From: ebiederm@xmission.com (Eric W. Biederman)
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>,
Jesse Brandeburg <jesse.brandeburg@gmail.com>,
Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
"linux-kernel\@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
NetDEV list <netdev@vger.kernel.org>,
Jesse Brandeburg <jesse.brandeburg@intel.com>
Subject: Re: Subject: [PATCH 1/2] x86: get back 15 vectors
Date: Mon, 04 Jan 2010 11:09:05 -0800 [thread overview]
Message-ID: <m1my0thelq.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <4B423B08.3010005@zytor.com> (H. Peter Anvin's message of "Mon\, 04 Jan 2010 11\:01\:28 -0800")
"H. Peter Anvin" <hpa@zytor.com> writes:
> On 01/04/2010 08:18 AM, Eric W. Biederman wrote:
>> Yinghai Lu <yinghai@kernel.org> writes:
>>
>> This patch is wrong.
>>
>>> between FIRST_EXTERNAL_VECTOR (0x20) and FIRST_DEVICE_VECTOR (0x41)
>>>
>>> for 0x20 and 0x2f, we are safe be used_vectors will prevent it to use used one.
>>
>> We can not use any of 0x20 - 0x2f for ioapic irqs. We need the entire
>> priority level to ensure that the irq move cleanup ipi is of a lower
>> priority.
>>
>
> Almost makes one want to abuse 0x1f for that. Although 0x00..0x1f are
> reserved for exceptions, the APICs range down to 0x10, and well, when
> 0x1f ends up actually getting used as an exception vector that we
> support, then we can trivially change that. In the meantime it would
> actually make use of an otherwise-unusable APIC priority level.
An optimization like that (with a big fat comment) seems reasonable
to me.
Eric
next prev parent reply other threads:[~2010-01-04 19:09 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-25 8:42 [PATCH] x86: increase NR_IRQS and nr_irqs Yinghai Lu
2009-12-28 9:47 ` Ingo Molnar
2009-12-29 5:08 ` [PATCH -v2] " Yinghai Lu
2009-12-30 12:21 ` [tip:x86/apic] x86: Increase " tip-bot for Yinghai Lu
2010-01-04 3:06 ` [PATCH -v2] x86: increase " Jesse Brandeburg
2010-01-04 3:20 ` Yinghai Lu
2010-01-04 6:56 ` Subject: [PATCH 1/2] x86: get back 15 vectors Yinghai Lu
2010-01-04 16:18 ` Eric W. Biederman
2010-01-04 18:40 ` Yinghai Lu
2010-01-04 19:04 ` Eric W. Biederman
2010-01-04 19:14 ` H. Peter Anvin
2010-01-04 19:01 ` H. Peter Anvin
2010-01-04 19:09 ` Eric W. Biederman [this message]
2010-01-04 19:35 ` Yinghai Lu
2010-01-04 19:45 ` Suresh Siddha
2010-01-04 19:50 ` H. Peter Anvin
2010-01-05 0:05 ` Suresh Siddha
2010-01-05 0:16 ` Yinghai Lu
2010-01-05 5:30 ` [tip:x86/apic] x86, apic: Reclaim IDT vectors 0x20-0x2f tip-bot for H. Peter Anvin
2010-01-04 19:48 ` Subject: [PATCH 1/2] x86: get back 15 vectors H. Peter Anvin
2010-01-04 20:06 ` Yinghai Lu
2010-01-04 20:14 ` Eric W. Biederman
2010-01-04 20:33 ` Yinghai Lu
2010-01-04 21:10 ` H. Peter Anvin
2010-01-04 21:20 ` Yinghai Lu
2010-01-04 21:33 ` H. Peter Anvin
2010-01-04 22:01 ` Yinghai Lu
2010-01-04 23:03 ` H. Peter Anvin
2010-01-04 23:32 ` Yinghai Lu
2010-01-04 23:38 ` H. Peter Anvin
2010-01-04 23:42 ` Yinghai Lu
2010-01-04 23:49 ` Yinghai Lu
2010-01-04 23:59 ` H. Peter Anvin
2010-01-05 5:30 ` [tip:x86/apic] x86, apic: Don't waste a vector to improve vector spread tip-bot for H. Peter Anvin
2010-01-04 20:08 ` Subject: [PATCH 1/2] x86: get back 15 vectors Eric W. Biederman
2010-01-04 6:58 ` [PATCH 2/2] x86: get more exact nr_irqs Yinghai Lu
2010-01-04 16:55 ` Eric W. Biederman
2010-01-04 19:03 ` Yinghai Lu
2010-01-04 19:16 ` Eric W. Biederman
2010-01-04 19:30 ` H. Peter Anvin
2010-01-04 19:47 ` Yinghai Lu
2010-01-04 20:05 ` Eric W. Biederman
2010-01-04 21:50 ` H. Peter Anvin
2010-01-04 6:59 ` [PATCH 1/2] x86: get back 15 vectors Yinghai Lu
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