From: Rusty Russell <rusty@rustcorp.com.au>
To: Lee Revell <rlrevell@joe-job.com>
Cc: Zwane Mwaikambo <zwane@linuxpower.ca>,
Dominik Brodowski <linux@dominikbrodowski.de>,
lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] [CPU-HOTPLUG] convert cpucontrol to be a rwsem
Date: Tue, 02 Nov 2004 10:48:23 +1100 [thread overview]
Message-ID: <1099352903.20402.2.camel@localhost.localdomain> (raw)
In-Reply-To: <1099332277.3647.43.camel@krustophenia.net>
On Mon, 2004-11-01 at 13:04 -0500, Lee Revell wrote:
> On Mon, 2004-11-01 at 07:00 -0700, Zwane Mwaikambo wrote:
> > Agreed it makes a lot more sense, i think there could be some places where
> > we use preempt_disable to protect against cpu offline which could
> > converted, but that can come later.
> >
>
> You know I picked up Robert Love's book the other day and was surprised
> to read we are not supposed to be using preempt_disable, there is a
> per_cpu interface for exactly this kind of thing. Which is currently
> recommended?
get_cpu() both ensures that this CPU won't go down, and ensures we won't
get scheduled off it. It returns the current processor ID, as well.
put_cpu() puts the CPU back.
In my experience it's usually clearer than preempt_disable().
Cheers,
Rusty.
--
A bad analogy is like a leaky screwdriver -- Richard Braakman
next prev parent reply other threads:[~2004-11-02 9:41 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-11-01 8:43 [PATCH] [CPU-HOTPLUG] convert cpucontrol to be a rwsem Dominik Brodowski
2004-11-01 9:05 ` Nick Piggin
2004-11-01 14:00 ` Zwane Mwaikambo
2004-11-01 18:04 ` Lee Revell
2004-11-01 23:48 ` Rusty Russell [this message]
2004-11-02 14:54 ` Lee Revell
2004-11-02 0:16 ` Zwane Mwaikambo
2004-11-02 22:28 ` Dominik Brodowski
2004-11-04 1:57 ` Rusty Russell
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=1099352903.20402.2.camel@localhost.localdomain \
--to=rusty@rustcorp.com.au \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@dominikbrodowski.de \
--cc=rlrevell@joe-job.com \
--cc=zwane@linuxpower.ca \
/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