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/f2fs.h b/fs/f2fs/f2fs.h
index d8921cf..8de34ab 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -625,6 +625,7 @@
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 */