On Thu, 23 Oct 2008 08:51:13 +0200 Jens Axboe <jens.axboe@xxxxxxxxxx> wrote: > 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. All that function does is to bump a per-cpu variable and once-per-thousand or so it does the balance. If it was causing problems in the splice application we want to know, because write() uses it! > In this case it's moot anyway, since we can kill it. Nope, we can only remove it if the fd is O_SYNC||is_sync(). -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
