Re: Unresponiveness of 2.4.16

Mike Fedyk (mfedyk@matchmail.com)
Tue, 27 Nov 2001 13:24:35 -0800


On Tue, Nov 27, 2001 at 12:57:19PM -0800, Andrew Morton wrote:
> Mike Fedyk wrote:
> >
> > > I'll send you a patch which makes the VM less inclined to page things
> > > out in the presence of heavy writes, and which decreases read
> > > latencies.
> > >
> > Is this patch posted anywhere?
>
> I sent it yesterday, in this thread. Here it is again.
>

Yep, saw it. I didn't realize (didn't read patch) that it modified the VM
swapping.

> Description:
>
> - Account for locked as well as dirty buffers when deciding
> to throttle writers.
>
> - Tweak VM to make it work the inactive list harder, before starting
> to evict pages or swap.
>
> - Change the elevator so that once a request's latency has
> expired, we can still perform merges in front of that
> request. But we no longer will insert new requests in
> front of that request.
>
> - Modify elevator so that new read requests do not have
> more than N write requests placed in front of them, where
> N is tunable per-device with `elvtune -b'.
>
> Theoretically, the last change needs significant alterations
> to the readhead code. But a rewrite of readhead made negligible
> difference (I wasn't able to trigger the failure scenario).
> Still crunching on this.
>

Sounds great.

I'll test it out.

MF
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