Re: [PATCH v12 4/5] arm64, numa: Add NUMA support for arm64 platforms.

[David Daney]

On 02/29/2016 09:34 AM, Robert Richter wrote:
> On 22.02.16 17:58:22, David Daney wrote:
> > From: Ganapatrao Kulkarni <gkulkarni@xxxxxxxxxxxxxxxxxx>
> >
> > Attempt to get the memory and CPU NUMA node via of_numa.  If that
> > fails, default the dummy NUMA node and map all memory and CPUs to node
> > 0.
> >
> > Tested-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> > Reviewed-by: Robert Richter <rrichter@xxxxxxxxxx>
> > Signed-off-by: Ganapatrao Kulkarni <gkulkarni@xxxxxxxxxxxxxxxxxx>
> > Signed-off-by: David Daney <david.daney@xxxxxxxxxx>
> > ---
> >   arch/arm64/Kconfig                |  26 +++
> >   arch/arm64/include/asm/mmzone.h   |  12 ++
> >   arch/arm64/include/asm/numa.h     |  45 +++++
> >   arch/arm64/include/asm/topology.h |  10 +
> >   arch/arm64/kernel/pci.c           |  10 +
> >   arch/arm64/kernel/setup.c         |   4 +
> >   arch/arm64/kernel/smp.c           |   4 +
> >   arch/arm64/mm/Makefile            |   1 +
> >   arch/arm64/mm/init.c              |  34 +++-
> >   arch/arm64/mm/mmu.c               |   1 +
> >   arch/arm64/mm/numa.c              | 403 ++++++++++++++++++++++++++++++++++++++
> >   11 files changed, 545 insertions(+), 5 deletions(-)
> >   create mode 100644 arch/arm64/include/asm/mmzone.h
> >   create mode 100644 arch/arm64/include/asm/numa.h
> >   create mode 100644 arch/arm64/mm/numa.c
>
> > +static int __init numa_init(int (*init_func)(void))
> > +{
> > +	int ret;
> > +
> > +	nodes_clear(numa_nodes_parsed);
> > +	nodes_clear(node_possible_map);
> > +	nodes_clear(node_online_map);
> > +	numa_free_distance();

        ^^^^^^^^^^^^^
     Cleanup for any previous numa_alloc_distance()

> > +
> > +	ret = numa_alloc_distance();
> > +	if (ret < 0)
> > +		return ret;
>
> If you move this before the remaining initializers, you will need to
> clean this up on error.

Yes, we do this.  See above.

> So better move it back after
> numa_register_nodes() as it was in v10. This should work since
> distances are used not earlier than numa is enabled.

I moved it here for a reason.

The init_func (of_numa_init() in this case) makes callbacks that use the 
numa_distance object.  We need to allocate it before using it. 
Allocating it after calling the init_func() is too late.


> -Robert
>
> > +
> > +	ret = init_func();
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	if (nodes_empty(numa_nodes_parsed))
> > +		return -EINVAL;
> > +
> > +	ret = numa_register_nodes();
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	setup_node_to_cpumask_map();
> > +
> > +	/* init boot processor */
> > +	cpu_to_node_map[0] = 0;
> > +	map_cpu_to_node(0, 0);
> > +
> > +	return 0;
> > +}