Date: Mon, 9 Sep 2013 18:18:19 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
        Eric Dumazet <eric.dumazet@gmail.com>, linux-kernel@vger.kernel.org,
        mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com,
        akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
        josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de,
        rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
        darren@dvhart.com, sbw@mit.edu, cl@linux.com
Subject: Re: [PATCH] rcu: Is it safe to enter an RCU read-side critical
 section?
Message-ID: <20130909161819.GF26785@twins.programming.kicks-ass.net>
References: <20130905195234.GA20555@linux.vnet.ibm.com>
 <20130906105934.GF20519@somewhere>
 <20130906151851.GQ3966@linux.vnet.ibm.com>
 <1378488088.31445.39.camel@edumazet-glaptop>
 <20130906174117.GU3966@linux.vnet.ibm.com>
 <20130906185927.GE2706@somewhere>
 <20130909105347.GK31370@twins.programming.kicks-ass.net>
 <20130909132343.GN3966@linux.vnet.ibm.com>
 <20130909133604.GC31370@twins.programming.kicks-ass.net>
 <20130909135320.GS3966@linux.vnet.ibm.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20130909135320.GS3966@linux.vnet.ibm.com>
User-Agent: Mutt/1.5.21 (2012-12-30)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1689
Lines: 33

On Mon, Sep 09, 2013 at 06:53:20AM -0700, Paul E. McKenney wrote:
> On Mon, Sep 09, 2013 at 03:36:04PM +0200, Peter Zijlstra wrote:
> > On Mon, Sep 09, 2013 at 06:23:43AM -0700, Paul E. McKenney wrote:
> > > And guys, I have to say that the advice on which per-CPU primitive to use
> > > varies wildly and randomly.  For all I know, each of you individually
> > > might well be sticking to the same story, but taken together, your
> > > collective advice is strongly resembling white noise.
> > 
> > Its partly because cl and I disagree on things. He doesn't seem to care
> > much about validation and believes that people will not make mistakes
> > with this stuff.
> 
> At some point, my only recourse would be to require an Acked-by from one
> of you for any per-CPU changes proposed by the other.  I really hope that
> it doesn't come to that, but this situation is getting a bit annoying.

Nah, I'll not hold that over you. I think the current storm-in-teacup
was mostly due us seeing something suspicous and not understanding the
explanation well or so.

> > And partly because I didn't get what was going on. While Frederic's
> > explanation might be correct it was incomprehensible for me.
> 
> And I freely admit that the comments on rcu_is_cpu_idle() are completely
> inadequate, and I do apologize for that.  Seemed clear at the time.
> But then it always does, doesn't it?  ;-)

Yeah, I'm only all too familiar with this problem :/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/