| |
|
 |
|
 |
|
|
|
| |
|
|
xen-devel
Re: [Xen-devel] [PATCH 00/04] Kexec / Kdump: Release 20061122 (xen-unsta
|
To: |
"Ian Campbell" <Ian.Campbell@xxxxxxxxxxxxx> |
|
Subject: |
Re: [Xen-devel] [PATCH 00/04] Kexec / Kdump: Release 20061122 (xen-unstable-12502) |
|
From: |
"Magnus Damm" <magnus.damm@xxxxxxxxx> |
|
Date: |
Wed, 29 Nov 2006 20:13:39 +0900 |
|
Cc: |
Ian Pratt <m+Ian.Pratt@xxxxxxxxxxxx>, Kazuo Moriwaka <moriwaka@xxxxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx, Akio Takebe <takebe_akio@xxxxxxxxxxxxxx>, Isaku Yamahata <yamahata@xxxxxxxxxxxxx>, Magnus Damm <magnus@xxxxxxxxxxxxx>, Horms <horms@xxxxxxxxxxxx> |
|
Delivery-date: |
Wed, 29 Nov 2006 03:13:42 -0800 |
|
Domainkey-signature: |
a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=LXjGvNfJu5SXv5nHt9PgC5POt7bT9nB+xq5MiU8f/QIIebNvHqXLzQE82yNZtaWJg8MEXF5lOXh02HzD4ou/ejEettZANLlla6ylDjTMTwpv/do0PyfyS3mvagNMbPH4Tiyi7TYqQFS6udlIla5i6fxee7bBOqC8OWz8Xu5fh9A= |
|
Envelope-to: |
www-data@xxxxxxxxxxxxxxxxxx |
|
In-reply-to: |
<1164792929.3336.228.camel@xxxxxxxxxxxxxxxxxxxxx> |
|
List-help: |
<mailto:xen-devel-request@lists.xensource.com?subject=help> |
|
List-id: |
Xen developer discussion <xen-devel.lists.xensource.com> |
|
List-post: |
<mailto:xen-devel@lists.xensource.com> |
|
List-subscribe: |
<http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe> |
|
List-unsubscribe: |
<http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe> |
|
References: |
<C192ED37.5016%Keir.Fraser@xxxxxxxxxxxx> <1164788262.30816.41.camel@localhost> <1164792929.3336.228.camel@xxxxxxxxxxxxxxxxxxxxx> |
|
Sender: |
xen-devel-bounces@xxxxxxxxxxxxxxxxxxx |
On 11/29/06, Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx> wrote:
On Wed, 2006-11-29 at 17:17 +0900, Magnus Damm wrote:
>
> The kexec tool creates (at load time) one PT_NOTE program header per
> note exported through /proc/iomem. The number of PT_NOTE program headers
> is the same as the NR_CPUS constant in the hypervisor.
The guest kernel creates entries in /proc/iomem by calling
kexec_get_cpu(cpu) until it returns EINVAL. This currently happens when
cpu>NR_CPUS.
I think this function should return EINVAL for cpu>num_present_cpus()
instead. Xen doesn't currently do PCPU hotplug and this wouldn't be the
only thing that would need fixing if it ever does (percpu data would be
another one I think ;-)).
This would cause the tools to create notes only for CPUs which really
exist. That would make the loop in machine_crash_kexec() unnecessary.
I feel that using bss instead of per-cpu data is more robust and will
make future cpu hotplug support a breeze to implement - at least in
the case of kexec. Using bss also makes the loop in
machine_crash_kexec() unnecessary.
Using num_present_cpus() will of course work as well, but I'd like to
avoid adding code that likely needs to be rewritten in the near
future.. But you know the future better than I do, so what do you
think? =)
Thanks!
/ magnus
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
|
|
| |
|
Home