Spdk/include/spdk_internal/event.h

/*-
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 *
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 *       from this software without specific prior written permission.
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 */

#ifndef SPDK_INTERNAL_EVENT_H
#define SPDK_INTERNAL_EVENT_H

#include "spdk/stdinc.h"

#ifdef __cplusplus
extern "C" {
#endif

#include "spdk/event.h"
#include "spdk/json.h"
#include "spdk/thread.h"
#include "spdk/util.h"

struct spdk_event {
	uint32_t		lcore;
	spdk_event_fn		fn;
	void			*arg1;
	void			*arg2;
};

enum spdk_reactor_state {
	SPDK_REACTOR_STATE_UNINITIALIZED = 0,
	SPDK_REACTOR_STATE_INITIALIZED = 1,
	SPDK_REACTOR_STATE_RUNNING = 2,
	SPDK_REACTOR_STATE_EXITING = 3,
	SPDK_REACTOR_STATE_SHUTDOWN = 4,
};

struct spdk_lw_thread {
	TAILQ_ENTRY(spdk_lw_thread)	link;
	uint64_t			tsc_start;
	uint32_t                        lcore;
	bool				resched;
	/* stats over a lifetime of a thread */
	struct spdk_thread_stats	total_stats;
	/* stats during the last scheduling period */
	struct spdk_thread_stats	current_stats;
};

/**
 * Completion callback to set reactor into interrupt mode or poll mode.
 *
 * \param cb_arg Argument to pass to the callback function.
 */
typedef void (*spdk_reactor_set_interrupt_mode_cb)(void *cb_arg);

struct spdk_reactor {
	/* Lightweight threads running on this reactor */
	TAILQ_HEAD(, spdk_lw_thread)			threads;
	uint32_t					thread_count;

	/* Logical core number for this reactor. */
	uint32_t					lcore;

	struct {
		uint32_t				is_valid : 1;
		uint32_t				reserved : 31;
	} flags;

	uint64_t					tsc_last;

	struct spdk_ring				*events;
	int						events_fd;

	/* The last known rusage values */
	struct rusage					rusage;
	uint64_t					last_rusage;

	uint64_t					busy_tsc;
	uint64_t					idle_tsc;

	/* Each bit of cpuset indicates whether a reactor probably requires event notification */
	struct spdk_cpuset				notify_cpuset;
	/* Indicate whether this reactor currently runs in interrupt */
	bool						in_interrupt;
	bool						set_interrupt_mode_in_progress;
	bool						new_in_interrupt;
	spdk_reactor_set_interrupt_mode_cb		set_interrupt_mode_cb_fn;
	void						*set_interrupt_mode_cb_arg;

	struct spdk_fd_group				*fgrp;
	int						resched_fd;
} __attribute__((aligned(SPDK_CACHE_LINE_SIZE)));

int spdk_reactors_init(void);
void spdk_reactors_fini(void);

void spdk_reactors_start(void);
void spdk_reactors_stop(void *arg1);

struct spdk_reactor *spdk_reactor_get(uint32_t lcore);

extern bool g_scheduling_in_progress;

/**
 * Allocate and pass an event to each reactor, serially.
 *
 * The allocated event is processed asynchronously - i.e. spdk_for_each_reactor
 * will return prior to `fn` being called on each reactor.
 *
 * \param fn This is the function that will be called on each reactor.
 * \param arg1 Argument will be passed to fn when called.
 * \param arg2 Argument will be passed to fn when called.
 * \param cpl This will be called on the originating reactor after `fn` has been
 * called on each reactor.
 */
void spdk_for_each_reactor(spdk_event_fn fn, void *arg1, void *arg2, spdk_event_fn cpl);

/**
 * Set reactor into interrupt mode or back to poll mode.
 *
 * Currently, this function is only permitted within spdk application thread.
 * Also it requires the corresponding reactor does not have any spdk_thread.
 *
 * \param lcore CPU core index of specified reactor.
 * \param new_in_interrupt Set interrupt mode for true, or poll mode for false.
 * \param cb_fn This will be called on spdk application thread after setting interupt mode.
 * \param cb_arg Argument will be passed to cb_fn when called.
 *
 * \return 0 on success, negtive errno on failure.
 */
int spdk_reactor_set_interrupt_mode(uint32_t lcore, bool new_in_interrupt,
				    spdk_reactor_set_interrupt_mode_cb cb_fn, void *cb_arg);

/**
 * Get a handle to spdk application thread.
 *
 * \return a pointer to spdk application thread on success or NULL on failure.
 */
struct spdk_thread *_spdk_get_app_thread(void);

struct spdk_governor_capabilities {
	bool priority;
};

/** Cores governor */
struct spdk_governor {
	char *name;

