Messages in this thread | | | Date | Sun, 27 Jan 2013 21:57:08 +1100 | From | Josh Triplett <> | Subject | Re: [PATCH tip/core/rcu 1/2] rcu: Provide RCU CPU stall warnings for tiny RCU |
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On Sat, Jan 26, 2013 at 04:23:46PM -0800, Paul E. McKenney wrote: > From: "Paul E. McKenney" <paul.mckenney@linaro.org> > > 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 <tglx@linutronix.de> > Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
One suggestion below; with that change, Reviewed-by: Josh Triplett <josh@joshtriplett.org>
> --- a/init/Kconfig > +++ b/init/Kconfig > @@ -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. > + [...] > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -970,7 +970,7 @@ config RCU_TORTURE_TEST_RUNNABLE > > config RCU_CPU_STALL_TIMEOUT > int "RCU CPU stall timeout in seconds" > - depends on TREE_RCU || TREE_PREEMPT_RCU > + depends on TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE
depends on RCU_STALL_COMMON
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