static inline void dedicated_idle_sleep(unsigned int cpu)
{
struct paca_struct *ppaca = &paca[cpu ^ 1];
/* Only sleep if the other thread is not idle */
if (!(ppaca->lppaca.idle)) {
local_irq_disable();
/*
* We are about to sleep the thread and so wont be polling any
* more.
*/
clear_thread_flag(TIF_POLLING_NRFLAG);
/*
* SMT dynamic mode. Cede will result in this thread going
* dormant, if the partner thread is still doing work. Thread
* wakes up if partner goes idle, an interrupt is presented, or
* a prod occurs. Returning from the cede enables external
* interrupts.
*/
if (!need_resched())
cede_processor();
else
local_irq_enable();
} else {
/*
* Give the HV an opportunity at the processor, since we are
* not doing any work.
*/
poll_pending();
}
}
int dedicated_idle(void)
{
long oldval;
struct paca_struct *lpaca = get_paca(), *ppaca;
unsigned long start_snooze;
unsigned long *smt_snooze_delay = &__get_cpu_var(smt_snooze_delay);
unsigned int cpu = smp_processor_id();
ppaca = &paca[cpu ^ 1];
while (1) {
/*
* Indicate to the HV that we are idle. Now would be
* a good time to find other work to dispatch.
*/
lpaca->lppaca.xIdle = 1;
oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
if (!oldval) {
set_thread_flag(TIF_POLLING_NRFLAG);
start_snooze = __get_tb() +
*smt_snooze_delay * tb_ticks_per_usec;
while (!need_resched() && !cpu_is_offline(cpu)) {
/*
* Go into low thread priority and possibly
* low power mode.
*/
HMT_low();
HMT_very_low();
if (*smt_snooze_delay == 0 ||
__get_tb() < start_snooze)
continue;
HMT_medium();
if (!(ppaca->lppaca.xIdle)) {
local_irq_disable();
/*
* We are about to sleep the thread
* and so wont be polling any
* more.
*/
clear_thread_flag(TIF_POLLING_NRFLAG);
/*
* SMT dynamic mode. Cede will result
* in this thread going dormant, if the
* partner thread is still doing work.
* Thread wakes up if partner goes idle,
* an interrupt is presented, or a prod
* occurs. Returning from the cede
* enables external interrupts.
*/
if (!need_resched())
cede_processor();
else
local_irq_enable();
} else {
/*
* Give the HV an opportunity at the
* processor, since we are not doing
* any work.
*/
poll_pending();
}
}
clear_thread_flag(TIF_POLLING_NRFLAG);
} else {
set_need_resched();
}
HMT_medium();
lpaca->lppaca.xIdle = 0;
schedule();
if (cpu_is_offline(cpu) && system_state == SYSTEM_RUNNING)
cpu_die();
}
return 0;
}