[PATCH v3 2/2] hugetlbfs: use tracepoints in hugetlbfs functions.

[Hongbo Li <lihongbo22@xxxxxxxxxx>]

Here we use the hugetlbfs tracepoint to track the call stack. And
the output in trace is as follows:

```
   touch-5265    [005] .....    43.246550: hugetlbfs_alloc_inode: dev 0,51 ino 24621 dir 21959 mode 0100644
   touch-5265    [005] .....    43.246638: hugetlbfs_setattr: dev 0,51 ino 24621 name testfile valid 0x20070 mode 0177777 old_size 0 size -51622648042749952
truncate-5266    [005] .....    45.590890: hugetlbfs_setattr: dev 0,51 ino 24621 name testfile valid 0x2068 mode 00 old_size 0 size 2097152
rm-5273    [007] .....   110.052783: hugetlbfs_evict_inode: dev 0,51 ino 24621 mode 0100644 size 2097152 nlink 0 seals 1 blocks 0
  <idle>-0       [007] ..s1.   110.059441: hugetlbfs_free_inode: dev 0,51 ino 24621 mode 0100644 size 2097152 nlink 0 seals 1 blocks 0
```

Signed-off-by: Hongbo Li <lihongbo22@xxxxxxxxxx>
---
 fs/hugetlbfs/inode.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 9f6cff356796..1689c01a11a0 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -39,6 +39,9 @@
 #include <linux/uaccess.h>
 #include <linux/sched/mm.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/hugetlbfs.h>
+
 static const struct address_space_operations hugetlbfs_aops;
 static const struct file_operations hugetlbfs_file_operations;
 static const struct inode_operations hugetlbfs_dir_inode_operations;
@@ -687,6 +690,7 @@ static void hugetlbfs_evict_inode(struct inode *inode)
 {
 	struct resv_map *resv_map;
 
+	trace_hugetlbfs_evict_inode(inode);
 	remove_inode_hugepages(inode, 0, LLONG_MAX);
 
 	/*
@@ -814,8 +818,10 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
 	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
 		return -EOPNOTSUPP;
 
-	if (mode & FALLOC_FL_PUNCH_HOLE)
-		return hugetlbfs_punch_hole(inode, offset, len);
+	if (mode & FALLOC_FL_PUNCH_HOLE) {
+		error = hugetlbfs_punch_hole(inode, offset, len);
+		goto out_nolock;
+	}
 
 	/*
 	 * Default preallocate case.
@@ -919,6 +925,9 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
 	inode_set_ctime_current(inode);
 out:
 	inode_unlock(inode);
+
+out_nolock:
+	trace_hugetlbfs_fallocate(inode, mode, offset, len, error);
 	return error;
 }
 
@@ -935,6 +944,8 @@ static int hugetlbfs_setattr(struct mnt_idmap *idmap,
 	if (error)
 		return error;
 
+	trace_hugetlbfs_setattr(inode, dentry, attr);
+
 	if (ia_valid & ATTR_SIZE) {
 		loff_t oldsize = inode->i_size;
 		loff_t newsize = attr->ia_size;
@@ -1033,6 +1044,7 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 			break;
 		}
 		lockdep_annotate_inode_mutex_key(inode);
+		trace_hugetlbfs_alloc_inode(inode, dir, mode);
 	} else {
 		if (resv_map)
 			kref_put(&resv_map->refs, resv_map_release);
@@ -1272,6 +1284,7 @@ static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 
 static void hugetlbfs_free_inode(struct inode *inode)
 {
+	trace_hugetlbfs_free_inode(inode);
 	kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 }
 
-- 
2.34.1