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| author | Paul E. McKenney <paul.mckenney@linaro.org> | 2013-02-11 10:23:27 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2013-03-26 08:04:43 -0700 |
| commit | 911af505ef407c2511106c224dd640f882f0f590 (patch) | |
| tree | 00656ef4be8d1195a568951333dd9618265c6435 /init | |
| parent | 34ed62461ae4970695974afb9a60ac3df0086830 (diff) | |
| download | lwn-911af505ef407c2511106c224dd640f882f0f590.tar.gz lwn-911af505ef407c2511106c224dd640f882f0f590.zip | |
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/Kconfig | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig index c8bd349eb638..307499704580 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 |