linux-kernel - Re: nohz problem with idle time on old hardware

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 9 Apr 2014 11:39:23 -0400
From:	Steven Rostedt <rostedt@...dmis.org>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	Viresh Kumar <viresh.kumar@...aro.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Matthew Whitehead <tedheadster@...il.com>,
	John Stultz <john.stultz@...aro.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	mwhitehe@...hat.com, Frederic Weisbecker <fweisbec@...il.com>
Subject: Re: nohz problem with idle time on old hardware

On Wed, 9 Apr 2014 11:31:43 -0400
Steven Rostedt <rostedt@...dmis.org> wrote:

> 
> Hmm, looking at the code, I see it probably should still do the check.
> 
> OK, nevermind ;-)

Reading even more of the code, now I'm totally confused :-)

When tick_setup_sched_timer() is called, if tick_nohz_enabled is set,
then we set tick_nohz_active.

This gets called by hrtimer_switch_to_hres(), and before that is
called, the tick_check_oneshot_changed() will never get to the
tick_nohz_switch_to_nohz() call.

Looks to me, the real answer is to nuke both the if statement *and* the
setting of the tick_nohz_active in that function. Both looks a bit
redundant to me.

-- Steve
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/