Re: [discuss] mmap, mbind and write to mmap'ed memory crashes 2.6.16-rc1[2] on 2 node X86_64

[Andi Kleen <ak@suse.de>]

On Wednesday 08 February 2006 16:59, Christoph Lameter wrote:
> On Wed, 8 Feb 2006, Andi Kleen wrote:
> 
> > On Wednesday 08 February 2006 16:42, Christoph Lameter wrote:
> > 
> > > However, this has implications for policy_zone. This variable should store
> > > the zone that policies apply to. However, in your case this zone will vary 
> > > which may lead to all sorts of weird behavior even if we fix 
> > > bind_zonelist. To which zone does policy apply? ZONE_NORMAL or ZONE_DMA32?
> > 
> > It really needs to apply to both (currently you can't police 4GB of your 
> > memory on x86-64) But I haven't worked out a good design how to implement it yet.
> 
> So a provisional solution would be to simply ignore empty zones in 
> bind_zonelist?

That would likely prevent the crash yes (Bharata can you test?)

But of course it still has the problem of a lot of memory being unpolicied
on machines with >4GB if there's both DMA32 and NORMAL.

> Or fall back to earlier zones (which includes unpolicied  
> zones in the bind zone list?)

Or that.

Thanks,
-Andi