[PATCH v3 3/6] sched/fair: Provide update_sg_lb_stats() with sched domain statistics

From: Ricardo Neri
Date: Thu May 13 2021 - 11:50:48 EST


Before deciding to pull tasks when using asymmetric packing of tasks,
on some architectures (e.g., x86) it is necessary to know not only the
state of dst_cpu but also of its SMT siblings. The decision to classify
a candidate busiest group as group_asym_packing is done in
update_sg_lb_stats(). Give this function access to the scheduling domain
statistics, which contains the statistics of the local group.

Cc: Aubrey Li <aubrey.li@xxxxxxxxx>
Cc: Ben Segall <bsegall@xxxxxxxxxx>
Cc: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Cc: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Cc: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
Cc: Len Brown <len.brown@xxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Quentin Perret <qperret@xxxxxxxxxx>
Cc: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
Originally-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>
---
Changes since v2:
* Introduced this patch.

Changes since v1:
* N/A
---
kernel/sched/fair.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 96b023432a1c..c8c04e9d0d3b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8455,6 +8455,7 @@ group_type group_classify(unsigned int imbalance_pct,
* @sg_status: Holds flag indicating the status of the sched_group
*/
static inline void update_sg_lb_stats(struct lb_env *env,
+ struct sd_lb_stats *sds,
struct sched_group *group,
struct sg_lb_stats *sgs,
int *sg_status)
@@ -8463,7 +8464,7 @@ static inline void update_sg_lb_stats(struct lb_env *env,

memset(sgs, 0, sizeof(*sgs));

- local_group = cpumask_test_cpu(env->dst_cpu, sched_group_span(group));
+ local_group = group == sds->local;

for_each_cpu_and(i, sched_group_span(group), env->cpus) {
struct rq *rq = cpu_rq(i);
@@ -9026,7 +9027,7 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd
update_group_capacity(env->sd, env->dst_cpu);
}

- update_sg_lb_stats(env, sg, sgs, &sg_status);
+ update_sg_lb_stats(env, sds, sg, sgs, &sg_status);

if (local_group)
goto next_group;
--
2.17.1