From 6c0b59640cce68d7574078d7d1e549bdb8f0128d Mon Sep 17 00:00:00 2001 From: Mario Limonciello Date: Wed, 26 Feb 2025 01:49:20 -0600 Subject: cpufreq/amd-pstate: Overhaul locking 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 Reviewed-by: Dhananjay Ugwekar Signed-off-by: Mario Limonciello --- drivers/cpufreq/amd-pstate.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -196,7 +196,6 @@ static inline int get_mode_idx_from_str( 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 c 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_ 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 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 devic 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(st 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 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);