1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_SWAP_SLOTS_H
3 #define _LINUX_SWAP_SLOTS_H
4 
5 #include <linux/swap.h>
6 #include <linux/spinlock.h>
7 #include <linux/mutex.h>
8 
9 #define SWAP_SLOTS_CACHE_SIZE			SWAP_BATCH
10 #define THRESHOLD_ACTIVATE_SWAP_SLOTS_CACHE	(5*SWAP_SLOTS_CACHE_SIZE)
11 #define THRESHOLD_DEACTIVATE_SWAP_SLOTS_CACHE	(2*SWAP_SLOTS_CACHE_SIZE)
12 
13 struct swap_slots_cache {
14 	bool		lock_initialized;
15 	struct mutex	alloc_lock; /* protects slots, nr, cur */
16 	swp_entry_t	*slots;
17 	int		nr;
18 	int		cur;
19 	spinlock_t	free_lock;  /* protects slots_ret, n_ret */
20 	swp_entry_t	*slots_ret;
21 	int		n_ret;
22 };
23 
24 void disable_swap_slots_cache_lock(void);
25 void reenable_swap_slots_cache_unlock(void);
26 void enable_swap_slots_cache(void);
27 void free_swap_slot(swp_entry_t entry);
28 
29 extern bool swap_slot_cache_enabled;
30 
31 #endif /* _LINUX_SWAP_SLOTS_H */
32