linux-kernel - Re: [patch 01/40] smpboot: Allow selfparking per cpu threads

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:	Fri, 8 Feb 2013 16:29:34 -0800
From:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Rusty Russell <rusty@...tcorp.com.au>,
	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>,
	Arjan van de Veen <arjan@...radead.org>,
	Paul Turner <pjt@...gle.com>,
	Richard Weinberger <rw@...utronix.de>,
	Magnus Damm <magnus.damm@...il.com>
Subject: Re: [patch 01/40] smpboot: Allow selfparking per cpu threads

On Thu, Jan 31, 2013 at 12:11:12PM -0000, Thomas Gleixner wrote:
> The stop machine threads are still killed when a cpu goes offline. The
> reason is that the thread is used to bring the cpu down, so it can't
> be parked along with the other per cpu threads.
> 
> Allow a per cpu thread to be excluded from automatic parking, so it
> can park itself once it's done
> 
> Add a create callback function as well.
> 
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>

Reviewed-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>

> ---
>  include/linux/smpboot.h |    5 +++++
>  kernel/smpboot.c        |    5 +++--
>  2 files changed, 8 insertions(+), 2 deletions(-)
> 
> Index: linux-2.6/include/linux/smpboot.h
> ===================================================================
> --- linux-2.6.orig/include/linux/smpboot.h
> +++ linux-2.6/include/linux/smpboot.h
> @@ -14,6 +14,8 @@ struct smpboot_thread_data;
>   * @thread_should_run:	Check whether the thread should run or not. Called with
>   *			preemption disabled.
>   * @thread_fn:		The associated thread function
> + * @create:		Optional setup function, called when the thread gets
> + *			created (Not called from the thread context)
>   * @setup:		Optional setup function, called when the thread gets
>   *			operational the first time
>   * @cleanup:		Optional cleanup function, called when the thread
> @@ -22,6 +24,7 @@ struct smpboot_thread_data;
>   *			parked (cpu offline)
>   * @unpark:		Optional unpark function, called when the thread is
>   *			unparked (cpu online)
> + * @selfparking:	Thread is not parked by the park function.
>   * @thread_comm:	The base name of the thread
>   */
>  struct smp_hotplug_thread {
> @@ -29,10 +32,12 @@ struct smp_hotplug_thread {
>  	struct list_head		list;
>  	int				(*thread_should_run)(unsigned int cpu);
>  	void				(*thread_fn)(unsigned int cpu);
> +	void				(*create)(unsigned int cpu);
>  	void				(*setup)(unsigned int cpu);
>  	void				(*cleanup)(unsigned int cpu, bool online);
>  	void				(*park)(unsigned int cpu);
>  	void				(*unpark)(unsigned int cpu);
> +	bool				selfparking;
>  	const char			*thread_comm;
>  };
> 
> Index: linux-2.6/kernel/smpboot.c
> ===================================================================
> --- linux-2.6.orig/kernel/smpboot.c
> +++ linux-2.6/kernel/smpboot.c
> @@ -183,9 +183,10 @@ __smpboot_create_thread(struct smp_hotpl
>  		kfree(td);
>  		return PTR_ERR(tsk);
>  	}
> -
>  	get_task_struct(tsk);
>  	*per_cpu_ptr(ht->store, cpu) = tsk;
> +	if (ht->create)
> +		ht->create(cpu);
>  	return 0;
>  }
> 
> @@ -225,7 +226,7 @@ static void smpboot_park_thread(struct s
>  {
>  	struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
> 
> -	if (tsk)
> +	if (tsk && !ht->selfparking)
>  		kthread_park(tsk);
>  }
> 
> 
> 

--
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/