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powernv/cpuidle: Redesign idle states management

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Deep idle states like sleep and winkle are per core idle states. A core
enters these states only when all the threads enter either the
particular idle state or a deeper one. There are tasks like fastsleep
hardware bug workaround and hypervisor core state save which have to be
done only by the last thread of the core entering deep idle state and
similarly tasks like timebase resync, hypervisor core register restore
that have to be done only by the first thread waking up from these
state.

The current idle state management does not have a way to distinguish the
first/last thread of the core waking/entering idle states. Tasks like
timebase resync are done for all the threads. This is not only is
suboptimal, but can cause functionality issues when subcores and kvm is
involved.

This patch adds the necessary infrastructure to track idle states of
threads in a per-core structure. It uses this info to perform tasks like
fastsleep workaround and timebase resync only once per core.

Signed-off-by: Shreyas B. Prabhu <[email protected]>
Originally-by: Preeti U. Murthy <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Michael Ellerman <[email protected]>
This commit is contained in:
Shreyas B. Prabhu 2014-12-10 00:26:52 +05:30 • committed by Michael Ellerman
commit 7cba160ad7
11 changed files with 296 additions and 58 deletions
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3
drivers/cpuidle/cpuidle-powernv.c
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@ -208,7 +208,8 @@ static int powernv_add_idle_states(void)
nr_idle_states++;
}
if (flags & OPAL_PM_SLEEP_ENABLED) {
if (flags & OPAL_PM_SLEEP_ENABLED ||
flags & OPAL_PM_SLEEP_ENABLED_ER1) {
/* Add FASTSLEEP state */
strcpy(powernv_states[nr_idle_states].name, "FastSleep");
strcpy(powernv_states[nr_idle_states].desc, "FastSleep");