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From: Suresh Siddha <suresh.b.siddha@intel.com>
To: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.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: Thu, 27 Sep 2012 12:20:57 -0700	[thread overview]
Message-ID: <1348773658.6644.36.camel@sbsiddha-desk.sc.intel.com> (raw)
In-Reply-To: <50649E1C.40602@linux.vnet.ibm.com>

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. The user-specified
affinity still has the cpu that 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.

hope this clears it!

thanks.


  reply	other threads:[~2012-09-27 19:20 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-26 17:38 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 [this message]
2012-09-27 20:33               ` Srivatsa S. Bhat
2012-10-09  8:51           ` Liu, Chuansheng

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