Merge tag 'pm-5.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management fix from Rafael Wysocki:
 "Remove recently added frequency invariance support from the CPPC
  cpufreq driver, because it has turned out to be problematic and it
  cannot be fixed properly on time for 5.13 (Viresh Kumar)"

* tag 'pm-5.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  Revert "cpufreq: CPPC: Add support for frequency invariance"

Author: torvalds

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

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);
 }
@@ -718,20 +504,14 @@ static void cppc_check_hisi_workaround(void)
 
 static int __init cppc_cpufreq_init(void)
 {
-	int ret;
-
 	if ((acpi_disabled) || !acpi_cpc_valid())
 		return -ENODEV;
 
 	INIT_LIST_HEAD(&cpu_data_list);
 
 	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();

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 {

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.