Re: VM patches in 2.6.4-rc1-mm2

From: Nick Piggin
Date: Wed Mar 10 2004 - 19:27:20 EST

Mike Fedyk wrote:

Nick Piggin wrote:

Mike Fedyk wrote:

Nick Piggin wrote:

Mainline doesn't put enough pressure on slab with highmem systems. This
creates a lot more ZONE_NORMAL pressure and that causes swapping.

Yep, saw that. Especially with 128MB Highmem (eg, 1G RAM)

Now with the 2.6 VM, you don't do any mapped memory scaning at all

You mean 2.6-mm?

Yes, either mm or linus.

Have there been any VM patches merged into mainline? Or are you saying that the imbalance in mainline would be enough to overcome to lack of scanning of mapped pages?

There have been no VM patches merged into mainline. I just mean that
neither mm or mainline does any mapped memory scanning when memory
pressure is low.

If you get a lot of pressure at one time it should push out your
inactive mapped pages. Will get most of the really inactive ones,
but it won't help pages becoming inactive in future.

Ok, I see. This might be happening, since it is steadily getting more into swap.

For the one that is swapping, yes this would be happening.

Hasn't looked at it much. Probably not until some of the more basic
VM patches can get merged into -linus.

Yes, I wonder if the VM patches helped -mm in the reaim tests...

Let's get the fsfaz (free slab for all zones) into mainline asap! :-D

Well all the ones in -mm now are probably right to go to 2.6.5
I hope.

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