Subject: Re: [PATCH] pseries/cpuidle: Remove redundant call to ppc64_runlatch_off() in cpu idle routines

From: "Srivatsa S. Bhat" <[email-masked]>
Date: Thu, 09 Jan 2014 13:37:40 +0530

On 01/09/2014 10:35 AM, Preeti U Murthy wrote:
> Commit fbd7740fdfdf9475f switched pseries cpu idle handling from complete idle
> loops to ppc_md.powersave functions. Earlier to this switch,
> ppc64_runlatch_off() had to be called in each of the idle routines. But after
> the switch this call is handled in arch_cpu_idle(),just before the call
> to ppc_md.powersave, where platform specific idle routines are called.
> 
> As a consequence, the call to ppc64_runlatch_off() got duplicated in the
> arch_cpu_idle() routine as well as in the some of the idle routines in
> pseries and commit fbd7740fdfdf9475f missed to get rid of these redundant
> calls. These calls were carried over subsequent enhancements to the pseries
> cpuidle routines. This patch takes care of eliminating this redundancy.
> 
> Signed-off-by: Preeti U Murthy <[email-masked]>
> ---

Reviewed-by: Srivatsa S. Bhat <[email-masked]>

Regards,
Srivatsa S. Bhat

> 
>  arch/powerpc/platforms/pseries/processor_idle.c |    3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/processor_idle.c b/arch/powerpc/platforms/pseries/processor_idle.c
> index a166e38..09e4f56 100644
> --- a/arch/powerpc/platforms/pseries/processor_idle.c
> +++ b/arch/powerpc/platforms/pseries/processor_idle.c
> @@ -17,7 +17,6 @@
>  #include <asm/reg.h>
>  #include <asm/machdep.h>
>  #include <asm/firmware.h>
> -#include <asm/runlatch.h>
>  #include <asm/plpar_wrappers.h>
> 
>  struct cpuidle_driver pseries_idle_driver = {
> @@ -63,7 +62,6 @@ static int snooze_loop(struct cpuidle_device *dev,
>  	set_thread_flag(TIF_POLLING_NRFLAG);
> 
>  	while ((!need_resched()) && cpu_online(cpu)) {
> -		ppc64_runlatch_off();
>  		HMT_low();
>  		HMT_very_low();
>  	}
> @@ -103,7 +101,6 @@ static int dedicated_cede_loop(struct cpuidle_device *dev,
>  	idle_loop_prolog(&in_purr);
>  	get_lppaca()->donate_dedicated_cpu = 1;
> 
> -	ppc64_runlatch_off();
>  	HMT_medium();
>  	check_and_cede_processor();
> 
>