Re: Change in default vm_dirty_ratio

Peter Zijlstra
2007-06-24T13:17:19Z

On Thu, 2007-06-21 at 16:08 -0700, Linus Torvalds wrote:
>
> On Thu, 21 Jun 2007, Matt Mackall wrote:
> >
> > Perhaps we want to throw some sliding window algorithms at it. We can
> > bound requests and total I/O and if requests get retired too slowly we
> > can shrink the windows. Alternately, we can grow the window if we're
> > retiring things within our desired timeframe.
>
> I suspect that would tend to be a good way to go. But it almost certainly
> has to be per-device, which implies that somebody would have to do some
> major coding/testing on this..
>
> The vm_dirty_ratio thing is a global value, and I think we need that
> regardless (for the independent issue of memory deadlocks etc), but if we
> *additionally* had a per-device throttle that was based on some kind of
> adaptive thing, we could probably raise the global (hard) vm_dirty_ratio a
> lot.

I just did quite a bit of that: