[tip:sched/urgent] sched: Fix migration thread runtime bogosity

tip-bot for Mike Galbraith
2012-08-13T16:54:20Z

Commit-ID: 8f6189684eb4e85e6c593cd710693f09c944450a
Gitweb: http://git.kernel.org/tip/8f6189684eb4e85e6c593cd710693f09c944450a
Author: Mike Galbraith <mgalbraith@suse.de>
AuthorDate: Sat, 4 Aug 2012 05:44:14 +0200
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Mon, 13 Aug 2012 18:41:55 +0200

sched: Fix migration thread runtime bogosity

Make stop scheduler class do the same accounting as other classes,

Migration threads can be caught in the act while doing exec balancing,
leading to the below due to use of unmaintained ->se.exec_start. The
load that triggered this particular instance was an apparently out of
control heavily threaded application that does system monitoring in
what equated to an exec bomb, with one of the VERY frequently migrated
tasks being ps.

%CPU PID USER CMD
99.3 45 root [migration/10]
97.7 53 root [migration/12]
97.0 57 root [migration/13]
90.1 49 root [migration/11]
89.6 65 root [migration/15]
88.7 17 root [migration/3]
80.4 37 root [migration/8]
78.1 41 root [migration/9]
44.2 13 root [migration/2]

Signed-off-by: Mike Galbraith <mgalbraith@suse.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1344051854.6739.19.camel@marge.simpson.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/sched/stop_task.c | 22 +++++++++++++++++++++-
1 files changed, 21 insertions(+), 1 deletions(-)