linux-kernel - Re: [PATCH v2] sched/rt: Disable RT_RUNTIME

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Message-ID: <4230c3d8-b33e-dcf8-46df-0687b10b9123@redhat.com>
Date:   Mon, 2 Jan 2017 18:21:49 +0100
From:   Daniel Bristot de Oliveira <bristot@...hat.com>
To:     Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     Steven Rostedt <rostedt@...dmis.org>,
        Clark Williams <williams@...hat.com>,
        "Luis Claudio R . Goncalves" <lgoncalv@...hat.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] sched/rt: Disable RT_RUNTIME_SHARE by default

On 11/16/2016 09:19 PM, Daniel Bristot de Oliveira wrote:
> The RT_RUNTIME_SHARE sched feature enables the sharing of rt_runtime
> between CPUs, allowing a CPU to run a real-time task up to 100% of the
> time while leaving more space for non-real-time tasks to run on the CPU
> that lend rt_runtime.
> 
> The problem is that a CPU can easily borrow enough rt_runtime to allow
> a spinning rt-task to run forever, starving per-cpu tasks like kworkers,
> which are non-real-time by design.
> 
> This patch disables RT_RUNTIME_SHARE by default, avoiding this problem.
> The feature will still be present for users that want to enable it,
> though. It also documents this option.
> 
> v1->v2:
>  Unified the documentation and the disabling in a single patch
> 
> Signed-off-by: Daniel Bristot de Oliveira <bristot@...hat.com>
> Cc: Ingo Molnar <mingo@...hat.com>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Steven Rostedt <rostedt@...dmis.org>
> Cc: Clark Williams <williams@...hat.com>
> Cc: Luis Claudio R. Goncalves <lgoncalv@...hat.com>
> Cc: linux-kernel@...r.kernel.org
> Acked-by: Steven Rostedt <rostedt@...dmis.org>
> Acked-by: Luis Claudio R. Goncalves <lgoncalv@...hat.com>

This is a gentle ping :-)

any additional comment for this patch?

-- Daniel