[PATCH 1/4] xfs: do not update xa_last_pushed_lsn for locked items

[Alex Elder]

On Thu, 2011-10-06 at 14:32 -0400, Christoph Hellwig wrote:
> If an item was locked we should not update xa_last_pushed_lsn and thus skip
> it when restarting the AIL scan as we need to be able to lock and write it
> out as soon as possible.  Otherwise heavy lock contention might starve AIL
> pushing too easily, especially given the larger backoff once we moved
> xa_last_pushed_lsn all the way to the target lsn.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> Reported-by: Stefan Priebe <s.priebe at profihost.ag>
> Tested-by: Stefan Priebe <s.priebe at profihost.ag>

I remember wondering about that one line during review, but
I believe I reasoned something about the "already being
reflushed or relogged" made it the right thing to do.

Your explanation makes sense though (but what do I know,
the original code seemed OK too...).

Reviewed-by: Alex Elder <aelder at sgi.com>