Messages in this thread Patch in this message | | | Date | Fri, 28 Apr 2017 15:20:01 +0200 | From | Peter Zijlstra <> | Subject | [PATCH 03/14] sched/topology: Fix building of overlapping sched-groups |
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When building the overlapping groups, we very obviously should start with the previous domain of _this_ @cpu, not CPU-0.
This can be readily demonstrated with a topology like:
node 0 1 2 3 0: 10 20 30 20 1: 20 10 20 30 2: 30 20 10 20 3: 20 30 20 10
Where (for example) CPU1 ends up generating the following nonsensical groups:
[] CPU1 attaching sched-domain: [] domain 0: span 0-2 level NUMA [] groups: 1 2 0 [] domain 1: span 0-3 level NUMA [] groups: 1-3 (cpu_capacity = 3072) 0-1,3 (cpu_capacity = 3072)
Where the fact that domain 1 doesn't include a group with span 0-2 is the obvious fail.
With patch this looks like:
[] CPU1 attaching sched-domain: [] domain 0: span 0-2 level NUMA [] groups: 1 0 2 [] domain 1: span 0-3 level NUMA [] groups: 0-2 (cpu_capacity = 3072) 0,2-3 (cpu_capacity = 3072)
Cc: stable@vger.kernel.org Fixes: e3589f6c81e4 ("sched: Allow for overlapping sched_domain spans") Debugged-by: Lauro Ramos Venancio <lvenanci@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- kernel/sched/topology.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -525,7 +525,7 @@ build_overlap_sched_groups(struct sched_ cpumask_clear(covered); - for_each_cpu(i, span) { + for_each_cpu_wrap(i, span, cpu) { struct cpumask *sg_span; if (cpumask_test_cpu(i, covered))
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