sched: Fix migration thread runtime bogosity
authorMike Galbraith <mgalbraith@suse.de>
Sat, 4 Aug 2012 03:44:14 +0000 (05:44 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 12 Oct 2012 20:39:01 +0000 (05:39 +0900)
commit93875bc33f71bf7a4851b44d387743866b13b130
treecb2efc3120da03ba6bddefd3f8b8eddc1dc91c21
parente08ea4c7d4e90aab75307c3c8018d2d4bbeebc0b
sched: Fix migration thread runtime bogosity

commit 8f6189684eb4e85e6c593cd710693f09c944450a upstream.

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>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kernel/sched/stop_task.c