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cpufreq/amd-pstate: Overhaul locking

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amd_pstate_cpu_boost_update() and refresh_frequency_limits() both
update the policy state and have nothing to do with the amd-pstate
driver itself.

A global "limits" lock doesn't make sense because each CPU can have
policies changed independently.  Each time a CPU changes values they
will atomically be written to the per-CPU perf member. Drop per CPU
locking cases.

The remaining "global" driver lock is used to ensure that only one
entity can change driver modes at a given time.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Reviewed-by: Dhananjay Ugwekar <dhananjay.ugwekar@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
This commit is contained in:
Mario Limonciello 2024-12-06 23:20:04 -06:00
parent 009d1c29a4
commit 6f0b13f16f
1 changed files with 3 additions and 10 deletions
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13
drivers/cpufreq/amd-pstate.c
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@ -196,7 +196,6 @@ static inline int get_mode_idx_from_str(const char *str, size_t size)
return -EINVAL;
}
static DEFINE_MUTEX(amd_pstate_limits_lock);
static DEFINE_MUTEX(amd_pstate_driver_lock);
static u8 msr_get_epp(struct amd_cpudata *cpudata)
@ -752,7 +751,6 @@ static int amd_pstate_set_boost(struct cpufreq_policy *policy, int state)
pr_err("Boost mode is not supported by this processor or SBIOS\n");
return -EOPNOTSUPP;
}
guard(mutex)(&amd_pstate_driver_lock);
ret = amd_pstate_cpu_boost_update(policy, state);
refresh_frequency_limits(policy);
@ -1170,8 +1168,6 @@ static ssize_t store_energy_performance_preference(
if (ret < 0)
return -EINVAL;
guard(mutex)(&amd_pstate_limits_lock);
ret = amd_pstate_set_energy_pref_index(policy, ret);
return ret ? ret : count;
@ -1344,8 +1340,10 @@ int amd_pstate_update_status(const char *buf, size_t size)
if (mode_idx < 0 || mode_idx >= AMD_PSTATE_MAX)
return -EINVAL;
if (mode_state_machine[cppc_state][mode_idx])
if (mode_state_machine[cppc_state][mode_idx]) {
guard(mutex)(&amd_pstate_driver_lock);
return mode_state_machine[cppc_state][mode_idx](mode_idx);
}
return 0;
}
@ -1366,7 +1364,6 @@ static ssize_t status_store(struct device *a, struct device_attribute *b,
char *p = memchr(buf, '\n', count);
int ret;
guard(mutex)(&amd_pstate_driver_lock);
ret = amd_pstate_update_status(buf, p ? p - buf : count);
return ret < 0 ? ret : count;
@ -1638,8 +1635,6 @@ static int amd_pstate_epp_cpu_offline(struct cpufreq_policy *policy)
if (cpudata->suspended)
return 0;
guard(mutex)(&amd_pstate_limits_lock);
if (trace_amd_pstate_epp_perf_enabled()) {
trace_amd_pstate_epp_perf(cpudata->cpu, perf.highest_perf,
AMD_CPPC_EPP_BALANCE_POWERSAVE,
@ -1679,8 +1674,6 @@ static int amd_pstate_epp_resume(struct cpufreq_policy *policy)
struct amd_cpudata *cpudata = policy->driver_data;
if (cpudata->suspended) {
guard(mutex)(&amd_pstate_limits_lock);
/* enable amd pstate from suspend state*/
amd_pstate_epp_reenable(policy);