	/* return - current frequency on success, 0 on failure */
	uint32_t (*get_core_curr_freq)(uint32_t lcore_id);

	int (*core_freq_up)(uint32_t lcore_id);
	int (*core_freq_down)(uint32_t lcore_id);
	int (*set_core_freq_max)(uint32_t lcore_id);
	int (*set_core_freq_min)(uint32_t lcore_id);

	int (*get_core_capabilities)(uint32_t lcore_id, struct spdk_governor_capabilities *capabilities);
	int (*init)(void);
	void (*deinit)(void);

	TAILQ_ENTRY(spdk_governor) link;
};

/**
 * Add the given governor to the list of registered governors.
 * This function should be invoked by referencing the macro
 * SPDK_GOVERNOR_REGISTER in the governor c file.
 *
 * \param governor Governor to be added.
 *
 * \return 0 on success or non-zero on failure.
 */
void _spdk_governor_list_add(struct spdk_governor *governor);

/**
 * Set the current governor.
 *
 * Always deinitalizes previously set governor.
 * No governor will be set if name parameter is NULL.
 * This function should be invoked on scheduling reactor.
 *
 * \param name Name of the governor to be used.
 *
 * \return 0 on success or non-zero on failure.
 */
int _spdk_governor_set(char *name);

/**
 * Get currently set governor.
 *
 */
struct spdk_governor *_spdk_governor_get(void);

/**
 * Macro used to register new cores governor.
 */
#define SPDK_GOVERNOR_REGISTER(governor) \
	static void __attribute__((constructor)) _spdk_governor_register_ ## governor(void) \
	{ \
		_spdk_governor_list_add(&governor); \
	} \

/**
 * Structure representing thread used for scheduling.
 */
struct spdk_scheduler_thread_info {
	uint32_t lcore;
	uint64_t thread_id;
	/* stats over a lifetime of a thread */
	struct spdk_thread_stats total_stats;
	/* stats during the last scheduling period */
	struct spdk_thread_stats current_stats;
};

/**
 * A list of cores and threads which is used for scheduling.
 */
struct spdk_scheduler_core_info {
	/* stats over a lifetime of a core */
	uint64_t total_idle_tsc;
	uint64_t total_busy_tsc;
	/* stats during the last scheduling period */
	uint64_t current_idle_tsc;
	uint64_t current_busy_tsc;

	uint32_t lcore;
	uint32_t threads_count;
	bool interrupt_mode;
	struct spdk_scheduler_thread_info *thread_infos;
};

/**
 * Thread scheduler.
 * Functions from this structure are invoked from scheduling reactor.
 */
struct spdk_scheduler {
	const char *name;

	/**
	 * This function is called to initialize a scheduler.
	 *
	 * \return 0 on success or non-zero on failure.
	 */
	int (*init)(void);

	/**
	 * This function is called to deinitialize a scheduler.
	 */
	void (*deinit)(void);

	/**
	 * Function to balance threads across cores by modifying
	 * the value of their lcore field.
	 *
	 * \param core_info Structure describing cores and threads on them.
	 * \param count Size of the core_info array.
	 */
	void (*balance)(struct spdk_scheduler_core_info *core_info, uint32_t count);

	TAILQ_ENTRY(spdk_scheduler)	link;
};

/**
 * Change current scheduler. If another scheduler was used prior,
 * it will be deinitalized. No scheduler will be set if name parameter
 * is NULL.
 * This function should be invoked from scheduling reactor.
 *
 * \param name Name of the scheduler to be used.
 *
 * \return 0 on success or non-zero on failure.
 */
int _spdk_scheduler_set(const char *name);

/**
 * Get currently set scheduler.
 *
 * \return a pointer to spdk scheduler or NULL if none is set.
 */
struct spdk_scheduler *_spdk_scheduler_get(void);

/**
 * Change current scheduling period.
 * Setting period to 0 disables scheduling.
 *
 * \param period Period to set in microseconds.
 */
void _spdk_scheduler_set_period(uint64_t period);

/**
 * Get scheduling period of currently set scheduler.
 *
 * \return Scheduling period in microseconds.
 */
uint64_t _spdk_scheduler_get_period(void);

/**
 * Add the given scheduler to the list of registered schedulers.
 * This function should be invoked by referencing the macro
 * SPDK_SCHEDULER_REGISTER in the scheduler c file.
 *
 * \param scheduler Scheduler to be added.
 */
void _spdk_scheduler_register(struct spdk_scheduler *scheduler);

/*
 * Macro used to register new scheduler.
 */
#define SPDK_SCHEDULER_REGISTER(scheduler) \
static void __attribute__((constructor)) _spdk_scheduler_register_ ## scheduler (void) \
{ \
	_spdk_scheduler_register(&scheduler); \
} \

#ifdef __cplusplus
}
#endif

#endif /* SPDK_INTERNAL_EVENT_H */