ocfs2: Use hrtimer to track ocfs2 fs lock stats

Patch makes use of the hrtimer to track times in ocfs2 lock stats.

The patch is a bit involved to ensure no additional impact on the memory
footprint. The size of ocfs2_inode_cache remains 1280 bytes on 32-bit systems.

A related change was to modify the unit of the max wait time from nanosec to
microsec allowing us to track max time larger than 4 secs. This change
necessitated the bumping of the output version in the debugfs file,
locking_state, from 2 to 3.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <jlbec@evilplan.org>

1 files changed, 14 insertions, 9 deletions

diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index 51cd6898e7f1..4e3d3c1363f3 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -147,6 +147,17 @@ struct ocfs2_lock_res_ops;
 
 typedef void (*ocfs2_lock_callback)(int status, unsigned long data);
 
+#ifdef CONFIG_OCFS2_FS_STATS
+struct ocfs2_lock_stats {
+        u64             ls_total;       /* Total wait in NSEC */
+        u32             ls_gets;        /* Num acquires */
+        u32             ls_fail;        /* Num failed acquires */
+
+        /* Storing max wait in usecs saves 24 bytes per inode */
+        u32             ls_max;         /* Max wait in USEC */
+};
+#endif
+
 struct ocfs2_lock_res {
         void                    *l_priv;
         struct ocfs2_lock_res_ops *l_ops;
@@ -182,15 +193,9 @@ struct ocfs2_lock_res {
         struct list_head         l_debug_list;
 
 #ifdef CONFIG_OCFS2_FS_STATS
-        unsigned long long       l_lock_num_prmode;        /* PR acquires */
-        unsigned long long       l_lock_num_exmode;        /* EX acquires */
-        unsigned int             l_lock_num_prmode_failed; /* Failed PR gets */
-        unsigned int             l_lock_num_exmode_failed; /* Failed EX gets */
-        unsigned long long       l_lock_total_prmode;      /* Tot wait for PR */
-        unsigned long long       l_lock_total_exmode;      /* Tot wait for EX */
-        unsigned int             l_lock_max_prmode;        /* Max wait for PR */
-        unsigned int             l_lock_max_exmode;        /* Max wait for EX */
-        unsigned int             l_lock_refresh;           /* Disk refreshes */
+        struct ocfs2_lock_stats  l_lock_prmode;         /* PR mode stats */
+        u32                      l_lock_refresh;        /* Disk refreshes */
+        struct ocfs2_lock_stats  l_lock_exmode;         /* EX mode stats */
 #endif
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
         struct lockdep_map       l_lockdep_map;