linux-kernel - Re: [RFC PATCH 05/15] nohz_task: Restart the tick when another task compete on the cpu

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: <1292860401.5021.9.camel@laptop>
Date:	Mon, 20 Dec 2010 16:53:21 +0100
From:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
To:	Frederic Weisbecker <fweisbec@...il.com>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Ingo Molnar <mingo@...e.hu>,
	Steven Rostedt <rostedt@...dmis.org>,
	Lai Jiangshan <laijs@...fujitsu.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Anton Blanchard <anton@....ibm.com>,
	Tim Pepper <lnxninja@...ux.vnet.ibm.com>
Subject: Re: [RFC PATCH 05/15] nohz_task: Restart the tick when another
 task compete on the cpu

On Mon, 2010-12-20 at 16:24 +0100, Frederic Weisbecker wrote:
> +#ifdef CONFIG_NO_HZ_TASK
> +       /*
> +        * CHECKME:
> +        * Ideally, we need to check if the target has a nohz task
> +        * and only send the IPI if so. But there is nothing but
> +        * a racy way to do that. Or can we assume at that point
> +        * of the wake up that if cpu_has_nohz_task(cpu) is 0, then
> +        * it's ok, even if it has a task about to switch to nohz
> +        * task mode?
> +        */
> +       if (rq->nr_running == 2)
> +               smp_send_update_nohz_task_cpu(cpu);
> +#endif 

This is the wrong place, use ttwu_activate(), since activate_task() is
the thing that pokes at nr_running.
--
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/