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| author | Mel Gorman <mgorman@techsingularity.net> | 2020-11-20 09:06:28 +0000 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2020-11-24 16:47:47 +0100 |
| commit | 5c339005f854fa75aa46078ad640919425658b3e (patch) | |
| tree | 9cfb55d51ceeda70e6023bd40626a1528f538ebd /kernel/sched/fair.c | |
| parent | abeae76a47005aa3f07c9be12d8076365622e25c (diff) | |
| download | linux-5c339005f854fa75aa46078ad640919425658b3e.tar.gz linux-5c339005f854fa75aa46078ad640919425658b3e.tar.bz2 linux-5c339005f854fa75aa46078ad640919425658b3e.zip | |
sched: Avoid unnecessary calculation of load imbalance at clone time
In find_idlest_group(), the load imbalance is only relevant when the group
is either overloaded or fully busy but it is calculated unconditionally.
This patch moves the imbalance calculation to the context it is required.
Technically, it is a micro-optimisation but really the benefit is avoiding
confusing one type of imbalance with another depending on the group_type
in the next patch.
No functional change.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20201120090630.3286-3-mgorman@techsingularity.net
Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 9d10abe00f72..2626c6bac9f7 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8777,9 +8777,6 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) .group_type = group_overloaded, }; - imbalance = scale_load_down(NICE_0_LOAD) * - (sd->imbalance_pct-100) / 100; - do { int local_group; @@ -8833,6 +8830,11 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) switch (local_sgs.group_type) { case group_overloaded: case group_fully_busy: + + /* Calculate allowed imbalance based on load */ + imbalance = scale_load_down(NICE_0_LOAD) * + (sd->imbalance_pct-100) / 100; + /* * When comparing groups across NUMA domains, it's possible for * the local domain to be very lightly loaded relative to the |