diff options
| author | Li Zefan <lizf@cn.fujitsu.com> | 2008-11-06 09:45:16 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-12-13 15:29:30 -0800 |
| commit | 1c03c0828f200dfde456836fe69febb72979b5c7 (patch) | |
| tree | 821bb7b5c30e60cda866bc93cfc02eb9b341f738 /kernel | |
| parent | 8695c0e41ee6fcfce99b7335565d6b1a2e2fbda8 (diff) | |
sched: fix a bug in sched domain degenerate
commit f29c9b1ccb52904ee442a933cf3dee628f9f4e62 upstream.
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>
Cc: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'kernel')
| -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 a992cbe01c7..719f8ba2c35 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6802,15 +6802,17 @@ 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)) { |