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/*
* linux/mm/swap.c
*
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
*/
/*
* This file contains the default values for the opereation of the
* Linux VM subsystem. Finetuning documentation can be found in
* linux/Documentation/sysctl/vm.txt.
* Started 18.12.91
* Swap aging added 23.2.95, Stephen Tweedie.
* Buffermem limits added 12.3.98, Rik van Riel.
*/
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/head.h>
#include <linux/kernel.h>
#include <linux/kernel_stat.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/swap.h>
#include <linux/fs.h>
#include <linux/swapctl.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <asm/dma.h>
#include <asm/system.h> /* for cli()/sti() */
#include <asm/uaccess.h> /* for copy_to/from_user */
#include <asm/bitops.h>
#include <asm/pgtable.h>
/*
* We identify three levels of free memory. We never let free mem
* fall below the freepages.min except for atomic allocations. We
* start background swapping if we fall below freepages.high free
* pages, and we begin intensive swapping below freepages.low.
*
* These values are there to keep GCC from complaining. Actual
* initialization is done in mm/page_alloc.c or arch/sparc(64)/mm/init.c.
*/
freepages_t freepages = {
48, /* freepages.min */
72, /* freepages.low */
96 /* freepages.high */
};
/* We track the number of pages currently being asynchronously swapped
out, so that we don't try to swap TOO many pages out at once */
atomic_t nr_async_pages = ATOMIC_INIT(0);
/*
* Constants for the page aging mechanism: the maximum age (actually,
* the maximum "youthfulness"); the quanta by which pages rejuvenate
* and age; and the initial age for new pages.
*/
swap_control_t swap_control = {
20, 3, 1, 3, /* Page aging */
32, 4, /* Aging cluster */
8192, 8192, /* Pageout and bufferout weights */
};
swapstat_t swapstats = {0};
buffer_mem_t buffer_mem = {
6, /* minimum percent buffer + cache memory */
20, /* borrow percent buffer + cache memory */
90 /* maximum percent buffer + cache memory */
};
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