From cc57aa8f4b3bece8c26c7929728edcc5fa6b5aed Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 21 Feb 2011 18:55:32 +0100 Subject: sched: Clean up some f_b_g() comments The existing comment tends to grow state (as it already has), split it up and place it near the actual tests. Signed-off-by: Peter Zijlstra Cc: Nikhil Rao Cc: Venkatesh Pallipadi Cc: Suresh Siddha Cc: Mike Galbraith LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 28 +++++++++++++--------------- 1 file changed, 13 insertions(+), 15 deletions(-) (limited to 'kernel/sched_fair.c') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index cd18600..03496eb 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -3113,19 +3113,9 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, */ update_sd_lb_stats(sd, this_cpu, idle, cpus, balance, &sds); - /* Cases where imbalance does not exist from POV of this_cpu */ - /* 1) this_cpu is not the appropriate cpu to perform load balancing - * at this level. - * 2) There is no busy sibling group to pull from. - * 3) This group is the busiest group. - * 4) This group is more busy than the avg busieness at this - * sched_domain. - * 5) The imbalance is within the specified limit. - * - * Note: when doing newidle balance, if the local group has excess - * capacity (i.e. nr_running < group_capacity) and the busiest group - * does not have any capacity, we force a load balance to pull tasks - * to the local group. In this case, we skip past checks 3, 4 and 5. + /* + * this_cpu is not the appropriate cpu to perform load balancing at + * this level. */ if (!(*balance)) goto ret; @@ -3134,19 +3124,27 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, check_asym_packing(sd, &sds, this_cpu, imbalance)) return sds.busiest; + /* There is no busy sibling group to pull tasks from */ if (!sds.busiest || sds.busiest_nr_running == 0) goto out_balanced; - /* SD_BALANCE_NEWIDLE trumps SMP nice when underutilized */ + /* SD_BALANCE_NEWIDLE trumps SMP nice when underutilized */ if (idle == CPU_NEWLY_IDLE && sds.this_has_capacity && !sds.busiest_has_capacity) goto force_balance; + /* + * If the local group is more busy than the selected busiest group + * don't try and pull any tasks. + */ if (sds.this_load >= sds.max_load) goto out_balanced; + /* + * Don't pull any tasks if this group is already above the domain + * average load. + */ sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr; - if (sds.this_load >= sds.avg_load) goto out_balanced; -- cgit v1.1