6  *  Swap reorganised 29.12.95, Stephen Tweedie
14 #include <linux/swap.h>
27 #include "swap.h"
69 	printk("%lu pages in swap cache\n", total_swapcache_pages());  in show_swap_cache_info()
70 	printk("Free swap  = %ldkB\n", K(get_nr_swap_pages()));  in show_swap_cache_info()
71 	printk("Total swap = %lukB\n", K(total_swap_pages));  in show_swap_cache_info()
107 	folio->swap = entry;  in add_to_swap_cache()
141  * been verified to be in the swap cache.
163 	folio->swap.val = 0;  in __delete_from_swap_cache()
171  * add_to_swap - allocate swap space for a folio
172  * @folio: folio we want to move to swap
174  * Allocate swap space for the folio and add the folio to the
175  * swap cache.
178  * Return: Whether the folio was added to the swap cache.
198 	 * deadlock in the swap out path.  in add_to_swap()
201 	 * Add it to the swap cache.  in add_to_swap()
233  * been verified to be in the swap cache and locked.
239 	swp_entry_t entry = folio->swap;  in delete_from_swap_cache()
282  * If we are the only user, then try to free up the swap cache.
299  * Perform a free_page(), also freeing any swap cache associated with
344  * Lookup a swap entry in the swap cache. A found folio will be returned
349  * Caller must lock the swap device or hold a reference to keep it valid.
395  * filemap_get_incore_folio - Find and get a folio from the page or swap caches.
400  * folio in the swap cache.
450 		 * First check the swap cache.  Since this is normally  in __read_swap_cache_async()
460 		 * Just skip read ahead for unused swap slot.  in __read_swap_cache_async()
463 		 * swap entry in swap cache and marking swap slot  in __read_swap_cache_async()
471 		 * Get a new folio to read into from swap.  Allocate it now if  in __read_swap_cache_async()
483 		 * Swap entry may have been freed since our caller observed it.  in __read_swap_cache_async()
494 		 * is set but the folio is not the swap cache yet. This can  in __read_swap_cache_async()
507 		 * in swap_map, but not yet added its folio to swap cache.  in __read_swap_cache_async()
513 	 * The swap entry is ours to swap in. Prepare the new folio.  in __read_swap_cache_async()
549  * Locate a page of swap in physical memory, reserving swap cache space
552  * the swap entry is no longer in use.
556  * swap cache folio lock.
595 		 * (and don't even bother to check whether swap type is same).  in __swapin_nr_pages()
639  * swap_cluster_readahead - swap in pages in hope we need them soon
640  * @entry: swap entry of this memory
647  * Primitive swap readahead code. We simply read an aligned block of
648  * (1 << page_cluster) entries in the swap area. This method is chosen
653  * are used for every page of the readahead: neighbouring pages on swap
676 	if (!start_offset)	/* First page is swap header. */  in swap_cluster_readahead()
724 		/* swap cache doesn't use writeback related tags */  in init_swap_address_space()
784  * swap_vma_readahead - swap in pages in hope we need them soon
785  * @targ_entry: swap entry of the targeted memory
793  * Primitive swap readahead code. We simply read in a few pages whose
861  * swapin_readahead - swap in pages in hope we need them soon
862  * @entry: swap entry of this memory
868  * It's a main entry function for swap readahead. By the configuration,
923 	swap_kobj = kobject_create_and_add("swap", mm_kobj);  in swap_init_sysfs()
925 		pr_err("failed to create swap kobject\n");  in swap_init_sysfs()
930 		pr_err("failed to register swap group\n");  in swap_init_sysfs()