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| author | Li Zefan <lizf@cn.fujitsu.com> | 2008-11-06 09:45:16 +0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-11-07 08:29:57 +0100 |
| commit | f29c9b1ccb52904ee442a933cf3dee628f9f4e62 (patch) | |
| tree | 836b4383a89a5aac64e50afd752a48b4bb0c167a | |
| parent | 4bab0ea1d42dd1927af9df6fbf0003fc00617c50 (diff) | |
| download | talos-op-linux-f29c9b1ccb52904ee442a933cf3dee628f9f4e62.tar.gz talos-op-linux-f29c9b1ccb52904ee442a933cf3dee628f9f4e62.zip | |
sched: fix a bug in sched domain degenerate
Impact: re-add incorrectly eliminated sched domain layers
(1) on i386 with SCHED_SMT and SCHED_MC enabled
# mount -t cgroup -o cpuset xxx /mnt
# echo 0 > /mnt/cpuset.sched_load_balance
# mkdir /mnt/0
# echo 0 > /mnt/0/cpuset.cpus
# dmesg
CPU0 attaching sched-domain:
domain 0: span 0 level CPU
groups: 0
(2) on i386 with SCHED_MC enabled but SCHED_SMT disabled
# same with (1)
# dmesg
CPU0 attaching NULL sched-domain.
The bug is that some sched domains may be skipped unintentionally when
degenerating (optimizing) sched domains.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/sched.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 82cc839c9210..4c7e2bcdfa89 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6877,15 +6877,17 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) struct sched_domain *tmp; /* Remove the sched domains which do not contribute to scheduling. */ - for (tmp = sd; tmp; tmp = tmp->parent) { + for (tmp = sd; tmp; ) { struct sched_domain *parent = tmp->parent; if (!parent) break; + if (sd_parent_degenerate(tmp, parent)) { tmp->parent = parent->parent; if (parent->parent) parent->parent->child = tmp; - } + } else + tmp = tmp->parent; } if (sd && sd_degenerate(sd)) { |
