f2fs: shrink nat_cache entries

This patch registers shrinking nat_cache entries.

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 7dd63b7..a05eb35 100644 (file)
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -328,11 +328,11 @@ static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
 int try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink)
 {
        struct f2fs_nm_info *nm_i = NM_I(sbi);
+       int nr = nr_shrink;
 
-       if (available_free_memory(sbi, NAT_ENTRIES))
+       if (!down_write_trylock(&nm_i->nat_tree_lock))
                return 0;
 
-       down_write(&nm_i->nat_tree_lock);
        while (nr_shrink && !list_empty(&nm_i->nat_entries)) {
                struct nat_entry *ne;
                ne = list_first_entry(&nm_i->nat_entries,
@@ -341,7 +341,7 @@ int try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink)
                nr_shrink--;
        }
        up_write(&nm_i->nat_tree_lock);
-       return nr_shrink;
+       return nr - nr_shrink;
 }
 
 /*

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 61b97f9..d5ee992 100644 (file)
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -306,8 +306,12 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi)
        /* try to shrink extent cache when there is no enough memory */
        f2fs_shrink_extent_tree(sbi, EXTENT_CACHE_SHRINK_NUMBER);
 
-       /* check the # of cached NAT entries and prefree segments */
-       if (try_to_free_nats(sbi, NAT_ENTRY_PER_BLOCK) ||
+       /* check the # of cached NAT entries */
+       if (!available_free_memory(sbi, NAT_ENTRIES))
+               try_to_free_nats(sbi, NAT_ENTRY_PER_BLOCK);
+
+       /* checkpoint is the only way to shrink partial cached entries */
+       if (!available_free_memory(sbi, NAT_ENTRIES) ||
                        excess_prefree_segs(sbi) ||
                        !available_free_memory(sbi, INO_ENTRIES))
                f2fs_sync_fs(sbi->sb, true);

diff --git a/fs/f2fs/shrinker.c b/fs/f2fs/shrinker.c
index 16e9b43..c4bd6ee 100644 (file)
--- a/fs/f2fs/shrinker.c
+++ b/fs/f2fs/shrinker.c
@@ -18,6 +18,11 @@ static LIST_HEAD(f2fs_list);
 static DEFINE_SPINLOCK(f2fs_list_lock);
 static unsigned int shrinker_run_no;
 
+static unsigned long __count_nat_entries(struct f2fs_sb_info *sbi)
+{
+       return NM_I(sbi)->nat_cnt - NM_I(sbi)->dirty_nat_cnt;
+}
+
 unsigned long f2fs_shrink_count(struct shrinker *shrink,
                                struct shrink_control *sc)
 {
@@ -37,7 +42,8 @@ unsigned long f2fs_shrink_count(struct shrinker *shrink,
                }
                spin_unlock(&f2fs_list_lock);
 
-               /* TODO: count # of objects */
+               /* shrink clean nat cache entries */
+               count += __count_nat_entries(sbi);
 
                spin_lock(&f2fs_list_lock);
                p = p->next;
@@ -76,7 +82,8 @@ unsigned long f2fs_shrink_scan(struct shrinker *shrink,
 
                sbi->shrinker_run_no = run_no;
 
-               /* TODO: shrink caches */
+               /* shrink clean nat cache entries */
+               freed += try_to_free_nats(sbi, nr);
 
                spin_lock(&f2fs_list_lock);
                p = p->next;