* Re: [PATCH v4 2/2] cpufreq: Pass the policy to cpufreq_driver->adjust_perf()
2026-03-16 8:18 ` [PATCH v4 2/2] cpufreq: Pass the policy to cpufreq_driver->adjust_perf() K Prateek Nayak
@ 2026-03-16 10:59 ` Gary Guo
2026-03-26 12:04 ` Gautham R. Shenoy
2026-03-26 13:16 ` Zhongqiu Han
2 siblings, 0 replies; 7+ messages in thread
From: Gary Guo @ 2026-03-16 10:59 UTC (permalink / raw)
To: K Prateek Nayak, Rafael J. Wysocki, Viresh Kumar, Huang Rui,
Gautham R. Shenoy, Mario Limonciello, Sebastian Andrzej Siewior,
Clark Williams, Steven Rostedt, Srinivas Pandruvada, Len Brown,
Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot,
Miguel Ojeda
Cc: Perry Yuan, linux-pm, linux-kernel, rust-for-linux,
linux-rt-devel, Dietmar Eggemann, Ben Segall, Mel Gorman,
Valentin Schneider, Boqun Feng, Gary Guo, Björn Roy Baron,
Benno Lossin, Andreas Hindborg, Alice Ryhl, Trevor Gross,
Danilo Krummrich, Bert Karwatzki
On Mon Mar 16, 2026 at 8:18 AM GMT, K Prateek Nayak wrote:
> cpufreq_cpu_get() can sleep on PREEMPT_RT in presence of concurrent
> writer(s), however amd-pstate depends on fetching the cpudata via the
> policy's driver data which necessitates grabbing the reference.
>
> Since schedutil governor can call "cpufreq_driver->update_perf()"
> during sched_tick/enqueue/dequeue with rq_lock held and IRQs disabled,
> fetching the policy object using the cpufreq_cpu_get() helper in the
> scheduler fast-path leads to "BUG: scheduling while atomic" on
> PREEMPT_RT [1].
>
> Pass the cached cpufreq policy object in sg_policy to the update_perf()
> instead of just the CPU. The CPU can be inferred using "policy->cpu".
>
> The lifetime of cpufreq_policy object outlasts that of the governor and
> the cpufreq driver (allocated when the CPU is onlined and only reclaimed
> when the CPU is offlined / the CPU device is removed) which makes it
> safe to be referenced throughout the governor's lifetime.
>
> Fixes: 1d215f0319c2 ("cpufreq: amd-pstate: Add fast switch function for AMD P-State")
> Reported-by: Bert Karwatzki <spasswolf@web.de>
> Closes:https://lore.kernel.org/all/20250731092316.3191-1-spasswolf@web.de/ [1]
> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
> Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com>
Acked-by: Gary Guo <gary@garyguo.net> # Rust
Looks like a sensible thing to do, interestingly I noted that this (as an
effect) aligns the C API to what the Rust-side cpufreq API already has.
Best,
Gary
> ---
> changelog v3..v4:
>
> o Added the Fixes tag. (Gautham, Chris Mason's review-prompts)
> ---
> drivers/cpufreq/amd-pstate.c | 3 +--
> drivers/cpufreq/cpufreq.c | 6 +++---
> drivers/cpufreq/intel_pstate.c | 4 ++--
> include/linux/cpufreq.h | 4 ++--
> kernel/sched/cpufreq_schedutil.c | 5 +++--
> rust/kernel/cpufreq.rs | 13 ++++++-------
> 6 files changed, 17 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 5faccb3d6b14..ad4b5f84773a 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -710,13 +710,12 @@ static unsigned int amd_pstate_fast_switch(struct cpufreq_policy *policy,
> return policy->cur;
> }
>
> -static void amd_pstate_adjust_perf(unsigned int cpu,
> +static void amd_pstate_adjust_perf(struct cpufreq_policy *policy,
> unsigned long _min_perf,
> unsigned long target_perf,
> unsigned long capacity)
> {
> u8 max_perf, min_perf, des_perf, cap_perf;
> - struct cpufreq_policy *policy __free(put_cpufreq_policy) = cpufreq_cpu_get(cpu);
> struct amd_cpudata *cpudata;
> union perf_cached perf;
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 2082a9e4384f..17a5b8e0ea1e 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -2231,7 +2231,7 @@ EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
>
> /**
> * cpufreq_driver_adjust_perf - Adjust CPU performance level in one go.
> - * @cpu: Target CPU.
> + * @policy: cpufreq policy object of the target CPU.
> * @min_perf: Minimum (required) performance level (units of @capacity).
> * @target_perf: Target (desired) performance level (units of @capacity).
> * @capacity: Capacity of the target CPU.
> @@ -2250,12 +2250,12 @@ EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
> * parallel with either ->target() or ->target_index() or ->fast_switch() for
> * the same CPU.
> */
> -void cpufreq_driver_adjust_perf(unsigned int cpu,
> +void cpufreq_driver_adjust_perf(struct cpufreq_policy *policy,
> unsigned long min_perf,
> unsigned long target_perf,
> unsigned long capacity)
> {
> - cpufreq_driver->adjust_perf(cpu, min_perf, target_perf, capacity);
> + cpufreq_driver->adjust_perf(policy, min_perf, target_perf, capacity);
> }
>
> /**
> diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> index 51938c5a47ca..1552b2d32a34 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -3239,12 +3239,12 @@ static unsigned int intel_cpufreq_fast_switch(struct cpufreq_policy *policy,
> return target_pstate * cpu->pstate.scaling;
> }
>
> -static void intel_cpufreq_adjust_perf(unsigned int cpunum,
> +static void intel_cpufreq_adjust_perf(struct cpufreq_policy *policy,
> unsigned long min_perf,
> unsigned long target_perf,
> unsigned long capacity)
> {
> - struct cpudata *cpu = all_cpu_data[cpunum];
> + struct cpudata *cpu = all_cpu_data[policy->cpu];
> u64 hwp_cap = READ_ONCE(cpu->hwp_cap_cached);
> int old_pstate = cpu->pstate.current_pstate;
> int cap_pstate, min_pstate, max_pstate, target_pstate;
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index cc894fc38971..4317c5a312bd 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -372,7 +372,7 @@ struct cpufreq_driver {
> * conditions) scale invariance can be disabled, which causes the
> * schedutil governor to fall back to the latter.
> */
> - void (*adjust_perf)(unsigned int cpu,
> + void (*adjust_perf)(struct cpufreq_policy *policy,
> unsigned long min_perf,
> unsigned long target_perf,
> unsigned long capacity);
> @@ -617,7 +617,7 @@ struct cpufreq_governor {
> /* Pass a target to the cpufreq driver */
> unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
> unsigned int target_freq);
> -void cpufreq_driver_adjust_perf(unsigned int cpu,
> +void cpufreq_driver_adjust_perf(struct cpufreq_policy *policy,
> unsigned long min_perf,
> unsigned long target_perf,
> unsigned long capacity);
> diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> index 153232dd8276..ae9fd211cec1 100644
> --- a/kernel/sched/cpufreq_schedutil.c
> +++ b/kernel/sched/cpufreq_schedutil.c
> @@ -461,6 +461,7 @@ static void sugov_update_single_perf(struct update_util_data *hook, u64 time,
> unsigned int flags)
> {
> struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
> + struct sugov_policy *sg_policy = sg_cpu->sg_policy;
> unsigned long prev_util = sg_cpu->util;
> unsigned long max_cap;
>
> @@ -482,10 +483,10 @@ static void sugov_update_single_perf(struct update_util_data *hook, u64 time,
> if (sugov_hold_freq(sg_cpu) && sg_cpu->util < prev_util)
> sg_cpu->util = prev_util;
>
> - cpufreq_driver_adjust_perf(sg_cpu->cpu, sg_cpu->bw_min,
> + cpufreq_driver_adjust_perf(sg_policy->policy, sg_cpu->bw_min,
> sg_cpu->util, max_cap);
>
> - sg_cpu->sg_policy->last_freq_update_time = time;
> + sg_policy->last_freq_update_time = time;
> }
>
> static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
> diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs
> index 76faa1ac8501..a83aec198336 100644
> --- a/rust/kernel/cpufreq.rs
> +++ b/rust/kernel/cpufreq.rs
> @@ -1256,18 +1256,17 @@ impl<T: Driver> Registration<T> {
> /// # Safety
> ///
> /// - This function may only be called from the cpufreq C infrastructure.
> + /// - The pointer arguments must be valid pointers.
> unsafe extern "C" fn adjust_perf_callback(
> - cpu: c_uint,
> + ptr: *mut bindings::cpufreq_policy,
> min_perf: c_ulong,
> target_perf: c_ulong,
> capacity: c_ulong,
> ) {
> - // SAFETY: The C API guarantees that `cpu` refers to a valid CPU number.
> - let cpu_id = unsafe { CpuId::from_u32_unchecked(cpu) };
> -
> - if let Ok(mut policy) = PolicyCpu::from_cpu(cpu_id) {
> - T::adjust_perf(&mut policy, min_perf, target_perf, capacity);
> - }
> + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the
> + // lifetime of `policy`.
> + let policy = unsafe { Policy::from_raw_mut(ptr) };
> + T::adjust_perf(policy, min_perf, target_perf, capacity);
> }
>
> /// Driver's `get_intermediate` callback.
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH v4 2/2] cpufreq: Pass the policy to cpufreq_driver->adjust_perf()
2026-03-16 8:18 ` [PATCH v4 2/2] cpufreq: Pass the policy to cpufreq_driver->adjust_perf() K Prateek Nayak
2026-03-16 10:59 ` Gary Guo
@ 2026-03-26 12:04 ` Gautham R. Shenoy
2026-03-26 13:16 ` Zhongqiu Han
2 siblings, 0 replies; 7+ messages in thread
From: Gautham R. Shenoy @ 2026-03-26 12:04 UTC (permalink / raw)
To: K Prateek Nayak
Cc: Rafael J. Wysocki, Viresh Kumar, Huang Rui, Mario Limonciello,
Sebastian Andrzej Siewior, Clark Williams, Steven Rostedt,
Srinivas Pandruvada, Len Brown, Ingo Molnar, Peter Zijlstra,
Juri Lelli, Vincent Guittot, Miguel Ojeda, Perry Yuan, linux-pm,
linux-kernel, rust-for-linux, linux-rt-devel, Dietmar Eggemann,
Ben Segall, Mel Gorman, Valentin Schneider, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl,
Trevor Gross, Danilo Krummrich, Bert Karwatzki
On Mon, Mar 16, 2026 at 08:18:49AM +0000, K Prateek Nayak wrote:
> cpufreq_cpu_get() can sleep on PREEMPT_RT in presence of concurrent
> writer(s), however amd-pstate depends on fetching the cpudata via the
> policy's driver data which necessitates grabbing the reference.
>
> Since schedutil governor can call "cpufreq_driver->update_perf()"
> during sched_tick/enqueue/dequeue with rq_lock held and IRQs disabled,
> fetching the policy object using the cpufreq_cpu_get() helper in the
> scheduler fast-path leads to "BUG: scheduling while atomic" on
> PREEMPT_RT [1].
>
> Pass the cached cpufreq policy object in sg_policy to the update_perf()
> instead of just the CPU. The CPU can be inferred using "policy->cpu".
>
> The lifetime of cpufreq_policy object outlasts that of the governor and
> the cpufreq driver (allocated when the CPU is onlined and only reclaimed
> when the CPU is offlined / the CPU device is removed) which makes it
> safe to be referenced throughout the governor's lifetime.
>
> Fixes: 1d215f0319c2 ("cpufreq: amd-pstate: Add fast switch function for AMD P-State")
> Reported-by: Bert Karwatzki <spasswolf@web.de>
> Closes:https://lore.kernel.org/all/20250731092316.3191-1-spasswolf@web.de/ [1]
> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
> Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
--
Thanks and Regards
gautham.
