/*-
 *   BSD LICENSE
 *
 *   Copyright (c) Intel Corporation. All rights reserved.
 *   Copyright (c) 2020 Mellanox Technologies LTD. All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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 */

#ifndef SPDK_THREAD_INTERNAL_H_
#define SPDK_THREAD_INTERNAL_H_

#include "spdk/stdinc.h"
#include "spdk/thread.h"

#define SPDK_MAX_POLLER_NAME_LEN	256
#define SPDK_MAX_THREAD_NAME_LEN	256

enum spdk_poller_state {
	/* The poller is registered with a thread but not currently executing its fn. */
	SPDK_POLLER_STATE_WAITING,

	/* The poller is currently running its fn. */
	SPDK_POLLER_STATE_RUNNING,

	/* The poller was unregistered during the execution of its fn. */
	SPDK_POLLER_STATE_UNREGISTERED,

	/* The poller is in the process of being paused.  It will be paused
	 * during the next time it's supposed to be executed.
	 */
	SPDK_POLLER_STATE_PAUSING,

	/* The poller is registered but currently paused.  It's on the
	 * paused_pollers list.
	 */
	SPDK_POLLER_STATE_PAUSED,
};

struct spdk_poller {
	TAILQ_ENTRY(spdk_poller)	tailq;

	/* Current state of the poller; should only be accessed from the poller's thread. */
	enum spdk_poller_state		state;

	uint64_t			period_ticks;
	uint64_t			next_run_tick;
	uint64_t			run_count;
	uint64_t			busy_count;
	spdk_poller_fn			fn;
	void				*arg;
	struct spdk_thread		*thread;

	char				name[SPDK_MAX_POLLER_NAME_LEN + 1];
};

enum spdk_thread_state {
	/* The thread is pocessing poller and message by spdk_thread_poll(). */
	SPDK_THREAD_STATE_RUNNING,

	/* The thread is in the process of termination. It reaps unregistering
	 * poller are releasing I/O channel.
	 */
	SPDK_THREAD_STATE_EXITING,

	/* The thread is exited. It is ready to call spdk_thread_destroy(). */
	SPDK_THREAD_STATE_EXITED,
};

struct spdk_thread {
	uint64_t			tsc_last;
	struct spdk_thread_stats	stats;
	/*
	 * Contains pollers actively running on this thread.  Pollers
	 *  are run round-robin. The thread takes one poller from the head
	 *  of the ring, executes it, then puts it back at the tail of
	 *  the ring.
	 */
	TAILQ_HEAD(active_pollers_head, spdk_poller)	active_pollers;
	/**
	 * Contains pollers running on this thread with a periodic timer.
	 */
	TAILQ_HEAD(timed_pollers_head, spdk_poller)	timed_pollers;
	/*
	 * Contains paused pollers.  Pollers on this queue are waiting until
	 * they are resumed (in which case they're put onto the active/timer
	 * queues) or unregistered.
	 */
	TAILQ_HEAD(paused_pollers_head, spdk_poller)	paused_pollers;
	struct spdk_ring		*messages;
	SLIST_HEAD(, spdk_msg)		msg_cache;
	size_t				msg_cache_count;
	spdk_msg_fn			critical_msg;
	uint64_t			id;
	enum spdk_thread_state		state;

	TAILQ_HEAD(, spdk_io_channel)	io_channels;
	TAILQ_ENTRY(spdk_thread)	tailq;

	char				name[SPDK_MAX_THREAD_NAME_LEN + 1];
	struct spdk_cpuset		cpumask;
	uint64_t			exit_timeout_tsc;

	/* User context allocated at the end */
	uint8_t				ctx[0];
};

const char *spdk_poller_state_str(enum spdk_poller_state state);

const char *spdk_io_device_get_name(struct io_device *dev);

#endif /* SPDK_THREAD_INTERNAL_H_ */