[PATCH 1/3] mm/lru_gen: Move some code around so that next patch is simpler

["Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>]

Move lrur_gen_add_folio to .c. We will support arch specific mapping
of page access count to generation in a later patch and will use
that when adding folio to lruvec. This move enables that.

No functional change in this patch.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 include/linux/mm_inline.h |  47 +----------
 mm/vmscan.c               | 172 ++++++++++++++++++++++++--------------
 2 files changed, 110 insertions(+), 109 deletions(-)

diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index 0e1d239a882c..2a86dc4d96ab 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -217,52 +217,7 @@ static inline void lru_gen_update_size(struct lruvec *lruvec, struct folio *foli
 	VM_WARN_ON_ONCE(lru_gen_is_active(lruvec, old_gen) && !lru_gen_is_active(lruvec, new_gen));
 }
 
-static inline bool lru_gen_add_folio(struct lruvec *lruvec, struct folio *folio, bool reclaiming)
-{
-	unsigned long seq;
-	unsigned long flags;
-	int gen = folio_lru_gen(folio);
-	int type = folio_is_file_lru(folio);
-	int zone = folio_zonenum(folio);
-	struct lru_gen_folio *lrugen = &lruvec->lrugen;
-
-	VM_WARN_ON_ONCE_FOLIO(gen != -1, folio);
-
-	if (folio_test_unevictable(folio) || !lrugen->enabled)
-		return false;
-	/*
-	 * There are three common cases for this page:
-	 * 1. If it's hot, e.g., freshly faulted in or previously hot and
-	 *    migrated, add it to the youngest generation.
-	 * 2. If it's cold but can't be evicted immediately, i.e., an anon page
-	 *    not in swapcache or a dirty page pending writeback, add it to the
-	 *    second oldest generation.
-	 * 3. Everything else (clean, cold) is added to the oldest generation.
-	 */
-	if (folio_test_active(folio))
-		seq = lrugen->max_seq;
-	else if ((type == LRU_GEN_ANON && !folio_test_swapcache(folio)) ||
-		 (folio_test_reclaim(folio) &&
-		  (folio_test_dirty(folio) || folio_test_writeback(folio))))
-		seq = lrugen->min_seq[type] + 1;
-	else
-		seq = lrugen->min_seq[type];
-
-	gen = lru_gen_from_seq(seq);
-	flags = (gen + 1UL) << LRU_GEN_PGOFF;
-	/* see the comment on MIN_NR_GENS about PG_active */
-	set_mask_bits(&folio->flags, LRU_GEN_MASK | BIT(PG_active), flags);
-
-	lru_gen_update_size(lruvec, folio, -1, gen);
-	/* for folio_rotate_reclaimable() */
-	if (reclaiming)
-		list_add_tail(&folio->lru, &lrugen->folios[gen][type][zone]);
-	else
-		list_add(&folio->lru, &lrugen->folios[gen][type][zone]);
-
-	return true;
-}
-
+bool lru_gen_add_folio(struct lruvec *lruvec, struct folio *folio, bool reclaiming);
 static inline bool lru_gen_del_folio(struct lruvec *lruvec, struct folio *folio, bool reclaiming)
 {
 	unsigned long flags;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 6d0cd2840cf0..edfe073b475e 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3748,29 +3748,6 @@ static bool positive_ctrl_err(struct ctrl_pos *sp, struct ctrl_pos *pv)
  *                          the aging
  ******************************************************************************/
 
