3.4-stable patches

added patches:
	sched-fix-migration-thread-runtime-bogosity.patch

diff --git a/queue-3.4/sched-fix-migration-thread-runtime-bogosity.patch b/queue-3.4/sched-fix-migration-thread-runtime-bogosity.patch
new file mode 100644 (file)
index 0000000..3323485
--- /dev/null
+++ b/queue-3.4/sched-fix-migration-thread-runtime-bogosity.patch
@@ -0,0 +1,86 @@
+From 8f6189684eb4e85e6c593cd710693f09c944450a Mon Sep 17 00:00:00 2001
+From: Mike Galbraith <mgalbraith@suse.de>
+Date: Sat, 4 Aug 2012 05:44:14 +0200
+Subject: sched: Fix migration thread runtime bogosity
+
+From: Mike Galbraith <mgalbraith@suse.de>
+
+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 |   22 +++++++++++++++++++++-
+ 1 file changed, 21 insertions(+), 1 deletion(-)
+
+--- a/kernel/sched/stop_task.c
++++ b/kernel/sched/stop_task.c
+@@ -27,8 +27,10 @@ static struct task_struct *pick_next_tas
+ {
+       struct task_struct *stop = rq->stop;
+ 
+-      if (stop && stop->on_rq)
++      if (stop && stop->on_rq) {
++              stop->se.exec_start = rq->clock_task;
+               return stop;
++      }
+ 
+       return NULL;
+ }
+@@ -52,6 +54,21 @@ static void yield_task_stop(struct rq *r
+ 
+ static void put_prev_task_stop(struct rq *rq, struct task_struct *prev)
+ {
++      struct task_struct *curr = rq->curr;
++      u64 delta_exec;
++
++      delta_exec = rq->clock_task - curr->se.exec_start;
++      if (unlikely((s64)delta_exec < 0))
++              delta_exec = 0;
++
++      schedstat_set(curr->se.statistics.exec_max,
++                      max(curr->se.statistics.exec_max, delta_exec));
++
++      curr->se.sum_exec_runtime += delta_exec;
++      account_group_exec_runtime(curr, delta_exec);
++
++      curr->se.exec_start = rq->clock_task;
++      cpuacct_charge(curr, delta_exec);
+ }
+ 
+ static void task_tick_stop(struct rq *rq, struct task_struct *curr, int queued)
+@@ -60,6 +77,9 @@ static void task_tick_stop(struct rq *rq
+ 
+ static void set_curr_task_stop(struct rq *rq)
+ {
++      struct task_struct *stop = rq->stop;
++
++      stop->se.exec_start = rq->clock_task;
+ }
+ 
+ static void switched_to_stop(struct rq *rq, struct task_struct *p)

diff --git a/queue-3.4/series b/queue-3.4/series
index a8bdf75f539918f78cab1a27285a32e54518ff6b..cd7706deae2efe3fe72d651219b6d2edc608eb7e 100644 (file)
--- a/queue-3.4/series
+++ b/queue-3.4/series
@@ -117,3 +117,4 @@ jffs2-don-t-fail-on-bitflips-in-oob.patch
 cifs-reinstate-the-forcegid-option.patch
 convert-properly-utf-8-to-utf-16.patch
 udf-fix-retun-value-on-error-path-in-udf_load_logicalvol.patch
+sched-fix-migration-thread-runtime-bogosity.patch