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| author | Deepthi Dharwar <deepthi@linux.vnet.ibm.com> | 2012-10-03 18:42:18 +0000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2012-10-18 10:57:24 +1100 |
| commit | 8ea959a17fe6e27f7954dddad5b17b0e33f0d7ee (patch) | |
| tree | e16bf4c3b7a9bbcb2822c862fccf7b1b8ab336b0 /arch | |
| parent | 817deb05df45577d4037230f2facee486c11d9df (diff) | |
| download | linux-8ea959a17fe6e27f7954dddad5b17b0e33f0d7ee.tar.bz2 | |
cpuidle/powerpc: Fix smt_snooze_delay functionality.
smt_snooze_delay was designed to delay idle loop's nap entry
in the native idle code before it got ported over to use as part of
the cpuidle framework.
A -ve value assigned to smt_snooze_delay should result in
busy looping, in other words disabling the entry to nap state.
- https://lists.ozlabs.org/pipermail/linuxppc-dev/2010-May/082450.html
This particular functionality can be achieved currently by
echo 1 > /sys/devices/system/cpu/cpu*/state1/disable
but it is broken when one assigns -ve value to the smt_snooze_delay
variable either via sysfs entry or ppc64_cpu util.
This patch aims to fix this, by disabling nap state when smt_snooze_delay
variable is set to -ve value.
Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/include/asm/processor.h | 4 | ||||
| -rw-r--r-- | arch/powerpc/kernel/sysfs.c | 2 | ||||
| -rw-r--r-- | arch/powerpc/platforms/pseries/processor_idle.c | 24 |
3 files changed, 20 insertions, 10 deletions
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h index 8734b3855272..87502046c0dc 100644 --- a/arch/powerpc/include/asm/processor.h +++ b/arch/powerpc/include/asm/processor.h @@ -388,9 +388,9 @@ extern int powersave_nap; /* set if nap mode can be used in idle loop */ extern void power7_nap(void); #ifdef CONFIG_PSERIES_IDLE -extern void update_smt_snooze_delay(int snooze); +extern void update_smt_snooze_delay(int cpu, int residency); #else -static inline void update_smt_snooze_delay(int snooze) {} +static inline void update_smt_snooze_delay(int cpu, int residency) {} #endif extern void flush_instruction_cache(void); diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c index 8302af649219..cf357a059ddb 100644 --- a/arch/powerpc/kernel/sysfs.c +++ b/arch/powerpc/kernel/sysfs.c @@ -50,7 +50,7 @@ static ssize_t store_smt_snooze_delay(struct device *dev, return -EINVAL; per_cpu(smt_snooze_delay, cpu->dev.id) = snooze; - update_smt_snooze_delay(snooze); + update_smt_snooze_delay(cpu->dev.id, snooze); return count; } diff --git a/arch/powerpc/platforms/pseries/processor_idle.c b/arch/powerpc/platforms/pseries/processor_idle.c index 02e425aa2af8..a32d56d1f854 100644 --- a/arch/powerpc/platforms/pseries/processor_idle.c +++ b/arch/powerpc/platforms/pseries/processor_idle.c @@ -33,13 +33,6 @@ static int max_idle_state = MAX_IDLE_STATE_COUNT - 1; static struct cpuidle_device __percpu *pseries_cpuidle_devices; static struct cpuidle_state *cpuidle_state_table; -void update_smt_snooze_delay(int snooze) -{ - struct cpuidle_driver *drv = cpuidle_get_driver(); - if (drv) - drv->states[0].target_residency = snooze; -} - static inline void idle_loop_prolog(unsigned long *in_purr, ktime_t *kt_before) { @@ -190,6 +183,23 @@ static struct cpuidle_state shared_states[MAX_IDLE_STATE_COUNT] = { .enter = &shared_cede_loop }, }; +void update_smt_snooze_delay(int cpu, int residency) +{ + struct cpuidle_driver *drv = cpuidle_get_driver(); + struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); + + if (cpuidle_state_table != dedicated_states) + return; + + if (residency < 0) { + /* Disable the Nap state on that cpu */ + if (dev) + dev->states_usage[1].disable = 1; + } else + if (drv) + drv->states[0].target_residency = residency; +} + static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n, unsigned long action, void *hcpu) { |