[tip:sched/core] sched/fair: Fix scale_rt_capacity() for SMT

From: tip-bot for Vincent Guittot
Date: Mon Sep 10 2018 - 06:08:13 EST


Commit-ID: 287cdaac5700c5b8970d739f73d742d863d3e2ca
Gitweb: https://git.kernel.org/tip/287cdaac5700c5b8970d739f73d742d863d3e2ca
Author: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
AuthorDate: Tue, 4 Sep 2018 11:36:26 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Mon, 10 Sep 2018 10:13:47 +0200

sched/fair: Fix scale_rt_capacity() for SMT

Since commit:

523e979d3164 ("sched/core: Use PELT for scale_rt_capacity()")

scale_rt_capacity() returns the remaining capacity and not a scale factor
to apply on cpu_capacity_orig. arch_scale_cpu() is directly called by
scale_rt_capacity() so we must take the sched_domain argument.

Reported-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Fixes: 523e979d3164 ("sched/core: Use PELT for scale_rt_capacity()")
Link: http://lkml.kernel.org/r/20180904093626.GA23936@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/fair.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c6b7d6daab20..f12d004be6a1 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7488,10 +7488,10 @@ static inline int get_sd_load_idx(struct sched_domain *sd,
return load_idx;
}

-static unsigned long scale_rt_capacity(int cpu)
+static unsigned long scale_rt_capacity(struct sched_domain *sd, int cpu)
{
struct rq *rq = cpu_rq(cpu);
- unsigned long max = arch_scale_cpu_capacity(NULL, cpu);
+ unsigned long max = arch_scale_cpu_capacity(sd, cpu);
unsigned long used, free;
unsigned long irq;

@@ -7513,7 +7513,7 @@ static unsigned long scale_rt_capacity(int cpu)

static void update_cpu_capacity(struct sched_domain *sd, int cpu)
{
- unsigned long capacity = scale_rt_capacity(cpu);
+ unsigned long capacity = scale_rt_capacity(sd, cpu);
struct sched_group *sdg = sd->groups;

cpu_rq(cpu)->cpu_capacity_orig = arch_scale_cpu_capacity(sd, cpu);