On 01/05/2013 02:07 PM, Alex Shi wrote: > There is 4 situations in the function: > 1, no task allowed group; > so min_load = ULONG_MAX, this_load = 0, idlest = NULL > 2, only local group task allowed; > so min_load = ULONG_MAX, this_load assigned, idlest = NULL > 3, only non-local task group allowed; > so min_load assigned, this_load = 0, idlest != NULL > 4, local group + another group are task allowed. > so min_load assigned, this_load assigned, idlest != NULL > > Current logical will return NULL in first 3 kinds of scenarios. > And still return NULL, if idlest group is heavier then the > local group in the 4th situation. > > Actually, I thought groups in situation 2,3 are also eligible to host > the task. And in 4th situation, agree to bias toward local group. > So, has this patch. > > Signed-off-by: Alex Shi <alex....@intel.com> > --- > kernel/sched/fair.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 6d3a95d..3c7b09a 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -3181,6 +3181,7 @@ find_idlest_group(struct sched_domain *sd, struct > task_struct *p, > int this_cpu, int load_idx) > { > struct sched_group *idlest = NULL, *group = sd->groups; > + struct sched_group *this_group = NULL; > unsigned long min_load = ULONG_MAX, this_load = 0; > int imbalance = 100 + (sd->imbalance_pct-100)/2; > > @@ -3215,14 +3216,19 @@ find_idlest_group(struct sched_domain *sd, struct > task_struct *p, > > if (local_group) { > this_load = avg_load; > - } else if (avg_load < min_load) { > + this_group = group; > + } > + if (avg_load < min_load) { > min_load = avg_load; > idlest = group; > } > } while (group = group->next, group != sd->groups); > > - if (!idlest || 100*this_load < imbalance*min_load) > - return NULL; > + if (this_group && idlest != this_group) > + /* Bias toward our group again */ > + if (100*this_load < imbalance*min_load) > + idlest = this_group; > + > return idlest; > } > Reviewed-by:Preeti U Murthy
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