cputime: Safely read cputime of full dynticks CPUs
While remotely reading the cputime of a task running in a
full dynticks CPU, the values stored in utime/stime fields
of struct task_struct may be stale. Its values may be those
of the last kernel <-> user transition time snapshot and
we need to add the tickless time spent since this snapshot.
To fix this, flush the cputime of the dynticks CPUs on
kernel <-> user transition and record the time / context
where we did this. Then on top of this snapshot and the current
time, perform the fixup on the reader side from task_times()
accessors.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
[fixed kvm module related build errors]
Signed-off-by: Sedat Dilek <sedat.dilek@gmail.com>
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index 624ef3f..7105d5c 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -153,7 +153,7 @@
*/
#define __irq_enter() \
do { \
- vtime_account_irq_enter(current); \
+ account_irq_enter_time(current); \
add_preempt_count(HARDIRQ_OFFSET); \
trace_hardirq_enter(); \
} while (0)
@@ -169,7 +169,7 @@
#define __irq_exit() \
do { \
trace_hardirq_exit(); \
- vtime_account_irq_exit(current); \
+ account_irq_exit_time(current); \
sub_preempt_count(HARDIRQ_OFFSET); \
} while (0)
