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 atomic_t zswap_stored_pages; 11 12 #ifdef CONFIG_ZSWAP 13 14 struct zswap_lruvec_state { 15 /* 16 * Number of pages in zswap that should be protected from the shrinker. 17 * This number is an estimate of the following counts: 18 * 19 * a) Recent page faults. 20 * b) Recent insertion to the zswap LRU. This includes new zswap stores, 21 * as well as recent zswap LRU rotations. 22 * 23 * These pages are likely to be warm, and might incur IO if the are written 24 * to swap. 25 */ 26 atomic_long_t nr_zswap_protected; 27 }; 28 29 unsigned long zswap_total_pages(void); 30 bool zswap_store(struct folio *folio); 31 bool zswap_load(struct folio *folio); 32 void zswap_invalidate(swp_entry_t swp); 33 int zswap_swapon(int type, unsigned long nr_pages); 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 zswap_is_enabled(void); 39 bool zswap_never_enabled(void); 40 #else 41 42 struct zswap_lruvec_state {}; 43 44 static inline bool zswap_store(struct folio *folio) 45 { 46 return false; 47 } 48 49 static inline bool zswap_load(struct folio *folio) 50 { 51 return false; 52 } 53 54 static inline void zswap_invalidate(swp_entry_t swp) {} 55 static inline int zswap_swapon(int type, unsigned long nr_pages) 56 { 57 return 0; 58 } 59 static inline void zswap_swapoff(int type) {} 60 static inline void zswap_memcg_offline_cleanup(struct mem_cgroup *memcg) {} 61 static inline void zswap_lruvec_state_init(struct lruvec *lruvec) {} 62 static inline void zswap_folio_swapin(struct folio *folio) {} 63 64 static inline bool zswap_is_enabled(void) 65 { 66 return false; 67 } 68 69 static inline bool zswap_never_enabled(void) 70 { 71 return true; 72 } 73 74 #endif 75 76 #endif /* _LINUX_ZSWAP_H */ 77