> ---
> changelog v3..v4:
>
> o Added the Fixes tag. (Gautham, Chris Mason's review-prompts)
> ---
> drivers/cpufreq/amd-pstate.c | 3 +--
> drivers/cpufreq/cpufreq.c | 6 +++---
> drivers/cpufreq/intel_pstate.c | 4 ++--
> include/linux/cpufreq.h | 4 ++--
> kernel/sched/cpufreq_schedutil.c | 5 +++--
> rust/kernel/cpufreq.rs | 13 ++++++-------
> 6 files changed, 17 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 5faccb3d6b14..ad4b5f84773a 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -710,13 +710,12 @@ static unsigned int amd_pstate_fast_switch(struct cpufreq_policy *policy,
> return policy->cur;
> }
>
> -static void amd_pstate_adjust_perf(unsigned int cpu,
> +static void amd_pstate_adjust_perf(struct cpufreq_policy *policy,
> unsigned long _min_perf,
> unsigned long target_perf,
> unsigned long capacity)
> {
> u8 max_perf, min_perf, des_perf, cap_perf;
> - struct cpufreq_policy *policy __free(put_cpufreq_policy) = cpufreq_cpu_get(cpu);
> struct amd_cpudata *cpudata;
> union perf_cached perf;
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 2082a9e4384f..17a5b8e0ea1e 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -2231,7 +2231,7 @@ EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
>
> /**
> * cpufreq_driver_adjust_perf - Adjust CPU performance level in one go.
> - * @cpu: Target CPU.
> + * @policy: cpufreq policy object of the target CPU.
> * @min_perf: Minimum (required) performance level (units of @capacity).
> * @target_perf: Target (desired) performance level (units of @capacity).
> * @capacity: Capacity of the target CPU.
> @@ -2250,12 +2250,12 @@ EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
> * parallel with either ->target() or ->target_index() or ->fast_switch() for
> * the same CPU.
> */
> -void cpufreq_driver_adjust_perf(unsigned int cpu,
> +void cpufreq_driver_adjust_perf(struct cpufreq_policy *policy,
> unsigned long min_perf,
> unsigned long target_perf,
> unsigned long capacity)
> {
> - cpufreq_driver->adjust_perf(cpu, min_perf, target_perf, capacity);
> + cpufreq_driver->adjust_perf(policy, min_perf, target_perf, capacity);
> }
>
> /**
> diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> index 51938c5a47ca..1552b2d32a34 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -3239,12 +3239,12 @@ static unsigned int intel_cpufreq_fast_switch(struct cpufreq_policy *policy,
> return target_pstate * cpu->pstate.scaling;
> }
>
> -static void intel_cpufreq_adjust_perf(unsigned int cpunum,
> +static void intel_cpufreq_adjust_perf(struct cpufreq_policy *policy,
> unsigned long min_perf,
> unsigned long target_perf,
> unsigned long capacity)
> {
> - struct cpudata *cpu = all_cpu_data[cpunum];
> + struct cpudata *cpu = all_cpu_data[policy->cpu];
> u64 hwp_cap = READ_ONCE(cpu->hwp_cap_cached);
> int old_pstate = cpu->pstate.current_pstate;
> int cap_pstate, min_pstate, max_pstate, target_pstate;
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index cc894fc38971..4317c5a312bd 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -372,7 +372,7 @@ struct cpufreq_driver {
> * conditions) scale invariance can be disabled, which causes the
> * schedutil governor to fall back to the latter.
