Re: [PATCH] mm: limit lowmem_reserve

From: Con Kolivas
Date: Thu May 18 2006 - 03:21:19 EST

On Thursday 18 May 2006 17:11, Nick Piggin wrote:
> If we're under memory pressure, kswapd will try to free up any candidate
> zone, yes.
> > On my test case this indeed happens and my ZONE_DMA never goes below 3000
> > pages free. If I lower the reserve even further my pages free gets stuck
> > at 3208 and can't free any more, and doesn't ever drop below that either.
> >
> > Here is the patch I was proposing
> What problem does that fix though?

It's a generic concern and I honestly don't know how significant it is which
is why I'm asking if it needs attention. That concern being that any time
we're under any sort of memory pressure, ZONE_DMA will undergo intense
reclaim even though there may not really be anything specifically going on in
ZONE_DMA. It just seems a waste of cycles doing that.

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