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authorFrederic Weisbecker <fweisbec@gmail.com>2013-04-26 15:16:31 +0200
committerFrederic Weisbecker <fweisbec@gmail.com>2013-04-26 18:56:59 +0200
commitc58b0df12a6b5c497637db0676effd00e1fbab13 (patch)
treefcceffefccc7c2e33d87406a5e4531c4c613a5ec
parent65e709dc0c25dbd563861924815e9a3a93878b75 (diff)
downloadlinaro-lsk-c58b0df12a6b5c497637db0676effd00e1fbab13.tar.gz
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>
-rw-r--r--init/Kconfig6
-rw-r--r--kernel/time/Kconfig4
2 files changed, 6 insertions, 4 deletions
diff --git a/init/Kconfig b/init/Kconfig
index edc8132584f..8f97a740771 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -306,7 +306,7 @@ choice
# 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 TICK_CPU_ACCOUNTING
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 VIRT_CPU_ACCOUNTING_GEN
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
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index 1ea2bba4a68..a2ddd650cb9 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -104,11 +104,13 @@ config NO_HZ_FULL
depends on SMP
# RCU_USER_QS dependency
depends on HAVE_CONTEXT_TRACKING
- depends on VIRT_CPU_ACCOUNTING_GEN
+ # VIRT_CPU_ACCOUNTING_GEN dependency
+ depends on 64BIT
select NO_HZ_COMMON
select RCU_USER_QS
select RCU_NOCB_CPU
select RCU_NOCB_CPU_ALL
+ select VIRT_CPU_ACCOUNTING_GEN
select CONTEXT_TRACKING_FORCE
select IRQ_WORK
help