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From: Menglong Dong <menglong.dong@linux.dev>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Menglong Dong <menglong8.dong@gmail.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Andrii Nakryiko <andrii@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Eduard <eddyz87@gmail.com>, Song Liu <song@kernel.org>,
	Yonghong Song <yonghong.song@linux.dev>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>,
	Stanislav Fomichev <sdf@fomichev.me>, Hao Luo <haoluo@google.com>,
	Jiri Olsa <jolsa@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	David Ahern <dsahern@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	jiang.biao@linux.dev, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	X86 ML <x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
	bpf <bpf@vger.kernel.org>,
	Network Development <netdev@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH bpf-next v9 05/11] bpf: support fsession for bpf_session_cookie
Date: Wed, 14 Jan 2026 10:38:46 +0800	[thread overview]
Message-ID: <2687399.Lt9SDvczpP@7940hx> (raw)
In-Reply-To: <CAADnVQJzkXysOO9jqdvJUYbe2t+urReRV2xWQ0L2z0qcjgxdcw@mail.gmail.com>

On 2026/1/14 10:33 Alexei Starovoitov <alexei.starovoitov@gmail.com> write:
> On Tue, Jan 13, 2026 at 5:24 PM Andrii Nakryiko
> <andrii.nakryiko@gmail.com> wrote:
> >
> > On Sat, Jan 10, 2026 at 6:12 AM Menglong Dong <menglong8.dong@gmail.com> wrote:
> > >
> > > Implement session cookie for fsession. In order to limit the stack usage,
> > > we make 4 as the maximum of the cookie count.
> >
> > This 4 is so random, tbh. Do we need to artificially limit it? Even if
> > all BPF_MAX_TRAMP_LINKS = 38 where using session cookies, it would be
> > 304 bytes. Not insignificant, but also not world-ending and IMO so
> > unlikely that I wouldn't add extra limits at all.
> 
> I forgot that we already have BPF_MAX_TRAMP_LINKS limit for the total
> number of progs. I guess extra 8 bytes per fsession prog isn't that bad.

Ah, so it's OK to not limit the session cookie. I'll remove such limitation
in the next version.

Thanks!
Menglong Dong

> 





  reply	other threads:[~2026-01-14  2:39 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-01-10 14:11 [PATCH bpf-next v9 00/11] bpf: fsession support Menglong Dong
2026-01-10 14:11 ` [PATCH bpf-next v9 01/11] bpf: add " Menglong Dong
2026-01-14  1:22   ` Andrii Nakryiko
2026-01-14  2:10     ` Menglong Dong
2026-01-14 18:56       ` Andrii Nakryiko
2026-01-15  2:05         ` Menglong Dong
2026-01-15  8:33         ` Menglong Dong
2026-01-10 14:11 ` [PATCH bpf-next v9 02/11] bpf: use last 8-bits for the nr_args in trampoline Menglong Dong
2026-01-14  1:22   ` Andrii Nakryiko
2026-01-14  2:19     ` Menglong Dong
2026-01-14  9:52       ` David Laight
2026-01-10 14:11 ` [PATCH bpf-next v9 03/11] bpf: change prototype of bpf_session_{cookie,is_return} Menglong Dong
2026-01-14  1:22   ` Andrii Nakryiko
2026-01-14  2:19     ` Menglong Dong
2026-01-10 14:11 ` [PATCH bpf-next v9 04/11] bpf: support fsession for bpf_session_is_return Menglong Dong
2026-01-14  1:22   ` Andrii Nakryiko
2026-01-14  2:25     ` Menglong Dong
2026-01-10 14:11 ` [PATCH bpf-next v9 05/11] bpf: support fsession for bpf_session_cookie Menglong Dong
2026-01-10 14:42   ` bot+bpf-ci
2026-01-11  1:54     ` Menglong Dong
2026-01-14  1:22   ` Andrii Nakryiko
2026-01-14  2:33     ` Alexei Starovoitov
2026-01-14  2:38       ` Menglong Dong [this message]
2026-01-14  2:48     ` Menglong Dong
2026-01-10 14:11 ` [PATCH bpf-next v9 06/11] bpf,x86: introduce emit_store_stack_imm64() for trampoline Menglong Dong
2026-01-14  1:22   ` Andrii Nakryiko
2026-01-14  2:31     ` Menglong Dong
2026-01-10 14:11 ` [PATCH bpf-next v9 07/11] bpf,x86: add fsession support for x86_64 Menglong Dong
2026-01-14  1:25   ` Andrii Nakryiko
2026-01-14  3:27     ` Menglong Dong
2026-01-14  3:35       ` Menglong Dong
2026-01-14 19:05       ` Andrii Nakryiko
2026-01-15  2:12         ` Menglong Dong
2026-01-10 14:11 ` [PATCH bpf-next v9 08/11] libbpf: add fsession support Menglong Dong
2026-01-14  1:24   ` Andrii Nakryiko
2026-01-14  3:27     ` Menglong Dong
2026-01-10 14:11 ` [PATCH bpf-next v9 09/11] selftests/bpf: add testcases for fsession Menglong Dong
2026-01-10 14:11 ` [PATCH bpf-next v9 10/11] selftests/bpf: add testcases for fsession cookie Menglong Dong
2026-01-10 14:11 ` [PATCH bpf-next v9 11/11] selftests/bpf: test fsession mixed with fentry and fexit Menglong Dong
2026-01-14  2:28 ` [PATCH bpf-next v9 00/11] bpf: fsession support Alexei Starovoitov
2026-01-14  2:52   ` Menglong Dong

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