include/linux/zswap.h

   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_long_t zswap_stored_pages;
  11
  12 #ifdef CONFIG_ZSWAP
  13
  14 struct zswap_lruvec_state {
  15         /*
  16          * Number of swapped in pages from disk, i.e not found in the zswap pool.
  17          *
  18          * This is consumed and subtracted from the lru size in
  19          * zswap_shrinker_count() to penalize past overshrinking that led to disk
  20          * swapins. The idea is that had we considered this many more pages in the
  21          * LRU active/protected and not written them back, we would not have had to
  22          * swapped them in.
  23          */
  24         atomic_long_t nr_disk_swapins;
  25 };
  26
  27 unsigned long zswap_total_pages(void);
  28 bool zswap_store(struct folio *folio);
  29 bool zswap_load(struct folio *folio);
  30 void zswap_invalidate(swp_entry_t swp);
  31 int zswap_swapon(int type, unsigned long nr_pages);
  32 void zswap_swapoff(int type);
  33 void zswap_memcg_offline_cleanup(struct mem_cgroup *memcg);
  34 void zswap_lruvec_state_init(struct lruvec *lruvec);
  35 void zswap_folio_swapin(struct folio *folio);
  36 bool zswap_is_enabled(void);
  37 bool zswap_never_enabled(void);
  38 #else
  39
  40 struct zswap_lruvec_state {};
  41
  42 static inline bool zswap_store(struct folio *folio)
  43 {
  44         return false;
  45 }
  46
  47 static inline bool zswap_load(struct folio *folio)
  48 {
  49         return false;
  50 }
  51
  52 static inline void zswap_invalidate(swp_entry_t swp) {}
  53 static inline int zswap_swapon(int type, unsigned long nr_pages)
  54 {
  55         return 0;
  56 }
  57 static inline void zswap_swapoff(int type) {}
  58 static inline void zswap_memcg_offline_cleanup(struct mem_cgroup *memcg) {}
  59 static inline void zswap_lruvec_state_init(struct lruvec *lruvec) {}
  60 static inline void zswap_folio_swapin(struct folio *folio) {}
  61
  62 static inline bool zswap_is_enabled(void)
  63 {
  64         return false;
  65 }
  66
  67 static inline bool zswap_never_enabled(void)
  68 {
  69         return true;
  70 }
  71
  72 #endif
  73
  74 #endif /* _LINUX_ZSWAP_H */