netdev - Re: [PATCH bpf-next v2 1/2] trace_helpers.c: Add helpers to poll multiple perf FDs for events

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4208c3df-6d3f-9647-8f89-b044d880690f@iogearbox.net>
Date:   Tue, 5 Jun 2018 11:27:20 +0200
From:   Daniel Borkmann <daniel@...earbox.net>
To:     Toke Høiland-Jørgensen <toke@...e.dk>,
        Jakub Kicinski <kubakici@...pl>
Cc:     netdev@...r.kernel.org,
        Alexei Starovoitov <alexei.starovoitov@...il.com>
Subject: Re: [PATCH bpf-next v2 1/2] trace_helpers.c: Add helpers to poll
 multiple perf FDs for events

On 06/05/2018 11:22 AM, Toke Høiland-Jørgensen wrote:
> Daniel Borkmann <daniel@...earbox.net> writes:
>> On 06/05/2018 12:26 AM, Jakub Kicinski wrote:
>>> On Mon, 04 Jun 2018 18:33:56 +0200, Toke Høiland-Jørgensen wrote:
>>>> This adds two new helper functions to trace_helpers that supports polling
>>>> multiple perf file descriptors for events. These are used to the XDP
>>>> perf_event_output example, which needs to work with one perf fd per CPU.
>>>>
>>>> Signed-off-by: Toke Høiland-Jørgensen <toke@...e.dk>
>>>
>>> Did you take a look at tools/bpf/bpftool/map_perf_ring.c ?
>>>
>>> I think the ability to poll multiple FDs could be generally useful and
>>> therefore better add it to libbpf.c than
>>> tools/testing/selftests/bpf/trace_helpers.c?  I'm not 100% sure myself...
>>
>> I think for it to land in libbpf this code needs to be more generalized
>> as it is right now and allowing for more flexibility like pinning RB
>> processing threads to CPUs, poll handling, etc.
> 
> Hmm, so how about we leave it in trace_helpers.c for now? I don't
> necessarily mind working on an addition to libbpf at some point, but
> don't have time to do so short term...

That's okay with me as well.