_attach layer for trampoline attachment Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 14/29] bpf: Add support to store multiple ids in bpf_tramp_id object Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 15/29] bpf: Add support to store multiple addrs " Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 16/29] bpf: Add bpf_tramp_id_single function Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 17/29] bpf: Resolve id in bpf_tramp_id_single Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 18/29] bpf: Add refcount_t to struct bpf_tramp_id Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 19/29] bpf: Add support to attach trampolines with multiple IDs Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 20/29] bpf: Add support for tracing multi link Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 21/29] libbpf: Add btf__find_by_glob_kind function Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 22/29] libbpf: Add support to link multi func tracing program Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 23/29] selftests/bpf: Add bpf_arg/bpf_ret_value test Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 24/29] selftests/bpf: Add fentry multi func test Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 25/29] selftests/bpf: Add fexit " Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 26/29] selftests/bpf: Add fentry/fexit " Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 27/29] selftests/bpf: Add mixed " Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 28/29] selftests/bpf: Add ret_mod " Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 29/29] selftests/bpf: Add attach " Jiri Olsa

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