netdev - Re: [PATCH bpf-next 0/4] Fix perf_buffer creation on systems with offline CPUs

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Date:   Sun, 9 Feb 2020 22:48:16 +0530
From:   Naresh Kamboju <naresh.kamboju@...aro.org>
To:     Andrii Nakryiko <andriin@...com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Sasha Levin <sashal@...nel.org>
Cc:     bpf <bpf@...r.kernel.org>, Netdev <netdev@...r.kernel.org>,
        ast@...com, Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii.nakryiko@...il.com>,
        Kernel Team <kernel-team@...com>,
        linux- stable <stable@...r.kernel.org>,
        lkft-triage@...ts.linaro.org,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Leo Yan <leo.yan@...aro.org>
Subject: Re: [PATCH bpf-next 0/4] Fix perf_buffer creation on systems with
 offline CPUs

On Thu, 12 Dec 2019 at 07:05, Andrii Nakryiko <andriin@...com> wrote:
>
> This patch set fixes perf_buffer__new() behavior on systems which have some of
> the CPUs offline/missing (due to difference between "possible" and "online"
> sets). perf_buffer will create per-CPU buffer and open/attach to corresponding
> perf_event only on CPUs present and online at the moment of perf_buffer
> creation. Without this logic, perf_buffer creation has no chances of
> succeeding on such systems, preventing valid and correct BPF applications from
> starting.
>
> Andrii Nakryiko (4):
>   libbpf: extract and generalize CPU mask parsing logic
>   selftests/bpf: add CPU mask parsing tests
>   libbpf: don't attach perf_buffer to offline/missing CPUs

perf build failed on stable-rc 5.5 branch.

libbpf.c: In function '__perf_buffer__new':
libbpf.c:6159:8: error: implicit declaration of function
'parse_cpu_mask_file'; did you mean 'parse_uint_from_file'?
[-Werror=implicit-function-declaration]
  err = parse_cpu_mask_file(online_cpus_file, &online, &n);
        ^~~~~~~~~~~~~~~~~~~
        parse_uint_from_file
libbpf.c:6159:8: error: nested extern declaration of
'parse_cpu_mask_file' [-Werror=nested-externs]

build log,
https://ci.linaro.org/view/lkft/job/openembedded-lkft-linux-stable-rc-5.5/DISTRO=lkft,MACHINE=hikey,label=docker-lkft/11/console

-- 
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https://lkft.linaro.org