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authorFrederic Weisbecker <fweisbec@gmail.com>2013-07-24 21:59:29 +0200
committerFrederic Weisbecker <fweisbec@gmail.com>2013-08-13 00:54:34 +0200
commitd84d27a491880b9902b45c09be8d9e9464fb9b74 (patch)
tree42d5c777dba71b3cfb119d918ff5ae90f4d8a20c /init
parent2e70933866ace52091a3c11a5c104c063ab0c445 (diff)
downloadlinux-d84d27a491880b9902b45c09be8d9e9464fb9b74.tar.gz
context_tracking: Remove full dynticks' hacky dependency on wide context tracking
Now that the full dynticks subsystem only enables the context tracking on full dynticks CPUs, lets remove the dependency on CONTEXT_TRACKING_FORCE This dependency was a hack to enable the context tracking widely for the full dynticks susbsystem until the latter becomes able to enable it in a more CPU-finegrained fashion. Now CONTEXT_TRACKING_FORCE only stands for testing on archs that work on support for the context tracking while full dynticks can't be used yet due to unmet dependencies. It simulates a system where all CPUs are full dynticks so that RCU user extended quiescent states and dynticks cputime accounting can be tested on the given arch. 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>
Diffstat (limited to 'init')
-rw-r--r--init/Kconfig28
1 files changed, 22 insertions, 6 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 247084be059..ffbf5d788bf 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -527,13 +527,29 @@ config RCU_USER_QS
config CONTEXT_TRACKING_FORCE
bool "Force context tracking"
depends on CONTEXT_TRACKING
- default CONTEXT_TRACKING
+ default y if !NO_HZ_FULL
help
- Probe on user/kernel boundaries by default in order to
- test the features that rely on it such as userspace RCU extended
- quiescent states.
- This test is there for debugging until we have a real user like the
- full dynticks mode.
+ The major pre-requirement for full dynticks to work is to
+ support the context tracking subsystem. But there are also
+ other dependencies to provide in order to make the full
+ dynticks working.
+
+ This option stands for testing when an arch implements the
+ context tracking backend but doesn't yet fullfill all the
+ requirements to make the full dynticks feature working.
+ Without the full dynticks, there is no way to test the support
+ for context tracking and the subsystems that rely on it: RCU
+ userspace extended quiescent state and tickless cputime
+ accounting. This option copes with the absence of the full
+ dynticks subsystem by forcing the context tracking on all
+ CPUs in the system.
+
+ Say Y only if you're working on the developpement of an
+ architecture backend for the context tracking.
+
+ Say N otherwise, this option brings an overhead that you
+ don't want in production.
+
config RCU_FANOUT
int "Tree-based hierarchical RCU fanout value"