> */
> - void (*adjust_perf)(unsigned int cpu,
> + void (*adjust_perf)(struct cpufreq_policy *policy,
> unsigned long min_perf,
> unsigned long target_perf,
> unsigned long capacity);
> @@ -617,7 +617,7 @@ struct cpufreq_governor {
> /* Pass a target to the cpufreq driver */
> unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
> unsigned int target_freq);
> -void cpufreq_driver_adjust_perf(unsigned int cpu,
> +void cpufreq_driver_adjust_perf(struct cpufreq_policy *policy,
> unsigned long min_perf,
> unsigned long target_perf,
> unsigned long capacity);
> diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> index 153232dd8276..ae9fd211cec1 100644
> --- a/kernel/sched/cpufreq_schedutil.c
> +++ b/kernel/sched/cpufreq_schedutil.c
> @@ -461,6 +461,7 @@ static void sugov_update_single_perf(struct update_util_data *hook, u64 time,
> unsigned int flags)
> {
> struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
> + struct sugov_policy *sg_policy = sg_cpu->sg_policy;
> unsigned long prev_util = sg_cpu->util;
> unsigned long max_cap;
>
> @@ -482,10 +483,10 @@ static void sugov_update_single_perf(struct update_util_data *hook, u64 time,
> if (sugov_hold_freq(sg_cpu) && sg_cpu->util < prev_util)
> sg_cpu->util = prev_util;
>
> - cpufreq_driver_adjust_perf(sg_cpu->cpu, sg_cpu->bw_min,
> + cpufreq_driver_adjust_perf(sg_policy->policy, sg_cpu->bw_min,
> sg_cpu->util, max_cap);
>
> - sg_cpu->sg_policy->last_freq_update_time = time;
> + sg_policy->last_freq_update_time = time;
> }
>
> static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
> diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs
> index 76faa1ac8501..a83aec198336 100644
> --- a/rust/kernel/cpufreq.rs
> +++ b/rust/kernel/cpufreq.rs
> @@ -1256,18 +1256,17 @@ impl<T: Driver> Registration<T> {
> /// # Safety
> ///
> /// - This function may only be called from the cpufreq C infrastructure.
> + /// - The pointer arguments must be valid pointers.
> unsafe extern "C" fn adjust_perf_callback(
> - cpu: c_uint,
> + ptr: *mut bindings::cpufreq_policy,
> min_perf: c_ulong,
> target_perf: c_ulong,
> capacity: c_ulong,
> ) {
> - // SAFETY: The C API guarantees that `cpu` refers to a valid CPU number.
> - let cpu_id = unsafe { CpuId::from_u32_unchecked(cpu) };
> -
> - if let Ok(mut policy) = PolicyCpu::from_cpu(cpu_id) {
> - T::adjust_perf(&mut policy, min_perf, target_perf, capacity);
> - }
> + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the
> + // lifetime of `policy`.
> + let policy = unsafe { Policy::from_raw_mut(ptr) };
> + T::adjust_perf(policy, min_perf, target_perf, capacity);
> }
>
> /// Driver's `get_intermediate` callback.
> --
> 2.34.1
>
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH v4 2/2] cpufreq: Pass the policy to cpufreq_driver->adjust_perf()
2026-03-16 8:18 ` [PATCH v4 2/2] cpufreq: Pass the policy to cpufreq_driver->adjust_perf() K Prateek Nayak
2026-03-16 10:59 ` Gary Guo
2026-03-26 12:04 ` Gautham R. Shenoy
@ 2026-03-26 13:16 ` Zhongqiu Han
2 siblings, 0 replies; 7+ messages in thread
From: Zhongqiu Han @ 2026-03-26 13:16 UTC (permalink / raw)
To: K Prateek Nayak, Rafael J. Wysocki, Viresh Kumar, Huang Rui,
Gautham R. Shenoy, Mario Limonciello, Sebastian Andrzej Siewior,
Clark Williams, Steven Rostedt, Srinivas Pandruvada, Len Brown,
Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot,
Miguel Ojeda
Cc: Perry Yuan, linux-pm, linux-kernel, rust-for-linux,
linux-rt-devel, Dietmar Eggemann, Ben Segall, Mel Gorman,
Valentin Schneider, Boqun Feng, Gary Guo, Björn Roy Baron,
Benno Lossin, Andreas Hindborg, Alice Ryhl, Trevor Gross,
Danilo Krummrich, Bert Karwatzki, zhongqiu.han
On 3/16/2026 4:18 PM, K Prateek Nayak wrote:
> cpufreq_cpu_get() can sleep on PREEMPT_RT in presence of concurrent
> writer(s), however amd-pstate depends on fetching the cpudata via the
> policy's driver data which necessitates grabbing the reference.
>
> Since schedutil governor can call "cpufreq_driver->update_perf()"
> during sched_tick/enqueue/dequeue with rq_lock held and IRQs disabled,
> fetching the policy object using the cpufreq_cpu_get() helper in the
> scheduler fast-path leads to "BUG: scheduling while atomic" on
> PREEMPT_RT [1].
>
> Pass the cached cpufreq policy object in sg_policy to the update_perf()
> instead of just the CPU. The CPU can be inferred using "policy->cpu".
Agreed, sugov_update_single_perf() is only invoked for CPUs belonging to
a non-shared policy; in this path, policy->cpu is guaranteed to match
sg_cpu->cpu. With that invariant, this patch looks correct to me.
>
> The lifetime of cpufreq_policy object outlasts that of the governor and
> the cpufreq driver (allocated when the CPU is onlined and only reclaimed
> when the CPU is offlined / the CPU device is removed) which makes it
> safe to be referenced throughout the governor's lifetime.
>
> Fixes: 1d215f0319c2 ("cpufreq: amd-pstate: Add fast switch function for AMD P-State")
> Reported-by: Bert Karwatzki <spasswolf@web.de>
> Closes:https://lore.kernel.org/all/20250731092316.3191-1-spasswolf@web.de/ [1]
> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
> Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com>
> ---
> changelog v3..v4:
>
> o Added the Fixes tag. (Gautham, Chris Mason's review-prompts)
> ---
> drivers/cpufreq/amd-pstate.c | 3 +--
> drivers/cpufreq/cpufreq.c | 6 +++---
> drivers/cpufreq/intel_pstate.c | 4 ++--
> include/linux/cpufreq.h | 4 ++--
> kernel/sched/cpufreq_schedutil.c | 5 +++--
> rust/kernel/cpufreq.rs | 13 ++++++-------
> 6 files changed, 17 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 5faccb3d6b14..ad4b5f84773a 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -710,13 +710,12 @@ static unsigned int amd_pstate_fast_switch(struct cpufreq_policy *policy,
> return policy->cur;
> }
>
> -static void amd_pstate_adjust_perf(unsigned int cpu,
> +static void amd_pstate_adjust_perf(struct cpufreq_policy *policy,
> unsigned long _min_perf,
> unsigned long target_perf,
> unsigned long capacity)
> {
> u8 max_perf, min_perf, des_perf, cap_perf;
> - struct cpufreq_policy *policy __free(put_cpufreq_policy) = cpufreq_cpu_get(cpu);
> struct amd_cpudata *cpudata;
> union perf_cached perf;
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 2082a9e4384f..17a5b8e0ea1e 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -2231,7 +2231,7 @@ EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
>
> /**
> * cpufreq_driver_adjust_perf - Adjust CPU performance level in one go.
> - * @cpu: Target CPU.
> + * @policy: cpufreq policy object of the target CPU.
> * @min_perf: Minimum (required) performance level (units of @capacity).
> * @target_perf: Target (desired) performance level (units of @capacity).
> * @capacity: Capacity of the target CPU.
> @@ -2250,12 +2250,12 @@ EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
> * parallel with either ->target() or ->target_index() or ->fast_switch() for
> * the same CPU.
