From: jason77.wang@gmail.com (Hui Wang)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: fix cpu_relax() in case of doing dmb
Date: Thu, 23 Aug 2012 10:47:41 +0800 [thread overview]
Message-ID: <503599CD.4060907@gmail.com> (raw)
In-Reply-To: <1345647138-8815-1-git-send-email-shawn.guo@linaro.org>
Shawn Guo wrote:
> There is an issue reported on imx6q restart function. The issue is only
> seen with the image building ARMv7 and ARMv6 together, where cpu_relax()
> is define to do dmb. It's been root-caused by Russell as below.
>
> Russell King - ARM Linux wrote:
>
>> I suspect having this dmb inside cpu_relax() is flooding the
>> interconnects with traffic, which then prevents other CPUs getting
>> a look-in (maybe there's no fairness when it comes to dmb's.
>>
>
> Fix the issue by insert a few NOPs into cpu_relax() where doing dmb.
>
Tested-by: Hui Wang <jason77.wang@gmail.com>
next prev parent reply other threads:[~2012-08-23 2:47 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-22 14:52 [PATCH] ARM: fix cpu_relax() in case of doing dmb Shawn Guo
2012-08-23 2:47 ` Hui Wang [this message]
2012-08-23 10:23 ` Dirk Behme
2012-08-23 10:43 ` Will Deacon
2012-08-23 13:58 ` Shawn Guo
2012-08-23 18:31 ` Jon Medhurst (Tixy)
2012-08-24 1:15 ` Shawn Guo
2012-08-24 9:14 ` Jon Medhurst (Tixy)
2012-08-24 1:10 ` Hui Wang
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=503599CD.4060907@gmail.com \
--to=jason77.wang@gmail.com \
--cc=linux-arm-kernel@lists.infradead.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;
as well as URLs for NNTP newsgroup(s).