From: Peter Zijlstra <peterz@infradead.org>
To: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: tglx@linutronix.de, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tick/broadcast-hrtimer : Fix suspicious RCU usage in idle loop
Date: Mon, 2 Mar 2015 15:53:54 +0100 [thread overview]
Message-ID: <20150302145354.GM21418@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20150226032202.20019.91636.stgit@preeti.in.ibm.com>
On Thu, Feb 26, 2015 at 08:52:02AM +0530, Preeti U Murthy wrote:
> The hrtimer mode of broadcast queues hrtimers in the idle entry
> path so as to wakeup cpus in deep idle states.
Callgraph please...
> hrtimer_{start/cancel}
> functions call into tracing which uses RCU. But it is not legal to call
> into RCU in cpuidle because it is one of the quiescent states. Hence
> protect this region with RCU_NONIDLE which informs RCU that the cpu
> is momentarily non-idle.
It it not clear to me that every user of bc_set_next() is from IDLE.
>From what I can tell it ends up being clockevents_program_event() and
that is called quite a lot.
Why is bc_set_next() a good function to annotate?
next prev parent reply other threads:[~2015-03-02 14:54 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-26 3:22 Preeti U Murthy
2015-03-02 14:53 ` Peter Zijlstra [this message]
2015-03-05 4:36 ` Preeti U Murthy
2015-03-16 14:56 ` Peter Zijlstra
2015-03-17 3:29 ` Preeti U Murthy
2015-03-17 4:19 ` Preeti U Murthy
2015-03-17 7:24 ` Peter Zijlstra
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