From: Eric Sandeen <sandeen@redhat.com>
To: ext4 development <linux-ext4@vger.kernel.org>
Subject: jbd2 batch time tuning behavior question
Date: Tue, 27 May 2014 11:47:06 -0500 [thread overview]
Message-ID: <5384C18A.7040501@redhat.com> (raw)
Question for Ted: With this commit, you introduced some documentation and some code which are not consistent AFAICT:
commit 30773840c19cea60dcef39545960d541b1ac1cf8
Author: Theodore Ts'o <tytso@mit.edu>
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
next reply other threads:[~2014-05-27 16:47 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-27 16:47 Eric Sandeen [this message]
2014-06-02 14:42 ` jbd2 batch time tuning behavior question Theodore Ts'o
2014-06-02 15:00 ` Eric Sandeen
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