f2fs: introduce trace_f2fs_priority_update

This patch introduces two new tracepoints for debug purpose.

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Author: chaseyu

fs/f2fs/checkpoint.c

@@ -130,16 +130,23 @@ static void uplift_priority(struct f2fs_rwsem *sem, struct f2fs_lock_context *lc
 		return;
 	set_user_nice(current, lc->new_nice);
 	lc->need_restore = true;
+
+	trace_f2fs_priority_uplift(sem->sbi, sem->name, is_write, current,
+		NICE_TO_PRIO(lc->orig_nice), NICE_TO_PRIO(lc->new_nice));
 }
 
-static void restore_priority(struct f2fs_lock_context *lc)
+static void restore_priority(struct f2fs_rwsem *sem, struct f2fs_lock_context *lc,
+						bool is_write)
 {
 	if (!lc->need_restore)
 		return;
 	/* someone has updated the priority */
 	if (task_nice(current) != lc->new_nice)
 		return;
 	set_user_nice(current, lc->orig_nice);
+
+	trace_f2fs_priority_restore(sem->sbi, sem->name, is_write, current,
+		NICE_TO_PRIO(lc->orig_nice), NICE_TO_PRIO(lc->new_nice));
 }
 
 void f2fs_down_read_trace(struct f2fs_rwsem *sem, struct f2fs_lock_context *lc)
@@ -153,7 +160,7 @@ int f2fs_down_read_trylock_trace(struct f2fs_rwsem *sem, struct f2fs_lock_contex
 {
 	uplift_priority(sem, lc, false);
 	if (!f2fs_down_read_trylock(sem)) {
-		restore_priority(lc);
+		restore_priority(sem, lc, false);
 		return 0;
 	}
 	trace_lock_elapsed_time_start(sem, lc);
@@ -163,7 +170,7 @@ int f2fs_down_read_trylock_trace(struct f2fs_rwsem *sem, struct f2fs_lock_contex
 void f2fs_up_read_trace(struct f2fs_rwsem *sem, struct f2fs_lock_context *lc)
 {
 	f2fs_up_read(sem);
-	restore_priority(lc);
+	restore_priority(sem, lc, false);
 	trace_lock_elapsed_time_end(sem, lc, false);
 }
 
@@ -178,7 +185,7 @@ int f2fs_down_write_trylock_trace(struct f2fs_rwsem *sem, struct f2fs_lock_conte
 {
 	uplift_priority(sem, lc, true);
 	if (!f2fs_down_write_trylock(sem)) {
-		restore_priority(lc);
+		restore_priority(sem, lc, true);
 		return 0;
 	}
 	trace_lock_elapsed_time_start(sem, lc);
@@ -188,7 +195,7 @@ int f2fs_down_write_trylock_trace(struct f2fs_rwsem *sem, struct f2fs_lock_conte
 void f2fs_up_write_trace(struct f2fs_rwsem *sem, struct f2fs_lock_context *lc)
 {
 	f2fs_up_write(sem);
-	restore_priority(lc);
+	restore_priority(sem, lc, true);
 	trace_lock_elapsed_time_end(sem, lc, true);
 }
 

include/trace/events/f2fs.h

@@ -2525,6 +2525,63 @@ TRACE_EVENT(f2fs_lock_elapsed_time,
 		__entry->other_time)
 );
 
+DECLARE_EVENT_CLASS(f2fs_priority_update,
+
+	TP_PROTO(struct f2fs_sb_info *sbi, enum f2fs_lock_name lock_name,
+		bool is_write, struct task_struct *p, int orig_prio,
+		int new_prio),
+
+	TP_ARGS(sbi, lock_name, is_write, p, orig_prio, new_prio),
+
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__array(char, comm, TASK_COMM_LEN)
+		__field(pid_t, pid)
+		__field(unsigned int, lock_name)
+		__field(bool, is_write)
+		__field(int, orig_prio)
+		__field(int, new_prio)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= sbi->sb->s_dev;
+		memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
+		__entry->pid		= p->pid;
+		__entry->lock_name	= lock_name;
+		__entry->is_write	= is_write;
+		__entry->orig_prio	= orig_prio;
+		__entry->new_prio	= new_prio;
+	),
+
+	TP_printk("dev = (%d,%d), comm: %s, pid: %d, lock_name: %s, "
+		"lock_type: %s, orig_prio: %d, new_prio: %d",
+		show_dev(__entry->dev),
+		__entry->comm,
+		__entry->pid,
+		show_lock_name(__entry->lock_name),
+		__entry->is_write ? "wlock" : "rlock",
+		__entry->orig_prio,
+		__entry->new_prio)
+);
+
+DEFINE_EVENT(f2fs_priority_update, f2fs_priority_uplift,
+
+	TP_PROTO(struct f2fs_sb_info *sbi, enum f2fs_lock_name lock_name,
+		bool is_write, struct task_struct *p, int orig_prio,
+		int new_prio),
+
+	TP_ARGS(sbi, lock_name, is_write, p, orig_prio, new_prio)
+);
+
+DEFINE_EVENT(f2fs_priority_update, f2fs_priority_restore,
+
+	TP_PROTO(struct f2fs_sb_info *sbi, enum f2fs_lock_name lock_name,
+		bool is_write, struct task_struct *p, int orig_prio,
+		int new_prio),
+
+	TP_ARGS(sbi, lock_name, is_write, p, orig_prio, new_prio)
+);
+
 #endif /* _TRACE_F2FS_H */
 
  /* This part must be outside protection */