|author||Frederic Weisbecker <firstname.lastname@example.org>||2012-11-27 19:33:25 +0100|
|committer||Paul E. McKenney <email@example.com>||2012-11-30 11:40:07 -0800|
context_tracking: New context tracking susbsystem
Create a new subsystem that probes on kernel boundaries to keep track of the transitions between level contexts with two basic initial contexts: user or kernel. This is an abstraction of some RCU code that use such tracking to implement its userspace extended quiescent state. We need to pull this up from RCU into this new level of indirection because this tracking is also going to be used to implement an "on demand" generic virtual cputime accounting. A necessary step to shutdown the tick while still accounting the cputime. Signed-off-by: Frederic Weisbecker <firstname.lastname@example.org> Cc: Andrew Morton <email@example.com> Cc: H. Peter Anvin <firstname.lastname@example.org> Cc: Ingo Molnar <email@example.com> Cc: Paul E. McKenney <firstname.lastname@example.org> Cc: Peter Zijlstra <email@example.com> Cc: Steven Rostedt <firstname.lastname@example.org> Cc: Thomas Gleixner <email@example.com> Cc: Li Zhong <firstname.lastname@example.org> Cc: Gilad Ben-Yossef <email@example.com> Reviewed-by: Steven Rostedt <firstname.lastname@example.org> [ paulmck: fix whitespace error and email address. ] Signed-off-by: Paul E. McKenney <email@example.com>
Diffstat (limited to 'init')
1 files changed, 14 insertions, 14 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 5ac6ee09422..2054e048bb9 100644
@@ -486,9 +486,13 @@ config PREEMPT_RCU
This option enables preemptible-RCU code that is common between
the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
bool "Consider userspace as in RCU extended quiescent state"
- depends on HAVE_RCU_USER_QS && SMP
+ depends on HAVE_CONTEXT_TRACKING && SMP
+ select CONTEXT_TRACKING
This option sets hooks on kernel / userspace boundaries and
puts RCU in extended quiescent state when the CPU runs in
@@ -497,24 +501,20 @@ config RCU_USER_QS
try to keep the timer tick on for RCU.
Unless you want to hack and help the development of the full
- tickless feature, you shouldn't enable this option. It also
+ dynticks mode, you shouldn't enable this option. It also
adds unnecessary overhead.
If unsure say N
- bool "Force userspace extended QS by default"
- depends on RCU_USER_QS
+ bool "Force context tracking"
+ depends on CONTEXT_TRACKING
- Set the hooks in user/kernel boundaries by default in order to
- test this feature that treats userspace as an extended quiescent
- state until we have a real user like a full adaptive nohz option.
- Unless you want to hack and help the development of the full
- tickless feature, you shouldn't enable this option. It adds
- unnecessary overhead.
- If unsure say N
+ 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.
int "Tree-based hierarchical RCU fanout value"