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| author | Frederic Weisbecker <fweisbec@gmail.com> | 2013-07-24 21:59:29 +0200 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2013-08-13 00:54:34 +0200 |
| commit | d84d27a491880b9902b45c09be8d9e9464fb9b74 (patch) | |
| tree | 42d5c777dba71b3cfb119d918ff5ae90f4d8a20c /init/Kconfig | |
| parent | nohz: Only enable context tracking on full dynticks CPUs (diff) | |
| download | linux-d84d27a491880b9902b45c09be8d9e9464fb9b74.tar.xz linux-d84d27a491880b9902b45c09be8d9e9464fb9b74.zip | |
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/Kconfig')
| -rw-r--r-- | init/Kconfig | 28 |
1 files changed, 22 insertions, 6 deletions
diff --git a/init/Kconfig b/init/Kconfig index 247084be0590..ffbf5d788bf3 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" |