Re: Change in default vm_dirty_ratio

Linus Torvalds
2007-06-21T23:08:53Z

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.

Linus