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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Andrii Nakryiko <andriin@fb.com>
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, ast@fb.com,
	daniel@iogearbox.net, andrii.nakryiko@gmail.com,
	kernel-team@fb.com
Subject: Re: [PATCH v2 bpf-next 07/14] selftests/bpf: add selftest for multi-prog sections and bpf-to-bpf calls
Date: Tue, 1 Sep 2020 22:41:32 -0700	[thread overview]
Message-ID: <20200902054132.y3p3spqt6vzxiy2t@ast-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <20200901015003.2871861-8-andriin@fb.com>

On Mon, Aug 31, 2020 at 06:49:56PM -0700, Andrii Nakryiko wrote:
> +
> +__noinline int sub1(int x)
> +{
> +	return x + 1;
> +}
> +
> +static __noinline int sub5(int v);
> +
> +__noinline int sub2(int y)
> +{
> +	return sub5(y + 2);
> +}
> +
> +static __noinline int sub3(int z)
> +{
> +	return z + 3 + sub1(4);
> +}
> +
> +static __noinline int sub4(int w)
> +{
> +	return w + sub3(5) + sub1(6);

Did you check that asm has these calls?
Since sub3 is static the compiler doesn't have to do the call.
'static noinline' doesn't mean that compiler have to do the call.
It can compute the value and replace a call with a constant.
It only has to keep the body of the function if the address of it
was taken.

  reply	other threads:[~2020-09-02  5:41 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-01  1:49 [PATCH v2 bpf-next 00/14] Add libbpf full support for BPF-to-BPF calls Andrii Nakryiko
2020-09-01  1:49 ` [PATCH v2 bpf-next 01/14] libbpf: ensure ELF symbols table is found before further ELF processing Andrii Nakryiko
2020-09-02  5:43   ` John Fastabend
2020-09-01  1:49 ` [PATCH v2 bpf-next 02/14] libbpf: parse multi-function sections into multiple BPF programs Andrii Nakryiko
2020-09-02  6:08   ` John Fastabend
2020-09-01  1:49 ` [PATCH v2 bpf-next 03/14] libbpf: support CO-RE relocations for multi-prog sections Andrii Nakryiko
2020-09-02  6:14   ` John Fastabend
2020-09-01  1:49 ` [PATCH v2 bpf-next 04/14] libbpf: make RELO_CALL work for multi-prog sections and sub-program calls Andrii Nakryiko
2020-09-02  5:36   ` Alexei Starovoitov
2020-09-02 19:52     ` Andrii Nakryiko
2020-09-01  1:49 ` [PATCH v2 bpf-next 05/14] libbpf: implement generalized .BTF.ext func/line info adjustment Andrii Nakryiko
2020-09-01  1:49 ` [PATCH v2 bpf-next 06/14] libbpf: add multi-prog section support for struct_ops Andrii Nakryiko
2020-09-01  1:49 ` [PATCH v2 bpf-next 07/14] selftests/bpf: add selftest for multi-prog sections and bpf-to-bpf calls Andrii Nakryiko
2020-09-02  5:41   ` Alexei Starovoitov [this message]
2020-09-02 19:57     ` Andrii Nakryiko
2020-09-01  1:49 ` [PATCH v2 bpf-next 08/14] tools/bpftool: replace bpf_program__title() with bpf_program__section_name() Andrii Nakryiko
2020-09-01  1:49 ` [PATCH v2 bpf-next 09/14] selftests/bpf: don't use deprecated libbpf APIs Andrii Nakryiko
2020-09-01  1:49 ` [PATCH v2 bpf-next 10/14] libbpf: deprecate notion of BPF program "title" in favor of "section name" Andrii Nakryiko
2020-09-01  1:50 ` [PATCH v2 bpf-next 11/14] selftests/bpf: turn fexit_bpf2bpf into test with subtests Andrii Nakryiko
2020-09-01  1:50 ` [PATCH v2 bpf-next 12/14] selftests/bpf: convert pyperf, strobemeta, and l4lb_noinline to __noinline Andrii Nakryiko
2020-09-02  5:45   ` Alexei Starovoitov
2020-09-02 19:58     ` Andrii Nakryiko
2020-09-01  1:50 ` [PATCH v2 bpf-next 13/14] selftests/bpf: modernize xdp_noinline test w/ skeleton and __noinline Andrii Nakryiko
2020-09-01  1:50 ` [PATCH v2 bpf-next 14/14] selftests/bpf: convert cls_redirect selftest to use __noinline Andrii Nakryiko
2020-09-02  5:46   ` Alexei Starovoitov
2020-09-02 19:58     ` Andrii Nakryiko

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