Re: [PATCH] cpuidle/powernv: Enter fastsleep on checking if deep idle states are allowed
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2014-09-15 06:59:18
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On Fri, 2014-09-12 at 16:31 +0530, Preeti U Murthy wrote:
quoted hunk ↗ jump to hunk
Today the procfs interface /proc/sys/kernel/powersave-nap is used to control entry into deep idle states beyond snooze. Check for the value of this parameter before entering fastsleep. We already do this check for nap in power7_idle(). Signed-off-by: Preeti U Murthy <redacted> --- drivers/cpuidle/cpuidle-powernv.c | 6 ++++++ 1 file changed, 6 insertions(+)diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c index a64be57..b8ba52e 100644 --- a/drivers/cpuidle/cpuidle-powernv.c +++ b/drivers/cpuidle/cpuidle-powernv.c@@ -69,6 +69,12 @@ static int fastsleep_loop(struct cpuidle_device *dev, unsigned long old_lpcr = mfspr(SPRN_LPCR); unsigned long new_lpcr; + /* + * Verify if snooze is the only valid cpuidle state + */ + if (!(powersave_nap > 0)) + return index; + if (unlikely(system_state < SYSTEM_RUNNING)) return index;
Doesn't the above mean we are just going to keep trying to go into fastsleep again and again? Or does the idle code work out that it didn't work based on the fact that we didn't sleep for the right period? We were talking about getting rid of powersave_nap altogether, but I think we decided we couldn't, I forget. cheers