From: "H. Peter Anvin" <hpa@zytor.com>
To: "Eric W. Biederman" <ebiederm@xmission.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 11:14:44 -0800 [thread overview]
Message-ID: <4B423E24.90106@zytor.com> (raw)
In-Reply-To: <m1vdfhhesx.fsf@fess.ebiederm.org>
On 01/04/2010 11:04 AM, Eric W. Biederman wrote:
>>
>> any reason that we can not use 0x40?
>
> Not that I now of. Reading the comment it looks like it was only
> skipped so that the initial assignment of vectors would be.
>
> 0x31, 0x41, 0x51, 0x61, 0x71, 0x81, 0x91, 0xa1, 0xb1, 0xc1, 0xd1, 0xe1
> Instead of.
> 0x30, 0x40, 0x50, 0x60, 0x70, 0x90, 0xa0, 0xb0, 0xc0, 0xc0, 0xe0
>
> Which doesn't seem to be the worst notion, but at the point we are looking
> for every vector we can get it does seem to be problematic.
>
This can presumably be worked around by tweaking the initial assignment
algorithm slightly, without losing a whole vector to that.
Also, if we abuse vector 0x1f as the IRQ reassignment vector, we free up
a full 16 vectors per CPU -- this seems worthwhile especially since it
is a decision that can be trivially undone in the future: this is all
kernel internal, we're not creating any kind of API.
-hpa
next prev parent reply other threads:[~2010-01-04 19:15 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 [this message]
2010-01-04 19:01 ` H. Peter Anvin
2010-01-04 19:09 ` Eric W. Biederman
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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