* [PATCH 0/3] cpufreq: intel_pstate: Locking and limits fix-ups
@ 2016-12-30 14:54 Rafael J. Wysocki
2016-12-30 14:56 ` [PATCH 1/3] cpufreq: intel_pstate: Use locking in intel_pstate_resume() Rafael J. Wysocki
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: Rafael J. Wysocki @ 2016-12-30 14:54 UTC (permalink / raw)
To: Linux PM, Srinivas Pandruvada; +Cc: LKML
Hi,
This series fixes a couple of possible locking issues and limits synchronization
in intel pstate.
[1/3] Add locking to intel_pstate_resume().
[2/3] Add locking to intel_cpufreq_verify_policy().
[3/3] Always keep all limits settings in sync.
Thanks,
Rafael
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 1/3] cpufreq: intel_pstate: Use locking in intel_pstate_resume()
2016-12-30 14:54 [PATCH 0/3] cpufreq: intel_pstate: Locking and limits fix-ups Rafael J. Wysocki
@ 2016-12-30 14:56 ` Rafael J. Wysocki
2016-12-30 14:57 ` [PATCH 2/3] cpufreq: intel_pstate: Use locking in intel_cpufreq_verify_policy() Rafael J. Wysocki
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Rafael J. Wysocki @ 2016-12-30 14:56 UTC (permalink / raw)
To: Linux PM; +Cc: Srinivas Pandruvada, LKML
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Theoretically, intel_pstate_resume() may be executed in parallel
with intel_pstate_set_policy(), if the latter is invoked via
cpufreq_update_policy() as a result of a notification, so use
intel_pstate_limits_lock in there too to avoid race conditions.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/cpufreq/intel_pstate.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
Index: linux-pm/drivers/cpufreq/intel_pstate.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
+++ linux-pm/drivers/cpufreq/intel_pstate.c
@@ -968,12 +968,20 @@ static int intel_pstate_hwp_save_state(s
static int intel_pstate_resume(struct cpufreq_policy *policy)
{
+ int ret;
+
if (!hwp_active)
return 0;
+ mutex_lock(&intel_pstate_limits_lock);
+
all_cpu_data[policy->cpu]->epp_policy = 0;
- return intel_pstate_hwp_set_policy(policy);
+ ret = intel_pstate_hwp_set_policy(policy);
+
+ mutex_unlock(&intel_pstate_limits_lock);
+
+ return ret;
}
static void intel_pstate_hwp_set_online_cpus(void)
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 2/3] cpufreq: intel_pstate: Use locking in intel_cpufreq_verify_policy()
2016-12-30 14:54 [PATCH 0/3] cpufreq: intel_pstate: Locking and limits fix-ups Rafael J. Wysocki
2016-12-30 14:56 ` [PATCH 1/3] cpufreq: intel_pstate: Use locking in intel_pstate_resume() Rafael J. Wysocki
@ 2016-12-30 14:57 ` Rafael J. Wysocki
2016-12-30 14:58 ` [PATCH 3/3] cpufreq: intel_pstate: Always keep all limits settings in sync Rafael J. Wysocki
2016-12-30 17:49 ` [PATCH 0/3] cpufreq: intel_pstate: Locking and limits fix-ups Srinivas Pandruvada
3 siblings, 0 replies; 5+ messages in thread
From: Rafael J. Wysocki @ 2016-12-30 14:57 UTC (permalink / raw)
To: Linux PM; +Cc: Srinivas Pandruvada, LKML
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Race conditions are possible if intel_cpufreq_verify_policy()
is executed in parallel with global limits updates from sysfs,
so the invocation of intel_pstate_update_perf_limits() in it
should be carried out under intel_pstate_limits_lock.
Make that happen.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/cpufreq/intel_pstate.c | 4 ++++
1 file changed, 4 insertions(+)
Index: linux-pm/drivers/cpufreq/intel_pstate.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
+++ linux-pm/drivers/cpufreq/intel_pstate.c
@@ -2157,8 +2157,12 @@ static int intel_cpufreq_verify_policy(s
if (per_cpu_limits)
perf_limits = cpu->perf_limits;
+ mutex_lock(&intel_pstate_limits_lock);
+
intel_pstate_update_perf_limits(policy, perf_limits);
+ mutex_unlock(&intel_pstate_limits_lock);
+
return 0;
}
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 3/3] cpufreq: intel_pstate: Always keep all limits settings in sync
2016-12-30 14:54 [PATCH 0/3] cpufreq: intel_pstate: Locking and limits fix-ups Rafael J. Wysocki
2016-12-30 14:56 ` [PATCH 1/3] cpufreq: intel_pstate: Use locking in intel_pstate_resume() Rafael J. Wysocki
2016-12-30 14:57 ` [PATCH 2/3] cpufreq: intel_pstate: Use locking in intel_cpufreq_verify_policy() Rafael J. Wysocki
@ 2016-12-30 14:58 ` Rafael J. Wysocki
2016-12-30 17:49 ` [PATCH 0/3] cpufreq: intel_pstate: Locking and limits fix-ups Srinivas Pandruvada
3 siblings, 0 replies; 5+ messages in thread
From: Rafael J. Wysocki @ 2016-12-30 14:58 UTC (permalink / raw)
To: Linux PM; +Cc: Srinivas Pandruvada, LKML
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Make intel_pstate update per-logical-CPU limits when the global
settings are changed to ensure that they are always in sync and
users will not see confusing values in per-logical-CPU sysfs
attributes.
