Re: Strange dcache memory pressure when highmem enabled

[Neil Brown]

On Tuesday October 14, akpm@xxxxxxxx wrote:
> Neil Brown <neilb@xxxxxxxxxxxxxxx> wrote:
> >
> > I noticed that shrink_caches calls shrink_dcache_memory independant
> >   of the classzone that is being shrunk.  So if we are trying to
> >   shrink ZONE_HIGHMEM, the dentry_cache is shrunk, even though the
> >   dentry_cache doesn't live in highmem.  However I'm not sure if I have
> >   understood the classzones well enough for that observation even to
> >   make sense.
> 
> Makes heaps of sense.  Here's an instabackport of what we did in
> 2.6:

Hey!!! That's what I call *Service*.

I'll give it a try tomorrow (let the poor students get a feeling of
stability first before I start changing things again :-)

> +			if (classzone - classzone->zone_pgdat->node_zones <
> +						ZONE_HIGHMEM) {

That's the bit I was missing.  I feel that once I fully understand
that, I will be a long way towards understanding the zones memory
management :-)

NeilBrown
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