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Message-ID: <29495f1d0706261217y3ba48400q7c64865082ba13df@mail.gmail.com>
Date: Tue, 26 Jun 2007 12:17:05 -0700
From: "Nish Aravamudan" <nish.aravamudan@gmail.com>
To: "Christoph Lameter" <clameter@sgi.com>
Subject: Re: [PATCH] slob: poor man's NUMA support.
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
       "Paul Mundt" <lethal@linux-sh.org>, "Matt Mackall" <mpm@selenic.com>,
       "Nick Piggin" <nickpiggin@yahoo.com.au>, linux-mm@kvack.org,
       linux-kernel@vger.kernel.org
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On 6/26/07, Christoph Lameter <clameter@sgi.com> wrote:
> On Tue, 26 Jun 2007, Nish Aravamudan wrote:
>
> > > No. alloc_pages follows memory policy. alloc_pages_node does not. One of
> > > the reasons that I want a new memory policy layer are these kinds of
> > > strange uses.
> >
> > What would break by changing, in alloc_pages_node()
> >
> >        if (nid < 0)
> >                nid = numa_node_id();
> >
> > to
> >
> >        if (nid < 0)
> >                return alloc_pages_current(gfp_mask, order);
> >
> > beyond needing to make alloc_pages_current() defined if !NUMA too.
>
> It would make alloc_pages_node obey memory policies instead of only
> following cpuset constraints. An a memory policy may redirect the
> allocation from the local node ;-).

heh, true true.

Hrm, I guess the simplest looking solution is rarely the best. Could
we add more smarts in alloc_pages_current() to make GFP_THISNODE be
equivalent to bind_zonelist(thisnode_only_mask)? I'll keep thinking,
maybe I'll come up with something.

Thanks,
Nish
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