From: Darrick J. Wong on
On Wed, Apr 21, 2010 at 11:27:27PM +0200, Jens Axboe wrote:
> On Wed, Apr 21 2010, Darrick J. Wong wrote:
> > Simple debugging patch used to watch for barrier requests. I've been using
> > this to watch ext4's barrier=1 behavior.
> But barriers are already being logged, if you watch blkparse data, it'll
> be RB or WB events. So I don't see what this addition provides that we
> don't already have?

I also have the function graph tracer turned on, so I can (try to) map barrier
requests to specific chunks of ext4 code. But, maybe there's a way to do this
with blkparse that I haven't found yet?

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