This reverts commit 4c38f2df71c8e33c0b64865992d693f5022eeaad.
There are few races in the frequency invariance support for CPPC driver,
namely the driver doesn't stop the kthread_work and irq_work on policy
exit during suspend/resume or CPU hotplug.
A proper fix won't be possible for the 5.13-rc, as it requires a lot of
changes. Lets revert the patch instead for now.
Fixes: 4c38f2df71c8 ("cpufreq: CPPC: Add support for frequency invariance")
Reported-by: Qian Cai <[email protected]>
Signed-off-by: Viresh Kumar <[email protected]>
---
V2: Revert the original patch instead of marking it broken.
drivers/cpufreq/Kconfig.arm | 10 --
drivers/cpufreq/cppc_cpufreq.c | 245 ++-------------------------------
include/linux/arch_topology.h | 1 -
kernel/sched/core.c | 1 -
4 files changed, 12 insertions(+), 245 deletions(-)
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index a5c5f70acfc9..e65e0a43be64 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -19,16 +19,6 @@ config ACPI_CPPC_CPUFREQ
If in doubt, say N.
-config ACPI_CPPC_CPUFREQ_FIE
- bool "Frequency Invariance support for CPPC cpufreq driver"
- depends on ACPI_CPPC_CPUFREQ && GENERIC_ARCH_TOPOLOGY
- default y
- help
- This extends frequency invariance support in the CPPC cpufreq driver,
- by using CPPC delivered and reference performance counters.
-
- If in doubt, say N.
-
config ARM_ALLWINNER_SUN50I_CPUFREQ_NVMEM
tristate "Allwinner nvmem based SUN50I CPUFreq driver"
depends on ARCH_SUNXI
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 3848b4c222e1..2f769b1630c5 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -10,18 +10,14 @@
#define pr_fmt(fmt) "CPPC Cpufreq:" fmt
-#include <linux/arch_topology.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/dmi.h>
-#include <linux/irq_work.h>
-#include <linux/kthread.h>
#include <linux/time.h>
#include <linux/vmalloc.h>
-#include <uapi/linux/sched/types.h>
#include <asm/unaligned.h>
@@ -61,204 +57,6 @@ static struct cppc_workaround_oem_info wa_info[] = {
}
};
-#ifdef CONFIG_ACPI_CPPC_CPUFREQ_FIE
-
-/* Frequency invariance support */
-struct cppc_freq_invariance {
- int cpu;
- struct irq_work irq_work;
- struct kthread_work work;
- struct cppc_perf_fb_ctrs prev_perf_fb_ctrs;
- struct cppc_cpudata *cpu_data;
-};
-
-static DEFINE_PER_CPU(struct cppc_freq_invariance, cppc_freq_inv);
-static struct kthread_worker *kworker_fie;
-static bool fie_disabled;
-
-static struct cpufreq_driver cppc_cpufreq_driver;
-static unsigned int hisi_cppc_cpufreq_get_rate(unsigned int cpu);
-static int cppc_perf_from_fbctrs(struct cppc_cpudata *cpu_data,
- struct cppc_perf_fb_ctrs fb_ctrs_t0,
- struct cppc_perf_fb_ctrs fb_ctrs_t1);
-
-/**
- * cppc_scale_freq_workfn - CPPC arch_freq_scale updater for frequency invariance
- * @work: The work item.
- *
- * The CPPC driver register itself with the topology core to provide its own
- * implementation (cppc_scale_freq_tick()) of topology_scale_freq_tick() which
- * gets called by the scheduler on every tick.
- *
- * Note that the arch specific counters have higher priority than CPPC counters,
- * if available, though the CPPC driver doesn't need to have any special
- * handling for that.
- *
- * On an invocation of cppc_scale_freq_tick(), we schedule an irq work (since we
- * reach here from hard-irq context), which then schedules a normal work item
- * and cppc_scale_freq_workfn() updates the per_cpu arch_freq_scale variable
- * based on the counter updates since the last tick.
- */
-static void cppc_scale_freq_workfn(struct kthread_work *work)
-{
- struct cppc_freq_invariance *cppc_fi;
- struct cppc_perf_fb_ctrs fb_ctrs = {0};
- struct cppc_cpudata *cpu_data;
- unsigned long local_freq_scale;
- u64 perf;
-
- cppc_fi = container_of(work, struct cppc_freq_invariance, work);
- cpu_data = cppc_fi->cpu_data;
-
- if (cppc_get_perf_ctrs(cppc_fi->cpu, &fb_ctrs)) {
- pr_warn("%s: failed to read perf counters\n", __func__);
- return;
- }
-
- cppc_fi->prev_perf_fb_ctrs = fb_ctrs;
- perf = cppc_perf_from_fbctrs(cpu_data, cppc_fi->prev_perf_fb_ctrs,
- fb_ctrs);
-
- perf <<= SCHED_CAPACITY_SHIFT;
- local_freq_scale = div64_u64(perf, cpu_data->perf_caps.highest_perf);
- if (WARN_ON(local_freq_scale > 1024))
- local_freq_scale = 1024;
-
- per_cpu(arch_freq_scale, cppc_fi->cpu) = local_freq_scale;
-}
-
-static void cppc_irq_work(struct irq_work *irq_work)
-{
- struct cppc_freq_invariance *cppc_fi;
-
- cppc_fi = container_of(irq_work, struct cppc_freq_invariance, irq_work);
- kthread_queue_work(kworker_fie, &cppc_fi->work);
-}
-
-static void cppc_scale_freq_tick(void)
-{
- struct cppc_freq_invariance *cppc_fi = &per_cpu(cppc_freq_inv, smp_processor_id());
-
- /*
- * cppc_get_perf_ctrs() can potentially sleep, call that from the right
- * context.
- */
- irq_work_queue(&cppc_fi->irq_work);
-}
-
-static struct scale_freq_data cppc_sftd = {
- .source = SCALE_FREQ_SOURCE_CPPC,
- .set_freq_scale = cppc_scale_freq_tick,
-};
-
-static void cppc_freq_invariance_policy_init(struct cpufreq_policy *policy,
- struct cppc_cpudata *cpu_data)
-{
- struct cppc_perf_fb_ctrs fb_ctrs = {0};
- struct cppc_freq_invariance *cppc_fi;
- int i, ret;
-
- if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate)
- return;
-
- if (fie_disabled)
- return;
-
- for_each_cpu(i, policy->cpus) {
- cppc_fi = &per_cpu(cppc_freq_inv, i);
- cppc_fi->cpu = i;
- cppc_fi->cpu_data = cpu_data;
- kthread_init_work(&cppc_fi->work, cppc_scale_freq_workfn);
- init_irq_work(&cppc_fi->irq_work, cppc_irq_work);
-
- ret = cppc_get_perf_ctrs(i, &fb_ctrs);
- if (ret) {
- pr_warn("%s: failed to read perf counters: %d\n",
- __func__, ret);
- fie_disabled = true;
- } else {
- cppc_fi->prev_perf_fb_ctrs = fb_ctrs;
- }
- }
-}
-
-static void __init cppc_freq_invariance_init(void)
-{
- struct sched_attr attr = {
- .size = sizeof(struct sched_attr),
- .sched_policy = SCHED_DEADLINE,
- .sched_nice = 0,
- .sched_priority = 0,
- /*
- * Fake (unused) bandwidth; workaround to "fix"
- * priority inheritance.
- */
- .sched_runtime = 1000000,
- .sched_deadline = 10000000,
- .sched_period = 10000000,
- };
- int ret;
-
- if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate)
- return;
-
- if (fie_disabled)
- return;
-
- kworker_fie = kthread_create_worker(0, "cppc_fie");
- if (IS_ERR(kworker_fie))
- return;
-
- ret = sched_setattr_nocheck(kworker_fie->task, &attr);
- if (ret) {
- pr_warn("%s: failed to set SCHED_DEADLINE: %d\n", __func__,
- ret);
- kthread_destroy_worker(kworker_fie);
- return;
- }
-
- /* Register for freq-invariance */
- topology_set_scale_freq_source(&cppc_sftd, cpu_present_mask);
-}
-
-static void cppc_freq_invariance_exit(void)
-{
- struct cppc_freq_invariance *cppc_fi;
- int i;
-
- if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate)
- return;
-
- if (fie_disabled)
- return;
-
- topology_clear_scale_freq_source(SCALE_FREQ_SOURCE_CPPC, cpu_present_mask);
-
- for_each_possible_cpu(i) {
- cppc_fi = &per_cpu(cppc_freq_inv, i);
- irq_work_sync(&cppc_fi->irq_work);
- }
-
- kthread_destroy_worker(kworker_fie);
- kworker_fie = NULL;
-}
-
-#else
-static inline void
-cppc_freq_invariance_policy_init(struct cpufreq_policy *policy,
- struct cppc_cpudata *cpu_data)
-{
-}
-
-static inline void cppc_freq_invariance_init(void)
-{
-}
-
-static inline void cppc_freq_invariance_exit(void)
-{
-}
-#endif /* CONFIG_ACPI_CPPC_CPUFREQ_FIE */
-
/* Callback function used to retrieve the max frequency from DMI */
static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private)
{
@@ -547,12 +345,9 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
cpu_data->perf_ctrls.desired_perf = caps->highest_perf;
ret = cppc_set_perf(cpu, &cpu_data->perf_ctrls);
- if (ret) {
+ if (ret)
pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
caps->highest_perf, cpu, ret);
- } else {
- cppc_freq_invariance_policy_init(policy, cpu_data);
- }
return ret;
}
@@ -565,12 +360,12 @@ static inline u64 get_delta(u64 t1, u64 t0)
return (u32)t1 - (u32)t0;
}
-static int cppc_perf_from_fbctrs(struct cppc_cpudata *cpu_data,
- struct cppc_perf_fb_ctrs fb_ctrs_t0,
- struct cppc_perf_fb_ctrs fb_ctrs_t1)
+static int cppc_get_rate_from_fbctrs(struct cppc_cpudata *cpu_data,
+ struct cppc_perf_fb_ctrs fb_ctrs_t0,
+ struct cppc_perf_fb_ctrs fb_ctrs_t1)
{
u64 delta_reference, delta_delivered;
- u64 reference_perf;
+ u64 reference_perf, delivered_perf;
reference_perf = fb_ctrs_t0.reference_perf;
@@ -579,21 +374,12 @@ static int cppc_perf_from_fbctrs(struct cppc_cpudata *cpu_data,
delta_delivered = get_delta(fb_ctrs_t1.delivered,
fb_ctrs_t0.delivered);
- /* Check to avoid divide-by zero and invalid delivered_perf */
- if (!delta_reference || !delta_delivered)
- return cpu_data->perf_ctrls.desired_perf;
-
- return (reference_perf * delta_delivered) / delta_reference;
-}
-
-static int cppc_get_rate_from_fbctrs(struct cppc_cpudata *cpu_data,
- struct cppc_perf_fb_ctrs fb_ctrs_t0,
- struct cppc_perf_fb_ctrs fb_ctrs_t1)
-{
- u64 delivered_perf;
-
- delivered_perf = cppc_perf_from_fbctrs(cpu_data, fb_ctrs_t0,
- fb_ctrs_t1);
+ /* Check to avoid divide-by zero */
+ if (delta_reference || delta_delivered)
+ delivered_perf = (reference_perf * delta_delivered) /
+ delta_reference;
+ else
+ delivered_perf = cpu_data->perf_ctrls.desired_perf;
return cppc_cpufreq_perf_to_khz(cpu_data, delivered_perf);
}
@@ -718,8 +504,6 @@ static void cppc_check_hisi_workaround(void)
static int __init cppc_cpufreq_init(void)
{
- int ret;
-
if ((acpi_disabled) || !acpi_cpc_valid())
return -ENODEV;
@@ -727,11 +511,7 @@ static int __init cppc_cpufreq_init(void)
cppc_check_hisi_workaround();
- ret = cpufreq_register_driver(&cppc_cpufreq_driver);
- if (!ret)
- cppc_freq_invariance_init();
-
- return ret;
+ return cpufreq_register_driver(&cppc_cpufreq_driver);
}
static inline void free_cpu_data(void)
@@ -748,7 +528,6 @@ static inline void free_cpu_data(void)
static void __exit cppc_cpufreq_exit(void)
{
- cppc_freq_invariance_exit();
cpufreq_unregister_driver(&cppc_cpufreq_driver);
free_cpu_data();
diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h
index f180240dc95f..11e555cfaecb 100644
--- a/include/linux/arch_topology.h
+++ b/include/linux/arch_topology.h
@@ -37,7 +37,6 @@ bool topology_scale_freq_invariant(void);
enum scale_freq_source {
SCALE_FREQ_SOURCE_CPUFREQ = 0,
SCALE_FREQ_SOURCE_ARCH,
- SCALE_FREQ_SOURCE_CPPC,
};
struct scale_freq_data {
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5226cc26a095..4ca80df205ce 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6389,7 +6389,6 @@ int sched_setattr_nocheck(struct task_struct *p, const struct sched_attr *attr)
{
return __sched_setscheduler(p, attr, false, true);
}
-EXPORT_SYMBOL_GPL(sched_setattr_nocheck);
/**
* sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
--
2.31.1.272.g89b43f80a514
On Fri, Jun 11, 2021 at 9:40 AM Viresh Kumar <[email protected]> wrote:
>
> On 11-06-21, 09:37, Peter Zijlstra wrote:
> > Alternatively: "depends on BROKEN" ?
>
> This is what I wanted to do, but Rafael didn't like it :)
>
> https://lore.kernel.org/linux-pm/28308fc0d38f252baf90e6ffb31fd2f8660be273.1623311808.git.viresh.kumar@linaro.org/
Right.
For new things I prefer to either fix them properly before the release
or revert and redo in a better way in the next cycle.
On Fri, Jun 11, 2021 at 5:18 AM Viresh Kumar <[email protected]> wrote:
>
> This reverts commit 4c38f2df71c8e33c0b64865992d693f5022eeaad.
>
> There are few races in the frequency invariance support for CPPC driver,
> namely the driver doesn't stop the kthread_work and irq_work on policy
> exit during suspend/resume or CPU hotplug.
>
> A proper fix won't be possible for the 5.13-rc, as it requires a lot of
> changes. Lets revert the patch instead for now.
>
> Fixes: 4c38f2df71c8 ("cpufreq: CPPC: Add support for frequency invariance")
> Reported-by: Qian Cai <[email protected]>
> Signed-off-by: Viresh Kumar <[email protected]>
> ---
> V2: Revert the original patch instead of marking it broken.
Applied as 5.13-rc material, thanks!