add-lazytime-tracepoints

   1 vfs: add lazytime tracepoints for better debugging
   2
   3 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
   4 ---
   5  fs/fs-writeback.c         |  9 +++++++--
   6  fs/inode.c                |  5 +++++
   7  include/trace/events/fs.h | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
   8  3 files changed, 74 insertions(+), 2 deletions(-)
   9
  10 diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
  11 index fd03782..63774aa 100644
  12 --- a/fs/fs-writeback.c
  13 +++ b/fs/fs-writeback.c
  14 @@ -27,6 +27,7 @@
  15  #include <linux/backing-dev.h>
  16  #include <linux/tracepoint.h>
  17  #include <linux/device.h>
  18 +#include <trace/events/fs.h>
  19  #include "internal.h"
  20
  21  /*
  22 @@ -490,8 +491,10 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
  23         if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
  24                 inode->i_state &= ~I_DIRTY_PAGES;
  25         dirty = inode->i_state & (I_DIRTY_SYNC | I_DIRTY_DATASYNC);
  26 -       if (dirty && (inode->i_state & I_DIRTY_TIME))
  27 +       if (dirty && (inode->i_state & I_DIRTY_TIME)) {
  28                 dirty |= I_DIRTY_TIME;
  29 +               trace_fs_lazytime_writeback(inode);
  30 +       }
  31         inode->i_state &= ~dirty;
  32         spin_unlock(&inode->i_lock);
  33         if (dirty & I_DIRTY_TIME)
  34 @@ -1338,8 +1341,10 @@ static void flush_sb_dirty_time(struct super_block *sb)
  35
  36                 list_del_init(&inode->i_wb_list);
  37                 spin_unlock(&wb->list_lock);
  38 -               if (inode->i_state & I_DIRTY_TIME)
  39 +               if (inode->i_state & I_DIRTY_TIME) {
  40                         mark_inode_dirty_sync(inode);
  41 +                       trace_fs_lazytime_flush(inode);
  42 +               }
  43                 spin_lock(&wb->list_lock);
  44         }
  45         spin_unlock(&wb->list_lock);
  46 diff --git a/fs/inode.c b/fs/inode.c
  47 index 1ec0629..e903c37 100644
  48 --- a/fs/inode.c
  49 +++ b/fs/inode.c
  50 @@ -20,6 +20,9 @@
  51  #include <linux/list_lru.h>
  52  #include "internal.h"
  53
  54 +#define CREATE_TRACE_POINTS
  55 +#include <trace/events/fs.h>
  56 +
  57  /*
  58   * Inode locking rules:
  59   *
  60 @@ -1440,6 +1443,7 @@ retry:
  61                         inode->i_state &= ~I_DIRTY_TIME;
  62                         spin_unlock(&inode->i_lock);
  63                         mark_inode_dirty_sync(inode);
  64 +                       trace_fs_lazytime_iput(inode);
  65                         goto retry;
  66                 }
  67                 iput_final(inode);
  68 @@ -1536,6 +1540,7 @@ static int update_time(struct inode *inode, struct timespec *time, int flags)
  69                 inode->i_state |= I_DIRTY_TIME;
  70                 spin_unlock(&inode->i_lock);
  71                 inode_requeue_dirtytime(inode);
  72 +               trace_fs_lazytime_defer(inode);
  73                 return 0;
  74         }
  75  force_dirty:
  76 diff --git a/include/trace/events/fs.h b/include/trace/events/fs.h
  77 new file mode 100644
  78 index 0000000..af0b8cc
  79 --- /dev/null
  80 +++ b/include/trace/events/fs.h
  81 @@ -0,0 +1,62 @@
  82 +#undef TRACE_SYSTEM
  83 +#define TRACE_SYSTEM fs
  84 +
  85 +#if !defined(_TRACE_FS_H) || defined(TRACE_HEADER_MULTI_READ)
  86 +#define _TRACE_FS_H
  87 +
  88 +#include <linux/tracepoint.h>
  89 +
  90 +DECLARE_EVENT_CLASS(fs__inode,
  91 +       TP_PROTO(struct inode *inode),
  92 +
  93 +       TP_ARGS(inode),
  94 +
  95 +       TP_STRUCT__entry(
  96 +               __field(        dev_t,  dev                     )
  97 +               __field(        ino_t,  ino                     )
  98 +               __field(        uid_t,  uid                     )
  99 +               __field(        gid_t,  gid                     )
 100 +               __field(        __u16, mode                     )
 101 +       ),
 102 +
 103 +       TP_fast_assign(
 104 +               __entry->dev    = inode->i_sb->s_dev;
 105 +               __entry->ino    = inode->i_ino;
 106 +               __entry->uid    = i_uid_read(inode);
 107 +               __entry->gid    = i_gid_read(inode);
 108 +               __entry->mode   = inode->i_mode;
 109 +       ),
 110 +
 111 +       TP_printk("dev %d,%d ino %lu mode 0%o uid %u gid %u",
 112 +                 MAJOR(__entry->dev), MINOR(__entry->dev),
 113 +                 (unsigned long) __entry->ino, __entry->mode,
 114 +                 __entry->uid, __entry->gid)
 115 +);
 116 +
 117 +DEFINE_EVENT(fs__inode, fs_lazytime_defer,
 118 +       TP_PROTO(struct inode *inode),
 119 +
 120 +       TP_ARGS(inode)
 121 +);
 122 +
 123 +DEFINE_EVENT(fs__inode, fs_lazytime_iput,
 124 +       TP_PROTO(struct inode *inode),
 125 +
 126 +       TP_ARGS(inode)
 127 +);
 128 +
 129 +DEFINE_EVENT(fs__inode, fs_lazytime_flush,
 130 +       TP_PROTO(struct inode *inode),
 131 +
 132 +       TP_ARGS(inode)
 133 +);
 134 +
 135 +DEFINE_EVENT(fs__inode, fs_lazytime_writeback,
 136 +       TP_PROTO(struct inode *inode),
 137 +
 138 +       TP_ARGS(inode)
 139 +);
 140 +#endif /* _TRACE_FS_H */
 141 +
 142 +/* This part must be outside protection */
 143 +#include <trace/define_trace.h>