| /* |
| * 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 |
| */ |
| } |