From e237882b8f83dd1a0eece1608bcb689d4f4b221b Mon Sep 17 00:00:00 2001 From: Aravind Gopalakrishnan Date: Mon, 10 Aug 2015 20:20:48 -0500 Subject: [PATCH] sched/numa: Fix NUMA_DIRECT topology identification Systems which have all nodes at a distance of at most 1 hop should be identified as 'NUMA_DIRECT'. However, the scheduler incorrectly identifies it as 'NUMA_BACKPLANE'. This is because 'n' is assigned to sched_max_numa_distance but the code (mis)interprets it to mean 'number of hops'. Rik had actually used sched_domains_numa_levels for detecting a 'NUMA_DIRECT' topology: http://marc.info/?l=linux-kernel&m=141279712429834&w=2 But that was changed when he removed the hops table in the subsequent version: http://marc.info/?l=linux-kernel&m=141353106106771&w=2 Fixing the issue here. Signed-off-by: Aravind Gopalakrishnan Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Rik van Riel Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1439256048-3748-1-git-send-email-Aravind.Gopalakrishnan@amd.com Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index b11f6240709b..ea6d74345e60 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6444,8 +6444,10 @@ static void init_numa_topology_type(void) n = sched_max_numa_distance; - if (n <= 1) + if (sched_domains_numa_levels <= 1) { sched_numa_topology_type = NUMA_DIRECT; + return; + } for_each_online_node(a) { for_each_online_node(b) { -- 2.20.1