rcu: Provide RCU CPU stall warnings for tiny RCU

Tiny RCU has historically omitted RCU CPU stall warnings in order to
reduce memory requirements, however, lack of these warnings caused
Thomas Gleixner some debugging pain recently.  Therefore, this commit
adds RCU CPU stall warnings to tiny RCU if RCU_TRACE=y.  This keeps
the memory footprint small, while still enabling CPU stall warnings
in kernels built to enable them.

Updated to include Josh Triplett's suggested use of RCU_STALL_COMMON
config variable to simplify #if expressions.

Reported-by: Thomas Gleixner <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Reviewed-by: Josh Triplett <[email protected]>
This commit is contained in:
Paul E. McKenney 2012-10-19 12:49:17 -07:00 • committed by Paul E. McKenney
commit 6bfc09e232
8 changed files with 130 additions and 51 deletions

View file

@ -486,6 +486,14 @@ config PREEMPT_RCU
This option enables preemptible-RCU code that is common between
the TREE_PREEMPT_RCU and TINY_PREEMPT_RCU implementations.
config RCU_STALL_COMMON
def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE )
help
This option enables RCU CPU stall code that is common between
the TINY and TREE variants of RCU. The purpose is to allow
the tiny variants to disable RCU CPU stall warnings, while
making these warnings mandatory for the tree variants.
config CONTEXT_TRACKING
bool