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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-06-27 13:42:20 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-09-07 16:27:19 -0700
commit8315f42295d2667a7f942f154b73a86fd7cb2227 (patch)
tree67057935dada3305e0dab95f546359b40cc29b96 /init
parent11ed7f934cb807f26da09547b5946c2e534d1dac (diff)
rcu: Add call_rcu_tasks()
This commit adds a new RCU-tasks flavor of RCU, which provides call_rcu_tasks(). This RCU flavor's quiescent states are voluntary context switch (not preemption!) and userspace execution (not the idle loop -- use some sort of schedule_on_each_cpu() if you need to handle the idle tasks. Note that unlike other RCU flavors, these quiescent states occur in tasks, not necessarily CPUs. Includes fixes from Steven Rostedt. This RCU flavor is assumed to have very infrequent latency-tolerant updaters. This assumption permits significant simplifications, including a single global callback list protected by a single global lock, along with a single task-private linked list containing all tasks that have not yet passed through a quiescent state. If experience shows this assumption to be incorrect, the required additional complexity will be added. Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'init')
-rw-r--r--init/Kconfig10
1 files changed, 10 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig
index e84c6423a2e5..c4539c4e177f 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -507,6 +507,16 @@ config PREEMPT_RCU
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
+ help
+ This option enables a task-based RCU implementation that uses
+ only voluntary context switch (not preemption!), idle, and
+ user-mode execution as quiescent states.
+
+ If unsure, say N.
+
config RCU_STALL_COMMON
def_bool ( TREE_RCU || TREE_PREEMPT_RCU || RCU_TRACE )
help