ext4: Use tracepoints for mb_history trace file

The /proc/fs/ext4/<dev>/mb_history was maintained manually, and had a
number of problems: it required a largish amount of memory to be
allocated for each ext4 filesystem, and the s_mb_history_lock
introduced a CPU contention problem.  

By ripping out the mb_history code and replacing it with ftrace
tracepoints, and we get more functionality: timestamps, event
filtering, the ability to correlate mballoc history with other ext4
tracepoints, etc.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 163 insertions, 0 deletions

diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index 7c6bbb7198a..b8320256dc5 100644
--- a/include/trace/events/ext4.h
+++ b/include/trace/events/ext4.h
@@ -743,6 +743,169 @@ TRACE_EVENT(ext4_alloc_da_blocks,
                   __entry->data_blocks, __entry->meta_blocks)
 );
 
+TRACE_EVENT(ext4_mballoc_alloc,
+        TP_PROTO(struct ext4_allocation_context *ac),
+
+        TP_ARGS(ac),
+
+        TP_STRUCT__entry(
+                __field(        dev_t,  dev                     )
+                __field(        ino_t,  ino                     )
+                __field(        __u16,  found                   )
+                __field(        __u16,  groups                  )
+                __field(        __u16,  buddy                   )
+                __field(        __u16,  flags                   )
+                __field(        __u16,  tail                    )
+                __field(        __u8,   cr                      )
+                __field(        __u32,  orig_logical            )
+                __field(          int,  orig_start              )
+                __field(        __u32,  orig_group              )
+                __field(          int,  orig_len                )
+                __field(        __u32,  goal_logical            )
+                __field(          int,  goal_start              )
+                __field(        __u32,  goal_group              )
+                __field(          int,  goal_len                )
+                __field(        __u32,  result_logical          )
+                __field(          int,  result_start            )
+                __field(        __u32,  result_group            )
+                __field(          int,  result_len              )
+        ),
+
+        TP_fast_assign(
+                __entry->dev            = ac->ac_inode->i_sb->s_dev;
+                __entry->ino            = ac->ac_inode->i_ino;
+                __entry->found          = ac->ac_found;
+                __entry->flags          = ac->ac_flags;
+                __entry->groups         = ac->ac_groups_scanned;
+                __entry->buddy          = ac->ac_buddy;
+                __entry->tail           = ac->ac_tail;
+                __entry->cr             = ac->ac_criteria;
+                __entry->orig_logical   = ac->ac_o_ex.fe_logical;
+                __entry->orig_start     = ac->ac_o_ex.fe_start;
+                __entry->orig_group     = ac->ac_o_ex.fe_group;
+                __entry->orig_len       = ac->ac_o_ex.fe_len;
+                __entry->goal_logical   = ac->ac_g_ex.fe_logical;
+                __entry->goal_start     = ac->ac_g_ex.fe_start;
+                __entry->goal_group     = ac->ac_g_ex.fe_group;
+                __entry->goal_len       = ac->ac_g_ex.fe_len;
+                __entry->result_logical = ac->ac_f_ex.fe_logical;
+                __entry->result_start   = ac->ac_f_ex.fe_start;
+                __entry->result_group   = ac->ac_f_ex.fe_group;
+                __entry->result_len     = ac->ac_f_ex.fe_len;
+        ),
+
+        TP_printk("dev %s inode %lu orig %u/%d/%u@%u goal %u/%d/%u@%u "
+                  "result %u/%d/%u@%u blks %u grps %u cr %u flags 0x%04x "
+                  "tail %u broken %u",
+                  jbd2_dev_to_name(__entry->dev), (unsigned long) __entry->ino,
+                  __entry->orig_group, __entry->orig_start,
+                  __entry->orig_len, __entry->orig_logical,
+                  __entry->goal_group, __entry->goal_start,
+                  __entry->goal_len, __entry->goal_logical,
+                  __entry->result_group, __entry->result_start,
+                  __entry->result_len, __entry->result_logical,
+                  __entry->found, __entry->groups, __entry->cr,
+                  __entry->flags, __entry->tail,
+                  __entry->buddy ? 1 << __entry->buddy : 0)
+);
+
+TRACE_EVENT(ext4_mballoc_prealloc,
