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References: <20230308073201.3102738-1-avagin@google.com>
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From:   Andrei Vagin <avagin@gmail.com>
Date:   Tue, 21 Mar 2023 11:19:03 -0700
Message-ID: <CANaxB-yLtPvd7z-9-dAGAM98hjFqTpN_oHbbpCawtFrPW6JBWQ@mail.gmail.com>
Subject: Re: [PATCH 0/6 v5 RESEND] seccomp: add the synchronous mode for seccomp_unotify
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Kees Cook <keescook@chromium.org>, linux-kernel@vger.kernel.org,
        Christian Brauner <brauner@kernel.org>,
        Chen Yu <yu.c.chen@intel.com>,
        Andrei Vagin <avagin@google.com>,
        Andy Lutomirski <luto@amacapital.net>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Ingo Molnar <mingo@redhat.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Peter Oskolkov <posk@google.com>,
        Tycho Andersen <tycho@tycho.pizza>,
        Will Drewry <wad@chromium.org>,
        Vincent Guittot <vincent.guittot@linaro.org>
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On Tue, Mar 7, 2023 at 11:32=E2=80=AFPM Andrei Vagin <avagin@google.com> wr=
ote:
>
> seccomp_unotify allows more privileged processes do actions on behalf
> of less privileged processes.
>
> In many cases, the workflow is fully synchronous. It means a target
> process triggers a system call and passes controls to a supervisor
> process that handles the system call and returns controls back to the
> target process. In this context, "synchronous" means that only one
> process is running and another one is waiting.
>
> The new WF_CURRENT_CPU flag advises the scheduler to move the wakee to
> the current CPU. For such synchronous workflows, it makes context
> switches a few times faster.
>
> Right now, each interaction takes 12=C2=B5s. With this patch, it takes ab=
out
> 3=C2=B5s.
>
> v2: clean up the first patch and add the test.
> v3: update commit messages and a few fixes suggested by Kees Cook.
> v4: update the third patch to avoid code duplications (suggested by
>     Peter Zijlstra)
>     Add the benchmark to the perf bench set.
> v5: Update the author email. No code changes.
>
> Kees is ready to take this patch set, but wants to get Acks from the
> sched folks.

Peter, could you review the second and third patches of this series?

Thanks,
Andrei