Date: Thu, 26 Jan 2006 16:57:06 -0800 (PST)
From: Christoph Lameter <clameter@engr.sgi.com>
To: Matthew Dobson <colpatch@us.ibm.com>
cc: linux-kernel@vger.kernel.org, sri@us.ibm.com, andrea@suse.de,
       pavel@suse.cz, linux-mm@kvack.org, pj@sgi.com, ak@suse.de
Subject: Re: [patch 3/9] mempool - Make mempools NUMA aware
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On Thu, 26 Jan 2006, Matthew Dobson wrote:

> > We need this for other issues as well. f.e. to establish memory allocation 
> > policies for the page cache, tmpfs and various other needs. Look at 
> > mempolicy.h which defines a subset of what we need. Currently there is no 
> > way to specify a policy when invoking the page allocator or slab 
> > allocator. The policy is implicily fetched from the current task structure 
> > which is not optimal.
> 
> I agree that the current, task-based policies are subobtimal.  Having to
> allocate and fill in even a small structure for each allocation is going to
> be a tough sell, though.  I suppose most allocations could get by with a
> small handfull of static generic "policy structures"...  This seems like it
> will turn into a signifcant rework of all the kernel's allocation routines,
> no small task.  Certainly not something that I'd even start without
> response from some other major players in the VM area...  Anyone?

No you would have a set of policies and only pass a pointer to the 
policies to the allocator. I.e. have one emergency policy allocated 
somewhere in the IP stack and then pass that to the allocator.

I guess that Andi Kleen and Paul Jackson would likely be interested in 
such an endeavor.
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