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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4B423E24.90106@zytor.com \
--to=hpa@zytor.com \
--cc=akpm@linux-foundation.org \
--cc=ebiederm@xmission.com \
--cc=jesse.brandeburg@gmail.com \
--cc=jesse.brandeburg@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=netdev@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=yinghai@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.