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authorPaul E. McKenney <paul.mckenney@linaro.org>2013-02-11 10:23:27 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2013-03-26 08:04:43 -0700
commit911af505ef407c2511106c224dd640f882f0f590 (patch)
tree00656ef4be8d1195a568951333dd9618265c6435 /init
parent34ed62461ae4970695974afb9a60ac3df0086830 (diff)
downloadvexpress-lsk-911af505ef407c2511106c224dd640f882f0f590.tar.gz
rcu: Provide compile-time control for no-CBs CPUs
Currently, the only way to specify no-CBs CPUs is via the rcu_nocbs kernel command-line parameter. This is inconvenient in some cases, particularly for randconfig testing, so this commit adds a new set of kernel configuration parameters. CONFIG_RCU_NOCB_CPU_NONE (the default) retains the old behavior, CONFIG_RCU_NOCB_CPU_ZERO offloads callback processing from CPU 0 (along with any other CPUs specified by the rcu_nocbs boot-time parameter), and CONFIG_RCU_NOCB_CPU_ALL offloads callback processing from all CPUs. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'init')
-rw-r--r--init/Kconfig39
1 files changed, 39 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig
index c8bd349eb63..30749970458 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -676,6 +676,45 @@ config RCU_NOCB_CPU
Say Y here if you want to help to debug reduced OS jitter.
Say N here if you are unsure.
+choice
+ prompt "Build-forced no-CBs CPUs"
+ default RCU_NOCB_CPU_NONE
+ help
+ This option allows no-CBs CPUs to be specified at build time.
+ Additional no-CBs CPUs may be specified by the rcu_nocbs=
+ boot parameter.
+
+config RCU_NOCB_CPU_NONE
+ bool "No build_forced no-CBs CPUs"
+ depends on RCU_NOCB_CPU
+ help
+ This option does not force any of the CPUs to be no-CBs CPUs.
+ Only CPUs designated by the rcu_nocbs= boot parameter will be
+ no-CBs CPUs.
+
+config RCU_NOCB_CPU_ZERO
+ bool "CPU 0 is a build_forced no-CBs CPU"
+ depends on RCU_NOCB_CPU
+ help
+ This option forces CPU 0 to be a no-CBs CPU. Additional CPUs
+ may be designated as no-CBs CPUs using the rcu_nocbs= boot
+ parameter will be no-CBs CPUs.
+
+ Select this if CPU 0 needs to be a no-CBs CPU for real-time
+ or energy-efficiency reasons.
+
+config RCU_NOCB_CPU_ALL
+ bool "All CPUs are build_forced no-CBs CPUs"
+ depends on RCU_NOCB_CPU
+ help
+ This option forces all CPUs to be no-CBs CPUs. The rcu_nocbs=
+ boot parameter will be ignored.
+
+ Select this if all CPUs need to be no-CBs CPUs for real-time
+ or energy-efficiency reasons.
+
+endchoice
+
endmenu # "RCU Subsystem"
config IKCONFIG