1. 09 2月, 2013 1 次提交
    • T
      ext4: pass context information to jbd2__journal_start() · 9924a92a
      Theodore Ts'o 提交于
      So we can better understand what bits of ext4 are responsible for
      long-running jbd2 handles, use jbd2__journal_start() so we can pass
      context information for logging purposes.
      
      The recommended way for finding the longer-running handles is:
      
         T=/sys/kernel/debug/tracing
         EVENT=$T/events/jbd2/jbd2_handle_stats
         echo "interval > 5" > $EVENT/filter
         echo 1 > $EVENT/enable
      
         ./run-my-fs-benchmark
      
         cat $T/trace > /tmp/problem-handles
      
      This will list handles that were active for longer than 20ms.  Having
      longer-running handles is bad, because a commit started at the wrong
      time could stall for those 20+ milliseconds, which could delay an
      fsync() or an O_SYNC operation.  Here is an example line from the
      trace file describing a handle which lived on for 311 jiffies, or over
      1.2 seconds:
      
      postmark-2917  [000] ....   196.435786: jbd2_handle_stats: dev 254,32 
         tid 570 type 2 line_no 2541 interval 311 sync 0 requested_blocks 1
         dirtied_blocks 0
      Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
      9924a92a
  2. 13 1月, 2013 1 次提交
  3. 11 12月, 2012 16 次提交