On Tue, 6 Mar 2001, Marcelo Tosatti wrote:
> On Fri, 2 Mar 2001, Mike Galbraith wrote:
>
> > On Thu, 1 Mar 2001, Rik van Riel wrote:
> >
> > > > > The merging at the elevator level only works if the requests sent to
> > > > > it are right next to each other on disk. This means that randomly
> > > > > sending stuff to disk really DOES DESTROY PERFORMANCE and there's
> > > > > nothing the elevator could ever hope to do about that.
> > > >
> > > > True to some (very real) extent because of the limited buffering
> > > > of requests. However, I can not find any useful information
> > > > that the vm is using to guarantee the IT does not destroy
> > > > performance by your own definition.
> > >
> > > Indeed. IMHO we should fix this by putting explicit IO
> > > clustering in the ->writepage() functions.
> >
> > I notice there's a patch sitting in my mailbox.. think I'll go read
> > it and think (grunt grunt;) about this issue some more.
>
> Mike,
>
> One important information which is not being considered by
> page_launder() now the dirty buffers watermark.
>
> In general, it should not try to avoid writing dirty pages if we're above
> the dirty buffers watermark.
Agreed in theory.. I'll go try to measure.
-Mike
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Wed Mar 07 2001 - 21:00:22 EST