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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2012-04-17 13:38:40 +0200
committerIngo Molnar <mingo@kernel.org>2012-04-26 12:54:52 +0200
commiteb95308ee2a69403909e111837b9068c64cfc349 (patch)
tree92e9a3368e75b94486dc54f2688453fed17d4eed /kernel/sched/features.h
parent2300fd67b4f29eec19addb15a8571837228f63fc (diff)
sched: Fix more load-balancing fallout
Commits 367456c756a6 ("sched: Ditch per cgroup task lists for load-balancing") and 5d6523ebd ("sched: Fix load-balance wreckage") left some more wreckage. By setting loop_max unconditionally to ->nr_running load-balancing could take a lot of time on very long runqueues (hackbench!). So keep the sysctl as max limit of the amount of tasks we'll iterate. Furthermore, the min load filter for migration completely fails with cgroups since inequality in per-cpu state can easily lead to such small loads :/ Furthermore the change to add new tasks to the tail of the queue instead of the head seems to have some effect.. not quite sure I understand why. Combined these fixes solve the huge hackbench regression reported by Tim when hackbench is ran in a cgroup. Reported-by: Tim Chen <tim.c.chen@linux.intel.com> Acked-by: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1335365763.28150.267.camel@twins [ got rid of the CONFIG_PREEMPT tuning and made small readability edits ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/features.h')
-rw-r--r--kernel/sched/features.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
index e61fd73913d..de00a486c5c 100644
--- a/kernel/sched/features.h
+++ b/kernel/sched/features.h
@@ -68,3 +68,4 @@ SCHED_FEAT(TTWU_QUEUE, true)
SCHED_FEAT(FORCE_SD_OVERLAP, false)
SCHED_FEAT(RT_RUNTIME_SHARE, true)
+SCHED_FEAT(LB_MIN, false)