From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>,
linux-kernel@vger.kernel.org, mingo@elte.hu, rjw@sisk.pl,
dipankar@in.ibm.com, tglx@linuxtronix.de
Subject: Re: [PATCH] rudimentary tracing for Classic RCU
Date: Fri, 10 Oct 2008 04:48:11 -0700 [thread overview]
Message-ID: <20081010114811.GB6633@linux.vnet.ibm.com> (raw)
In-Reply-To: <48EDAD55.2000502@cn.fujitsu.com>
On Thu, Oct 09, 2008 at 03:05:57PM +0800, Lai Jiangshan wrote:
> Andi Kleen wrote:
> >> In this case, why not define it as:
> >> static char buf[20*NR_CPUS + 100];
> >
> > Actually you should near never use NR_CPUS now but always num_possible_cpus()
> > (or even num_online_cpus()) Using NR_CPUS can lead to extreme waste
> > of memory on kernels which are compiled for 4096 CPUs for example.
> >
> > And with num_possible_cpus() kmalloc is needed.
> >
> > -Andi
>
> I thought the default value of NR_CPUS is 32.
>
> if NR_CPUS is too large, I think using seq_file is good idea,
> and rcuclassic_trace_mutex is not need too.
I never have used seq_file, to be honest. I would welcome a patch from
you applying it to my rcucb and rcudata patch set.
Thanx, Paul
next prev parent reply other threads:[~2008-10-10 11:48 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-06 14:12 scheduler hang on cpu re-hotplug with 2.6.27rc8 Andi Kleen
2008-10-06 23:28 ` RCU " Andi Kleen
2008-10-07 3:08 ` Paul E. McKenney
2008-10-07 7:15 ` Andi Kleen
2008-10-07 15:26 ` Paul E. McKenney
2008-10-07 15:49 ` Andi Kleen
2008-10-07 16:34 ` Paul E. McKenney
2008-10-07 21:09 ` Andi Kleen
2008-10-07 21:22 ` Paul E. McKenney
2008-10-09 1:08 ` [PATCH] rudimentary tracing for Classic RCU Paul E. McKenney
2008-10-09 6:20 ` Lai Jiangshan
2008-10-09 6:55 ` Andi Kleen
2008-10-09 7:05 ` Lai Jiangshan
2008-10-09 7:14 ` KOSAKI Motohiro
2008-10-09 7:26 ` Lai Jiangshan
2008-10-09 8:06 ` Andi Kleen
2008-10-10 11:48 ` Paul E. McKenney [this message]
2008-10-09 11:50 ` Paul E. McKenney
2008-10-09 11:50 ` Paul E. McKenney
2008-10-09 10:23 ` Frédéric Weisbecker
2008-10-09 10:53 ` Andi Kleen
2008-10-09 11:44 ` Frédéric Weisbecker
2008-10-09 11:54 ` Paul E. McKenney
2008-10-09 13:01 ` Frédéric Weisbecker
2008-10-10 3:44 ` [PATCH] v2 " Paul E. McKenney
2008-10-13 23:09 ` [PATCH] v3 " Paul E. McKenney
2008-10-14 3:53 ` Lai Jiangshan
2008-10-14 14:35 ` Paul E. McKenney
2008-10-23 11:12 ` Lai Jiangshan
2008-10-26 21:59 ` Paul E. McKenney
2008-10-27 21:50 ` Paul E. McKenney
2008-10-27 23:57 ` Paul E. McKenney
2008-10-29 1:16 ` Paul E. McKenney
2008-10-29 1:31 ` Lai Jiangshan
2008-10-30 15:52 ` Paul E. McKenney
2008-10-09 1:33 ` RCU hang on cpu re-hotplug with 2.6.27rc8 Paul E. McKenney
2008-10-09 4:56 ` Andi Kleen
2008-10-09 7:24 ` Thomas Gleixner
2008-10-09 8:22 ` Andi Kleen
2008-10-09 11:44 ` Paul E. McKenney
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