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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2012-05-31 12:05:32 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-06-06 16:52:27 +0200 |
| commit | c3decf0dfbc95736b7c0ab68fa4e5854c4734da9 (patch) | |
| tree | c21748af2b4c7e4b738cefd2076c1ccc6ed2c664 /kernel | |
| parent | c1174876874dcf8986806e4dad3d7d07af20b439 (diff) | |
| download | lwn-c3decf0dfbc95736b7c0ab68fa4e5854c4734da9.tar.gz lwn-c3decf0dfbc95736b7c0ab68fa4e5854c4734da9.zip | |
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')
| -rw-r--r-- | kernel/sched/core.c | 13 | ||||
| -rw-r--r-- | kernel/sched/fair.c | 2 |
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, 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 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) } while (group != child->groups); } - sdg->sgp->power = power; + sdg->sgp->power_orig = sdg->sgp->power = power; } /* |