Re: [PATCH] modified segq for 2.5

Rik van Riel
2002-09-09T23:53:58Z

On Mon, 9 Sep 2002, William Lee Irwin III wrote:
> On Mon, 9 Sep 2002, William Lee Irwin III wrote:
> >> Ideally some distinction would be nice, even if only to distinguish I/O
> >> demanded to be done directly by the workload from background writeback
> >> and/or readahead.
>
> On Mon, Sep 09, 2002 at 07:54:29PM -0300, Rik van Riel wrote:
> > OK, are we talking about page replacement or does queue scanning
> > have priority over the quality of page replacement ? ;)
>
> This is relatively tangential. The concern expressed has more to do
> with VM writeback starving workload-issued I/O than page replacement.

If that happens, the asynchronous writeback threshold should be
lower. Maybe we could even tune this dynamically ...

Compromising on page replacement is generally a Bad Idea(tm) because
page faults are expensive, very expensive.

Rik
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