-/* promote pages accessed through page tables */
-static int folio_update_gen(struct folio *folio, int gen)
-{
-	unsigned long new_flags, old_flags = READ_ONCE(folio->flags);
-
-	VM_WARN_ON_ONCE(gen >= MAX_NR_GENS);
-	VM_WARN_ON_ONCE(!rcu_read_lock_held());
-
-	do {
-		/* lru_gen_del_folio() has isolated this page? */
-		if (!(old_flags & LRU_GEN_MASK)) {
-			/* for shrink_folio_list() */
-			new_flags = old_flags | BIT(PG_referenced);
-			continue;
-		}
-
-		new_flags = old_flags & ~(LRU_GEN_MASK | LRU_REFS_MASK | LRU_REFS_FLAGS);
-		new_flags |= (gen + 1UL) << LRU_GEN_PGOFF;
-	} while (!try_cmpxchg(&folio->flags, &old_flags, new_flags));
-
-	return ((old_flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;
-}
-
 /* protect pages accessed multiple times through file descriptors */
 static int folio_inc_gen(struct lruvec *lruvec, struct folio *folio, bool reclaiming)
 {
@@ -3801,6 +3778,70 @@ static int folio_inc_gen(struct lruvec *lruvec, struct folio *folio, bool reclai
 	return new_gen;
 }
 
+static unsigned long get_pte_pfn(pte_t pte, struct vm_area_struct *vma, unsigned long addr)
+{
+	unsigned long pfn = pte_pfn(pte);
+
+	VM_WARN_ON_ONCE(addr < vma->vm_start || addr >= vma->vm_end);
+
+	if (!pte_present(pte) || is_zero_pfn(pfn))
+		return -1;
+
+	if (WARN_ON_ONCE(pte_devmap(pte) || pte_special(pte)))
+		return -1;
+
+	if (WARN_ON_ONCE(!pfn_valid(pfn)))
+		return -1;
+
+	return pfn;
+}
+
+static struct folio *get_pfn_folio(unsigned long pfn, struct mem_cgroup *memcg,
+				   struct pglist_data *pgdat, bool can_swap)
+{
+	struct folio *folio;
+
+	/* try to avoid unnecessary memory loads */
+	if (pfn < pgdat->node_start_pfn || pfn >= pgdat_end_pfn(pgdat))
+		return NULL;
+
+	folio = pfn_folio(pfn);
+	if (folio_nid(folio) != pgdat->node_id)
+		return NULL;
+
+	if (folio_memcg_rcu(folio) != memcg)
+		return NULL;
+
+	/* file VMAs can contain anon pages from COW */
+	if (!folio_is_file_lru(folio) && !can_swap)
+		return NULL;
+
+	return folio;
+}
+
+/* promote pages accessed through page tables */
+static int folio_update_gen(struct folio *folio, int gen)
+{
+	unsigned long new_flags, old_flags = READ_ONCE(folio->flags);
+
+	VM_WARN_ON_ONCE(gen >= MAX_NR_GENS);
+	VM_WARN_ON_ONCE(!rcu_read_lock_held());
+
+	do {
+		/* lru_gen_del_folio() has isolated this page? */
+		if (!(old_flags & LRU_GEN_MASK)) {
+			/* for shrink_folio_list() */
+			new_flags = old_flags | BIT(PG_referenced);
+			continue;
+		}
+
+		new_flags = old_flags & ~(LRU_GEN_MASK | LRU_REFS_MASK | LRU_REFS_FLAGS);
+		new_flags |= (gen + 1UL) << LRU_GEN_PGOFF;
+	} while (!try_cmpxchg(&folio->flags, &old_flags, new_flags));
+
+	return ((old_flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;
+}
+
 static void update_batch_size(struct lru_gen_mm_walk *walk, struct folio *folio,
 			      int old_gen, int new_gen)
 {
@@ -3910,23 +3951,6 @@ static bool get_next_vma(unsigned long mask, unsigned long size, struct mm_walk
 	return false;
 }
 
-static unsigned long get_pte_pfn(pte_t pte, struct vm_area_struct *vma, unsigned long addr)
-{
-	unsigned long pfn = pte_pfn(pte);
-
-	VM_WARN_ON_ONCE(addr < vma->vm_start || addr >= vma->vm_end);
-
-	if (!pte_present(pte) || is_zero_pfn(pfn))
-		return -1;
-
-	if (WARN_ON_ONCE(pte_devmap(pte) || pte_special(pte)))
-		return -1;
-
-	if (WARN_ON_ONCE(!pfn_valid(pfn)))
-		return -1;
-
-	return pfn;
-}
 
