f2fs: reduce competition among node page writes

We do not need to block on ->node_write among different node page writers e.g.
fsync/flush, unless we have a node page writer from write_checkpoint.
So it's better use rw_semaphore instead of mutex type for ->node_write to
promote performance.

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

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index cea20b8..6aeed5b 100644 (file)
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -762,10 +762,10 @@ retry_flush_dents:
         * until finishing nat/sit flush.
         */
 retry_flush_nodes:
-       mutex_lock(&sbi->node_write);
+       down_write(&sbi->node_write);
 
        if (get_pages(sbi, F2FS_DIRTY_NODES)) {
-               mutex_unlock(&sbi->node_write);
+               up_write(&sbi->node_write);
                sync_node_pages(sbi, 0, &wbc);
                goto retry_flush_nodes;
        }
@@ -774,7 +774,7 @@ retry_flush_nodes:
 
 static void unblock_operations(struct f2fs_sb_info *sbi)
 {
-       mutex_unlock(&sbi->node_write);
+       up_write(&sbi->node_write);
        f2fs_unlock_all(sbi);
 }
 

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 80c7869..9942567 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -452,7 +452,7 @@ struct f2fs_sb_info {
        struct inode *meta_inode;               /* cache meta blocks */
        struct mutex cp_mutex;                  /* checkpoint procedure lock */
        struct rw_semaphore cp_rwsem;           /* blocking FS operations */
-       struct mutex node_write;                /* locking node writes */
+       struct rw_semaphore node_write;         /* locking node writes */
        struct mutex writepages;                /* mutex for writepages() */
        bool por_doing;                         /* recovery is doing or not */
        wait_queue_head_t cp_wait;

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index a90f51d..7b5b5de 100644 (file)
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1231,12 +1231,12 @@ static int f2fs_write_node_page(struct page *page,
        if (wbc->for_reclaim)
                goto redirty_out;
 
-       mutex_lock(&sbi->node_write);
+       down_read(&sbi->node_write);
        set_page_writeback(page);
        write_node_page(sbi, page, &fio, nid, ni.blk_addr, &new_addr);
        set_node_addr(sbi, &ni, new_addr, is_fsync_dnode(page));
        dec_page_count(sbi, F2FS_DIRTY_NODES);
-       mutex_unlock(&sbi->node_write);
+       up_read(&sbi->node_write);
        unlock_page(page);
        return 0;
 

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index f253e22..657582f 100644 (file)
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -953,7 +953,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
        mutex_init(&sbi->gc_mutex);
        mutex_init(&sbi->writepages);
        mutex_init(&sbi->cp_mutex);
-       mutex_init(&sbi->node_write);
+       init_rwsem(&sbi->node_write);
        sbi->por_doing = false;
        spin_lock_init(&sbi->stat_lock);