Re: [PATCH 3/4] sched: Make sleeping inside spinlock detection working in !CONFIG_PREEMPT

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

On Wed, Jun 08, 2011 at 07:48:34PM +0200, Frederic Weisbecker wrote:
> Select CONFIG_PREEMPT_COUNT when we enable the sleeping inside
> spinlock detection, so that the preempt offset gets correctly
> incremented/decremented from preempt_disable()/preempt_enable().
> 
> This makes the preempt count eventually working in !CONFIG_PREEMPT
> when that debug option is set and thus fixes the detection of explicit
> preemption disabled sections under such config. Code that sleeps
> in explicitly preempt disabled section can be finally spotted
> in non-preemptible kernels.
> 
> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

> Cc: Ingo Molnar <mingo@elte.hu>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> ---
>  lib/Kconfig.debug |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
> 
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 28afa4c..a7dd7b5 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -650,6 +650,7 @@ config TRACE_IRQFLAGS
> 
>  config DEBUG_SPINLOCK_SLEEP
>  	bool "Spinlock debugging: sleep-inside-spinlock checking"
> +	select PREEMPT_COUNT
>  	depends on DEBUG_KERNEL
>  	help
>  	  If you say Y here, various routines which may sleep will become very
> -- 
> 1.7.5.4
>