[PATCH v3 -next 04/15] mm: vmscan: move vmscan sysctls to mm/vmscan.c

This moves vm_swappiness and zone_reclaim_mode to mm/vmscan.c,
as part of the kernel/sysctl.c cleaning, also moves some external
variable declarations and function declarations from include/linux/swap.h
into mm/internal.h.

Signed-off-by: Kaixiong Yu <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
---
v3:
 - change the title
---
 include/linux/swap.h |  9 ---------
 kernel/sysctl.c      | 19 -------------------
 mm/internal.h        | 10 ++++++++++
 mm/vmscan.c          | 23 +++++++++++++++++++++++
 4 files changed, 33 insertions(+), 28 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index ca533b478c21..c95fb8d87b05 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -425,19 +425,10 @@ extern int vm_swappiness;
 long remove_mapping(struct address_space *mapping, struct folio *folio);
 
 #ifdef CONFIG_NUMA
-extern int node_reclaim_mode;
 extern int sysctl_min_unmapped_ratio;
 extern int sysctl_min_slab_ratio;
-#else
-#define node_reclaim_mode 0
 #endif
 
-static inline bool node_reclaim_enabled(void)
-{
-	/* Is any node_reclaim_mode bit set? */
-	return node_reclaim_mode & (RECLAIM_ZONE|RECLAIM_WRITE|RECLAIM_UNMAP);
-}
-
 void check_move_unevictable_folios(struct folio_batch *fbatch);
 
 extern void __meminit kswapd_run(int nid);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 9fad501311a1..184d39944e16 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2061,15 +2061,6 @@ static struct ctl_table vm_table[] = {
 		.proc_handler	= dirtytime_interval_handler,
 		.extra1		= SYSCTL_ZERO,
 	},
-	{
-		.procname	= "swappiness",
-		.data		= &vm_swappiness,
-		.maxlen		= sizeof(vm_swappiness),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_TWO_HUNDRED,
-	},
 	{
 		.procname	= "drop_caches",
 		.data		= &sysctl_drop_caches,
@@ -2117,16 +2108,6 @@ static struct ctl_table vm_table[] = {
 		.extra1		= SYSCTL_ZERO,
 	},
 #endif
-#ifdef CONFIG_NUMA
-	{
-		.procname	= "zone_reclaim_mode",
-		.data		= &node_reclaim_mode,
-		.maxlen		= sizeof(node_reclaim_mode),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-	},
-#endif
 #ifdef CONFIG_MMU
 	{
 		.procname	= "mmap_min_addr",
diff --git a/mm/internal.h b/mm/internal.h
index 906da6280c2d..84c46fe6a07c 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1038,9 +1038,13 @@ static inline void mminit_verify_zonelist(void)
 #define NODE_RECLAIM_SUCCESS	1
 
 #ifdef CONFIG_NUMA
+extern int node_reclaim_mode;
+
 extern int node_reclaim(struct pglist_data *, gfp_t, unsigned int);
 extern int find_next_best_node(int node, nodemask_t *used_node_mask);
 #else
+#define node_reclaim_mode 0
+
 static inline int node_reclaim(struct pglist_data *pgdat, gfp_t mask,
 				unsigned int order)
 {
@@ -1052,6 +1056,12 @@ static inline int find_next_best_node(int node, nodemask_t *used_node_mask)
 }
 #endif
 
+static inline bool node_reclaim_enabled(void)
+{
+	/* Is any node_reclaim_mode bit set? */
+	return node_reclaim_mode & (RECLAIM_ZONE|RECLAIM_WRITE|RECLAIM_UNMAP);
+}
+
 /*
  * mm/memory-failure.c
  */
diff --git a/mm/vmscan.c b/mm/vmscan.c
index f9919b522c01..1188978e46d5 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -7384,6 +7384,28 @@ void __meminit kswapd_stop(int nid)
 	pgdat_kswapd_unlock(pgdat);
 }
 
+static struct ctl_table vmscan_sysctl_table[] = {
+	{
+		.procname	= "swappiness",
+		.data		= &vm_swappiness,
+		.maxlen		= sizeof(vm_swappiness),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_TWO_HUNDRED,
+	},
+#ifdef CONFIG_NUMA
+	{
+		.procname	= "zone_reclaim_mode",
+		.data		= &node_reclaim_mode,
+		.maxlen		= sizeof(node_reclaim_mode),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+	}
+#endif
+};
+
 static int __init kswapd_init(void)
 {
 	int nid;
@@ -7391,6 +7413,7 @@ static int __init kswapd_init(void)
 	swap_setup();
 	for_each_node_state(nid, N_MEMORY)
  		kswapd_run(nid);
+	register_sysctl_init("vm", vmscan_sysctl_table);
 	return 0;
 }
 
-- 
2.34.1