Revert "f2fs: do not skip dentry block writes"

The periodic checkpoint can resolve the previous issue.
So, now we can use this again to improve the reported performance regression:

https://lkml.org/lkml/2015/10/8/20

This reverts commit 15bec0ff5a9ba6d203178fa8772259df6207942a.

4 files changed, 14 insertions, 1 deletions

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index a903423e4cd5..bc04e9201fd6 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1340,6 +1340,11 @@ static int f2fs_write_data_pages(struct address_space *mapping,
         if (!get_dirty_pages(inode) && wbc->sync_mode == WB_SYNC_NONE)
                 return 0;
 
+        if (S_ISDIR(inode->i_mode) && wbc->sync_mode == WB_SYNC_NONE &&
+                        get_dirty_pages(inode) < nr_pages_to_skip(sbi, DATA) &&
+                        available_free_memory(sbi, DIRTY_DENTS))
+                goto skip_write;
+
         /* during POR, we don't need to trigger writepage at all. */
         if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
                 goto skip_write;
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 1fe49ca20757..4d9bedfe101c 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -52,6 +52,11 @@ bool available_free_memory(struct f2fs_sb_info *sbi, int type)
                 mem_size = (nm_i->nat_cnt * sizeof(struct nat_entry)) >>
                                                         PAGE_CACHE_SHIFT;
                 res = mem_size < ((avail_ram * nm_i->ram_thresh / 100) >> 2);
+        } else if (type == DIRTY_DENTS) {
+                if (sbi->sb->s_bdi->wb.dirty_exceeded)
+                        return false;
+                mem_size = get_pages(sbi, F2FS_DIRTY_DENTS);
+                res = mem_size < ((avail_ram * nm_i->ram_thresh / 100) >> 1);
         } else if (type == INO_ENTRIES) {
                 int i;
 
diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h
index 51c62edf2e89..7427e956ad81 100644
--- a/fs/f2fs/node.h
+++ b/fs/f2fs/node.h
@@ -118,6 +118,7 @@ static inline void raw_nat_from_node_info(struct f2fs_nat_entry *raw_ne,
 enum mem_type {
         FREE_NIDS,      /* indicates the free nid list */
         NAT_ENTRIES,    /* indicates the cached nat entry */
+        DIRTY_DENTS,    /* indicates dirty dentry pages */
         INO_ENTRIES,    /* indicates inode entries */
         EXTENT_CACHE,   /* indicates extent cache */
         BASE_CHECK,     /* check kernel status */
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index e9afb5884312..ee44d346ea44 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -699,7 +699,9 @@ static inline int nr_pages_to_skip(struct f2fs_sb_info *sbi, int type)
         if (sbi->sb->s_bdi->wb.dirty_exceeded)
                 return 0;
 
-        if (type == NODE)
+        if (type == DATA)
+                return sbi->blocks_per_seg;
+        else if (type == NODE)
                 return 3 * sbi->blocks_per_seg;
         else if (type == META)
                 return MAX_BIO_BLOCKS(sbi);