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-rw-r--r--fs/f2fs/Kconfig7
-rw-r--r--fs/f2fs/f2fs.h10
2 files changed, 17 insertions, 0 deletions
diff --git a/fs/f2fs/Kconfig b/fs/f2fs/Kconfig
index f46a7339d6cf..03ef087537c7 100644
--- a/fs/f2fs/Kconfig
+++ b/fs/f2fs/Kconfig
@@ -143,3 +143,10 @@ config F2FS_IOSTAT
Support getting IO statistics through sysfs and printing out periodic
IO statistics tracepoint events. You have to turn on "iostat_enable"
sysfs node to enable this feature.
+
+config F2FS_UNFAIR_RWSEM
+ bool "F2FS unfair rw_semaphore"
+ depends on F2FS_FS && BLK_CGROUP
+ help
+ Use unfair rw_semaphore, if system configured IO priority by block
+ cgroup.
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index efc4f1fe2ffd..68d791ec8b27 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -132,7 +132,9 @@ typedef u32 nid_t;
struct f2fs_rwsem {
struct rw_semaphore internal_rwsem;
+#ifdef CONFIG_F2FS_UNFAIR_RWSEM
wait_queue_head_t read_waiters;
+#endif
};
struct f2fs_mount_info {
@@ -2131,7 +2133,9 @@ static inline void __init_f2fs_rwsem(struct f2fs_rwsem *sem,
const char *sem_name, struct lock_class_key *key)
{
__init_rwsem(&sem->internal_rwsem, sem_name, key);
+#ifdef CONFIG_F2FS_UNFAIR_RWSEM
init_waitqueue_head(&sem->read_waiters);
+#endif
}
static inline int f2fs_rwsem_is_locked(struct f2fs_rwsem *sem)
@@ -2146,7 +2150,11 @@ static inline int f2fs_rwsem_is_contended(struct f2fs_rwsem *sem)
static inline void f2fs_down_read(struct f2fs_rwsem *sem)
{
+#ifdef CONFIG_F2FS_UNFAIR_RWSEM
wait_event(sem->read_waiters, down_read_trylock(&sem->internal_rwsem));
+#else
+ down_read(&sem->internal_rwsem);
+#endif
}
static inline int f2fs_down_read_trylock(struct f2fs_rwsem *sem)
@@ -2181,7 +2189,9 @@ static inline int f2fs_down_write_trylock(struct f2fs_rwsem *sem)
static inline void f2fs_up_write(struct f2fs_rwsem *sem)
{
up_write(&sem->internal_rwsem);
+#ifdef CONFIG_F2FS_UNFAIR_RWSEM
wake_up_all(&sem->read_waiters);
+#endif
}
static inline void f2fs_lock_op(struct f2fs_sb_info *sbi)