include/linux/swap.h

25 #define SWAP_FLAG_PREFER	0x8000	/* set if swap priority specified */
27 #define SWAP_FLAG_DISCARD	0x10000 /* enable discard for swap */
28 #define SWAP_FLAG_DISCARD_ONCE	0x20000 /* discard swap area at swapon-time */
43  * be swapped to.  The swap type and the offset into that swap type are
52  * Use some of the swap files numbers for other purposes. This
121  * Magic header for a swap area. The first part of the union is
122  * what the swap magic looks like for the old (limited to 128MB)
123  * swap area format, the second part of the union adds - in the
127  * Having the magic at the end of the PAGE_SIZE makes detecting swap
135 		char magic[10];			/* SWAP-SPACE or SWAPSPACE2 */
184  * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
185  * disk blocks.  A rbtree of swap extents maps the entire swapfile (Where the
207 	SWP_WRITEOK	= (1 << 1),	/* ok to write to this swap?	*/
215 	SWP_AREA_DISCARD = (1 << 9),	/* single-time swap area discards */
216 	SWP_PAGE_DISCARD = (1 << 10),	/* freed swap page-cluster discards */
239  * We use this to track usage of a cluster. A cluster is a block of swap disk
251 				 * elements corresponding to the swap cluster.
273  * The first page in the swap file is the swap header, which is always marked
288  * The purpose is to optimize SWAP throughput on these device.
295  * The in-memory structure used to track swap areas.
298 	struct percpu_ref users;	/* indicate and keep swap device valid. */
300 	signed short	prio;		/* swap priority of this type */
314 	unsigned int pages;		/* total of usable pages of swap */
318 	struct rb_root swap_extent_root;/* root of the swap extent rbtree */
319 	struct block_device *bdev;	/* swap device or bdev of swap file */
336 					 * protect swap count continuation page
357 	swp_entry_t entry = folio->swap;  in page_swap_entry()
378 /* linux/mm/swap.c */
460 /* Swap 50% full? Release swapcache more aggressively.. */