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Subject: Re: [PATCH 01/32 RESEND] nohz: Drop useless call in
 tick_nohz_start_idle()
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Anton Blanchard <anton@au1.ibm.com>, Avi Kivity <avi@redhat.com>,
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        "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
        Paul Menage <menage@google.com>,
        Stephen Hemminger <shemminger@vyatta.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Tim Pepper <lnxninja@linux.vnet.ibm.com>
Date: Mon, 29 Aug 2011 16:23:10 +0200
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On Mon, 2011-08-15 at 17:51 +0200, Frederic Weisbecker wrote:
> The call to update_ts_time_stats() there is useless. All
> we need is to save the idle entry_time.
> 
> 
Would have been clearer if you just said the call was a NOP. The whole
second sentence distracts and confuses as its irrelevant to the change
at hand.

If you want to expand you can explain that its a NOP because
update_ts_time_stats() requires either ts->idle_active and/or
@last_update_time and our callsite has neither.

Although this assumes its never called when ts->idle_active is already
set, is this so (likely)? Do we want a WARN_ON_ONCE() testing that
assumption?