include/linux/swapctl.h

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 1 #ifndef _LINUX_SWAPCTL_H
 2 #define _LINUX_SWAPCTL_H
 3
 4 #include <asm/page.h>
 5 #include <linux/fs.h>
 6
 7 /* Swap tuning control */
 8
 9 typedefstruct swap_control_v6
 10 {
 11 unsigned int sc_max_page_age;
 12 unsigned int sc_page_advance;
 13 unsigned int sc_page_decline;
 14 unsigned int sc_page_initial_age;
 15 unsigned int sc_age_cluster_fract;
 16 unsigned int sc_age_cluster_min;
 17 unsigned int sc_pageout_weight;
 18 unsigned int sc_bufferout_weight;
 19 } swap_control_v6;
 20 typedefstruct swap_control_v6 swap_control_t;
 21 extern swap_control_t swap_control;
 22
 23 typedefstruct swapstat_v1
 24 {
 25 unsigned int wakeups;
 26 unsigned int pages_reclaimed;
 27 unsigned int pages_shm;
 28 unsigned int pages_mmap;
 29 unsigned int pages_swap;
 30 } swapstat_v1;
 31 typedef swapstat_v1 swapstat_t;
 32 extern swapstat_t swapstats;
 33
 34 typedefstruct buffer_mem_v1
 35 {
 36 unsigned int min_percent;
 37 unsigned int borrow_percent;
 38 unsigned int max_percent;
 39 } buffer_mem_v1;
 40 typedef buffer_mem_v1 buffer_mem_t;
 41 extern buffer_mem_t buffer_mem;
 42
 43 typedefstruct freepages_v1
 44 {
 45 unsigned int min;
 46 unsigned int low;
 47 unsigned int high;
 48 } freepages_v1;
 49 typedef freepages_v1 freepages_t;
 50 extern freepages_t freepages;
 51
 52 #define SC_VERSION 1
 53 #define SC_MAX_VERSION 1
 54
 55 #ifdef __KERNEL__
 56
 57 /* Define the maximum (least urgent) priority for the page reclaim code */
 58 #define RCL_MAXPRI 6
 59 /* We use an extra priority in the swap accounting code to represent
 60  failure to free a resource at any priority */
 61 #define RCL_FAILURE (RCL_MAXPRI + 1)
 62
 63 #define AGE_CLUSTER_FRACT (swap_control.sc_age_cluster_fract)
 64 #define AGE_CLUSTER_MIN (swap_control.sc_age_cluster_min)
 65 #define PAGEOUT_WEIGHT (swap_control.sc_pageout_weight)
 66 #define BUFFEROUT_WEIGHT (swap_control.sc_bufferout_weight)
 67
 68 /* Page aging (see mm/swap.c) */
 69
 70 #define MAX_PAGE_AGE (swap_control.sc_max_page_age)
 71 #define PAGE_ADVANCE (swap_control.sc_page_advance)
 72 #define PAGE_DECLINE (swap_control.sc_page_decline)
 73 #define PAGE_INITIAL_AGE (swap_control.sc_page_initial_age)
 74
 75 /* Given a resource of N units (pages or buffers etc), we only try to
 76  * age and reclaim AGE_CLUSTER_FRACT per 1024 resources each time we
 77  * scan the resource list. */
 78 staticinlineintAGE_CLUSTER_SIZE(int resources)
 79 {
 80 unsigned int n = (resources * AGE_CLUSTER_FRACT) >>10;
 81 if(n < AGE_CLUSTER_MIN)
 82 return AGE_CLUSTER_MIN;
 83 else
 84 return n;
 85 }
 86
 87 staticinlinevoidtouch_page(struct page *page)
 88 {
 89 if(page->age < (MAX_PAGE_AGE - PAGE_ADVANCE))
 90  page->age += PAGE_ADVANCE;
 91 else
 92  page->age = MAX_PAGE_AGE;
 93 }
 94
 95 staticinlinevoidage_page(struct page *page)
 96 {
 97 if(page->age > PAGE_DECLINE)
 98  page->age -= PAGE_DECLINE;
 99 else
 100  page->age =0;
 101 }
 102
 103 staticinlineintage_of(unsigned long addr)
 104 {
 105 return mem_map[MAP_NR(addr)].age;
 106 }
 107
 108 staticinlinevoidset_page_new(unsigned long addr)
 109 {
 110  mem_map[MAP_NR(addr)].age = PAGE_INITIAL_AGE;
 111 }
 112
 113 #endif/* __KERNEL */
 114
 115 #endif/* _LINUX_SWAPCTL_H */