From: Tejun Heo <tj@kernel.org>
To: Peter Hurley <peter@hurleysoftware.com>
Cc: laijs@cn.fujitsu.com, linux-scsi@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux1394-devel@lists.sourceforge.net,
target-devel@vger.kernel.org
Subject: Re: [PATCH 4/9] firewire: don't use PREPARE_DELAYED_WORK
Date: Sat, 22 Feb 2014 09:38:59 -0500 [thread overview]
Message-ID: <20140222143859.GD12830@htj.dyndns.org> (raw)
In-Reply-To: <5307E550.4040004@hurleysoftware.com>
Hey,
On Fri, Feb 21, 2014 at 06:46:24PM -0500, Peter Hurley wrote:
> It's a long story but the short version is that
> Documentation/memory-barriers.txt recently was overhauled to reflect
> what cpus actually do and what the different archs actually
> deliver.
>
> Turns out that unlock + lock is not guaranteed by all archs to be
> a full barrier. Thus the smb_mb__after_unlock_lock().
>
> This is now all spelled out in memory-barriers.txt under the
> sub-heading "IMPLICIT KERNEL MEMORY BARRIERS".
So, that one is for unlock/lock sequence, not smp_mb__after_unlock().
Urgh... kinda dislike adding smp_rmb() there as it's one of the
barriers which translate to something weighty on most, if not all,
archs.
Thanks.
--
tejun
------------------------------------------------------------------------------
Managing the Performance of Cloud-Based Applications
Take advantage of what the Cloud has to offer - Avoid Common Pitfalls.
Read the Whitepaper.
http://pubads.g.doubleclick.net/gampad/clk?id=121054471&iu=/4140/ostg.clktrk
next prev parent reply other threads:[~2014-02-22 14:38 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1392929071-16555-1-git-send-email-tj@kernel.org>
2014-02-20 20:44 ` [PATCH 4/9] firewire: don't use PREPARE_DELAYED_WORK Tejun Heo
2014-02-21 1:44 ` Peter Hurley
2014-02-21 1:59 ` Tejun Heo
2014-02-21 2:07 ` Peter Hurley
2014-02-21 2:13 ` Tejun Heo
2014-02-21 5:13 ` Peter Hurley
2014-02-21 10:03 ` Tejun Heo
2014-02-21 12:51 ` Peter Hurley
2014-02-21 13:06 ` Tejun Heo
2014-02-21 16:53 ` Peter Hurley
2014-02-21 16:57 ` Tejun Heo
2014-02-21 23:01 ` Peter Hurley
2014-02-21 23:18 ` Tejun Heo
2014-02-21 23:46 ` Peter Hurley
2014-02-22 14:38 ` Tejun Heo [this message]
2014-02-22 14:48 ` Peter Hurley
2014-02-22 18:43 ` James Bottomley
2014-02-22 18:48 ` Peter Hurley
2014-02-22 18:52 ` James Bottomley
2014-02-22 19:03 ` Peter Hurley
2014-02-23 1:23 ` memory-barriers.txt again (was Re: [PATCH 4/9] firewire: don't use PREPARE_DELAYED_WORK) Stefan Richter
2014-02-23 16:37 ` Paul E. McKenney
2014-02-23 20:35 ` Peter Hurley
2014-02-23 23:50 ` Paul E. McKenney
2014-02-24 0:09 ` Peter Hurley
2014-02-24 16:26 ` Paul E. McKenney
2014-02-24 0:32 ` Stefan Richter
2014-02-24 16:27 ` Paul E. McKenney
2014-02-23 20:05 ` [PATCH 4/9] firewire: don't use PREPARE_DELAYED_WORK James Bottomley
2014-02-23 22:32 ` Peter Hurley
2014-02-21 20:45 ` Stefan Richter
2014-03-07 15:26 ` [PATCH UPDATED " Tejun Heo
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=20140222143859.GD12830@htj.dyndns.org \
--to=tj@kernel.org \
--cc=laijs@cn.fujitsu.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=linux1394-devel@lists.sourceforge.net \
--cc=peter@hurleysoftware.com \
--cc=target-devel@vger.kernel.org \
/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