Messages in this thread Patch in this message | | | From | Valentin Schneider <> | Subject | [PATCH v2] sched/topology, cpuset: Account for housekeeping CPUs to avoid empty cpumasks | Date | Mon, 4 Nov 2019 00:39:06 +0000 |
| |
Michal noted that a cpuset's effective_cpus can be a non-empy mask, but because of the masking done with housekeeping_cpumask(HK_FLAG_DOMAIN) further down the line, we can still end up with an empty cpumask being passed down to partition_sched_domains_locked().
Do the proper thing and don't just check the mask is non-empty - check that its intersection with housekeeping_cpumask(HK_FLAG_DOMAIN) is non-empty.
Fixes: cd1cb3350561 ("sched/topology: Don't try to build empty sched domains") Reported-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> --- kernel/cgroup/cpuset.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index c87ee6412b36..e4c10785dc7c 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -798,8 +798,14 @@ static int generate_sched_domains(cpumask_var_t **domains, cpumask_subset(cp->cpus_allowed, top_cpuset.effective_cpus)) continue; + /* + * Skip cpusets that would lead to an empty sched domain. + * That could be because effective_cpus is empty, or because + * it's only spanning CPUs outside the housekeeping mask. + */ if (is_sched_load_balance(cp) && - !cpumask_empty(cp->effective_cpus)) + cpumask_intersects(cp->effective_cpus, + housekeeping_cpumask(HK_FLAG_DOMAIN))) csa[csn++] = cp; /* skip @cp's subtree if not a partition root */ -- 2.22.0
| |