Re: [PATCH] Document Linux Memory Policy

[Lee Schermerhorn <Lee.Schermerhorn@hp.com>]

On Fri, 2007-06-01 at 13:45 -0700, Christoph Lameter wrote:
> On Fri, 1 Jun 2007, Gleb Natapov wrote:
> 
> > > Same here and I wish we had a clean memory region based implementation.
> > > But that is just what your patches do *not* provide. Instead they are file 
> > > based. They should be memory region based.
> > Do you want a solution that doesn't associate memory policy with a file
> > (if a file is mapped shared and disk backed) like Lee's solution does, but
> > instead install it into VMA and respect the policy during pagecache page
> > allocation on behalf of the process? So two process should cooperate
> 
> Right.

> 
> > (bind same part of a file to a same memory node in each process) to get
> > consistent result? If yes this will work for me.
> 
> Yes.

But, what if the processes install different policies... if they're NOT
cooperating.  This was your previous objection.  In fact, you've used
just the scenario that Gleb describes as an objection--that different
tasks could have different policies in their address spaces.  Not a
problem if the policy is shared.  Let one task do the setup.  Done!  It
just works.  Keep those uncooperative tasks away from your file.

What happened to consistency? ;-)

Lee

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