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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-07-02 10:13:24 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-07-07 15:13:44 -0700
commitb58cc46c5f6b57f1c814e374dbc47176e6b4938e (patch)
treeda592215d7ebbd15cdb0773770cd45ed91c538d2 /init/Kconfig
parentfbce7497ee5af800a1c350c73f3c3f103cb27a15 (diff)
downloadlinux-linaro-stable-b58cc46c5f6b57f1c814e374dbc47176e6b4938e.tar.gz
rcu: Don't offload callbacks unless specifically requested
Enabling NO_HZ_FULL currently has the side effect of enabling callback offloading on all CPUs. This results in lots of additional rcuo kthreads, and can also increase context switching and wakeups, even in cases where callback offloading is neither needed nor particularly desirable. This commit therefore enables callback offloading on a given CPU only if specifically requested at build time or boot time, or if that CPU has been specifically designated (again, either at build time or boot time) as a nohz_full CPU. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'init/Kconfig')
-rw-r--r--init/Kconfig4
1 files changed, 2 insertions, 2 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 9d76b99af1b9..9332d33346ac 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -737,7 +737,7 @@ choice
config RCU_NOCB_CPU_NONE
bool "No build_forced no-CBs CPUs"
- depends on RCU_NOCB_CPU && !NO_HZ_FULL
+ depends on RCU_NOCB_CPU && !NO_HZ_FULL_ALL
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
@@ -751,7 +751,7 @@ config RCU_NOCB_CPU_NONE
config RCU_NOCB_CPU_ZERO
bool "CPU 0 is a build_forced no-CBs CPU"
- depends on RCU_NOCB_CPU && !NO_HZ_FULL
+ depends on RCU_NOCB_CPU && !NO_HZ_FULL_ALL
help
This option forces CPU 0 to be a no-CBs CPU, so that its RCU
callbacks are invoked by a per-CPU kthread whose name begins