f2fs: remove unnecessary threshold

The NM_WOUT_THRESHOLD is now obsolete since f2fs starts to control on a basis
of the memory footprint.
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/debug.c

@@ -250,10 +250,10 @@ static int stat_show(struct seq_file *s, void *v)
 			   si->ndirty_dent, si->ndirty_dirs);
 		seq_printf(s, "  - meta: %4d in %4d\n",
 			   si->ndirty_meta, si->meta_pages);
-		seq_printf(s, "  - NATs: %5d > %lu\n",
-			   si->nats, NM_WOUT_THRESHOLD);
-		seq_printf(s, "  - SITs: %5d\n  - free_nids: %5d\n",
-			   si->sits, si->fnids);
+		seq_printf(s, "  - NATs: %9d\n  - SITs: %9d\n",
+			   si->nats, si->sits);
+		seq_printf(s, "  - free_nids: %9d\n",
+			   si->fnids);
 		seq_puts(s, "\nDistribution of User Blocks:");
 		seq_puts(s, " [ valid | invalid | free ]\n");
 		seq_puts(s, "  [");

fs/f2fs/node.c

@@ -224,7 +224,7 @@ int try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink)
 {
 	struct f2fs_nm_info *nm_i = NM_I(sbi);
 
-	if (available_free_memory(nm_i, NAT_ENTRIES) || nr_shrink <= 0)
+	if (available_free_memory(nm_i, NAT_ENTRIES))
 		return 0;
 
 	write_lock(&nm_i->nat_tree_lock);
@@ -1830,9 +1830,6 @@ void flush_nat_entries(struct f2fs_sb_info *sbi)
 	if (!flushed)
 		mutex_unlock(&curseg->curseg_mutex);
 	f2fs_put_page(page, 1);
-
-	/* 2) shrink nat caches if necessary */
-	try_to_free_nats(sbi, nm_i->nat_cnt - NM_WOUT_THRESHOLD);
 }
 
 static int init_node_manager(struct f2fs_sb_info *sbi)

fs/f2fs/node.h

@@ -20,9 +20,6 @@
 /* maximum readahead size for node during getting data blocks */
 #define MAX_RA_NODE		128
 
-/* maximum cached nat entries to manage memory footprint */
-#define NM_WOUT_THRESHOLD	(64 * NAT_ENTRY_PER_BLOCK)
-
 /* control the memory footprint threshold (10MB per 1GB ram) */
 #define DEF_RAM_THRESHOLD	10