From: Pavel Machek <pavel@ucw.cz>
To: Norbert van Bolhuis <nvbolhuis@aimvalley.nl>
Cc: linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>
Subject: Re: PROBLEM: CONFIG_NO_HZ could cause software timeouts
Date: Sun, 6 Sep 2009 07:27:17 +0200 [thread overview]
Message-ID: <20090906052717.GC1324@ucw.cz> (raw)
In-Reply-To: <4A9F9F64.5080305@aimvalley.nl>
On Thu 2009-09-03 12:50:12, Norbert van Bolhuis wrote:
>
> The problem occurs when e.g. drivers use time_after(jiffes, timeout).
>
> CONFIG_NO_HZ could make jiffies advance by more than 1.
> This is done by: tick_nohz_update_jiffies->tick_do_update_jiffies64->do_timer
jiffies really should be up-to-date as long as you are running
anything else than idle loop. If not, that's a bug ... and nasty one.
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
prev parent reply other threads:[~2009-09-06 5:27 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-03 10:50 PROBLEM: CONFIG_NO_HZ could cause software timeouts Norbert van Bolhuis
2009-09-03 11:22 ` Corrado Zoccolo
2009-09-03 11:59 ` Norbert van Bolhuis
2009-09-05 18:19 ` Marcin Slusarz
2009-09-06 5:58 ` Pavel Machek
2009-09-06 10:11 ` Marcin Slusarz
2009-09-06 5:27 ` Pavel Machek [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=20090906052717.GC1324@ucw.cz \
--to=pavel@ucw.cz \
--cc=linux-kernel@vger.kernel.org \
--cc=nvbolhuis@aimvalley.nl \
--cc=tglx@linutronix.de \
/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