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Release 4.14 drivers/cpuidle/cpuidle-pseries.c

Directory: drivers/cpuidle
// SPDX-License-Identifier: GPL-2.0
/*
 *  cpuidle-pseries - idle state cpuidle driver.
 *  Adapted from drivers/idle/intel_idle.c and
 *  drivers/acpi/processor_idle.c
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <linux/cpuidle.h>
#include <linux/cpu.h>
#include <linux/notifier.h>

#include <asm/paca.h>
#include <asm/reg.h>
#include <asm/machdep.h>
#include <asm/firmware.h>
#include <asm/runlatch.h>
#include <asm/plpar_wrappers.h>


struct cpuidle_driver pseries_idle_driver = {
	.name             = "pseries_idle",
	.owner            = THIS_MODULE,
};


static int max_idle_state __read_mostly;

static struct cpuidle_state *cpuidle_state_table __read_mostly;

static u64 snooze_timeout __read_mostly;

static bool snooze_timeout_en __read_mostly;


static inline void idle_loop_prolog(unsigned long *in_purr) { ppc64_runlatch_off(); *in_purr = mfspr(SPRN_PURR); /* * Indicate to the HV that we are idle. Now would be * a good time to find other work to dispatch. */ get_lppaca()->idle = 1; }

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Deepthi Dharwar2890.32%150.00%
Nico Pitre39.68%150.00%
Total31100.00%2100.00%


static inline void idle_loop_epilog(unsigned long in_purr) { u64 wait_cycles; wait_cycles = be64_to_cpu(get_lppaca()->wait_state_cycles); wait_cycles += mfspr(SPRN_PURR) - in_purr; get_lppaca()->wait_state_cycles = cpu_to_be64(wait_cycles); get_lppaca()->idle = 0; if (irqs_disabled()) local_irq_enable(); ppc64_runlatch_on(); }

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Deepthi Dharwar2947.54%125.00%
Anton Blanchard2032.79%125.00%
Nico Pitre1118.03%125.00%
Daniel Lezcano11.64%125.00%
Total61100.00%4100.00%


static int snooze_loop(struct cpuidle_device *dev, struct cpuidle_driver *drv, int index) { unsigned long in_purr; u64 snooze_exit_time; set_thread_flag(TIF_POLLING_NRFLAG); idle_loop_prolog(&in_purr); local_irq_enable(); snooze_exit_time = get_tb() + snooze_timeout; while (!need_resched()) { HMT_low(); HMT_very_low(); if (likely(snooze_timeout_en) && get_tb() > snooze_exit_time) { /* * Task has not woken up but we are exiting the polling * loop anyway. Require a barrier after polling is * cleared to order subsequent test of need_resched(). */ clear_thread_flag(TIF_POLLING_NRFLAG); smp_mb(); break; } } HMT_medium(); clear_thread_flag(TIF_POLLING_NRFLAG); idle_loop_epilog(in_purr); return index; }

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Deepthi Dharwar6261.39%240.00%
Shilpasri G Bhat2019.80%120.00%
Nicholas Piggin1918.81%240.00%
Total101100.00%5100.00%


static void check_and_cede_processor(void) { /* * Ensure our interrupt state is properly tracked, * also checks if no interrupt has occurred while we * were soft-disabled */ if (prep_irq_for_idle()) { cede_processor(); #ifdef CONFIG_TRACE_IRQFLAGS /* Ensure that H_CEDE returns with IRQs on */ if (WARN_ON(!(mfmsr() & MSR_EE))) __hard_irq_enable(); #endif } }

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Benjamin Herrenschmidt4097.56%266.67%
Anton Blanchard12.44%133.33%
Total41100.00%3100.00%


static int dedicated_cede_loop(struct cpuidle_device *dev, struct cpuidle_driver *drv, int index) { unsigned long in_purr; idle_loop_prolog(&in_purr); get_lppaca()->donate_dedicated_cpu = 1; HMT_medium(); check_and_cede_processor(); get_lppaca()->donate_dedicated_cpu = 0; idle_loop_epilog(in_purr); return index; }

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Deepthi Dharwar5698.25%150.00%
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Total57100.00%2100.00%


static int shared_cede_loop(struct cpuidle_device *dev, struct cpuidle_driver *drv, int index) { unsigned long in_purr; idle_loop_prolog(&in_purr); /* * Yield the processor to the hypervisor. We return if * an external interrupt occurs (which are driven prior * to returning here) or if a prod occurs from another * processor. When returning here, external interrupts * are enabled. */ check_and_cede_processor(); idle_loop_epilog(in_purr); return index; }

