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Message-ID: <86802c440807291521k6e6277b5ta05b180d0d1c963a@mail.gmail.com>
Date: Tue, 29 Jul 2008 15:21:02 -0700
From: "Yinghai Lu" <yhlu.kernel@gmail.com>
To: "Mike Travis" <travis@sgi.com>
Subject: Re: kernel BUG at arch/x86/kernel/io_apic_64.c:357!
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
       "Dhaval Giani" <dhaval@linux.vnet.ibm.com>,
       "Thomas Gleixner" <tglx@linutronix.de>, "Ingo Molnar" <mingo@elte.hu>,
       lkml <linux-kernel@vger.kernel.org>, "Jack Steiner" <steiner@sgi.com>,
       "Alan Mayer" <ajm@sgi.com>, "Cliff Wickman" <cpw@sgi.com>
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On Tue, Jul 29, 2008 at 3:17 PM, Mike Travis <travis@sgi.com> wrote:
> Eric W. Biederman wrote:
>> "Yinghai Lu" <yhlu.kernel@gmail.com> writes:
>>
>>> On Tue, Jul 29, 2008 at 11:35 AM, Yinghai Lu <yhlu.kernel@gmail.com> wrote:
>>>> On Tue, Jul 29, 2008 at 9:09 AM, Dhaval Giani <dhaval@linux.vnet.ibm.com>
>>> wrote:
>>>>> Hi Ingo, Thomas,
>>>>>
>>>>> Hit this on 2.6.27-rc1
>>>>>
>>>>> (The kernel bug is at line 356 (Its 357 as I applied a debug patch to
>>>>> print out the irq) (Full dmesg and .config attached)
>>>> can you boot with "debug apic=verbose pci=routeirq"?
>>> please try attached patch
>
> I didn't follow this from the start but one reason why NR_IRQS based on
> NR_CPUS is a bad idea, is the huge (nearly 300Mb) increase in memory usage
> (that's mostly wasted.)  I believe there's another patch coming real soon
> now to make irq allocations dynamic.  (I had also hoped to look closer at
> your irq abstraction patch you sent a while back.  Does that also address
> this issue?)

Yes.

>
> But this would be a show stopper for SGI being able to ship systems if the
> distros do not want to waste this much memory and won't set NR_CPUS=4096.

wonder if nr_irqs need to be probed dynamically too.

YH
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