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| author | Frederic Weisbecker <fweisbec@gmail.com> | 2012-12-16 20:00:34 +0100 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2013-01-27 20:35:47 +0100 |
| commit | 6a61671bb2f3a1bd12cd17b8fca811a624782632 (patch) | |
| tree | 0afc2915fb7e517472710a49a524510322dd5baa /kernel/context_tracking.c | |
| parent | kvm: Prepare to add generic guest entry/exit callbacks (diff) | |
| download | linux-6a61671bb2f3a1bd12cd17b8fca811a624782632.tar.xz linux-6a61671bb2f3a1bd12cd17b8fca811a624782632.zip | |
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>
Diffstat (limited to 'kernel/context_tracking.c')
| -rw-r--r-- | kernel/context_tracking.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c index 9002e92e6372..74f68f4dc6c2 100644 --- a/kernel/context_tracking.c +++ b/kernel/context_tracking.c @@ -1,8 +1,9 @@ #include <linux/context_tracking.h> +#include <linux/kvm_host.h> #include <linux/rcupdate.h> #include <linux/sched.h> #include <linux/hardirq.h> - +#include <linux/export.h> DEFINE_PER_CPU(struct context_tracking, context_tracking) = { #ifdef CONFIG_CONTEXT_TRACKING_FORCE @@ -61,6 +62,24 @@ void user_exit(void) local_irq_restore(flags); } +void guest_enter(void) +{ + if (vtime_accounting_enabled()) + vtime_guest_enter(current); + else + __guest_enter(); +} +EXPORT_SYMBOL_GPL(guest_enter); + +void guest_exit(void) +{ + if (vtime_accounting_enabled()) + vtime_guest_exit(current); + else + __guest_exit(); +} +EXPORT_SYMBOL_GPL(guest_exit); + void context_tracking_task_switch(struct task_struct *prev, struct task_struct *next) { |