path: root/Documentation/RCU
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authorPranith Kumar <bobby.prani@gmail.com>2014-09-22 14:00:48 -0400
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-10-29 10:20:05 -0700
commit28f6569ab7d036cd4ee94c26bb76dc1b3f3fc056 (patch)
treedd09624ed00e1f67fdd87bf670da19761ed78ea6 /Documentation/RCU
parent21871d7eff2c96ae67e18e00adf59d56940e2fcc (diff)
rcu: Remove redundant TREE_PREEMPT_RCU config option
PREEMPT_RCU and TREE_PREEMPT_RCU serve the same function after TINY_PREEMPT_RCU has been removed. This patch removes TREE_PREEMPT_RCU and uses PREEMPT_RCU config option in its place. Signed-off-by: Pranith Kumar <bobby.prani@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'Documentation/RCU')
4 files changed, 9 insertions, 9 deletions
diff --git a/Documentation/RCU/rcu.txt b/Documentation/RCU/rcu.txt
index bf778332a28f..745f429fda79 100644
--- a/Documentation/RCU/rcu.txt
+++ b/Documentation/RCU/rcu.txt
@@ -36,7 +36,7 @@ o How can the updater tell when a grace period has completed
executed in user mode, or executed in the idle loop, we can
safely free up that item.
- Preemptible variants of RCU (CONFIG_TREE_PREEMPT_RCU) get the
+ Preemptible variants of RCU (CONFIG_PREEMPT_RCU) get the
same effect, but require that the readers manipulate CPU-local
counters. These counters allow limited types of blocking within
RCU read-side critical sections. SRCU also uses CPU-local
@@ -81,7 +81,7 @@ o I hear that RCU is patented? What is with that?
o I hear that RCU needs work in order to support realtime kernels?
This work is largely completed. Realtime-friendly RCU can be
- enabled via the CONFIG_TREE_PREEMPT_RCU kernel configuration
+ enabled via the CONFIG_PREEMPT_RCU kernel configuration
parameter. However, work is in progress for enabling priority
boosting of preempted RCU read-side critical sections. This is
needed if you have CPU-bound realtime threads.
diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt
index ef5a2fd4ff70..783e0720994d 100644
--- a/Documentation/RCU/stallwarn.txt
+++ b/Documentation/RCU/stallwarn.txt
@@ -77,7 +77,7 @@ This message indicates that CPU 5 detected that it was causing a stall,
and that the stall was affecting RCU-sched. This message will normally be
followed by a stack dump of the offending CPU. On TREE_RCU kernel builds,
RCU and RCU-sched are implemented by the same underlying mechanism,
-while on TREE_PREEMPT_RCU kernel builds, RCU is instead implemented
+while on PREEMPT_RCU kernel builds, RCU is instead implemented
by rcu_preempt_state.
On the other hand, if the offending CPU fails to print out a stall-warning
@@ -89,7 +89,7 @@ INFO: rcu_bh_state detected stalls on CPUs/tasks: { 3 5 } (detected by 2, 2502 j
This message indicates that CPU 2 detected that CPUs 3 and 5 were both
causing stalls, and that the stall was affecting RCU-bh. This message
will normally be followed by stack dumps for each CPU. Please note that
-TREE_PREEMPT_RCU builds can be stalled by tasks as well as by CPUs,
+PREEMPT_RCU builds can be stalled by tasks as well as by CPUs,
and that the tasks will be indicated by PID, for example, "P3421".
It is even possible for a rcu_preempt_state stall to be caused by both
CPUs -and- tasks, in which case the offending CPUs and tasks will all
@@ -205,10 +205,10 @@ o A CPU-bound real-time task in a CONFIG_PREEMPT kernel, which might
o A CPU-bound real-time task in a CONFIG_PREEMPT_RT kernel that
is running at a higher priority than the RCU softirq threads.
This will prevent RCU callbacks from ever being invoked,
- and in a CONFIG_TREE_PREEMPT_RCU kernel will further prevent
+ and in a CONFIG_PREEMPT_RCU kernel will further prevent
RCU grace periods from ever completing. Either way, the
system will eventually run out of memory and hang. In the
- CONFIG_TREE_PREEMPT_RCU case, you might see stall-warning
+ CONFIG_PREEMPT_RCU case, you might see stall-warning
o A hardware or software issue shuts off the scheduler-clock
diff --git a/Documentation/RCU/trace.txt b/Documentation/RCU/trace.txt
index 910870b15acd..b63b9bb3bc0c 100644
--- a/Documentation/RCU/trace.txt
+++ b/Documentation/RCU/trace.txt
@@ -8,7 +8,7 @@ The following sections describe the debugfs files and formats, first
for rcutree and next for rcutiny.
-CONFIG_TREE_RCU and CONFIG_TREE_PREEMPT_RCU debugfs Files and Formats
+CONFIG_TREE_RCU and CONFIG_PREEMPT_RCU debugfs Files and Formats
These implementations of RCU provide several debugfs directories under the
top-level directory "rcu":
@@ -18,7 +18,7 @@ rcu/rcu_preempt
Each directory contains files for the corresponding flavor of RCU.
-Note that rcu/rcu_preempt is only present for CONFIG_TREE_PREEMPT_RCU.
+Note that rcu/rcu_preempt is only present for CONFIG_PREEMPT_RCU.
For CONFIG_TREE_RCU, the RCU flavor maps onto the RCU-sched flavor,
so that activity for both appears in rcu/rcu_sched.
diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt
index e48c57f1943b..88dfce182f66 100644
--- a/Documentation/RCU/whatisRCU.txt
+++ b/Documentation/RCU/whatisRCU.txt
@@ -137,7 +137,7 @@ rcu_read_lock()
Used by a reader to inform the reclaimer that the reader is
entering an RCU read-side critical section. It is illegal
to block while in an RCU read-side critical section, though
- kernels built with CONFIG_TREE_PREEMPT_RCU can preempt RCU
+ kernels built with CONFIG_PREEMPT_RCU can preempt RCU
read-side critical sections. Any RCU-protected data structure
accessed during an RCU read-side critical section is guaranteed to
remain unreclaimed for the full duration of that critical section.

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