From: "H. Peter Anvin" <hpa@zytor.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>,
Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
Yinghai Lu <yinghai@kernel.org>,
"Maciej W. Rozycki" <macro@linux-mips.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [patch] x86, apic: use 0x20 for the IRQ_MOVE_CLEANUP_VECTOR instead of 0x1f
Date: Mon, 11 Jan 2010 16:42:26 -0800 [thread overview]
Message-ID: <4B4BC572.4070002@zytor.com> (raw)
In-Reply-To: <m17hro6ua9.fsf@fess.ebiederm.org>
On 01/11/2010 04:28 PM, Eric W. Biederman wrote:
>
> Without changes assign_irq_vector will reuse vectors in the range
> IRQ0_VECTOR to IRQ15_VECTOR in the code as it we currently ship it,
> when we switch irq0-15 into ioapic mode.
>
> Switching the loop to cover IRQ0_VECTOR to IRQ15_VECTOR is not a
> problem. I don't think it will find anything free as we assign those
> vectors on all cpus, but the data structures are fine.
>
The question there is if we can treat the resulting ioapic IRQs as
normal movable IRQs, and just let the target-moving mechanism take care
of it. After all, there is a discrete event at which we decide that any
particular interrupt is an IOAPIC interrupt instead of XT-PIC.
Obviously, the vectors that remain XT-PIC vectors have to remain
allocated on all vectors for all time.
Another question is why we reserve the legacy IRQ 2 vector at all --
except when ACPI is present! I don't think it could ever be tickled,
and it sort of felt as a "just in case" thing that could be removed.
-hpa
next prev parent reply other threads:[~2010-01-12 0:43 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-09 2:09 [patch] x86, apic: use 0x20 for the IRQ_MOVE_CLEANUP_VECTOR instead of 0x1f Suresh Siddha
2010-01-09 2:19 ` H. Peter Anvin
2010-01-09 2:50 ` Yinghai Lu
2010-01-11 22:53 ` Suresh Siddha
2010-01-11 22:57 ` H. Peter Anvin
2010-01-11 23:10 ` Eric W. Biederman
2010-01-11 23:13 ` H. Peter Anvin
2010-01-12 0:06 ` Suresh Siddha
2010-01-12 0:13 ` H. Peter Anvin
2010-01-12 0:28 ` Eric W. Biederman
2010-01-12 0:36 ` H. Peter Anvin
2010-01-12 1:52 ` Eric W. Biederman
2010-01-12 2:17 ` H. Peter Anvin
2010-01-12 2:27 ` Eric W. Biederman
2010-01-12 10:25 ` Alan Cox
2010-01-13 20:36 ` Eric W. Biederman
2010-01-13 20:38 ` H. Peter Anvin
2010-01-13 20:53 ` H. Peter Anvin
2010-01-13 20:58 ` H. Peter Anvin
2010-01-12 0:42 ` H. Peter Anvin [this message]
2010-01-11 23:00 ` Eric W. Biederman
2010-01-11 23:07 ` H. Peter Anvin
2010-01-09 3:07 ` Yinghai Lu
2010-01-09 3:20 ` H. Peter Anvin
2010-01-09 3:23 ` H. Peter Anvin
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