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authorIngo Molnar <mingo@kernel.org>2014-11-20 08:57:58 +0100
committerIngo Molnar <mingo@kernel.org>2014-11-20 08:57:58 +0100
commitd360b78f99e5d1724279644c8eb51d5cf0de4027 (patch)
tree011c67bd0654b141e8f7f9fe1d8e1338b05663ba /init/Kconfig
parentfc14f9c1272f62c3e8d01300f52467c0d9af50f9 (diff)
parent9ea6c5885681e3d9ce9844ba9dc57371a5cfc6d2 (diff)
downloadlinux-linaro-stable-d360b78f99e5d1724279644c8eb51d5cf0de4027.tar.gz
Merge branch 'rcu/next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull RCU updates from Paul E. McKenney: - Streamline RCU's use of per-CPU variables, shifting from "cpu" arguments to functions to "this_"-style per-CPU variable accessors. - Signal-handling RCU updates. - Real-time updates. - Torture-test updates. - Miscellaneous fixes. - Documentation updates. Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'init/Kconfig')
-rw-r--r--init/Kconfig49
1 files changed, 21 insertions, 28 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 2081a4d3d917..903505e66d1d 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -477,7 +477,7 @@ config TREE_RCU
thousands of CPUs. It also scales down nicely to
smaller systems.
-config TREE_PREEMPT_RCU
+config PREEMPT_RCU
bool "Preemptible tree-based hierarchical RCU"
depends on PREEMPT
select IRQ_WORK
@@ -501,12 +501,6 @@ config TINY_RCU
endchoice
-config PREEMPT_RCU
- def_bool TREE_PREEMPT_RCU
- help
- This option enables preemptible-RCU code that is common between
- TREE_PREEMPT_RCU and, in the old days, TINY_PREEMPT_RCU.
-
config TASKS_RCU
bool "Task_based RCU implementation using voluntary context switch"
default n
@@ -518,7 +512,7 @@ config TASKS_RCU
If unsure, say N.
config RCU_STALL_COMMON
- def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE )
+ def_bool ( TREE_RCU || PREEMPT_RCU || RCU_TRACE )
help
This option enables RCU CPU stall code that is common between
the TINY and TREE variants of RCU. The purpose is to allow
@@ -576,7 +570,7 @@ config RCU_FANOUT
int "Tree-based hierarchical RCU fanout value"
range 2 64 if 64BIT
range 2 32 if !64BIT
- depends on TREE_RCU || TREE_PREEMPT_RCU
+ depends on TREE_RCU || PREEMPT_RCU
default 64 if 64BIT
default 32 if !64BIT
help
@@ -596,7 +590,7 @@ config RCU_FANOUT_LEAF
int "Tree-based hierarchical RCU leaf-level fanout value"
range 2 RCU_FANOUT if 64BIT
range 2 RCU_FANOUT if !64BIT
- depends on TREE_RCU || TREE_PREEMPT_RCU
+ depends on TREE_RCU || PREEMPT_RCU
default 16
help
This option controls the leaf-level fanout of hierarchical
@@ -621,7 +615,7 @@ config RCU_FANOUT_LEAF
config RCU_FANOUT_EXACT
bool "Disable tree-based hierarchical RCU auto-balancing"
- depends on TREE_RCU || TREE_PREEMPT_RCU
+ depends on TREE_RCU || PREEMPT_RCU
default n
help
This option forces use of the exact RCU_FANOUT value specified,
@@ -652,11 +646,11 @@ config RCU_FAST_NO_HZ
Say N if you are unsure.
config TREE_RCU_TRACE
- def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU )
+ def_bool RCU_TRACE && ( TREE_RCU || PREEMPT_RCU )
select DEBUG_FS
help
This option provides tracing for the TREE_RCU and
- TREE_PREEMPT_RCU implementations, permitting Makefile to
+ PREEMPT_RCU implementations, permitting Makefile to
trivially select kernel/rcutree_trace.c.
config RCU_BOOST
@@ -672,30 +666,31 @@ config RCU_BOOST
Say Y here if you are working with real-time apps or heavy loads
Say N here if you are unsure.
-config RCU_BOOST_PRIO
- int "Real-time priority to boost RCU readers to"
+config RCU_KTHREAD_PRIO
+ int "Real-time priority to use for RCU worker threads"
range 1 99
depends on RCU_BOOST
default 1
help
- This option specifies the real-time priority to which long-term
- preempted RCU readers are to be boosted. If you are working
- with a real-time application that has one or more CPU-bound
- threads running at a real-time priority level, you should set
- RCU_BOOST_PRIO to a priority higher then the highest-priority
- real-time CPU-bound thread. The default RCU_BOOST_PRIO value
- of 1 is appropriate in the common case, which is real-time
+ This option specifies the SCHED_FIFO priority value that will be
+ assigned to the rcuc/n and rcub/n threads and is also the value
+ used for RCU_BOOST (if enabled). If you are working with a
+ real-time application that has one or more CPU-bound threads
+ running at a real-time priority level, you should set
+ RCU_KTHREAD_PRIO to a priority higher than the highest-priority
+ real-time CPU-bound application thread. The default RCU_KTHREAD_PRIO
+ value of 1 is appropriate in the common case, which is real-time
applications that do not have any CPU-bound threads.
Some real-time applications might not have a single real-time
thread that saturates a given CPU, but instead might have
multiple real-time threads that, taken together, fully utilize
- that CPU. In this case, you should set RCU_BOOST_PRIO to
+ that CPU. In this case, you should set RCU_KTHREAD_PRIO to
a priority higher than the lowest-priority thread that is
conspiring to prevent the CPU from running any non-real-time
tasks. For example, if one thread at priority 10 and another
thread at priority 5 are between themselves fully consuming
- the CPU time on a given CPU, then RCU_BOOST_PRIO should be
+ the CPU time on a given CPU, then RCU_KTHREAD_PRIO should be
set to priority 6 or higher.
Specify the real-time priority, or take the default if unsure.
@@ -715,7 +710,7 @@ config RCU_BOOST_DELAY
config RCU_NOCB_CPU
bool "Offload RCU callback processing from boot-selected CPUs"
- depends on TREE_RCU || TREE_PREEMPT_RCU
+ depends on TREE_RCU || PREEMPT_RCU
default n
help
Use this option to reduce OS jitter for aggressive HPC or
@@ -739,6 +734,7 @@ config RCU_NOCB_CPU
choice
prompt "Build-forced no-CBs CPUs"
default RCU_NOCB_CPU_NONE
+ depends on RCU_NOCB_CPU
help
This option allows no-CBs CPUs (whose RCU callbacks are invoked
from kthreads rather than from softirq context) to be specified
@@ -747,7 +743,6 @@ choice
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
@@ -761,7 +756,6 @@ 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
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
@@ -776,7 +770,6 @@ config RCU_NOCB_CPU_ZERO
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. All CPUs' RCU callbacks will