[PATCH v3 1/8] sched/topology: Compute sd_weight considering cpuset partitions

From: K Prateek Nayak

Date: Tue Jan 20 2026 - 06:33:30 EST


The "sd_weight" used for calculating the load balancing interval, and
its limits, considers the span weight of the entire topology level
without accounting for cpuset partitions.

Compute the "sd_weight" after computing the "sd_span" considering the
cpu_map covered by the partition, and set the load balancing interval,
and its limits accordingly.

Fixes: cb83b629bae03 ("sched/numa: Rewrite the CONFIG_NUMA sched domain support")
Signed-off-by: K Prateek Nayak <kprateek.nayak@xxxxxxx>
---
Changelog rfc v2..v3:

o New patch.
---
kernel/sched/topology.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index cf643a5ddedd..649674bb6c3c 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -1638,8 +1638,6 @@ sd_init(struct sched_domain_topology_level *tl,
int sd_id, sd_weight, sd_flags = 0;
struct cpumask *sd_span;

- sd_weight = cpumask_weight(tl->mask(tl, cpu));
-
if (tl->sd_flags)
sd_flags = (*tl->sd_flags)();
if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS,
@@ -1647,8 +1645,6 @@ sd_init(struct sched_domain_topology_level *tl,
sd_flags &= TOPOLOGY_SD_FLAGS;

*sd = (struct sched_domain){
- .min_interval = sd_weight,
- .max_interval = 2*sd_weight,
.busy_factor = 16,
.imbalance_pct = 117,

@@ -1668,7 +1664,6 @@ sd_init(struct sched_domain_topology_level *tl,
,

.last_balance = jiffies,
- .balance_interval = sd_weight,

/* 50% success rate */
.newidle_call = 512,
@@ -1685,6 +1680,11 @@ sd_init(struct sched_domain_topology_level *tl,
cpumask_and(sd_span, cpu_map, tl->mask(tl, cpu));
sd_id = cpumask_first(sd_span);

+ sd_weight = cpumask_weight(sd_span);
+ sd->min_interval = sd_weight;
+ sd->max_interval = 2 * sd_weight;
+ sd->balance_interval = sd_weight;
+
sd->flags |= asym_cpu_capacity_classify(sd_span, cpu_map);

WARN_ONCE((sd->flags & (SD_SHARE_CPUCAPACITY | SD_ASYM_CPUCAPACITY)) ==
--
2.34.1