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To: Heiko J Schick <schihei@de.ibm.com>
Subject: Re: [openib-general] [PATCH 06/16] ehca: interrupt handling routines
References: <4468BD63.6070509@de.ibm.com>
From: Roland Dreier <rdreier@cisco.com>
Date: Fri, 26 May 2006 13:06:44 -0700
In-Reply-To: <4468BD63.6070509@de.ibm.com> (Heiko J. Schick's message of "Mon,
	15 May 2006 19:41:55 +0200")
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Cc: linux-kernel@vger.kernel.org, openib-general@openib.org,
	linuxppc-dev@ozlabs.org, Christoph Raisch <RAISCH@de.ibm.com>,
	Hoang-Nam Nguyen <HNGUYEN@de.ibm.com>, Marcus Eder <MEDER@de.ibm.com>
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 > +	for_each_online_cpu(cpu) {
 > +		task = create_comp_task(pool, cpu);
 > +		if (task) {
 > +			kthread_bind(task, cpu);
 > +			wake_up_process(task);
 > +		}
 > +	}

How does this creation of a thread pool work with respect to CPU
hotplug?  What happens if a CPU goes away?  How about if only one CPU
is running when the driver is loaded, and then 15 more are hot-added?

 > +	for (i = 0; i < NR_CPUS; i++) {
 > +		if (cpu_online(i))
 > +			destroy_comp_task(pool, i);
 > +	}

And it seems in the destroy function, you will possibly leak threads
or try to kill a non-existent thread if the set of online CPUs has
changed since the driver started...

 - R.