> */
> -void cpufreq_driver_adjust_perf(unsigned int cpu,
> +void cpufreq_driver_adjust_perf(struct cpufreq_policy *policy,
> unsigned long min_perf,
> unsigned long target_perf,
> unsigned long capacity)
> {
> - cpufreq_driver->adjust_perf(cpu, min_perf, target_perf, capacity);
> + cpufreq_driver->adjust_perf(policy, min_perf, target_perf, capacity);
> }
>
> /**
> diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> index 51938c5a47ca..1552b2d32a34 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -3239,12 +3239,12 @@ static unsigned int intel_cpufreq_fast_switch(struct cpufreq_policy *policy,
> return target_pstate * cpu->pstate.scaling;
> }
>
> -static void intel_cpufreq_adjust_perf(unsigned int cpunum,
> +static void intel_cpufreq_adjust_perf(struct cpufreq_policy *policy,
> unsigned long min_perf,
> unsigned long target_perf,
> unsigned long capacity)
> {
> - struct cpudata *cpu = all_cpu_data[cpunum];
> + struct cpudata *cpu = all_cpu_data[policy->cpu];
> u64 hwp_cap = READ_ONCE(cpu->hwp_cap_cached);
> int old_pstate = cpu->pstate.current_pstate;
> int cap_pstate, min_pstate, max_pstate, target_pstate;
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index cc894fc38971..4317c5a312bd 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -372,7 +372,7 @@ struct cpufreq_driver {
> * conditions) scale invariance can be disabled, which causes the
> * schedutil governor to fall back to the latter.
> */
> - void (*adjust_perf)(unsigned int cpu,
> + void (*adjust_perf)(struct cpufreq_policy *policy,
> unsigned long min_perf,
> unsigned long target_perf,
> unsigned long capacity);
> @@ -617,7 +617,7 @@ struct cpufreq_governor {
> /* Pass a target to the cpufreq driver */
> unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
> unsigned int target_freq);
> -void cpufreq_driver_adjust_perf(unsigned int cpu,
> +void cpufreq_driver_adjust_perf(struct cpufreq_policy *policy,
> unsigned long min_perf,
> unsigned long target_perf,
> unsigned long capacity);
> diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> index 153232dd8276..ae9fd211cec1 100644
> --- a/kernel/sched/cpufreq_schedutil.c
> +++ b/kernel/sched/cpufreq_schedutil.c
> @@ -461,6 +461,7 @@ static void sugov_update_single_perf(struct update_util_data *hook, u64 time,
> unsigned int flags)
> {
> struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
> + struct sugov_policy *sg_policy = sg_cpu->sg_policy;
> unsigned long prev_util = sg_cpu->util;
> unsigned long max_cap;
>
> @@ -482,10 +483,10 @@ static void sugov_update_single_perf(struct update_util_data *hook, u64 time,
> if (sugov_hold_freq(sg_cpu) && sg_cpu->util < prev_util)
> sg_cpu->util = prev_util;
>
> - cpufreq_driver_adjust_perf(sg_cpu->cpu, sg_cpu->bw_min,
> + cpufreq_driver_adjust_perf(sg_policy->policy, sg_cpu->bw_min,
> sg_cpu->util, max_cap);
>
> - sg_cpu->sg_policy->last_freq_update_time = time;
> + sg_policy->last_freq_update_time = time;
> }
>
> static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
> diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs
> index 76faa1ac8501..a83aec198336 100644
> --- a/rust/kernel/cpufreq.rs
> +++ b/rust/kernel/cpufreq.rs
> @@ -1256,18 +1256,17 @@ impl<T: Driver> Registration<T> {
> /// # Safety
> ///
> /// - This function may only be called from the cpufreq C infrastructure.
> + /// - The pointer arguments must be valid pointers.
> unsafe extern "C" fn adjust_perf_callback(
> - cpu: c_uint,
> + ptr: *mut bindings::cpufreq_policy,
> min_perf: c_ulong,
> target_perf: c_ulong,
> capacity: c_ulong,
> ) {
> - // SAFETY: The C API guarantees that `cpu` refers to a valid CPU number.
> - let cpu_id = unsafe { CpuId::from_u32_unchecked(cpu) };
> -
> - if let Ok(mut policy) = PolicyCpu::from_cpu(cpu_id) {
> - T::adjust_perf(&mut policy, min_perf, target_perf, capacity);
> - }
> + // SAFETY: The `ptr` is guaranteed to be valid by the contract with the C code for the
> + // lifetime of `policy`.
> + let policy = unsafe { Policy::from_raw_mut(ptr) };
> + T::adjust_perf(policy, min_perf, target_perf, capacity);
> }
>
> /// Driver's `get_intermediate` callback.
--
Thx and BRs,
Zhongqiu Han
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