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#ifndef _LINUX_SWAPCTL_H

#define _LINUX_SWAPCTL_H

#include <asm/page.h>

#include <linux/fs.h>

/* Swap tuning control */

/* First, enumerate the different reclaim policies */

enum RCL_POLICY {RCL_ROUND_ROBIN, RCL_BUFF_FIRST, RCL_PERSIST};

typedef struct swap_control_v5

{

        int     sc_max_page_age;

        int     sc_page_advance;

        int     sc_page_decline;

        int     sc_page_initial_age;

        int     sc_max_buff_age;

        int     sc_buff_advance;

        int     sc_buff_decline;

        int     sc_buff_initial_age;

        int     sc_age_cluster_fract;

        int     sc_age_cluster_min;

        int     sc_pageout_weight;

        int     sc_bufferout_weight;

        int     sc_buffer_grace;

        int     sc_nr_buffs_to_free;

        int     sc_nr_pages_to_free;

        enum RCL_POLICY sc_policy;

} swap_control_v5;

typedef struct swap_control_v5 swap_control_t;

extern swap_control_t swap_control;

typedef struct kswapd_control_v1

{

        int     maxpages;

        int     pages_buff;

        int     pages_shm;

        int     pages_mmap;

        int     pages_swap;

} kswapd_control_v1;

typedef kswapd_control_v1 kswapd_control_t;

extern kswapd_control_t kswapd_ctl;

typedef struct swapstat_v1

{

        int     wakeups;

        int     pages_reclaimed;

        int     pages_shm;

        int     pages_mmap;

        int     pages_swap;

} swapstat_v1;

typedef swapstat_v1 swapstat_t;

extern swapstat_t swapstats;

extern int min_free_pages, free_pages_low, free_pages_high;

#define SC_VERSION      1

#define SC_MAX_VERSION  1

#ifdef __KERNEL__

/* Define the maximum (least urgent) priority for the page reclaim code */

#define RCL_MAXPRI 6

/* We use an extra priority in the swap accounting code to represent

   failure to free a resource at any priority */

#define RCL_FAILURE (RCL_MAXPRI + 1)

#define RCL_POLICY              (swap_control.sc_policy)

#define AGE_CLUSTER_FRACT       (swap_control.sc_age_cluster_fract)

#define AGE_CLUSTER_MIN         (swap_control.sc_age_cluster_min)

#define PAGEOUT_WEIGHT          (swap_control.sc_pageout_weight)

#define BUFFEROUT_WEIGHT        (swap_control.sc_bufferout_weight)

#define NR_BUFFS_TO_FREE        (swap_control.sc_nr_buffs_to_free)

#define NR_PAGES_TO_FREE        (swap_control.sc_nr_pages_to_free)

#define BUFFERMEM_GRACE         (swap_control.sc_buffer_grace)

/* Page aging (see mm/swap.c) */

#define MAX_PAGE_AGE            (swap_control.sc_max_page_age)

#define PAGE_ADVANCE            (swap_control.sc_page_advance)

#define PAGE_DECLINE            (swap_control.sc_page_decline)

#define PAGE_INITIAL_AGE        (swap_control.sc_page_initial_age)

#define MAX_BUFF_AGE            (swap_control.sc_max_buff_age)

#define BUFF_ADVANCE            (swap_control.sc_buff_advance)

#define BUFF_DECLINE            (swap_control.sc_buff_decline)

#define BUFF_INITIAL_AGE        (swap_control.sc_buff_initial_age)

/* Given a resource of N units (pages or buffers etc), we only try to

 * age and reclaim AGE_CLUSTER_FRACT per 1024 resources each time we

 * scan the resource list. */

static inline int AGE_CLUSTER_SIZE(int resources)

{

        int n = (resources * AGE_CLUSTER_FRACT) >> 10;

        if (n < AGE_CLUSTER_MIN)

                return AGE_CLUSTER_MIN;

        else

                return n;

}

static inline void touch_page(struct page *page)

{

        if (page->age < (MAX_PAGE_AGE - PAGE_ADVANCE))

                page->age += PAGE_ADVANCE;

        else

                page->age = MAX_PAGE_AGE;

}

static inline void age_page(struct page *page)

{

        if (page->age > PAGE_DECLINE)

                page->age -= PAGE_DECLINE;

        else

                page->age = 0;

}

static inline int age_of(unsigned long addr)

{

        return mem_map[MAP_NR(addr)].age;

}

static inline void set_page_new(unsigned long addr)

{

        mem_map[MAP_NR(addr)].age = PAGE_INITIAL_AGE;

}

#endif /* __KERNEL */

#endif /* _LINUX_SWAPCTL_H */