Re: [PATCH v4][RFC] hugetlb: add per-node nr_hugepages sysfs attribute

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

On Wed, 2007-06-13 at 13:29 -0700, Nishanth Aravamudan wrote:
> On 13.06.2007 [16:05:10 -0400], Lee Schermerhorn wrote:
> > On Wed, 2007-06-13 at 12:19 -0700, Nishanth Aravamudan wrote:
> > > On 13.06.2007 [14:23:47 -0400], Lee Schermerhorn wrote:
> > > > On Wed, 2007-06-13 at 08:28 -0700, Nishanth Aravamudan wrote:
> > > > <snip>
> > > > > 
> > > > > commit 05a7edb8c909c674cdefb0323348825cf3e2d1d0
> > > > > Author: Nishanth Aravamudan <nacc@us.ibm.com>
> > > > > Date:   Thu Jun 7 08:54:48 2007 -0700
> > > > > 
> > > > > hugetlb: add per-node nr_hugepages sysfs attribute
> > > > > 
> > > > > Allow specifying the number of hugepages to allocate on a particular
> > > > > node. Our current global sysctl will try its best to put hugepages
> > > > > equally on each node, but htat may not always be desired. This allows
> > > > > the admin to control the layout of hugepage allocation at a finer level
> > > > > (while not breaking the existing interface). Add callbacks in the sysfs
> > > > > node registration and unregistration functions into hugetlb to add the
> > > > > nr_hugepages attribute, which is a no-op if !NUMA or !HUGETLB.
> > > > > 
> > > > > Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
> > > > > Cc: William Lee Irwin III <wli@holomorphy.com>
> > > > > Cc: Christoph Lameter <clameter@sgi.com>
> > > > > Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
> > > > > Cc: Anton Blanchard <anton@sambar.org>
> > > > > Cc: Andrew Morton <akpm@linux-foundation.org>
> > > > > 
> > > > > ---
> > > > > Do the dummy function definitions need to be (void)0?
> > > > > 
> > > > 
> > > > <snip>
> > 
> > I tested hugepage allocation on my HP rx8620 platform [16 cpu ia64,
> > 32GB in 4 "real" nodes and one pseudo-node containing only DMA
> > memory].  As expected, I don't get a balanced distribution across the
> > real nodes.  Here's what I see:
> 
> Hrm, not good.
> 
> Can you try without any of my add-on patches, but just the original set
> from Christoph?

I can do that.  However, I've tested with two patches:  one to the
"GFP_THISNODE" behavior in alloc_pages_node(), and one for interleaving
in your "fix hugetlb pool allocation..." patch.  With these 2 patches,
hugetlb allocation appears to work on my platform, at least via the
vm.nr_hugepages sysctl.  Haven't tried your per node attribute yet, and
I'm just rebooting to try the command line.  I'll try out the x86_64
platform tomorrow.

I'll post the fixes in response to the respective patches from you and
Christoph.

Lee


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