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Commit c58b0df1 authored by Frederic Weisbecker's avatar Frederic Weisbecker
Browse files

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: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarFrederic 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>
parent 65e709dc

init/Kconfig

+3 −3
Original line number Original line Diff line number Diff line
@@ -306,7 +306,7 @@ choice 
# Kind of a stub config for the pure tick based cputime accounting

# Kind of a stub config for the pure tick based cputime accounting

config TICK_CPU_ACCOUNTING

config TICK_CPU_ACCOUNTING

	bool "Simple tick based cputime accounting"

	bool "Simple tick based cputime accounting"

	depends on !S390

	depends on !S390 && !NO_HZ_FULL

	help

	help

	  This is the basic tick based cputime accounting that maintains

	  This is the basic tick based cputime accounting that maintains

	  statistics about user, system and idle time spent on per jiffies

	  statistics about user, system and idle time spent on per jiffies
@@ -316,7 +316,7 @@ config TICK_CPU_ACCOUNTING 




config VIRT_CPU_ACCOUNTING_NATIVE

config VIRT_CPU_ACCOUNTING_NATIVE

	bool "Deterministic task and CPU time accounting"

	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

	select VIRT_CPU_ACCOUNTING

	help

	help

	  Select this option to enable more accurate task and CPU time

	  Select this option to enable more accurate task and CPU time
@@ -346,7 +346,7 @@ config VIRT_CPU_ACCOUNTING_GEN 




config IRQ_TIME_ACCOUNTING

config IRQ_TIME_ACCOUNTING

	bool "Fine granularity task level 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

	help

	  Select this option to enable fine granularity task irq time

	  Select this option to enable fine granularity task irq time

	  accounting. This is done by reading a timestamp on each

	  accounting. This is done by reading a timestamp on each

kernel/time/Kconfig

+3 −1
Original line number Original line Diff line number Diff line
@@ -104,11 +104,13 @@ config NO_HZ_FULL 
	depends on SMP

	depends on SMP

	# RCU_USER_QS dependency

	# RCU_USER_QS dependency

	depends on HAVE_CONTEXT_TRACKING

	depends on HAVE_CONTEXT_TRACKING

	depends on VIRT_CPU_ACCOUNTING_GEN

	# VIRT_CPU_ACCOUNTING_GEN dependency

	depends on 64BIT

	select NO_HZ_COMMON

	select NO_HZ_COMMON

	select RCU_USER_QS

	select RCU_USER_QS

	select RCU_NOCB_CPU

	select RCU_NOCB_CPU

	select RCU_NOCB_CPU_ALL

	select RCU_NOCB_CPU_ALL

	select VIRT_CPU_ACCOUNTING_GEN

	select CONTEXT_TRACKING_FORCE

	select CONTEXT_TRACKING_FORCE

	select IRQ_WORK

	select IRQ_WORK

	help

	help