From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
linux-kernel@vger.kernel.org,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Rik van Riel <riel@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC PATCH] sched/cputime: drop local_irq_safe() in vtime_init_idle()
Date: Thu, 14 Apr 2016 15:41:17 +0200 [thread overview]
Message-ID: <570F9DFD.5080807@linutronix.de> (raw)
In-Reply-To: <20160414131827.GA7090@lerouge>
On 04/14/2016 03:18 PM, Frederic Weisbecker wrote:
> I think I tried this but I got lockdep warnings because the other updaters
> happen on IRQ.
I booted and played a little but lockdep didn't scream here so far.
> In practive we can't be interrupted since the idle task hasn't even started.
>
> Now we can probably get rid of the write_seqcount_stuff here because what
> is initialized there is supposed to be visible by the idle task once it runs.
>
> But I'm more worried about readers.
Most idle_thread_get() callers happen at boottime. Then I see two
during CPU-up (cpu-hotplug) at runtime. One from _cpu_up() via
idle_thread_get() and the second via bringup_cpu() and the second in
bringup_cpu().
Sebastian
next prev parent reply other threads:[~2016-04-14 13:41 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-14 12:29 [RFC PATCH] sched/cputime: drop local_irq_safe() in vtime_init_idle() Sebastian Andrzej Siewior
2016-04-14 13:07 ` Rik van Riel
2016-04-14 13:18 ` Frederic Weisbecker
2016-04-14 13:41 ` Sebastian Andrzej Siewior [this message]
2016-04-14 14:23 ` Frederic Weisbecker
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