nohz: Select VIRT_CPU_ACCOUNTING_GEN from full dynticks config
Turn the full dynticks passive dependency on VIRT_CPU_ACCOUNTING_GEN
to an active one.
The full dynticks Kconfig is currently hidden behind the full dynticks
cputime accounting, which is an awkward and counter-intuitive layout:
the user first has to select the dynticks cputime accounting in order
to make the full dynticks feature to be visible.
We definetly want it the other way around. The usual way to perform
this kind of active dependency is use "select" on the depended target.
Now we can't use the Kconfig "select" instruction when the target is
a "choice".
So this patch inspires on how the RCU subsystem Kconfig interact
with its dependencies on SMP and PREEMPT: we make sure that cputime
accounting can't propose another option than VIRT_CPU_ACCOUNTING_GEN
when NO_HZ_FULL is selected by using the right "depends on" instruction
for each cputime accounting choices.
v2: Keep full dynticks cputime accounting available even without
full dynticks, as per Paul McKenney's suggestion.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.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>
diff --git a/init/Kconfig b/init/Kconfig
index edc8132..8f97a74 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -306,7 +306,7 @@
# Kind of a stub config for the pure tick based cputime accounting
config TICK_CPU_ACCOUNTING
bool "Simple tick based cputime accounting"
- depends on !S390
+ depends on !S390 && !NO_HZ_FULL
help
This is the basic tick based cputime accounting that maintains
statistics about user, system and idle time spent on per jiffies
@@ -316,7 +316,7 @@
config VIRT_CPU_ACCOUNTING_NATIVE
bool "Deterministic task and CPU time accounting"
- depends on HAVE_VIRT_CPU_ACCOUNTING
+ depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL
select VIRT_CPU_ACCOUNTING
help
Select this option to enable more accurate task and CPU time
@@ -346,7 +346,7 @@
config IRQ_TIME_ACCOUNTING
bool "Fine granularity task level IRQ time accounting"
- depends on HAVE_IRQ_TIME_ACCOUNTING
+ depends on HAVE_IRQ_TIME_ACCOUNTING && !NO_HZ_FULL
help
Select this option to enable fine granularity task irq time
accounting. This is done by reading a timestamp on each