Messages in this thread | | | Date | Fri, 4 Jan 2013 14:01:42 +0100 | Subject | Re: [RFC PATCH v1 15/31] ARC: Process/scheduling/clock/Timers/Delay Management | From | Frederic Weisbecker <> |
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2013/1/2 Vineet Gupta <Vineet.Gupta1@synopsys.com>: > On Tuesday 13 November 2012 01:59 AM, Thomas Gleixner wrote: >> On Wed, 7 Nov 2012, Vineet Gupta wrote: >>> +void cpu_idle(void) >>> +{ >>> + /* Since we SLEEP in idle loop, TIF_POLLING_NRFLAG can't be set */ >>> + >>> + /* endless idle loop with no priority at all */ >>> + while (1) { >>> + tick_nohz_idle_enter(); >>> + >>> + while (!need_resched()) >>> + arch_idle(); >>> + >>> + tick_nohz_idle_exit(); >>> + >>> + preempt_enable_no_resched(); >>> + schedule(); >>> + preempt_disable(); >> >> schedule_preempt_disabled() please > > > OK ! And it seems I was also missing the calls to rcu_idle_enter()/exit() to track > commit 1268fbc746ea "nohz: Remove tick_nohz_idle_enter_norcu() / ..."
Right!
They must be placed around the code that sets the low power mode, when you know there is no use of RCU between rcu_idle_enter() / rcu_idle_exit(). Here this would be likely:
while (1) { tick_nohz_idle_enter();
+ rcu_idle_enter(); while (!need_resched()) arch_idle(); + rcu_idle_exit()
tick_nohz_idle_exit(); schedule_preempt_disabled(); }
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