Revert "f2fs: enhance multi-threads performance"

This reports performance regression by Yuanhan Liu.
The basic idea was to reduce one-point mutex, but it turns out this causes
another contention like context swithes.

https://lkml.org/lkml/2015/4/21/11

Until finishing the analysis on this issue, I'd like to revert this for a while.

This reverts commit 78373b7319abdf15050af5b1632c4c8b8b398f33.

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index b91b0e10678eb1adcb87e45628f7794caa0dcc9b..1e1aae669fa86275d7b6c932aeda89ded129ce17 100644 (file)
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1513,6 +1513,7 @@ static int f2fs_write_data_pages(struct address_space *mapping,
 {
        struct inode *inode = mapping->host;
        struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+       bool locked = false;
        int ret;
        long diff;
 
@@ -1533,7 +1534,13 @@ static int f2fs_write_data_pages(struct address_space *mapping,
 
        diff = nr_pages_to_write(sbi, DATA, wbc);
 
+       if (!S_ISDIR(inode->i_mode)) {
+               mutex_lock(&sbi->writepages);
+               locked = true;
+       }
        ret = write_cache_pages(mapping, wbc, __f2fs_writepage, mapping);
+       if (locked)
+               mutex_unlock(&sbi->writepages);
 
        f2fs_submit_merged_bio(sbi, DATA, WRITE);
 

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index d8921cf2ba9a04454e553a75535dfa84d2b4da67..8de34ab6d5b1c5340276a5780bac1c133ac582fb 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -625,6 +625,7 @@ struct f2fs_sb_info {
        struct mutex cp_mutex;                  /* checkpoint procedure lock */
        struct rw_semaphore cp_rwsem;           /* blocking FS operations */
        struct rw_semaphore node_write;         /* locking node writes */
+       struct mutex writepages;                /* mutex for writepages() */
        wait_queue_head_t cp_wait;
 
        struct inode_management im[MAX_INO_ENTRY];      /* manage inode cache */

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 160b88346b2477466f3ed34d4d2dff2509742d7e..b2dd1b01f07634e27f42fc09e8fd627a70395e3e 100644 (file)
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1035,6 +1035,7 @@ try_onemore:
        sbi->raw_super = raw_super;
        sbi->raw_super_buf = raw_super_buf;
        mutex_init(&sbi->gc_mutex);
+       mutex_init(&sbi->writepages);
        mutex_init(&sbi->cp_mutex);
        init_rwsem(&sbi->node_write);
        clear_sbi_flag(sbi, SBI_POR_DOING);