context_tracking: Optimize guest APIs off case with static key
Optimize guest entry/exit APIs with static keys. This minimize
the overhead for those who enable CONFIG_NO_HZ_FULL without
always using it. Having no range passed to nohz_full= should
result in the probes overhead to be minimized.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kevin Hilman <khilman@linaro.org>
diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index 38ab60b..8854ead 100644
--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -95,8 +95,23 @@
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
-extern void guest_enter(void);
-extern void guest_exit(void);
+static inline void guest_enter(void)
+{
+ if (static_key_false(&context_tracking_enabled) &&
+ vtime_accounting_enabled())
+ vtime_guest_enter(current);
+ else
+ current->flags |= PF_VCPU;
+}
+
+static inline void guest_exit(void)
+{
+ if (static_key_false(&context_tracking_enabled) &&
+ vtime_accounting_enabled())
+ vtime_guest_exit(current);
+ else
+ current->flags &= ~PF_VCPU;
+}
#else
static inline void guest_enter(void)
{