jbd2 batch time tuning behavior question

Question for Ted: With this commit, you introduced some documentation and some code which are not consistent AFAICT:

commit 30773840c19cea60dcef39545960d541b1ac1cf8

Author: Theodore Ts'o <[email protected]>
Date:   Sat Jan 3 20:27:38 2009 -0500

ext4: add fsync batch tuning knobs

<snip>

+                       the transaction.   The commit time is capped by
+                       the max_batch_time, which defaults to 15000us
+                       (15ms).   This optimization can be turned off
+                       entirely by setting max_batch_time to 0.

<snip>

+ case Opt_max_batch_time:
+ if (match_int(&args[0], &option))
+ return 0;
+ if (option < 0)
+ return 0;
+ if (option == 0)
+ option = EXT4_DEF_MAX_BATCH_TIME;
+ sbi->s_max_batch_time = option;
+ break;

Docs say "0" turns it off, but option handling turns "0" into EXT4_DEF_MAX_BATCH_TIME. What was the real intent here; should the docs or the behavior be changed?

Thanks,
-Eric

Nice catch! I would think it's probably better if we make the behavior change to match the docs.

Want to send a patch, since you found the problem, or shall I create a patch myself to fix things up?

Thanks,

- Ted

I can send the patch, I just wondered what the intent was.

Thanks,
-Eric