LXR linux-old/mm/swap

   1/*
   2 *  linux/mm/swap_state.c
   3 *
   4 *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
   5 *  Swap reorganised 29.12.95, Stephen Tweedie
   6 */
   7
   8#include <linux/mm.h>
   9#include <linux/sched.h>
  10#include <linux/head.h>
  11#include <linux/kernel.h>
  12#include <linux/kernel_stat.h>
  13#include <linux/errno.h>
  14#include <linux/string.h>
  15#include <linux/stat.h>
  16#include <linux/swap.h>
  17#include <linux/fs.h>
  18#include <linux/swapctl.h>
  19#include <linux/init.h>
  20
  21#include <asm/dma.h>
  22#include <asm/system.h> /* for cli()/sti() */
  23#include <asm/uaccess.h> /* for cop_to/from_user */
  24#include <asm/bitops.h>
  25#include <asm/pgtable.h>
  26
  27#ifdef SWAP_CACHE_INFO
  28unsigned long swap_cache_add_total = 0;
  29unsigned long swap_cache_add_success = 0;
  30unsigned long swap_cache_del_total = 0;
  31unsigned long swap_cache_del_success = 0;
  32unsigned long swap_cache_find_total = 0;
  33unsigned long swap_cache_find_success = 0;
  34
  35void show_swap_cache_info(void)
  36{
  37        printk("Swap cache: add %ld/%ld, delete %ld/%ld, find %ld/%ld\n",
  38                swap_cache_add_total, swap_cache_add_success, 
  39                swap_cache_del_total, swap_cache_del_success,
  40                swap_cache_find_total, swap_cache_find_success);
  41}
  42#endif
  43
  44int add_to_swap_cache(struct page *page, unsigned long entry)
  45{
  46        struct swap_info_struct * p = &swap_info[SWP_TYPE(entry)];
  47
  48#ifdef SWAP_CACHE_INFO
  49        swap_cache_add_total++;
  50#endif
  51        if ((p->flags & SWP_WRITEOK) == SWP_WRITEOK) {
  52                page->pg_swap_entry = entry;
  53                if (PageTestandSetSwapCache(page))
  54                        printk("swap_cache: replacing non-empty entry\n");
  55#ifdef SWAP_CACHE_INFO
  56                swap_cache_add_success++;
  57#endif
  58                return 1;
  59        }
  60        return 0;
  61}
  62
  63void swap_duplicate(unsigned long entry)
  64{
  65        struct swap_info_struct * p;
  66        unsigned long offset, type;
  67
  68        if (!entry)
  69                return;
  70        offset = SWP_OFFSET(entry);
  71        type = SWP_TYPE(entry);
  72        if (type & SHM_SWP_TYPE)
  73                return;
  74        if (type >= nr_swapfiles) {
  75                printk("Trying to duplicate nonexistent swap-page\n");
  76                return;
  77        }
  78        p = type + swap_info;
  79        if (offset >= p->max) {
  80                printk("swap_duplicate: weirdness\n");
  81                return;
  82        }
  83        if (!p->swap_map[offset]) {
  84                printk("swap_duplicate: trying to duplicate unused page\n");
  85                return;
  86        }
  87        p->swap_map[offset]++;
  88        return;
  89}
  90
  91