Hi Kim:
then all other threads may get the same next_lock value from sbi->next_lock_num in function mutex_lock_op,
and wait to get the same lock at position fs_lock[next_lock], it unbalance the fs_lock usage.
It may lost performance when we do the multithread test.
Here is the patch to fix this problem:
Signed-off-by: Yu Chao <[email protected]>
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
old mode 100644
new mode 100755
index 467d42d..983bb45
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -371,6 +371,7 @@ struct f2fs_sb_info {
struct mutex fs_lock[NR_GLOBAL_LOCKS]; /* blocking FS operations */
struct mutex node_write; /* locking node writes */
struct mutex writepages; /* mutex for writepages() */
+ spinlock_t spin_lock; /* lock for next_lock_num */
unsigned char next_lock_num; /* round-robin global locks */
int por_doing; /* recovery is doing or not */
int on_build_free_nids; /* build_free_nids is doing */
@@ -533,15 +534,19 @@ static inline void mutex_unlock_all(struct f2fs_sb_info *sbi)
static inline int mutex_lock_op(struct f2fs_sb_info *sbi)
{
- unsigned char next_lock = sbi->next_lock_num % NR_GLOBAL_LOCKS;
+ unsigned char next_lock;
int i = 0;
for (; i < NR_GLOBAL_LOCKS; i++)
if (mutex_trylock(&sbi->fs_lock[i]))
return i;
- mutex_lock(&sbi->fs_lock[next_lock]);
+ spin_lock(&sbi->spin_lock);
+ next_lock = sbi->next_lock_num % NR_GLOBAL_LOCKS;
sbi->next_lock_num++;
+ spin_unlock(&sbi->spin_lock);
+
+ mutex_lock(&sbi->fs_lock[next_lock]);
return next_lock;
}
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
old mode 100644
new mode 100755
index 75c7dc3..4f27596
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -657,6 +657,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
mutex_init(&sbi->cp_mutex);
for (i = 0; i < NR_GLOBAL_LOCKS; i++)
mutex_init(&sbi->fs_lock[i]);
+ spin_lock_init(&sbi->spin_lock);
mutex_init(&sbi->node_write);
sbi->por_doing = 0;
spin_lock_init(&sbi->stat_lock);
(END)
|
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