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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. Fine-tuning 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/kernel_stat.h>
#include <linux/swap.h>
#include <linux/swapctl.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <asm/dma.h>
#include <asm/uaccess.h> /* for copy_to/from_user */
#include <asm/pgtable.h>
/* How many pages do we try to swap or page in/out together? */
int page_cluster;
pager_daemon_t pager_daemon = {
512, /* base number for calculating the number of tries */
SWAP_CLUSTER_MAX, /* minimum number of tries */
8, /* do swap I/O in clusters of this size */
};
/*
* Move an inactive page to the active list.
*/
static inline void activate_page_nolock(struct page * page)
{
if (PageLRU(page) && !PageActive(page)) {
del_page_from_inactive_list(page);
add_page_to_active_list(page);
}
}
void activate_page(struct page * page)
{
spin_lock(&pagemap_lru_lock);
activate_page_nolock(page);
spin_unlock(&pagemap_lru_lock);
}
/**
* lru_cache_add: add a page to the page lists
* @page: the page to add
*/
void lru_cache_add(struct page * page)
{
if (!TestSetPageLRU(page)) {
spin_lock(&pagemap_lru_lock);
add_page_to_inactive_list(page);
spin_unlock(&pagemap_lru_lock);
}
}
/**
* __lru_cache_del: remove a page from the page lists
* @page: the page to add
*
* This function is for when the caller already holds
* the pagemap_lru_lock.
*/
void __lru_cache_del(struct page * page)
{
if (TestClearPageLRU(page)) {
if (PageActive(page)) {
del_page_from_active_list(page);
} else {
del_page_from_inactive_list(page);
}
}
}
/**
* lru_cache_del: remove a page from the page lists
* @page: the page to remove
*/
void lru_cache_del(struct page * page)
{
spin_lock(&pagemap_lru_lock);
__lru_cache_del(page);
spin_unlock(&pagemap_lru_lock);
}
/*
* Perform any setup for the swap system
*/
void __init swap_setup(void)
{
unsigned long megs = num_physpages >> (20 - PAGE_SHIFT);
/* Use a smaller cluster for small-memory machines */
if (megs < 16)
page_cluster = 2;
else
page_cluster = 3;
/*
* Right now other parts of the system means that we
* _really_ don't want to cluster much more
*/
}
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