[PATCH v3 4/6] cpufreq: powernv: Call throttle_check() on receiving OCC_THROTTLE

Shilpasri G Bhat
2015-05-04T09:00:57Z

Re-evaluate the chip's throttled state on recieving OCC_THROTTLE
notification by executing *throttle_check() on any one of the cpu on
the chip. This is a sanity check to verify if we were indeed
throttled/unthrottled after receiving OCC_THROTTLE notification.

We cannot call *throttle_check() directly from the notification
handler because we could be handling chip1's notification in chip2. So
initiate an smp_call to execute *throttle_check(). We are irq-disabled
in the notification handler, so use a worker thread to smp_call
throttle_check() on any of the cpu in the chipmask.

Signed-off-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
---
drivers/cpufreq/powernv-cpufreq.c | 28 ++++++++++++++++++++++++++--
1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
index 9268424..9618813 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -50,6 +50,8 @@ static bool rebooting, throttled, occ_reset;
static struct chip {
unsigned int id;
bool throttled;
+ cpumask_t mask;
+ struct work_struct throttle;
} *chips;

static int nr_chips;
@@ -310,8 +312,9 @@ static inline unsigned int get_nominal_index(void)
return powernv_pstate_info.max - powernv_pstate_info.nominal;
}

-static void powernv_cpufreq_throttle_check(unsigned int cpu)
+static void powernv_cpufreq_throttle_check(void *data)
{
+ unsigned int cpu = smp_processor_id();
unsigned long pmsr;
int pmsr_pmax, pmsr_lp, i;

@@ -373,7 +376,7 @@ static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
return 0;

if (!throttled)
- powernv_cpufreq_throttle_check(smp_processor_id());
+ powernv_cpufreq_throttle_check(NULL);

freq_data.pstate_id = powernv_freqs[new_index].driver_data;

@@ -418,6 +421,14 @@ static struct notifier_block powernv_cpufreq_reboot_nb = {
.notifier_call = powernv_cpufreq_reboot_notifier,
};

+void powernv_cpufreq_work_fn(struct work_struct *work)
+{
+ struct chip *chip = container_of(work, struct chip, throttle);
+
+ smp_call_function_any(&chip->mask,
+ powernv_cpufreq_throttle_check, NULL, 0);
+}
+
static char throttle_reason[][30] = {
"No throttling",
"Power Cap",
@@ -433,6 +444,7 @@ static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
struct opal_msg *occ_msg = msg;
uint64_t token;
uint64_t chip_id, reason;
+ int i;

if (msg_type != OPAL_MSG_OCC)
return 0;
@@ -466,6 +478,10 @@ static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
occ_reset = false;
throttled = false;
pr_info("OCC: Active\n");
+
+ for (i = 0; i < nr_chips; i++)
+ schedule_work(&chips[i].throttle);
+
return 0;
}

@@ -476,6 +492,12 @@ static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
else if (!reason)
pr_info("OCC: Chip %u %s\n", (unsigned int)chip_id,
throttle_reason[reason]);
+ else
+ return 0;
+
+ for (i = 0; i < nr_chips; i++)
+ if (chips[i].id == chip_id)
+ schedule_work(&chips[i].throttle);
}
return 0;
}
@@ -527,6 +549,8 @@ static int init_chip_info(void)
for (i = 0; i < nr_chips; i++) {
chips[i].id = chip[i];
chips[i].throttled = false;
+ cpumask_copy(&chips[i].mask, cpumask_of_node(chip[i]));
+ INIT_WORK(&chips[i].throttle, powernv_cpufreq_work_fn);
}

return 0;
--
1.9.3