linux-kernel - Re: Future of NOHZ full/isolation development (was Re: [NOHZ] Remove scheduler_tick_max

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]

Message-ID: <CAKohpompt7Gizq2GRVsCkoGvsZxKzBM_FWjzGaNjkdSu=aM__Q@mail.gmail.com>
Date:	Wed, 12 Nov 2014 20:46:10 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Frederic Weisbecker <fweisbec@...il.com>,
	Christoph Lameter <cl@...ux.com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Gilad Ben-Yossef <gilad@...yossef.com>,
	Tejun Heo <tj@...nel.org>,
	John Stultz <john.stultz@...aro.org>,
	Mike Frysinger <vapier@...too.org>,
	Minchan Kim <minchan.kim@...il.com>,
	Hakan Akkan <hakanakkan@...il.com>,
	Max Krasnyansky <maxk@....qualcomm.com>,
	Hugh Dickins <hughd@...gle.com>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...nel.org>,
	Kevin Hilman <khilman@...aro.org>
Subject: Re: Future of NOHZ full/isolation development (was Re: [NOHZ] Remove scheduler_tick_max_deferment)

On 12 November 2014 20:36, Peter Zijlstra <peterz@...radead.org> wrote:
> I don't think you need to add anything. We already have tracepoints for
> every single interrupt (and therefore also for the hrtimer one) and we
> have expiry tracepoints.

I will crosscheck this again but as far as I remember these spurious interrupts
aren't caught with tracers currently. Not even the irq_enter/exit ones.

I saw that piece of code long back (and obviously don't understand it
completely). But the problem was that because these are spurious
clockevent interrupts, we don't have anything to do on that interrupt.
No tick/sched/softirq processing. And the irq-handling code returns before
even calling trace_irq_enter().

And that's why I had to add those prints initially.
--
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/