On Thu, 13 Apr 2017, Peter Zijlstra wrote:
>
> That makes my machine sad...
> [ 9.786610] work_on_cpu+0x82/0x90
> [ 9.790404] ? __usermodehelper_disable+0x110/0x110
> [ 9.795846] ? __acpi_processor_get_throttling+0x20/0x20
> [ 9.801773] acpi_processor_set_throttling+0x199/0x220
> [ 9.807506] ? trace_hardirqs_on_caller+0xfb/0x1d0
> [ 9.812851] acpi_processor_get_throttling_ptc+0xec/0x180
> [ 9.818876] __acpi_processor_get_throttling+0xf/0x20
> [ 9.824511] work_for_cpu_fn+0x14/0x20
> [ 9.828692] process_one_work+0x261/0x670
> [ 9.833165] worker_thread+0x21b/0x3f0
> [ 9.837348] kthread+0x108/0x140
> [ 9.840947] ? process_one_work+0x670/0x670
> [ 9.845611] ? kthread_create_on_node+0x40/0x40
> [ 9.850667] ret_from_fork+0x31/0x40
Yuck. So the call chain is:
acpi_processor_get_throttling()
work_on_cpu(acpi_processor_get_throttling)
That work does:
__acpi_processor_get_throttling()
acpi_processor_get_throttling_ptc()
acpi_processor_set_throttling()
work_on_cpu(__acpi_processor_set_throttling)
Why the heck calls a get_throttling() function set_throttling()? I'm mildly
surprised.
Does the delta patch below cure the problem?
Thanks,
tglx
8<--------------
--- a/drivers/acpi/processor_throttling.c
+++ b/drivers/acpi/processor_throttling.c
@@ -62,8 +62,8 @@ struct acpi_processor_throttling_arg {
#define THROTTLING_POSTCHANGE (2)
static int acpi_processor_get_throttling(struct acpi_processor *pr);
-int acpi_processor_set_throttling(struct acpi_processor *pr,
- int state, bool force);
+static int __acpi_processor_set_throttling(struct acpi_processor *pr,
+ int state, bool force, bool direct);
static int acpi_processor_update_tsd_coord(void)
{
@@ -891,7 +891,8 @@ static int acpi_processor_get_throttling
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Invalid throttling state, reset\n"));
state = 0;
- ret = acpi_processor_set_throttling(pr, state, true);
+ ret = __acpi_processor_set_throttling(pr, state, true,
+ true);
if (ret)
return ret;
}
@@ -1075,8 +1076,15 @@ static long acpi_processor_throttling_fn
arg->target_state, arg->force);
}
-int acpi_processor_set_throttling(struct acpi_processor *pr,
- int state, bool force)
+static int call_on_cpu(int cpu, long (*fn)(void *), void *arg, bool direct)
+{
+ if (direct)
+ return fn(arg);
+ return work_on_cpu(cpu, fn, arg);
+}
+
+static int __acpi_processor_set_throttling(struct acpi_processor *pr,
+ int state, bool force, bool direct)
{
int ret = 0;
unsigned int i;
@@ -1125,7 +1133,8 @@ int acpi_processor_set_throttling(struct
arg.pr = pr;
arg.target_state = state;
arg.force = force;
- ret = work_on_cpu(pr->id, acpi_processor_throttling_fn, &arg);
+ ret = call_on_cpu(pr->id, acpi_processor_throttling_fn, &arg,
+ direct);
} else {
/*
* When the T-state coordination is SW_ALL or HW_ALL,
@@ -1158,8 +1167,8 @@ int acpi_processor_set_throttling(struct
arg.pr = match_pr;
arg.target_state = state;
arg.force = force;
- ret = work_on_cpu(pr->id, acpi_processor_throttling_fn,
- &arg);
+ ret = call_on_cpu(pr->id, acpi_processor_throttling_fn,
+ &arg, direct);
}
}
/*
@@ -1177,6 +1186,12 @@ int acpi_processor_set_throttling(struct
return ret;
}
+int acpi_processor_set_throttling(struct acpi_processor *pr, int state,
+ bool force)
+{
+ return __acpi_processor_set_throttling(pr, state, force, false);
+}
+
int acpi_processor_get_throttling_info(struct acpi_processor *pr)
{
int result = 0;
