[PATCH v8 2/6] cpufreq: powernv: Hot-plug safe the kworker thread
From: Shilpasri G Bhat <hidden>
Date: 2016-02-02 19:42:58
Also in:
linux-pm, lkml
Subsystem:
cpu frequency scaling framework, the rest · Maintainers:
"Rafael J. Wysocki", Viresh Kumar, Linus Torvalds
In the kworker_thread powernv_cpufreq_work_fn(), we can end up
sending an IPI to a cpu going offline. This is a rare corner case
which is fixed using {get/put}_online_cpus(). Along with this fix,
this patch adds changes to do oneshot cpumask_{clear/and} operation.
Suggested-by: Shreyas B Prabhu <redacted>
Suggested-by: Gautham R Shenoy <redacted>
Signed-off-by: Shilpasri G Bhat <redacted>
Reviewed-by: Gautham R. Shenoy <redacted>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
---
No changes from v7.
drivers/cpufreq/powernv-cpufreq.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
index 53f980b..a271b0f 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c@@ -28,6 +28,7 @@ #include <linux/of.h> #include <linux/reboot.h> #include <linux/slab.h> +#include <linux/cpu.h> #include <asm/cputhreads.h> #include <asm/firmware.h>
@@ -423,18 +424,19 @@ void powernv_cpufreq_work_fn(struct work_struct *work) { struct chip *chip = container_of(work, struct chip, throttle); unsigned int cpu; - cpumask_var_t mask; + cpumask_t mask; - smp_call_function_any(&chip->mask, + get_online_cpus(); + cpumask_and(&mask, &chip->mask, cpu_online_mask); + smp_call_function_any(&mask, powernv_cpufreq_throttle_check, NULL, 0); if (!chip->restore) - return; + goto out; chip->restore = false; - cpumask_copy(mask, &chip->mask); - for_each_cpu_and(cpu, mask, cpu_online_mask) { - int index, tcpu; + for_each_cpu(cpu, &mask) { + int index; struct cpufreq_policy policy; cpufreq_get_policy(&policy, cpu);
@@ -442,9 +444,10 @@ void powernv_cpufreq_work_fn(struct work_struct *work) policy.cur, CPUFREQ_RELATION_C, &index); powernv_cpufreq_target_index(&policy, index); - for_each_cpu(tcpu, policy.cpus) - cpumask_clear_cpu(tcpu, mask); + cpumask_andnot(&mask, &mask, policy.cpus); } +out: + put_online_cpus(); } static char throttle_reason[][30] = {
--
1.9.3