#ifndef CACHE_H
#define CACHE_H

#include <linux/slab.h>
#define bio_rw_ahead(bio)       ((bio)->bi_rw & (1 << BIO_RW_AHEAD))

#include "hashtable.h"
#include "netclient.h"

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Anemone Memory Client");

#define KERNEL_SECTOR_SIZE 512
#define CACHE_SIZE 4096  /* 16M */
#define PAGE_OUT_OVER_NET 1
#define PAGE_IN_OVER_NET  2
#define MAX_PREFETCH      256

//#define TRACE

extern atomic64_t  outstanding_reqs;

extern ulong cache_size;

extern ulong water_low, water_high;

extern bool water_weight;

/* Percentages, not # requests */
#define WATER_LOW	90
#define WATER_HIGH	96
//#define WATER

extern ulong cache_hits;
extern ulong cache_reads;

/* Cache Structures */
typedef struct cache {
	kmem_cache_t			*page_cache;
	spinlock_t				*lock;
	int						(*replacement)(struct cache *);
	void					(*retrieve_finish)(void *);
	void					*dev; /* very specific, only for use in returning to 
								   * retrieve finish */
	int						stored_pages;
	int						stored_write_pages;
	int						cache_size;
	int						cache_write_limit;					

	list_head				lh;
	list_head				list_free;
	HashTable				ht;
	/* Points to itself */
	struct cache			*cache;
} Cache;

struct cache_entry {
  struct list_head	queue;             /* points to the linked list that makes up the cache */
  ulong			offset;            /* Offset of page */
  u8			*page;             /* the page */
  int			write;
  struct sk_buff	*skb;              /* This may or may not point to an sk_buff. If it does, 
					    * then the cache must take care to call kfree_skb when the 
					    * page is kicked out of memory (this is to avoid a memcpy). */

  ulong			use_count;         /* maintains a counter of how many uses this entry has */
  int			answered;
	
  int			swapped; 	   /* added to support asynchronous write status */
  int                   prefetch;          /* added to support prefetch read status */
};

/* Hashing Function */
ulong cache_hash(void *);

/* Equal Function */
bool cache_entry_equal(void *, void *);

/* Cache Functions */
int cache_init(Cache *cache, int cacheSize, int (*rep)(Cache *), \
			   void (*retrieve_finish)(void *), void *dev, \
			   spinlock_t *lock, struct request_queue * queue);

int cache_cleanup(Cache *);
int cache_add(Cache *, ulong, ulong, void *);
void *cache_retrieve(Cache *, ulong, void *);
void *cache_retrieve_no_net(Cache *, ulong);
void cache_retrieve_finish(void *, struct sk_buff *, ulong, bool, void *);
int cache_remove(Cache *, ulong);
int cache_remove_and_dec(Cache *, ulong);

/* MRU Replacement Policy */
int mru_replace(struct cache *cache);
void mru_finish(void *cache, void *r, bool success);

#endif