From: Tejun Heo <tj@kernel.org>
To: Ming Lei <tom.leiming@gmail.com>
Cc: Christoph Lameter <cl@linux.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
linux-kernel@vger.kernel.org, yong.zhang0@gmail.com
Subject: Re: [PATCH] percpu: use raw_local_irq_* in _this_cpu op
Date: Tue, 14 Feb 2012 08:19:01 -0800 [thread overview]
Message-ID: <20120214161901.GL12117@google.com> (raw)
In-Reply-To: <CACVXFVMyihmG3NexXOqTUoJb8UJFa7dJqYGOr6oC_y5heFSo1A@mail.gmail.com>
On Tue, Feb 14, 2012 at 11:30:06AM +0800, Ming Lei wrote:
> On Tue, Feb 14, 2012 at 1:23 AM, Tejun Heo <tj@kernel.org> wrote:
> > On Mon, Feb 13, 2012 at 07:03:38PM +0800, Ming Lei wrote:
> >> It doesn't make sense to trace irq off or do irq flags
> >> lock proving inside 'this_cpu' operations, so replace local_irq_*
> >> with raw_local_irq_* in 'this_cpu' op.
> >>
> >> Also the patch fixes one lockdep warning[1], which is caused
> >> by the added local_irq_save/restore(flags) in this_cpu_inc
> >> called by __debug_atomic_inc: kernel/lockdep.c
> >
> > I think this isn't gonna hurt anything but I don't understand why the
> > lockdep warning is triggering when using traced version. Can you
> > please explain that in a bit more detail in the patch description?
>
> In trace_hardirqs_on_caller:kernel/lockdep.c, __debug_atomic_inc
> will be called to add on 'this_cpu' variable, so may introduce recursive
> trace_hardirqs_on|off_caller called.
Ah, okay, so lockdep itself is using this_cpu ops. Can you please
repost the patch with the above info in the description?
Thank you.
--
tejun
prev parent reply other threads:[~2012-02-14 16:19 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-13 11:03 [PATCH] percpu: use raw_local_irq_* in _this_cpu op Ming Lei
2012-02-13 14:59 ` Christoph Lameter
2012-02-13 17:23 ` Tejun Heo
2012-02-14 3:30 ` Ming Lei
2012-02-14 7:40 ` Yong Zhang
2012-02-14 14:53 ` Ming Lei
2012-02-14 16:19 ` Tejun Heo [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=20120214161901.GL12117@google.com \
--to=tj@kernel.org \
--cc=a.p.zijlstra@chello.nl \
--cc=cl@linux.com \
--cc=linux-kernel@vger.kernel.org \
--cc=tom.leiming@gmail.com \
--cc=yong.zhang0@gmail.com \
/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.