+        TP_PROTO(struct ext4_allocation_context *ac),
+
+        TP_ARGS(ac),
+
+        TP_STRUCT__entry(
+                __field(        dev_t,  dev                     )
+                __field(        ino_t,  ino                     )
+                __field(        __u32,  orig_logical            )
+                __field(          int,  orig_start              )
+                __field(        __u32,  orig_group              )
+                __field(          int,  orig_len                )
+                __field(        __u32,  result_logical          )
+                __field(          int,  result_start            )
+                __field(        __u32,  result_group            )
+                __field(          int,  result_len              )
+        ),
+
+        TP_fast_assign(
+                __entry->dev            = ac->ac_inode->i_sb->s_dev;
+                __entry->ino            = ac->ac_inode->i_ino;
+                __entry->orig_logical   = ac->ac_o_ex.fe_logical;
+                __entry->orig_start     = ac->ac_o_ex.fe_start;
+                __entry->orig_group     = ac->ac_o_ex.fe_group;
+                __entry->orig_len       = ac->ac_o_ex.fe_len;
+                __entry->result_logical = ac->ac_b_ex.fe_logical;
+                __entry->result_start   = ac->ac_b_ex.fe_start;
+                __entry->result_group   = ac->ac_b_ex.fe_group;
+                __entry->result_len     = ac->ac_b_ex.fe_len;
+        ),
+
+        TP_printk("dev %s inode %lu orig %u/%d/%u@%u result %u/%d/%u@%u",
+                  jbd2_dev_to_name(__entry->dev), (unsigned long) __entry->ino,
+                  __entry->orig_group, __entry->orig_start,
+                  __entry->orig_len, __entry->orig_logical,
+                  __entry->result_group, __entry->result_start,
+                  __entry->result_len, __entry->result_logical)
+);
+
+TRACE_EVENT(ext4_mballoc_discard,
+        TP_PROTO(struct ext4_allocation_context *ac),
+
+        TP_ARGS(ac),
+
+        TP_STRUCT__entry(
+                __field(        dev_t,  dev                     )
+                __field(        ino_t,  ino                     )
+                __field(        __u32,  result_logical          )
+                __field(          int,  result_start            )
+                __field(        __u32,  result_group            )
+                __field(          int,  result_len              )
+        ),
+
+        TP_fast_assign(
+                __entry->dev            = ac->ac_inode->i_sb->s_dev;
+                __entry->ino            = ac->ac_inode->i_ino;
+                __entry->result_logical = ac->ac_b_ex.fe_logical;
+                __entry->result_start   = ac->ac_b_ex.fe_start;
+                __entry->result_group   = ac->ac_b_ex.fe_group;
+                __entry->result_len     = ac->ac_b_ex.fe_len;
+        ),
+
+        TP_printk("dev %s inode %lu extent %u/%d/%u@%u ",
+                  jbd2_dev_to_name(__entry->dev), (unsigned long) __entry->ino,
+                  __entry->result_group, __entry->result_start,
+                  __entry->result_len, __entry->result_logical)
+);
+
+TRACE_EVENT(ext4_mballoc_free,
+        TP_PROTO(struct ext4_allocation_context *ac),
+
+        TP_ARGS(ac),
+
+        TP_STRUCT__entry(
+                __field(        dev_t,  dev                     )
+                __field(        ino_t,  ino                     )
+                __field(        __u32,  result_logical          )
+                __field(          int,  result_start            )
+                __field(        __u32,  result_group            )
+                __field(          int,  result_len              )
+        ),
+
+        TP_fast_assign(
+                __entry->dev            = ac->ac_inode->i_sb->s_dev;
+                __entry->ino            = ac->ac_inode->i_ino;
+                __entry->result_logical = ac->ac_b_ex.fe_logical;
+                __entry->result_start   = ac->ac_b_ex.fe_start;
+                __entry->result_group   = ac->ac_b_ex.fe_group;
+                __entry->result_len     = ac->ac_b_ex.fe_len;
+        ),
+
+        TP_printk("dev %s inode %lu extent %u/%d/%u@%u ",
+                  jbd2_dev_to_name(__entry->dev), (unsigned long) __entry->ino,
+                  __entry->result_group, __entry->result_start,
+                  __entry->result_len, __entry->result_logical)
+);
+
 #endif /* _TRACE_EXT4_H */
 
 /* This part must be outside protection */