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From: "H. Peter Anvin" <hpa@zytor.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Yinghai Lu <yinghai@kernel.org>, Ingo Molnar <mingo@elte.hu>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Jesse Brandeburg <jesse.brandeburg@intel.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/5] x86: update nr_irqs according cpu num
Date: Fri, 08 Jan 2010 13:15:49 -0800	[thread overview]
Message-ID: <4B47A085.1010703@zytor.com> (raw)
In-Reply-To: <m1my0oici4.fsf@fess.ebiederm.org>

On 01/08/2010 12:10 PM, Eric W. Biederman wrote:
> 
> I don't know if we ever actually perform vector sharing.  The only case
> I recall where the code could share vectors is if the firmware tables
> told us to irq sources were the same interrupt.  I don't think that
> happens.  We do have the remains of support for vector sharing
> in the code but I don't think it is utilized.  MSI interrupts certainly
> can not share vectors.
> 

We probably will need to support that at some point, though, simply
because it's not all that hard to construct a system in which there are
more MSI-X interrupts than there are possible vectors in the system.

Until then we can do 224 * nr_cpus_ids, but it's still not the right thing.

> Yes.  It was enough of a pain the first pass at it that we wound
> up with nr_irqs, a value that can vary at boot time.
> 
> Once YH's radix tree changes get it in.  A war on NR_IRQS and nr_irqs
> seems appropriate.

Agreed.

	-hpa


  reply	other threads:[~2010-01-08 21:24 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-08 11:53 [PATCH 1/5] irq: remove not need bootmem code Yinghai Lu
2010-01-08 11:53 ` [PATCH 2/5] radix: move radix init early Yinghai Lu
2010-01-08 11:53 ` [PATCH 3/5] sparseirq: change irq_desc_ptrs to static Yinghai Lu
2010-01-08 11:53 ` [PATCH 4/5] sparseirq: use radix_tree instead of ptrs array Yinghai Lu
2010-01-08 12:14   ` Cyrill Gorcunov
2010-01-08 18:43     ` Eric W. Biederman
2010-01-08 11:53 ` [PATCH 5/5] x86: update nr_irqs according cpu num Yinghai Lu
2010-01-08 19:11   ` Eric W. Biederman
2010-01-08 19:21     ` H. Peter Anvin
2010-01-08 20:06       ` Yinghai Lu
2010-01-08 21:11         ` H. Peter Anvin
2010-01-08 20:10       ` Eric W. Biederman
2010-01-08 21:15         ` H. Peter Anvin [this message]
2010-01-08 19:49     ` Yinghai Lu
2010-01-08 20:20       ` Eric W. Biederman
2010-01-08 20:43         ` Yinghai Lu
2010-01-08 18:52 ` [PATCH 1/5] irq: remove not need bootmem code Eric W. Biederman

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