linux-kernel - Re: [PATCH 01/10] workqueue: add wq_numa_tbl_len and wq_numa_possible

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Date:	Thu, 21 Mar 2013 00:43:08 +0800
From:	Lai Jiangshan <eag0628@...il.com>
To:	Tejun Heo <tj@...nel.org>
Cc:	laijs@...fujitsu.com, axboe@...nel.dk, jack@...e.cz,
	fengguang.wu@...el.com, jmoyer@...hat.com, zab@...hat.com,
	linux-kernel@...r.kernel.org, herbert@...dor.apana.org.au,
	davem@...emloft.net, linux-crypto@...r.kernel.org
Subject: Re: [PATCH 01/10] workqueue: add wq_numa_tbl_len and wq_numa_possible_cpumask[]

On Wed, Mar 20, 2013 at 11:48 PM, Tejun Heo <tj@...nel.org> wrote:
> On Wed, Mar 20, 2013 at 11:43:30PM +0800, Lai Jiangshan wrote:
>> > +       for_each_node(node)
>> > +               BUG_ON(!alloc_cpumask_var_node(&wq_numa_possible_cpumask[node],
>> > +                                              GFP_KERNEL, node));
>> > +       for_each_possible_cpu(cpu) {
>> > +               node = cpu_to_node(cpu);
>> > +               if (WARN_ON(node == NUMA_NO_NODE)) {
>> > +                       pr_err("workqueue: NUMA node mapping not available for cpu%d, disabling NUMA support\n", cpu);
>>
>> since you used WARN_ON(), not BUG_ON(), I think you need to free
>> allocated memory here.
>
> I don't know.  Is it necessary?  It shouldn't happen sans bugs in arch
> code and we're vomiting warning message with full stack trace.  The
> system will function but something is seriously screwed.  I don't
> think it matters whether we free the puny number of bytes there or
> not and I don't wanna nest deeper there. :P


I agree with you, but many people use semantic analysis tools to do
hunting in the kernel. they may interrupt you again.

>
> --
> tejun
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