4.18-stable review patch. If anyone has any objections, please let me know.
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From: Srikar Dronamraju srikar@linux.vnet.ibm.com
[ Upstream commit e5e96fafd9028b1478b165db78c52d981c14f471 ]
With the following commit:
051f3ca02e46 ("sched/topology: Introduce NUMA identity node sched domain")
the scheduler introduced a new NUMA level. However this leads to the NUMA topology on 2 node systems to not be marked as NUMA_DIRECT anymore.
After this commit, it gets reported as NUMA_BACKPLANE, because sched_domains_numa_level is now 2 on 2 node systems.
Fix this by allowing setting systems that have up to 2 NUMA levels as NUMA_DIRECT.
While here remove code that assumes that level can be 0.
Signed-off-by: Srikar Dronamraju srikar@linux.vnet.ibm.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: Andre Wild wild@linux.vnet.ibm.com Cc: Heiko Carstens heiko.carstens@de.ibm.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Mel Gorman mgorman@techsingularity.net Cc: Michael Ellerman mpe@ellerman.id.au Cc: Peter Zijlstra peterz@infradead.org Cc: Rik van Riel riel@surriel.com Cc: Suravee Suthikulpanit suravee.suthikulpanit@amd.com Cc: Thomas Gleixner tglx@linutronix.de Cc: linuxppc-dev linuxppc-dev@lists.ozlabs.org Fixes: 051f3ca02e46 "Introduce NUMA identity node sched domain" Link: http://lkml.kernel.org/r/1533920419-17410-1-git-send-email-srikar@linux.vnet... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/sched/topology.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
--- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -1295,7 +1295,7 @@ static void init_numa_topology_type(void
n = sched_max_numa_distance;
- if (sched_domains_numa_levels <= 1) { + if (sched_domains_numa_levels <= 2) { sched_numa_topology_type = NUMA_DIRECT; return; } @@ -1380,9 +1380,6 @@ void sched_init_numa(void) break; }
- if (!level) - return; - /* * 'level' contains the number of unique distances *