From: ebiederm@xmission.com (Eric W. Biederman)
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Mike Travis <travis@sgi.com>, Yinghai Lu <yhlu.kernel@gmail.com>,
Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
Dhaval Giani <dhaval@linux.vnet.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 00/16] dyn_array and nr_irqs support v2
Date: Mon, 04 Aug 2008 20:40:05 -0700 [thread overview]
Message-ID: <m1ej54nn8q.fsf@frodo.ebiederm.org> (raw)
In-Reply-To: <4897BD23.8060801@zytor.com> (H. Peter Anvin's message of "Mon, 04 Aug 2008 19:38:27 -0700")
"H. Peter Anvin" <hpa@zytor.com> writes:
> Mike Travis wrote:
>>>
>>> So on my wish list is to stably encode the MSI interurrpt numbers. And
>>> using a sparse irq address space I can. As it only takes 28 bits to hold
>>> the complete bus + device + function + msi source [ 0-4095 ]
>>
>> Don't you need "domain" (node) in the bus:device:function:vector combination?
>> (Or [hack] use a lot bigger field for bus with the node encoded into it.)
>>
>
> You definitely need domain, and that blows the 32-bit limit quite out of the
> water.
Yes. Although when I dreamed it up it domain wasn't more then a twinkle in
someone's eye on x86. I'm not certain it is much more than that now.
The interesting implication of this is that if you have the right hardware
and are absolutely loopy you can have more interrupt sources than can
be described in a 32bit unsigned int, and certainly more than any sane person
would allocate in a statically sized array.
Eric
next prev parent reply other threads:[~2008-08-05 3:43 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-01 9:37 [PATCH 00/16] dyn_array and nr_irqs support v2 Yinghai Lu
2008-08-01 9:37 ` [PATCH 01/16] x86: 64bit support more than 256 irq Yinghai Lu
2008-08-01 9:37 ` [PATCH 02/16] x86: introduce nr_irqs for 64bit v3 Yinghai Lu
2008-08-01 9:37 ` [PATCH 03/16] add dyn_array support Yinghai Lu
2008-08-01 9:37 ` [PATCH 04/16] make irq_timer_state to use dyn_array Yinghai Lu
2008-08-01 9:37 ` [PATCH 05/16] make irq2_iommu " Yinghai Lu
2008-08-01 9:37 ` [PATCH 06/16] make irq_desc " Yinghai Lu
2008-08-01 9:37 ` [PATCH 07/16] x86: make 64bit support dyn_array Yinghai Lu
2008-08-01 9:37 ` [PATCH 08/16] serial: change remove NR_IRQS in 8250.c v2 Yinghai Lu
2008-08-01 9:37 ` [PATCH 09/16] add per_cpu_dyn_array support Yinghai Lu
2008-08-01 9:37 ` [PATCH 10/16] irq: make irqs in kernel stat use per_cpu_dyn_array Yinghai Lu
2008-08-01 9:37 ` [PATCH 11/16] x86 remove irq_vectors_limit.h Yinghai Lu
2008-08-01 9:37 ` [PATCH 12/16] x86: make 32bit use dyn_array Yinghai Lu
2008-08-01 9:37 ` [PATCH 13/16] add per_cpu_dyn_array for arch percpu support Yinghai Lu
2008-08-01 9:37 ` [PATCH 14/16] x86: get mp_irqs from madt Yinghai Lu
2008-08-01 9:37 ` [PATCH 15/16] x86: make 32bit more like with io_apic/dyn_array to 64 bit Yinghai Lu
2008-08-01 9:37 ` [PATCH 16/16] x86: alloc dyn_array all alltogether Yinghai Lu
2008-08-01 20:46 ` [PATCH 00/16] dyn_array and nr_irqs support v2 Eric W. Biederman
2008-08-01 21:30 ` Yinghai Lu
2008-08-01 21:57 ` Yinghai Lu
2008-08-01 22:45 ` Eric W. Biederman
2008-08-01 22:10 ` Yinghai Lu
2008-08-01 22:38 ` Eric W. Biederman
2008-08-02 1:09 ` Yinghai Lu
2008-08-02 1:36 ` H. Peter Anvin
2008-08-02 1:41 ` Eric W. Biederman
2008-08-02 2:01 ` Yinghai Lu
2008-08-02 2:03 ` H. Peter Anvin
2008-08-02 2:39 ` Eric W. Biederman
2008-08-02 3:28 ` H. Peter Anvin
2008-08-02 4:42 ` Eric W. Biederman
2008-08-02 15:41 ` H. Peter Anvin
2008-08-02 20:20 ` Eric W. Biederman
2008-08-04 12:57 ` Mike Travis
2008-08-05 2:38 ` H. Peter Anvin
2008-08-05 3:40 ` Eric W. Biederman [this message]
2008-08-05 3:48 ` H. Peter Anvin
2008-08-01 21:47 ` Mike Travis
2008-08-02 2:58 ` Yinghai Lu
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