sched: Always initialize cpu-power
Commit-ID: c3decf0dfbc95736b7c0ab68fa4e5854c4734da9 Gitweb: http://git.kernel.org/tip/c3decf0dfbc95736b7c0ab68fa4e5854c4734da9 Author: Peter Zijlstra <[email protected]> AuthorDate: Thu, 31 May 2012 12:05:32 +0200 Committer: Ingo Molnar <[email protected]> CommitDate: Wed, 6 Jun 2012 16:52:27 +0200
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 <[email protected]>
Signed-off-by Ingo Molnar <[email protected]>
--- kernel/sched/core.c | 13 ++++++++++++- kernel/sched/fair.c | 2 +- 2 files changed, 13 insertions(+), 2 deletions(-)
kernel/sched/core.c +12 -1
@@ -5604,7 +5604,12 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,break ; } -if (!group->sgp->power) { +/* +* Even though we initialize ->power to something semi-sane, +* we leave power_orig unset. This allows us to detect if +* domain iteration is still funny without causing /0 traps. +*/ +if (!group->sgp->power_orig) {printk (KERN_CONT "\n" );printk (KERN_ERR "ERROR: domain->cpu_power not " "set\n" );
@@ -6075,6 +6080,12 @@ build_overlap_sched_groups(struct sched_domain *sd, int cpu)if (atomic_inc_return (&sg->sgp->ref) ==1 )build_group_mask (sd, sg); +/* +* Initialize sgp->power such that even if we mess up the +* domains and no possible iteration will get us here, we won't +* die on a /0 trap. +*/ + sg->sgp->power =SCHED_POWER_SCALE *cpumask_weight (sg_span);/* * Make sure the first group of this domain contains the
kernel/sched/fair.c +1 -1
@@ -3602,7 +3602,7 @@ void update_group_power(struct sched_domain *sd, int cpu) }while (group != child->groups); } - sdg->sgp->power = power; + sdg->sgp->power_orig = sdg->sgp->power = power; }/*