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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2012-05-31 06:05:32 -0400
committerIngo Molnar <mingo@kernel.org>2012-06-06 10:52:27 -0400
commitc3decf0dfbc95736b7c0ab68fa4e5854c4734da9 (patch)
treec21748af2b4c7e4b738cefd2076c1ccc6ed2c664 /kernel/sched
parentc1174876874dcf8986806e4dad3d7d07af20b439 (diff)
sched: Always initialize cpu-power
Often when we run into mis-shapen topologies the balance iteration fails to update the cpu power properly and we'll end up in /0 traps. Always initialize the cpu-power to a semi-sane value so that we can at least boot the machine, even if the load-balancer might not function correctly. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-3lbhyj25sr169ha7z3qht5na@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/core.c13
-rw-r--r--kernel/sched/fair.c2
2 files changed, 13 insertions, 2 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 781acb91a50a..725ee7c1c8cf 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5604,7 +5604,12 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
5604 break; 5604 break;
5605 } 5605 }
5606 5606
5607 if (!group->sgp->power) { 5607 /*
5608 * Even though we initialize ->power to something semi-sane,
5609 * we leave power_orig unset. This allows us to detect if
5610 * domain iteration is still funny without causing /0 traps.
5611 */
5612 if (!group->sgp->power_orig) {
5608 printk(KERN_CONT "\n"); 5613 printk(KERN_CONT "\n");
5609 printk(KERN_ERR "ERROR: domain->cpu_power not " 5614 printk(KERN_ERR "ERROR: domain->cpu_power not "
5610 "set\n"); 5615 "set\n");
@@ -6075,6 +6080,12 @@ build_overlap_sched_groups(struct sched_domain *sd, int cpu)
6075 if (atomic_inc_return(&sg->sgp->ref) == 1) 6080 if (atomic_inc_return(&sg->sgp->ref) == 1)
6076 build_group_mask(sd, sg); 6081 build_group_mask(sd, sg);
6077 6082
6083 /*
6084 * Initialize sgp->power such that even if we mess up the
6085 * domains and no possible iteration will get us here, we won't
6086 * die on a /0 trap.
6087 */
6088 sg->sgp->power = SCHED_POWER_SCALE * cpumask_weight(sg_span);
6078 6089
6079 /* 6090 /*
6080 * Make sure the first group of this domain contains the 6091 * Make sure the first group of this domain contains the
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 54cbaa4e7b37..c9fd6d673d05 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3602,7 +3602,7 @@ void update_group_power(struct sched_domain *sd, int cpu)
3602 } while (group != child->groups); 3602 } while (group != child->groups);
3603 } 3603 }
3604 3604
3605 sdg->sgp->power = power; 3605 sdg->sgp->power_orig = sdg->sgp->power = power;
3606} 3606}
3607 3607
3608/* 3608/*