On Fri, 28 Apr 2017, Paul E. McKenney wrote: > Hello, Nicolas! > > Saw the TTY write up LWN and figured I should send this your way. > It should be worth about 2K compared to current -next, which gave > up the 2K compared to v4.10. So really getting things back to where > they were. > > My current plan is to push this into v4.13.
Excellent! If every maintainer finds a way to (optionally) reduce the size of the code they maintain by 2K then we'll get a much smaller kernel pretty soon. > > Thanx, Paul > > ------------------------------------------------------------------------ > > commit e01ef0529ed548c1b30206058c2b5eecbbc07998 > Author: Paul E. McKenney <paul...@linux.vnet.ibm.com> > Date: Fri Apr 28 13:53:04 2017 -0700 > > srcu: Make SRCU be once again optional > > Commit d160a727c40e ("srcu: Make SRCU be built by default") in response > to build errors, which were caused by code that included srcu.h > despite !SRCU. However, srcutiny.o is almost 2K of code, which is not > insignificant for those attempting to run the Linux kernel on IoT devices. > This commit therefore makes SRCU be once again optional, and adjusts > srcu.h to allow error-free inclusion in !SRCU kernel builds. > > Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com> > Cc: Nicolas Pitre <nicolas.pi...@linaro.org> Acked-by: Nicolas Pitre <n...@linaro.org> > > diff --git a/include/linux/srcu.h b/include/linux/srcu.h > index 167ad8831aaf..c0143fe2e39d 100644 > --- a/include/linux/srcu.h > +++ b/include/linux/srcu.h > @@ -62,7 +62,7 @@ int init_srcu_struct(struct srcu_struct *sp); > #include <linux/srcutree.h> > #elif defined(CONFIG_CLASSIC_SRCU) > #include <linux/srcuclassic.h> > -#else > +#elif defined(CONFIG_SRCU) > #error "Unknown SRCU implementation specified to kernel configuration" > #endif > > diff --git a/init/Kconfig b/init/Kconfig > index 42a346b0df43..fe72c12e06a5 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -521,7 +521,6 @@ config RCU_EXPERT > > config SRCU > bool > - default y > help > This option selects the sleepable version of RCU. This version > permits arbitrary sleeping or blocking within RCU read-side critical > >