From: Chase Venters <chase.venters@clientec.com>
To: Rene Herman <rene.herman@keyaccess.nl>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: 2.6.17-rc3 -- SMP alternatives: switching to UP code
Date: Tue, 9 May 2006 20:55:01 -0500 [thread overview]
Message-ID: <200605092055.23265.chase.venters@clientec.com> (raw)
In-Reply-To: <4461341B.7050602@keyaccess.nl>
On Tuesday 09 May 2006 19:29, Rene Herman wrote:
> Hi list.
>
> I just noticed this in the 2.6.17-rc3 dmesg:
>
> ===
> Checking 'hlt' instruction... OK.
> SMP alternatives: switching to UP code
> Freeing SMP alternatives: 0k freed
> ACPI: setting ELCR to 0400 (from 1608)
> ===
>
> Should I be seeing this "SMP alternatives" thing on a !CONFIG_SMP
> kernel? It does say 0k, but something is apparently being done at
> runtime still. Why?
This is part of a recent patch by Gerd Hoffmann:
>> Implement SMP alternatives, i.e. switching at runtime between different
>> code versions for UP and SMP. The code can patch both SMP->UP and UP->SMP.
>> The UP->SMP case is useful for CPU hotplug.
An explicit test of the smp variable (not CONFIG_SMP macro) exists in this
code. I missed the discussion about this patch, but it appears from reading
the patch notes that the behavior is intentional. More information can be
found in the git and lkml archives.
> Rene.
Thanks,
Chase
next prev parent reply other threads:[~2006-05-10 1:55 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-05-10 0:30 2.6.17-rc3 -- SMP alternatives: switching to UP code Rene Herman
2006-05-10 1:55 ` Chase Venters [this message]
2006-05-10 9:28 ` Gerd Hoffmann
2006-05-10 11:41 ` Rene Herman
2006-05-11 12:13 ` [patch] SMP alternatives: skip with UP kernels Gerd Hoffmann
2006-05-11 21:07 ` Rene Herman
2006-05-12 11:41 ` Gerd Hoffmann
2006-05-15 21:41 ` Rene Herman
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=200605092055.23265.chase.venters@clientec.com \
--to=chase.venters@clientec.com \
--cc=linux-kernel@vger.kernel.org \
--cc=rene.herman@keyaccess.nl \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox