[3.8.y.z extended stable] Patch "ACPI / processor: Rework processor throttling with work_on_cpu()" has been added to staging queue
Kamal Mostafa
kamal at canonical.com
Mon Mar 24 21:19:50 UTC 2014
This is a note to let you know that I have just added a patch titled
ACPI / processor: Rework processor throttling with work_on_cpu()
to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree
which can be found at:
http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue
This patch is scheduled to be released in version 3.8.13.20.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
------
>From 2e7518beb636b379437924247ee074b5d95fc590 Mon Sep 17 00:00:00 2001
From: Lan Tianyu <tianyu.lan at intel.com>
Date: Wed, 26 Feb 2014 21:03:05 +0800
Subject: ACPI / processor: Rework processor throttling with work_on_cpu()
commit f3ca4164529b875374c410193bbbac0ee960895f upstream.
acpi_processor_set_throttling() uses set_cpus_allowed_ptr() to make
sure that the (struct acpi_processor)->acpi_processor_set_throttling()
callback will run on the right CPU. However, the function may be
called from a worker thread already bound to a different CPU in which
case that won't work.
Make acpi_processor_set_throttling() use work_on_cpu() as appropriate
instead of abusing set_cpus_allowed_ptr().
Reported-and-tested-by: Jiri Olsa <jolsa at redhat.com>
Signed-off-by: Lan Tianyu <tianyu.lan at intel.com>
[rjw: Changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
drivers/acpi/processor_throttling.c | 69 +++++++++++++++++--------------------
1 file changed, 32 insertions(+), 37 deletions(-)
diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c
index 1d02b7b..c653cc2 100644
--- a/drivers/acpi/processor_throttling.c
+++ b/drivers/acpi/processor_throttling.c
@@ -59,6 +59,12 @@ struct throttling_tstate {
int target_state; /* target T-state */
};
+struct acpi_processor_throttling_arg {
+ struct acpi_processor *pr;
+ int target_state;
+ bool force;
+};
+
#define THROTTLING_PRECHANGE (1)
#define THROTTLING_POSTCHANGE (2)
@@ -1062,16 +1068,24 @@ static int acpi_processor_set_throttling_ptc(struct acpi_processor *pr,
return 0;
}
+static long acpi_processor_throttling_fn(void *data)
+{
+ struct acpi_processor_throttling_arg *arg = data;
+ struct acpi_processor *pr = arg->pr;
+
+ return pr->throttling.acpi_processor_set_throttling(pr,
+ arg->target_state, arg->force);
+}
+
int acpi_processor_set_throttling(struct acpi_processor *pr,
int state, bool force)
{
- cpumask_var_t saved_mask;
int ret = 0;
unsigned int i;
struct acpi_processor *match_pr;
struct acpi_processor_throttling *p_throttling;
+ struct acpi_processor_throttling_arg arg;
struct throttling_tstate t_state;
- cpumask_var_t online_throttling_cpus;
if (!pr)
return -EINVAL;
@@ -1082,14 +1096,6 @@ int acpi_processor_set_throttling(struct acpi_processor *pr,
if ((state < 0) || (state > (pr->throttling.state_count - 1)))
return -EINVAL;
- if (!alloc_cpumask_var(&saved_mask, GFP_KERNEL))
- return -ENOMEM;
-
- if (!alloc_cpumask_var(&online_throttling_cpus, GFP_KERNEL)) {
- free_cpumask_var(saved_mask);
- return -ENOMEM;
- }
-
if (cpu_is_offline(pr->id)) {
/*
* the cpu pointed by pr->id is offline. Unnecessary to change
@@ -1098,17 +1104,15 @@ int acpi_processor_set_throttling(struct acpi_processor *pr,
return -ENODEV;
}
- cpumask_copy(saved_mask, ¤t->cpus_allowed);
t_state.target_state = state;
p_throttling = &(pr->throttling);
- cpumask_and(online_throttling_cpus, cpu_online_mask,
- p_throttling->shared_cpu_map);
+
/*
* The throttling notifier will be called for every
* affected cpu in order to get one proper T-state.
* The notifier event is THROTTLING_PRECHANGE.
*/
- for_each_cpu(i, online_throttling_cpus) {
+ for_each_cpu_and(i, cpu_online_mask, p_throttling->shared_cpu_map) {
t_state.cpu = i;
acpi_processor_throttling_notifier(THROTTLING_PRECHANGE,
&t_state);
@@ -1120,21 +1124,18 @@ int acpi_processor_set_throttling(struct acpi_processor *pr,
* it can be called only for the cpu pointed by pr.
*/
if (p_throttling->shared_type == DOMAIN_COORD_TYPE_SW_ANY) {
- /* FIXME: use work_on_cpu() */
- if (set_cpus_allowed_ptr(current, cpumask_of(pr->id))) {
- /* Can't migrate to the pr->id CPU. Exit */
- ret = -ENODEV;
- goto exit;
- }
- ret = p_throttling->acpi_processor_set_throttling(pr,
- t_state.target_state, force);
+ arg.pr = pr;
+ arg.target_state = state;
+ arg.force = force;
+ ret = work_on_cpu(pr->id, acpi_processor_throttling_fn, &arg);
} else {
/*
* When the T-state coordination is SW_ALL or HW_ALL,
* it is necessary to set T-state for every affected
* cpus.
*/
- for_each_cpu(i, online_throttling_cpus) {
+ for_each_cpu_and(i, cpu_online_mask,
+ p_throttling->shared_cpu_map) {
match_pr = per_cpu(processors, i);
/*
* If the pointer is invalid, we will report the
@@ -1155,13 +1156,12 @@ int acpi_processor_set_throttling(struct acpi_processor *pr,
"on CPU %d\n", i));
continue;
}
- t_state.cpu = i;
- /* FIXME: use work_on_cpu() */
- if (set_cpus_allowed_ptr(current, cpumask_of(i)))
- continue;
- ret = match_pr->throttling.
- acpi_processor_set_throttling(
- match_pr, t_state.target_state, force);
+
+ arg.pr = match_pr;
+ arg.target_state = state;
+ arg.force = force;
+ ret = work_on_cpu(pr->id, acpi_processor_throttling_fn,
+ &arg);
}
}
/*
@@ -1170,17 +1170,12 @@ int acpi_processor_set_throttling(struct acpi_processor *pr,
* affected cpu to update the T-states.
* The notifier event is THROTTLING_POSTCHANGE
*/
- for_each_cpu(i, online_throttling_cpus) {
+ for_each_cpu_and(i, cpu_online_mask, p_throttling->shared_cpu_map) {
t_state.cpu = i;
acpi_processor_throttling_notifier(THROTTLING_POSTCHANGE,
&t_state);
}
- /* restore the previous state */
- /* FIXME: use work_on_cpu() */
- set_cpus_allowed_ptr(current, saved_mask);
-exit:
- free_cpumask_var(online_throttling_cpus);
- free_cpumask_var(saved_mask);
+
return ret;
}
--
1.8.3.2
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