From: Richard Weinberger <richard@nod.at>
To: Pekka Enberg <penberg@kernel.org>
Cc: Tejun Heo <tj@kernel.org>, Christoph Lameter <cl@linux.com>,
linux-kernel@vger.kernel.org,
user-mode-linux-devel@lists.sourceforge.net, hpa@zytor.com
Subject: Re: um: this_cpu_cmpxchg16b_emu
Date: Tue, 12 Apr 2011 22:27:03 +0200 [thread overview]
Message-ID: <201104122227.03688.richard@nod.at> (raw)
In-Reply-To: <BANLkTimsw1N=0QkEsySBE58GJx7g12XQpQ@mail.gmail.com>
Am Dienstag 12 April 2011, 21:22:47 schrieb Pekka Enberg:
> On Tue, Apr 12, 2011 at 08:41:11PM +0200, Richard Weinberger wrote:
> >> Am Dienstag 12 April 2011, 20:10:37 schrieb Christoph Lameter:
> >> > On Tue, 12 Apr 2011, Richard Weinberger wrote:
> >> > > This patch implements this_cpu_cmpxchg16b_emu() for UML.
> >> >
> >> > Is this really necessary? Just undefine CONFIG_CMPXCHG_LOCAL for UML
> >> > and the asm code will not be used.
> >>
> >> UML includes arch/x86/Kconfig.cpu which defines CONFIG_CMPXCHG_LOCAL
> >> automatically. Just disabling CONFIG_CMPXCHG_LOCAL for UML is IMHO not
> >> very nice. When chpxchg is available also UML should use it...
>
> On Tue, Apr 12, 2011 at 10:20 PM, Tejun Heo <tj@kernel.org> wrote:
> > Ugh... I'd really like to avoid things like this for UML. Is there
> > any SLUB performance sensitive workload running on UML? I've never
> > seen any UML in production environment. Wouldn't it be better to keep
> > things simple?
>
> Yes, it would be. :-)
Okay. Then let's keep it simple. :-)
I'll disable CONFIG_CMPXCHG_LOCAL for UML.
Has someone looked at my this_cpu_cmpxchg16b_emu() implementation,
is it correct? Especially the call to C stuff.
I've tested it, it works fine.
Thanks,
//richard
prev parent reply other threads:[~2011-04-12 20:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-12 14:09 [uml-devel] um: this_cpu_cmpxchg16b_emu Richard Weinberger
2011-04-12 18:10 ` Christoph Lameter
2011-04-12 18:41 ` Richard Weinberger
2011-04-12 19:20 ` Tejun Heo
2011-04-12 19:22 ` Pekka Enberg
2011-04-12 20:27 ` Richard Weinberger [this message]
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=201104122227.03688.richard@nod.at \
--to=richard@nod.at \
--cc=cl@linux.com \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=penberg@kernel.org \
--cc=tj@kernel.org \
--cc=user-mode-linux-devel@lists.sourceforge.net \
/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