Subject: Re: jbd2: don't wake kjournald unnecessarily

From: Theodore Ts'o <[email-masked]>
Date: Mon, 21 Jan 2013 18:11:30 -0500

On Tue, Jan 22, 2013 at 12:04:32AM +0100, Sedat Dilek wrote:
> 
> Beyond the FUSE/LOOP fun, will you apply this patch to your linux-next GIT tree?
> 
> Feel free to add...
> 
>      Tested-by: Sedat Dilek <[email-masked]>
> 
> A similiar patch for JBD went through your tree into mainline (see [1] and [2]).

I'm not at all convinced that this patch has anything to do with your
problem.  I don't see how it could affect things, and I believe you
mentioned that you saw the problem even with this patch applied?  (I'm
not sure; some of your messages which you sent were hard to
understand, and you mentioned something about trying to send messages
when low on sleep :-).

In any case, the reason why I haven't pulled this patch into the ext4
tree is because I was waiting for Eric and some of the performance
team folks at Red Hat to supply some additional information about why
this commit was making a difference in performance for a particular
proprietary, closed source benchmark.

I'm very suspicious about applying patches under the "cargo cult"
school of programming.  ("We don't understand why it makes a
difference, but it seems to be good, so bombs away!" :-)

Regards,

					- Ted