lkml.org 
[lkml]   [2020]   [Mar]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/3] powerpc/numa: Set numa_node for all possible cpus
On Wed 11-03-20 16:32:35, Srikar Dronamraju wrote:
> A Powerpc system with multiple possible nodes and with CONFIG_NUMA
> enabled always used to have a node 0, even if node 0 does not any cpus
> or memory attached to it. As per PAPR, node affinity of a cpu is only
> available once its present / online. For all cpus that are possible but
> not present, cpu_to_node() would point to node 0.
>
> To ensure a cpuless, memoryless dummy node is not online, powerpc need
> to make sure all possible but not present cpu_to_node are set to a
> proper node.

Just curious, is this somehow related to
http://lkml.kernel.org/r/20200227182650.GG3771@dhcp22.suse.cz?

> Cc: linuxppc-dev@lists.ozlabs.org
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: Vlastimil Babka <vbabka@suse.cz>
> Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
> Cc: Christopher Lameter <cl@linux.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> ---
> arch/powerpc/mm/numa.c | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
> index 8a399db..54dcd49 100644
> --- a/arch/powerpc/mm/numa.c
> +++ b/arch/powerpc/mm/numa.c
> @@ -931,8 +931,20 @@ void __init mem_topology_setup(void)
>
> reset_numa_cpu_lookup_table();
>
> - for_each_present_cpu(cpu)
> - numa_setup_cpu(cpu);
> + for_each_possible_cpu(cpu) {
> + /*
> + * Powerpc with CONFIG_NUMA always used to have a node 0,
> + * even if it was memoryless or cpuless. For all cpus that
> + * are possible but not present, cpu_to_node() would point
> + * to node 0. To remove a cpuless, memoryless dummy node,
> + * powerpc need to make sure all possible but not present
> + * cpu_to_node are set to a proper node.
> + */
> + if (cpu_present(cpu))
> + numa_setup_cpu(cpu);
> + else
> + set_cpu_numa_node(cpu, first_online_node);
> + }
> }
>
> void __init initmem_init(void)
> --
> 1.8.3.1

--
Michal Hocko
SUSE Labs

\
 
 \ /
  Last update: 2020-03-11 12:58    [W:0.177 / U:2.600 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site