[PATCH v2 3/3] mm: move reclaim-internal declarations out of swap.h

[Jianyue Wu]

Keep include/linux/swap.h focused on swap-facing interfaces by moving
MM-internal reclaim and workingset declarations into mm/internal.h.

Leave the small set of LRU helper declarations that are used outside mm/
in swap.h so this cleanup does not need a new public header under
include/linux/.

Signed-off-by: Jianyue Wu <wujianyue000@xxxxxxxxx>
---
 include/linux/swap.h | 75 +++++-----------------------------------------------
 mm/internal.h        | 66 +++++++++++++++++++++++++++++++++++++++++++++
 mm/memfd.c           |  1 +
 3 files changed, 73 insertions(+), 69 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index c36f72877e8b..1ef6ae7b2db7 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -292,39 +292,17 @@ static inline swp_entry_t page_swap_entry(struct page *page)
 	return entry;
 }
 
-/* linux/mm/workingset.c */
-bool workingset_test_recent(void *shadow, bool file, bool *workingset,
-				bool flush);
-void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages);
-void *workingset_eviction(struct folio *folio, struct mem_cgroup *target_memcg);
-void workingset_refault(struct folio *folio, void *shadow);
-void workingset_activation(struct folio *folio);
-
 /* linux/mm/page_alloc.c */
 extern unsigned long totalreserve_pages;
 
 /* Definition of global_zone_page_state not available yet */
 #define nr_free_pages() global_zone_page_state(NR_FREE_PAGES)
 
-
-/* linux/mm/swap.c */
-void lru_note_cost_unlock_irq(struct lruvec *lruvec, bool file,
-		unsigned int nr_io, unsigned int nr_rotated);
-void lru_note_cost_refault(struct folio *);
-void folio_add_lru(struct folio *);
-void folio_add_lru_vma(struct folio *, struct vm_area_struct *);
-void mark_page_accessed(struct page *);
-void folio_mark_accessed(struct folio *);
-
-static inline bool folio_may_be_lru_cached(struct folio *folio)
-{
-	/*
-	 * Holding PMD-sized folios in per-CPU LRU cache unbalances accounting.
-	 * Holding small numbers of low-order mTHP folios in per-CPU LRU cache
-	 * will be sensible, but nobody has implemented and tested that yet.
-	 */
-	return !folio_test_large(folio);
-}
+/* Generic folio LRU helpers used outside mm/. */
+void folio_add_lru(struct folio *folio);
+void mark_page_accessed(struct page *page);
+void folio_mark_accessed(struct folio *folio);
+void lru_add_drain_all(void);
 
 extern atomic_t lru_disable_count;
 
@@ -333,43 +311,7 @@ static inline bool lru_cache_disabled(void)
 	return atomic_read(&lru_disable_count);
 }
 
-static inline void lru_cache_enable(void)
-{
-	atomic_dec(&lru_disable_count);
-}
-
-extern void lru_cache_disable(void);
-extern void lru_add_drain(void);
-extern void lru_add_drain_cpu(int cpu);
-extern void lru_add_drain_cpu_zone(struct zone *zone);
-extern void lru_add_drain_all(void);
-void folio_deactivate(struct folio *folio);
-void folio_mark_lazyfree(struct folio *folio);
-extern void swap_readahead_setup(void);
-
 /* linux/mm/vmscan.c */
-extern unsigned long zone_reclaimable_pages(struct zone *zone);
-extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
-					gfp_t gfp_mask, nodemask_t *mask);
-unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru, int zone_idx);
-
-#define MEMCG_RECLAIM_MAY_SWAP (1 << 1)
-#define MEMCG_RECLAIM_PROACTIVE (1 << 2)
-#define MIN_SWAPPINESS 0
-#define MAX_SWAPPINESS 200
-
-/* Just reclaim from anon folios in proactive memory reclaim */
-#define SWAPPINESS_ANON_ONLY (MAX_SWAPPINESS + 1)
-
-extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
-						  unsigned long nr_pages,
-						  gfp_t gfp_mask,
-						  unsigned int reclaim_options,
-						  int *swappiness);
-extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
-						gfp_t gfp_mask, bool noswap,
-						pg_data_t *pgdat,
-						unsigned long *nr_scanned);
 extern unsigned long shrink_all_memory(unsigned long nr_pages);
 extern int vm_swappiness;
 long remove_mapping(struct address_space *mapping, struct folio *folio);
@@ -390,11 +332,6 @@ static inline void reclaim_unregister_node(struct node *node)
 }
 #endif /* CONFIG_SYSFS && CONFIG_NUMA */
 