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Deepthi Dharwar4097.56%150.00%
Benjamin Herrenschmidt12.44%150.00%
Total41100.00%2100.00%

/* * States for dedicated partition case. */ static struct cpuidle_state dedicated_states[] = { { /* Snooze */ .name = "snooze", .desc = "snooze", .exit_latency = 0, .target_residency = 0, .enter = &snooze_loop }, { /* CEDE */ .name = "CEDE", .desc = "CEDE", .exit_latency = 10, .target_residency = 100, .enter = &dedicated_cede_loop }, }; /* * States for shared partition case. */ static struct cpuidle_state shared_states[] = { { /* Shared Cede */ .name = "Shared Cede", .desc = "Shared Cede", .exit_latency = 0, .target_residency = 0, .enter = &shared_cede_loop }, };
static int pseries_cpuidle_cpu_online(unsigned int cpu) { struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); if (dev && cpuidle_get_driver()) { cpuidle_pause_and_lock(); cpuidle_enable_device(dev); cpuidle_resume_and_unlock(); } return 0; }

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Deepthi Dharwar3680.00%480.00%
Sebastian Andrzej Siewior920.00%120.00%
Total45100.00%5100.00%


static int pseries_cpuidle_cpu_dead(unsigned int cpu) { struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); if (dev && cpuidle_get_driver()) { cpuidle_pause_and_lock(); cpuidle_disable_device(dev); cpuidle_resume_and_unlock(); } return 0; }

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Sebastian Andrzej Siewior3066.67%125.00%
Deepthi Dharwar1533.33%375.00%
Total45100.00%4100.00%

/* * pseries_cpuidle_driver_init() */
static int pseries_cpuidle_driver_init(void) { int idle_state; struct cpuidle_driver *drv = &pseries_idle_driver; drv->state_count = 0; for (idle_state = 0; idle_state < max_idle_state; ++idle_state) { /* Is the state not enabled? */ if (cpuidle_state_table[idle_state].enter == NULL) continue; drv->states[drv->state_count] = /* structure copy */ cpuidle_state_table[idle_state]; drv->state_count += 1; } return 0; }

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Deepthi Dharwar77100.00%2100.00%
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/* * pseries_idle_probe() * Choose state table for shared versus dedicated partition */
static int pseries_idle_probe(void) { if (cpuidle_disable != IDLE_NO_OVERRIDE) return -ENODEV; if (firmware_has_feature(FW_FEATURE_SPLPAR)) { if (lppaca_shared_proc(get_lppaca())) { cpuidle_state_table = shared_states; max_idle_state = ARRAY_SIZE(shared_states); } else { cpuidle_state_table = dedicated_states; max_idle_state = ARRAY_SIZE(dedicated_states); } } else return -ENODEV; if (max_idle_state > 1) { snooze_timeout_en = true; snooze_timeout = cpuidle_state_table[1].target_residency * tb_ticks_per_usec; } return 0; }

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Deepthi Dharwar6772.04%466.67%
Shilpasri G Bhat2324.73%116.67%
Anton Blanchard33.23%116.67%
Total93100.00%6100.00%


static int __init pseries_processor_idle_init(void) { int retval; retval = pseries_idle_probe(); if (retval) return retval; pseries_cpuidle_driver_init(); retval = cpuidle_register(&pseries_idle_driver, NULL); if (retval) { printk(KERN_DEBUG "Registration of pseries driver failed.\n"); return retval; } retval = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "cpuidle/pseries:online", pseries_cpuidle_cpu_online, NULL); WARN_ON(retval < 0); retval = cpuhp_setup_state_nocalls(CPUHP_CPUIDLE_DEAD, "cpuidle/pseries:DEAD", NULL, pseries_cpuidle_cpu_dead); WARN_ON(retval < 0); printk(KERN_DEBUG "pseries_idle_driver registered\n"); return 0; }

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Deepthi Dharwar6463.37%375.00%
Sebastian Andrzej Siewior3736.63%125.00%
Total101100.00%4100.00%

device_initcall(pseries_processor_idle_init);

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Deepthi Dharwar64773.19%1040.00%
Sebastian Andrzej Siewior768.60%14.00%
Shilpasri G Bhat515.77%14.00%
Benjamin Herrenschmidt424.75%28.00%
Anton Blanchard242.71%312.00%
Nicholas Piggin232.60%312.00%
Nico Pitre141.58%14.00%
Preeti U. Murthy30.34%14.00%
David Howells20.23%14.00%
Daniel Lezcano10.11%14.00%
Greg Kroah-Hartman10.11%14.00%
Total884100.00%25100.00%
Directory: drivers/cpuidle
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