linux-kernel - Re: [patch 30/34] tile: Enter idle with preemption disabled

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Date:	Thu, 28 Mar 2013 21:13:06 +0530
From:	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>
To:	Thomas Gleixner <tglx@...utronix.de>
CC:	LKML <linux-kernel@...r.kernel.org>, linux-arch@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Paul McKenney <paulmck@...ux.vnet.ibm.com>,
	Ingo Molnar <mingo@...e.hu>,
	Peter Zijlstra <peterz@...radead.org>,
	Magnus Damm <magnus.damm@...il.com>,
	Chris Metcalf <cmetcalf@...era.com>
Subject: Re: [patch 30/34] tile: Enter idle with preemption disabled

On 03/22/2013 03:23 AM, Thomas Gleixner wrote:
> cpu_idle() needs to be called with preemption disabled.
> 
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
> Cc: Chris Metcalf <cmetcalf@...era.com>
> ---
>  arch/tile/kernel/smpboot.c |    2 --
>  1 file changed, 2 deletions(-)
> 
> Index: linux-2.6/arch/tile/kernel/smpboot.c
> ===================================================================
> --- linux-2.6.orig/arch/tile/kernel/smpboot.c
> +++ linux-2.6/arch/tile/kernel/smpboot.c
> @@ -207,8 +207,6 @@ void __cpuinit online_secondary(void)
>  	/* Set up tile-timer clock-event device on this cpu */
>  	setup_tile_timer();
> 
> -	preempt_enable();
> -

Hmm, so shouldn't we call preempt_disabled() here?

I see that start_secondary() calls preempt_disabled(), but I didn't quite
understand as to which of the *_secondary() functions have to call
it... especially since its the online_secondary() function which calls
cpu_idle().

>  	cpu_idle();
>  }
> 
> 
> 
 
Regards,
Srivatsa S. Bhat

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