-#ifdef CONFIG_NUMA
-extern int sysctl_min_unmapped_ratio;
-extern int sysctl_min_slab_ratio;
-#endif
-
 void check_move_unevictable_folios(struct folio_batch *fbatch);
 
 extern void __meminit kswapd_run(int nid);
@@ -554,7 +491,7 @@ static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
 
 void lru_reparent_memcg(struct mem_cgroup *memcg, struct mem_cgroup *parent, int nid);
 #else
-static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
+static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
 {
 	return READ_ONCE(vm_swappiness);
 }
diff --git a/mm/internal.h b/mm/internal.h
index 5602393054f3..5475ba38a621 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -24,6 +24,72 @@
 
 struct folio_batch;
 
+bool workingset_test_recent(void *shadow, bool file, bool *workingset,
+			    bool flush);
+void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages);
+void *workingset_eviction(struct folio *folio,
+			  struct mem_cgroup *target_memcg);
+void workingset_refault(struct folio *folio, void *shadow);
+void workingset_activation(struct folio *folio);
+
+void lru_note_cost_unlock_irq(struct lruvec *lruvec, bool file,
+		unsigned int nr_io, unsigned int nr_rotated)
+		__releases(lruvec->lru_lock);
+void lru_note_cost_refault(struct folio *folio);
+void folio_add_lru_vma(struct folio *folio, struct vm_area_struct *vma);
+
+static inline bool folio_may_be_lru_cached(struct folio *folio)
+{
+	/*
+	 * Holding PMD-sized folios in per-CPU LRU cache unbalances accounting.
+	 * Holding small numbers of low-order mTHP folios in per-CPU LRU cache
+	 * will be sensible, but nobody has implemented and tested that yet.
+	 */
+	return !folio_test_large(folio);
+}
+
+static inline void lru_cache_enable(void)
+{
+	atomic_dec(&lru_disable_count);
+}
+
+void lru_cache_disable(void);
+void lru_add_drain(void);
+void lru_add_drain_cpu(int cpu);
+void lru_add_drain_cpu_zone(struct zone *zone);
+void folio_deactivate(struct folio *folio);
+void folio_mark_lazyfree(struct folio *folio);
+void swap_readahead_setup(void);
+
+unsigned long zone_reclaimable_pages(struct zone *zone);
+unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
+				gfp_t gfp_mask, nodemask_t *mask);
+unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru,
+			      int zone_idx);
+
+#define MEMCG_RECLAIM_MAY_SWAP (1 << 1)
+#define MEMCG_RECLAIM_PROACTIVE (1 << 2)
+#define MIN_SWAPPINESS 0
+#define MAX_SWAPPINESS 200
+
+/* Just reclaim from anon folios in proactive memory reclaim */
+#define SWAPPINESS_ANON_ONLY (MAX_SWAPPINESS + 1)
+
+unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
+					   unsigned long nr_pages,
+					   gfp_t gfp_mask,
+					   unsigned int reclaim_options,
+					   int *swappiness);
+unsigned long mem_cgroup_shrink_node(struct mem_cgroup *memcg,
+				     gfp_t gfp_mask, bool noswap,
+				     pg_data_t *pgdat,
+				     unsigned long *nr_scanned);
+
+#ifdef CONFIG_NUMA
+extern int sysctl_min_unmapped_ratio;
+extern int sysctl_min_slab_ratio;
+#endif
+
 /*
  * Maintains state across a page table move. The operation assumes both source
  * and destination VMAs already exist and are specified by the user.
diff --git a/mm/memfd.c b/mm/memfd.c
index abe13b291ddc..6c72fe6caef7 100644
--- a/mm/memfd.c
+++ b/mm/memfd.c
@@ -19,6 +19,7 @@
 #include <linux/memfd.h>
 #include <linux/pid_namespace.h>
 #include <uapi/linux/memfd.h>
+#include "internal.h"
 #include "swap.h"
 
 /*

-- 
2.43.0