Re: [PATCH] Add block device speciffic splice write method

From: Jens Axboe
Date: Thu Oct 23 2008 - 02:52:41 EST

On Wed, Oct 22 2008, Andrew Morton wrote:
> On Thu, 23 Oct 2008 08:29:23 +0200 Jens Axboe <jens.axboe@xxxxxxxxxx> wrote:
> > > But really it'd be better if the throttling happened down in
> > > pipe_to_file(), on a per-page basis. As it stands we can dirty an
> > > arbitrary number of pagecache pages without throttling. I think?
> >
> > That's pretty exactly why it isn't done in the actor, to avoid doing it
> > per-page. As it's going to be PIPE_BUFFERS (16) pages max, I think this
> > is better.
> >
> > Back in the splice early days, the balance_dirty_pages() actually showed
> > up in profiles when it was done on a per-page basis. So I'm reluctant to
> > change it :-)
> That's why (the misnamed) balance_dirty_pages_ratelimited() exists?

I think that is what was used, but the details are a little hazy at this
point. So I can't say for sure. In this case it's moot anyway, since we
can kill it.

Jens Axboe

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