 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG)
 static unsigned long get_pmd_pfn(pmd_t pmd, struct vm_area_struct *vma, unsigned long addr)
@@ -3948,29 +3972,6 @@ static unsigned long get_pmd_pfn(pmd_t pmd, struct vm_area_struct *vma, unsigned
 }
 #endif
 
-static struct folio *get_pfn_folio(unsigned long pfn, struct mem_cgroup *memcg,
-				   struct pglist_data *pgdat, bool can_swap)
-{
-	struct folio *folio;
-
-	/* try to avoid unnecessary memory loads */
-	if (pfn < pgdat->node_start_pfn || pfn >= pgdat_end_pfn(pgdat))
-		return NULL;
-
-	folio = pfn_folio(pfn);
-	if (folio_nid(folio) != pgdat->node_id)
-		return NULL;
-
-	if (folio_memcg_rcu(folio) != memcg)
-		return NULL;
-
-	/* file VMAs can contain anon pages from COW */
-	if (!folio_is_file_lru(folio) && !can_swap)
-		return NULL;
-
-	return folio;
-}
-
 static bool suitable_to_scan(int total, int young)
 {
 	int n = clamp_t(int, cache_line_size() / sizeof(pte_t), 2, 8);
@@ -5557,6 +5558,51 @@ static void lru_gen_shrink_node(struct pglist_data *pgdat, struct scan_control *
 	pgdat->kswapd_failures = 0;
 }
 
+bool lru_gen_add_folio(struct lruvec *lruvec, struct folio *folio, bool reclaiming)
+{
+	unsigned long seq;
+	unsigned long flags;
+	int gen = folio_lru_gen(folio);
+	int type = folio_is_file_lru(folio);
+	int zone = folio_zonenum(folio);
+	struct lru_gen_folio *lrugen = &lruvec->lrugen;
+
+	VM_WARN_ON_ONCE_FOLIO(gen != -1, folio);
+
+	if (folio_test_unevictable(folio) || !lrugen->enabled)
+		return false;
+	/*
+	 * There are three common cases for this page:
+	 * 1. If it's hot, e.g., freshly faulted in or previously hot and
+	 *    migrated, add it to the youngest generation.
+	 * 2. If it's cold but can't be evicted immediately, i.e., an anon page
+	 *    not in swapcache or a dirty page pending writeback, add it to the
+	 *    second oldest generation.
+	 * 3. Everything else (clean, cold) is added to the oldest generation.
+	 */
+	if (folio_test_active(folio))
+		seq = lrugen->max_seq;
+	else if ((type == LRU_GEN_ANON && !folio_test_swapcache(folio)) ||
+		 (folio_test_reclaim(folio) &&
+		  (folio_test_dirty(folio) || folio_test_writeback(folio))))
+		seq = lrugen->min_seq[type] + 1;
+	else
+		seq = lrugen->min_seq[type];
+
+	gen = lru_gen_from_seq(seq);
+	flags = (gen + 1UL) << LRU_GEN_PGOFF;
+	/* see the comment on MIN_NR_GENS about PG_active */
+	set_mask_bits(&folio->flags, LRU_GEN_MASK | BIT(PG_active), flags);
+
+	lru_gen_update_size(lruvec, folio, -1, gen);
+	/* for folio_rotate_reclaimable() */
+	if (reclaiming)
+		list_add_tail(&folio->lru, &lrugen->folios[gen][type][zone]);
+	else
+		list_add(&folio->lru, &lrugen->folios[gen][type][zone]);
+
+	return true;
+}
 /******************************************************************************
  *                          state change
  ******************************************************************************/
-- 
2.40.1