tree 24bbb1691ec816aed648a895882526ce361ec92f
parent 40ae3487628235e5f1eb27542cca0cdb6e5dbe16
author Theodore Ts'o <tytso@mit.edu> 1360207823 -0500
committer Theodore Ts'o <tytso@mit.edu> 1360207823 -0500

jbd2: track request delay statistics

Track the delay between when we first request that the commit begin
and when it actually begins, so we can see how much of a gap exists.
In theory, this should just be the remaining scheduling quantuum of
the thread which requested the commit (assuming it was not a
synchronous operation which triggered the commit request) plus
scheduling overhead; however, it's possible that real time processes
might get in the way of letting the kjournald thread from executing.

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