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Subject[tip:sched/core] sched: Allow all architectures to set ' capacity_orig'
Commit-ID:  26bc3c50d3b3984564c270da86f1fbbfb774dbcd
Gitweb: http://git.kernel.org/tip/26bc3c50d3b3984564c270da86f1fbbfb774dbcd
Author: Vincent Guittot <vincent.guittot@linaro.org>
AuthorDate: Tue, 26 Aug 2014 13:06:47 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 19 Sep 2014 12:35:27 +0200

sched: Allow all architectures to set 'capacity_orig'

'capacity_orig' is only changed for systems with an SMT sched_domain level in order
to reflect the lower capacity of CPUs. Heterogenous systems also have to reflect an
original capacity that is different from the default value.

Create a more generic function arch_scale_cpu_capacity that can be also used by
non SMT platforms to set capacity_orig.

The __weak implementation of arch_scale_cpu_capacity() is the previous SMT variant,
in order to keep backward compatibility with the use of capacity_orig.

arch_scale_smt_capacity() and default_scale_smt_capacity() have been removed as
they were not used elsewhere than in arch_scale_cpu_capacity().

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Reviewed-by: Preeti U. Murthy <preeti@linux.vnet.ibm.com>
[ Added default_scale_cpu_capacity() back. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: riel@redhat.com
Cc: Morten.Rasmussen@arm.com
Cc: efault@gmx.de
Cc: nicolas.pitre@linaro.org
Cc: daniel.lezcano@linaro.org
Cc: dietmar.eggemann@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409051215-16788-5-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/sched/fair.c | 27 +++++++++++----------------
1 file changed, 11 insertions(+), 16 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index eb87229..be530e4 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5705,19 +5705,17 @@ unsigned long __weak arch_scale_freq_capacity(struct sched_domain *sd, int cpu)
return default_scale_capacity(sd, cpu);
}

-static unsigned long default_scale_smt_capacity(struct sched_domain *sd, int cpu)
+static unsigned long default_scale_cpu_capacity(struct sched_domain *sd, int cpu)
{
- unsigned long weight = sd->span_weight;
- unsigned long smt_gain = sd->smt_gain;
+ if ((sd->flags & SD_SHARE_CPUCAPACITY) && (sd->span_weight > 1))
+ return sd->smt_gain / sd->span_weight;

- smt_gain /= weight;
-
- return smt_gain;
+ return SCHED_CAPACITY_SCALE;
}

-unsigned long __weak arch_scale_smt_capacity(struct sched_domain *sd, int cpu)
+unsigned long __weak arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
{
- return default_scale_smt_capacity(sd, cpu);
+ return default_scale_cpu_capacity(sd, cpu);
}

static unsigned long scale_rt_capacity(int cpu)
@@ -5756,18 +5754,15 @@ static unsigned long scale_rt_capacity(int cpu)

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

- if ((sd->flags & SD_SHARE_CPUCAPACITY) && weight > 1) {
- if (sched_feat(ARCH_CAPACITY))
- capacity *= arch_scale_smt_capacity(sd, cpu);
- else
- capacity *= default_scale_smt_capacity(sd, cpu);
+ if (sched_feat(ARCH_CAPACITY))
+ capacity *= arch_scale_cpu_capacity(sd, cpu);
+ else
+ capacity *= default_scale_cpu_capacity(sd, cpu);

- capacity >>= SCHED_CAPACITY_SHIFT;
- }
+ capacity >>= SCHED_CAPACITY_SHIFT;

sdg->sgc->capacity_orig = capacity;


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