Commit 3e70df91 authored by Paul Gortmaker's avatar Paul Gortmaker Committed by Paul E. McKenney
Browse files

rcu: deprecate "all" option to rcu_nocbs= 



With the core bitmap support now accepting "N" as a placeholder for
the end of the bitmap, "all" can be represented as "0-N" and has the
advantage of not being specific to RCU (or any other subsystem).

So deprecate the use of "all" by removing documentation references
to it.  The support itself needs to remain for now, since we don't
know how many people out there are using it currently, but since it
is in an __init area anyway, it isn't worth losing sleep over.

Cc: Yury Norov <yury.norov@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Acked-by: default avatarYury Norov <yury.norov@gmail.com>
Signed-off-by: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 99c58d1a

Documentation/admin-guide/kernel-parameters.txt

+1 −3
Original line number Diff line number Diff line
@@ -4068,9 +4068,7 @@ 
				see CONFIG_RAS_CEC help text.



	rcu_nocbs=	[KNL]

			The argument is a cpu list, as described above,

			except that the string "all" can be used to

			specify every CPU on the system.

			The argument is a cpu list, as described above.



			In kernels built with CONFIG_RCU_NOCB_CPU=y, set

			the specified list of CPUs to be no-callback CPUs.

kernel/rcu/tree_plugin.h

+2 −4
Original line number Diff line number Diff line
@@ -1464,14 +1464,12 @@ static void rcu_cleanup_after_idle(void) 


/*

 * Parse the boot-time rcu_nocb_mask CPU list from the kernel parameters.

 * The string after the "rcu_nocbs=" is either "all" for all CPUs, or a

 * comma-separated list of CPUs and/or CPU ranges.  If an invalid list is

 * given, a warning is emitted and all CPUs are offloaded.

 * If the list is invalid, a warning is emitted and all CPUs are offloaded.

 */

static int __init rcu_nocb_setup(char *str)

{

	alloc_bootmem_cpumask_var(&rcu_nocb_mask);

	if (!strcasecmp(str, "all"))

	if (!strcasecmp(str, "all"))		/* legacy: use "0-N" instead */

		cpumask_setall(rcu_nocb_mask);

	else

		if (cpulist_parse(str, rcu_nocb_mask)) {