1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_ZSWAP_H
3 #define _LINUX_ZSWAP_H
4 
5 #include <linux/types.h>
6 #include <linux/mm_types.h>
7 
8 struct lruvec;
9 
10 extern u64 zswap_pool_total_size;
11 extern atomic_t zswap_stored_pages;
12 
13 #ifdef CONFIG_ZSWAP
14 
15 struct zswap_lruvec_state {
16 	/*
17 	 * Number of pages in zswap that should be protected from the shrinker.
18 	 * This number is an estimate of the following counts:
19 	 *
20 	 * a) Recent page faults.
21 	 * b) Recent insertion to the zswap LRU. This includes new zswap stores,
22 	 *    as well as recent zswap LRU rotations.
23 	 *
24 	 * These pages are likely to be warm, and might incur IO if the are written
25 	 * to swap.
26 	 */
27 	atomic_long_t nr_zswap_protected;
28 };
29 
30 bool zswap_store(struct folio *folio);
31 bool zswap_load(struct folio *folio);
32 void zswap_invalidate(int type, pgoff_t offset);
33 void zswap_swapon(int type);
34 void zswap_swapoff(int type);
35 void zswap_memcg_offline_cleanup(struct mem_cgroup *memcg);
36 void zswap_lruvec_state_init(struct lruvec *lruvec);
37 void zswap_folio_swapin(struct folio *folio);
38 bool is_zswap_enabled(void);
39 #else
40 
41 struct zswap_lruvec_state {};
42 
zswap_store(struct folio * folio)43 static inline bool zswap_store(struct folio *folio)
44 {
45 	return false;
46 }
47 
zswap_load(struct folio * folio)48 static inline bool zswap_load(struct folio *folio)
49 {
50 	return false;
51 }
52 
zswap_invalidate(int type,pgoff_t offset)53 static inline void zswap_invalidate(int type, pgoff_t offset) {}
zswap_swapon(int type)54 static inline void zswap_swapon(int type) {}
zswap_swapoff(int type)55 static inline void zswap_swapoff(int type) {}
zswap_memcg_offline_cleanup(struct mem_cgroup * memcg)56 static inline void zswap_memcg_offline_cleanup(struct mem_cgroup *memcg) {}
zswap_lruvec_state_init(struct lruvec * lruvec)57 static inline void zswap_lruvec_state_init(struct lruvec *lruvec) {}
zswap_folio_swapin(struct folio * folio)58 static inline void zswap_folio_swapin(struct folio *folio) {}
59 
is_zswap_enabled(void)60 static inline bool is_zswap_enabled(void)
61 {
62 	return false;
63 }
64 
65 #endif
66 
67 #endif /* _LINUX_ZSWAP_H */
68