From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Chuansheng Liu <chuansheng.liu@intel.com>,
tglx@linutronix.de, mingo@redhat.com, x86@kernel.org,
linux-kernel@vger.kernel.org, yanmin_zhang@linux.intel.com,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
"rusty@rustcorp.com.au" <rusty@rustcorp.com.au>
Subject: Re: [PATCH RESEND] x86/fixup_irq: Clean the offlining CPU from the irq affinity mask
Date: Fri, 28 Sep 2012 02:03:24 +0530 [thread overview]
Message-ID: <5064B814.9010106@linux.vnet.ibm.com> (raw)
In-Reply-To: <1348773658.6644.36.camel@sbsiddha-desk.sc.intel.com>
On 09/28/2012 12:50 AM, Suresh Siddha wrote:
> On Fri, 2012-09-28 at 00:12 +0530, Srivatsa S. Bhat wrote:
>> On 09/27/2012 04:16 AM, Suresh Siddha wrote:
>>>
>>> No. irq_set_affinity()
>>>
>>
>> Um? That takes the updated/changed affinity and sets data->affinity to
>> that value no? You mentioned that probably the intention of the original
>> code was to preserve the user-set affinity mask, but still change the
>> underlying interrupt routing. Sorry, but I still didn't quite understand
>> what is that part of the code that achieves that.
>
> For the HW routing to be changed we AND it with cpu_online_map and use
> that for programming the interrupt entries etc.
Ah, now I see.. you were referring to the __assign_irq_vector() code, whereas
I was looking only at fixup_irqs() and was trying to find the code that did
what you said.. that's what got me confused earlier :-)
> The user-specified
> affinity still has the cpu that is offlined.
>
Right, so data->affinity is untouched, whereas cfg->domain is updated when
the CPU is offlined..
> And when the cpu comes online and if it is part of the user-specified
> affinity, then the HW routing can be again modified to include the new
> cpu.
>
Right, got it.
> hope this clears it!
>
Yep, thanks a lot!
Regards,
Srivatsa S. Bhat
next prev parent reply other threads:[~2012-09-27 20:34 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-26 17:38 [PATCH RESEND] x86/fixup_irq: Clean the offlining CPU from the irq affinity mask Chuansheng Liu
2012-09-26 8:49 ` Srivatsa S. Bhat
2012-09-26 8:51 ` Liu, Chuansheng
2012-09-26 8:56 ` Liu, Chuansheng
2012-09-26 9:02 ` Srivatsa S. Bhat
2012-09-26 23:45 ` Chuansheng Liu
2012-09-26 15:47 ` Srivatsa S. Bhat
2012-09-26 16:03 ` Srivatsa S. Bhat
2012-09-26 17:06 ` Suresh Siddha
2012-09-26 17:30 ` Srivatsa S. Bhat
2012-09-26 22:46 ` Suresh Siddha
2012-09-27 18:42 ` Srivatsa S. Bhat
2012-09-27 19:20 ` Suresh Siddha
2012-09-27 20:33 ` Srivatsa S. Bhat [this message]
2012-10-09 8:51 ` Liu, Chuansheng
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