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Date:   Fri, 8 Jan 2021 10:32:36 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Sebastian Siewior <bigeasy@linutronix.de>
Cc:     Ran Wang <ran.wang_1@nxp.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Jiafei Pan <jiafei.pan@nxp.com>,
        linux-rt-users@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] [RFC] rt: kernel/sched/core: fix kthread_park() pending
 too long when CPU un-plugged
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On Thu, Jan 07, 2021 at 04:28:43PM +0100, Sebastian Siewior wrote:
> This sleep can be triggered by ptrace/strace() and with brief testing I
> can trigger the sleep there but I don't get it anywhere near where I
> would notice it with cyclictest.

It's a single task wakeup (the caller), doing that from hardirq context
really should not be a problem, we do lots of that in RT already.