This also fixes the problem that setting the "no_turbo" global
attribute to 1 in the "passive" mode (ie. when intel_pstate acts
as a regular cpufreq driver) when scaling_governor is set to
"performance" has no effect.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/cpufreq/intel_pstate.c | 30 ++++++++++++++----------------
1 file changed, 14 insertions(+), 16 deletions(-)
Index: linux-pm/drivers/cpufreq/intel_pstate.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
+++ linux-pm/drivers/cpufreq/intel_pstate.c
@@ -857,13 +857,13 @@ static struct freq_attr *hwp_cpufreq_att
NULL,
};
-static void intel_pstate_hwp_set(const struct cpumask *cpumask)
+static void intel_pstate_hwp_set(struct cpufreq_policy *policy)
{
int min, hw_min, max, hw_max, cpu, range, adj_range;
struct perf_limits *perf_limits = limits;
u64 value, cap;
- for_each_cpu(cpu, cpumask) {
+ for_each_cpu(cpu, policy->cpus) {
int max_perf_pct, min_perf_pct;
struct cpudata *cpu_data = all_cpu_data[cpu];
s16 epp;
@@ -949,7 +949,7 @@ skip_epp:
static int intel_pstate_hwp_set_policy(struct cpufreq_policy *policy)
{
if (hwp_active)
- intel_pstate_hwp_set(policy->cpus);
+ intel_pstate_hwp_set(policy);
return 0;
}
@@ -984,11 +984,12 @@ static int intel_pstate_resume(struct cp
return ret;
}
-static void intel_pstate_hwp_set_online_cpus(void)
+static void intel_pstate_update_policies(void)
{
- get_online_cpus();
- intel_pstate_hwp_set(cpu_online_mask);
- put_online_cpus();
+ int cpu;
+
+ for_each_possible_cpu(cpu)
+ cpufreq_update_policy(cpu);
}
/************************** debugfs begin ************************/
@@ -1109,11 +1110,10 @@ static ssize_t store_no_turbo(struct kob
limits->no_turbo = clamp_t(int, input, 0, 1);
- if (hwp_active)
- intel_pstate_hwp_set_online_cpus();
-
mutex_unlock(&intel_pstate_limits_lock);
+ intel_pstate_update_policies();
+
return count;
}
@@ -1138,11 +1138,10 @@ static ssize_t store_max_perf_pct(struct
limits->max_perf_pct);
limits->max_perf = div_ext_fp(limits->max_perf_pct, 100);
- if (hwp_active)
- intel_pstate_hwp_set_online_cpus();
-
mutex_unlock(&intel_pstate_limits_lock);
+ intel_pstate_update_policies();
+
return count;
}
@@ -1167,11 +1166,10 @@ static ssize_t store_min_perf_pct(struct
limits->min_perf_pct);
limits->min_perf = div_ext_fp(limits->min_perf_pct, 100);
- if (hwp_active)
- intel_pstate_hwp_set_online_cpus();
-
mutex_unlock(&intel_pstate_limits_lock);
+ intel_pstate_update_policies();
+
return count;
}
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 0/3] cpufreq: intel_pstate: Locking and limits fix-ups
2016-12-30 14:54 [PATCH 0/3] cpufreq: intel_pstate: Locking and limits fix-ups Rafael J. Wysocki
` (2 preceding siblings ...)
2016-12-30 14:58 ` [PATCH 3/3] cpufreq: intel_pstate: Always keep all limits settings in sync Rafael J. Wysocki
@ 2016-12-30 17:49 ` Srinivas Pandruvada
3 siblings, 0 replies; 5+ messages in thread
From: Srinivas Pandruvada @ 2016-12-30 17:49 UTC (permalink / raw)
To: Rafael J. Wysocki, Linux PM; +Cc: LKML
On Fri, 2016-12-30 at 15:54 +0100, Rafael J. Wysocki wrote:
> Hi,
>
> This series fixes a couple of possible locking issues and limits
> synchronization
> in intel pstate.
>
> [1/3] Add locking to intel_pstate_resume().
> [2/3] Add locking to intel_cpufreq_verify_policy().
> [3/3] Always keep all limits settings in sync.
>
Looks good to me.
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Thanks,
Srinivas
^ permalink raw reply [flat|nested] 5+ messages in thread
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2016-12-30 14:54 [PATCH 0/3] cpufreq: intel_pstate: Locking and limits fix-ups Rafael J. Wysocki
2016-12-30 14:56 ` [PATCH 1/3] cpufreq: intel_pstate: Use locking in intel_pstate_resume() Rafael J. Wysocki
2016-12-30 14:57 ` [PATCH 2/3] cpufreq: intel_pstate: Use locking in intel_cpufreq_verify_policy() Rafael J. Wysocki
2016-12-30 14:58 ` [PATCH 3/3] cpufreq: intel_pstate: Always keep all limits settings in sync Rafael J. Wysocki
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