//
// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// kernel --
//
// Author           : Thierry Delisle
// Created On       : Tue Jan 17 12:27:26 2017
// Last Modified By : Peter A. Buhr
// Last Modified On : Tue Feb  4 12:29:26 2020
// Update Count     : 22
//

#pragma once

#include <stdbool.h>
#include <stdint.h>

#include "invoke.h"
#include "time_t.hfa"
#include "coroutine.hfa"

#include "containers/stackLockFree.hfa"

extern "C" {
#include <pthread.h>
#include <semaphore.h>
}

//-----------------------------------------------------------------------------
// Locks
struct semaphore {
	__spinlock_t lock;
	int count;
	__queue_t($thread) waiting;
};

void  ?{}(semaphore & this, int count = 1);
void ^?{}(semaphore & this);
bool   P (semaphore & this);
bool   V (semaphore & this);
bool   V (semaphore & this, unsigned count);


//-----------------------------------------------------------------------------
// Processor
extern struct cluster * mainCluster;

// Processor id, required for scheduling threads
struct __processor_id_t {
	unsigned id;

	#if !defined(__CFA_NO_STATISTICS__)
		struct __stats_t * stats;
	#endif
};

coroutine processorCtx_t {
	struct processor * proc;
};

// Wrapper around kernel threads
struct __attribute__((aligned(128))) processor {
	// Main state
	inline __processor_id_t;

	// Cluster from which to get threads
	struct cluster * cltr;

	// Set to true to notify the processor should terminate
	volatile bool do_terminate;

	// Coroutine ctx who does keeps the state of the processor
	struct processorCtx_t runner;

	// Name of the processor
	const char * name;

	// Handle to pthreads
	pthread_t kernel_thread;

	// RunThread data
	// Action to do after a thread is ran
	$thread * destroyer;

	// Preemption data
	// Node which is added in the discrete event simulaiton
	struct alarm_node_t * preemption_alarm;

	// If true, a preemption was triggered in an unsafe region, the processor must preempt as soon as possible
	bool pending_preemption;

	// Idle lock (kernel semaphore)
	__bin_sem_t idle;

	// Termination synchronisation (user semaphore)
	semaphore terminated;

	// pthread Stack
	void * stack;

	// Link lists fields
	Link(processor) link;

	#if !defined(__CFA_NO_STATISTICS__)
		int print_stats;
		bool print_halts;
	#endif

#ifdef __CFA_DEBUG__
	// Last function to enable preemption on this processor
	const char * last_enable;
#endif
};

void  ?{}(processor & this, const char name[], struct cluster & cltr);
void ^?{}(processor & this);

static inline void  ?{}(processor & this)                    { this{ "Anonymous Processor", *mainCluster}; }
static inline void  ?{}(processor & this, struct cluster & cltr)    { this{ "Anonymous Processor", cltr}; }
static inline void  ?{}(processor & this, const char name[]) { this{name, *mainCluster }; }

static inline Link(processor) * ?`next( processor * this ) { return &this->link; }

//-----------------------------------------------------------------------------
// I/O
struct __io_data;

#define CFA_CLUSTER_IO_POLLER_USER_THREAD    (1 << 0) // 0x01
#define CFA_CLUSTER_IO_POLLER_THREAD_SUBMITS (1 << 1) // 0x02
#define CFA_CLUSTER_IO_EAGER_SUBMITS         (1 << 2) // 0x04
#define CFA_CLUSTER_IO_KERNEL_POLL_SUBMITS   (1 << 3) // 0x08
#define CFA_CLUSTER_IO_KERNEL_POLL_COMPLETES (1 << 4) // 0x10
#define CFA_CLUSTER_IO_BUFFLEN_OFFSET        16


//-----------------------------------------------------------------------------
// Cluster Tools

// Intrusives lanes which are used by the relaxed ready queue
struct __attribute__((aligned(128))) __intrusive_lane_t;
void  ?{}(__intrusive_lane_t & this);
void ^?{}(__intrusive_lane_t & this);

// Counter used for wether or not the lanes are all empty
struct __attribute__((aligned(128))) __snzi_node_t;
struct __snzi_t {
	unsigned mask;
	int root;
	__snzi_node_t * nodes;
};

void  ?{}( __snzi_t & this, unsigned depth );
void ^?{}( __snzi_t & this );

//TODO adjust cache size to ARCHITECTURE
// Structure holding the relaxed ready queue
struct __ready_queue_t {
	// Data tracking how many/which lanes are used
	// Aligned to 128 for cache locality
	__snzi_t snzi;

	// Data tracking the actual lanes
	// On a seperate cacheline from the used struct since
	// used can change on each push/pop but this data
	// only changes on shrink/grow
	struct {
		// Arary of lanes
		__intrusive_lane_t * volatile data;

		// Number of lanes (empty or not)
		volatile size_t count;
	} lanes;
};

void  ?{}(__ready_queue_t & this);
void ^?{}(__ready_queue_t & this);

//-----------------------------------------------------------------------------
// Cluster
struct __attribute__((aligned(128))) cluster {
	// Ready queue for threads
	__ready_queue_t ready_queue;

	// Name of the cluster
	const char * name;

	// Preemption rate on this cluster
	Duration preemption_rate;

	// List of idle processors
	StackLF(processor) idles;
	volatile unsigned int nprocessors;

	// List of threads
	__spinlock_t thread_list_lock;
	__dllist_t(struct $thread) threads;
	unsigned int nthreads;

	// Link lists fields
	struct __dbg_node_cltr {
		cluster * next;
		cluster * prev;
	} node;

	struct __io_data * io;

	#if !defined(__CFA_NO_STATISTICS__)
		struct __stats_t * stats;
		int print_stats;
	#endif
};
extern Duration default_preemption();

void ?{} (cluster & this, const char name[], Duration preemption_rate, unsigned flags);
void ^?{}(cluster & this);

static inline void ?{} (cluster & this)                                           { this{"Anonymous Cluster", default_preemption(), 0}; }
static inline void ?{} (cluster & this, Duration preemption_rate)                 { this{"Anonymous Cluster", preemption_rate, 0}; }
static inline void ?{} (cluster & this, const char name[])                        { this{name, default_preemption(), 0}; }
static inline void ?{} (cluster & this, unsigned flags)                           { this{"Anonymous Cluster", default_preemption(), flags}; }
static inline void ?{} (cluster & this, Duration preemption_rate, unsigned flags) { this{"Anonymous Cluster", preemption_rate, flags}; }
static inline void ?{} (cluster & this, const char name[], unsigned flags)        { this{name, default_preemption(), flags}; }

static inline [cluster *&, cluster *& ] __get( cluster & this ) __attribute__((const)) { return this.node.[next, prev]; }

static inline struct processor * active_processor() { return TL_GET( this_processor ); } // UNSAFE
static inline struct cluster   * active_cluster  () { return TL_GET( this_processor )->cltr; }

#if !defined(__CFA_NO_STATISTICS__)
	static inline void print_stats_at_exit( cluster & this, int flags ) {
		this.print_stats |= flags;
	}

	static inline void print_stats_at_exit( processor & this, int flags ) {
		this.print_stats |= flags;
	}

	void print_halts( processor & this );
#endif

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