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SubjectRe: [linux-pm] [PATCH 5/5] x86 idle: remove NOP hlt_use_halt()
* Len Brown <lenb@kernel.org> [2011-03-24 03:08:28]:

> From: Len Brown <len.brown@intel.com>
>
> hlt_use_halt() no longer has any effect,
> except to complicate the indentation in default_idle().
>
> no functional change.
>
> Signed-off-by: Len Brown <len.brown@intel.com>
> ---
> arch/x86/kernel/process.c | 39 ++++++++++++++-------------------------
> 1 files changed, 14 insertions(+), 25 deletions(-)
>
> diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
> index 8688ade..094d4ac 100644
> --- a/arch/x86/kernel/process.c
> +++ b/arch/x86/kernel/process.c
> @@ -342,39 +342,28 @@ EXPORT_SYMBOL(boot_option_idle_override);
> void (*pm_idle)(void);
> EXPORT_SYMBOL(pm_idle);
>
> -static inline int hlt_use_halt(void)
> -{
> - return 1;
> -}
> -
> /*
> * We use this if we don't have any better
> * idle routine..
> */
> void default_idle(void)
> {
> - if (hlt_use_halt()) {
> - trace_power_start(POWER_CSTATE, 1, smp_processor_id());
> - trace_cpu_idle(1, smp_processor_id());
> - current_thread_info()->status &= ~TS_POLLING;
> - /*
> - * TS_POLLING-cleared state must be visible before we
> - * test NEED_RESCHED:
> - */
> - smp_mb();
> + trace_power_start(POWER_CSTATE, 1, smp_processor_id());
> + trace_cpu_idle(1, smp_processor_id());
> + current_thread_info()->status &= ~TS_POLLING;
> + /*
> + * TS_POLLING-cleared state must be visible before we
> + * test NEED_RESCHED:
> + */
> + smp_mb();
>
> - if (!need_resched())
> - safe_halt(); /* enables interrupts racelessly */
> - else
> - local_irq_enable();
> - current_thread_info()->status |= TS_POLLING;
> - trace_power_end(smp_processor_id());
> - trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id());
> - } else {
> + if (!need_resched())
> + safe_halt(); /* enables interrupts racelessly */
> + else
> local_irq_enable();
> - /* loop is done by the caller */
> - cpu_relax();
> - }
> + current_thread_info()->status |= TS_POLLING;
> + trace_power_end(smp_processor_id());
> + trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id());
> }
> #ifdef CONFIG_APM_MODULE
> EXPORT_SYMBOL(default_idle);

Hi Len,

The cleanup looks good.

--Vaidy



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