linux/kernel/sched
Chris Friesen f9c904b761 sched/cputime: Fix steal_account_process_tick() to always return jiffies
The callers of steal_account_process_tick() expect it to return
whether a jiffy should be considered stolen or not.

Currently the return value of steal_account_process_tick() is in
units of cputime, which vary between either jiffies or nsecs
depending on CONFIG_VIRT_CPU_ACCOUNTING_GEN.

If cputime has nsecs granularity and there is a tiny amount of
stolen time (a few nsecs, say) then we will consider the entire
tick stolen and will not account the tick on user/system/idle,
causing /proc/stats to show invalid data.

The fix is to change steal_account_process_tick() to accumulate
the stolen time and only account it once it's worth a jiffy.

(Thanks to Frederic Weisbecker for suggestions to fix a bug in my
first version of the patch.)

Signed-off-by: Chris Friesen <chris.friesen@windriver.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/56DBBDB8.40305@mail.usask.ca
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-08 12:24:56 +01:00
..
auto_group.c sched/core: Move the sched_to_prio[] arrays out of line 2015-12-04 10:34:46 +01:00
auto_group.h sched, timer: Convert usages of ACCESS_ONCE() in the scheduler to READ_ONCE()/WRITE_ONCE() 2015-05-08 12:11:32 +02:00
clock.c Merge branch 'for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2016-01-11 18:53:13 -08:00
completion.c sched/completion: Serialize completion_done() with complete() 2015-02-18 14:27:40 +01:00
core.c sched/deadline: Remove dl_new from struct sched_dl_entity 2016-03-08 12:24:55 +01:00
cpuacct.c cgroup: rename cgroup_subsys->base_cftypes to ->legacy_cftypes 2014-07-15 11:05:09 -04:00
cpuacct.h sched/cpuacct: Initialize root cpuacct earlier 2013-04-10 13:54:20 +02:00
cpudeadline.c sched/deadline: Unify dl_time_before() usage 2015-09-23 09:51:25 +02:00
cpudeadline.h sched/deadline: Unify dl_time_before() usage 2015-09-23 09:51:25 +02:00
cpupri.c Merge commit '3cf2f34' into sched/core, to fix build error 2014-06-12 13:46:37 +02:00
cpupri.h sched/cpupri: Remove unnecessary definitions in cpupri.h 2014-11-16 10:58:59 +01:00
cputime.c sched/cputime: Fix steal_account_process_tick() to always return jiffies 2016-03-08 12:24:56 +01:00
deadline.c sched/deadline: Remove dl_new from struct sched_dl_entity 2016-03-08 12:24:55 +01:00
debug.c sched/debug: Add deadline scheduler bandwidth ratio to /proc/sched_debug 2016-02-29 09:53:07 +01:00
fair.c sched/fair: Consolidate nohz CPU load update code 2016-02-29 09:53:04 +01:00
features.h sched/fair: Convert arch_scale_cpu_capacity() from weak function to #define 2015-09-13 09:52:55 +02:00
idle_task.c sched/fair: Remove empty idle enter and exit functions 2015-11-23 09:37:51 +01:00
idle.c Merge branches 'pm-cpuidle', 'pm-cpufreq', 'pm-domains' and 'pm-sleep' 2016-01-29 21:45:17 +01:00
loadavg.c sched: Move the loadavg code to a more obvious location 2015-05-08 12:04:12 +02:00
Makefile wait.[ch]: Introduce the simple waitqueue (swait) implementation 2016-02-25 11:27:16 +01:00
rt.c sched/rt: Kick RT bandwidth timer immediately on start up 2016-02-29 09:53:07 +01:00
sched.h sched/debug: Move sched_domain_sysctl to debug.c 2016-02-29 09:53:06 +01:00
stats.c sched: use %*pb[l] to print bitmaps including cpumasks and nodemasks 2015-02-13 21:21:37 -08:00
stats.h sched/debug: Make schedstats a runtime tunable that is disabled by default 2016-02-09 11:54:23 +01:00
stop_task.c sched: Make sched_class::set_cpus_allowed() unconditional 2015-08-12 12:06:09 +02:00
swait.c wait.[ch]: Introduce the simple waitqueue (swait) implementation 2016-02-25 11:27:16 +01:00
wait.c sched/wait: Fix the signal handling fix 2015-12-13 14:30:59 -08:00