diff options
author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2009-08-22 16:56:53 -0400 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2009-08-23 04:32:40 -0400 |
commit | 6b3ef48adf847f7adf11c870e3ffacac150f1564 (patch) | |
tree | e1403ce515bf00ade99ec806f6ab6b6db999aa0b /Documentation/RCU | |
parent | f41d911f8c49a5d65c86504c19e8204bb605c4fd (diff) |
rcu: Remove CONFIG_PREEMPT_RCU
Now that CONFIG_TREE_PREEMPT_RCU is in place, there is no
further need for CONFIG_PREEMPT_RCU. Remove it, along with
whatever subtle bugs it may (or may not) contain.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: josht@linux.vnet.ibm.com
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
LKML-Reference: <125097461396-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'Documentation/RCU')
-rw-r--r-- | Documentation/RCU/rcu.txt | 10 | ||||
-rw-r--r-- | Documentation/RCU/whatisRCU.txt | 8 |
2 files changed, 9 insertions, 9 deletions
diff --git a/Documentation/RCU/rcu.txt b/Documentation/RCU/rcu.txt index 7aa2002ade77..2a23523ce471 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 | |||
36 | executed in user mode, or executed in the idle loop, we can | 36 | executed in user mode, or executed in the idle loop, we can |
37 | safely free up that item. | 37 | safely free up that item. |
38 | 38 | ||
39 | Preemptible variants of RCU (CONFIG_PREEMPT_RCU) get the | 39 | Preemptible variants of RCU (CONFIG_TREE_PREEMPT_RCU) get the |
40 | same effect, but require that the readers manipulate CPU-local | 40 | same effect, but require that the readers manipulate CPU-local |
41 | counters. These counters allow limited types of blocking | 41 | counters. These counters allow limited types of blocking |
42 | within RCU read-side critical sections. SRCU also uses | 42 | within RCU read-side critical sections. SRCU also uses |
@@ -79,10 +79,10 @@ o I hear that RCU is patented? What is with that? | |||
79 | o I hear that RCU needs work in order to support realtime kernels? | 79 | o I hear that RCU needs work in order to support realtime kernels? |
80 | 80 | ||
81 | This work is largely completed. Realtime-friendly RCU can be | 81 | This work is largely completed. Realtime-friendly RCU can be |
82 | enabled via the CONFIG_PREEMPT_RCU kernel configuration parameter. | 82 | enabled via the CONFIG_TREE_PREEMPT_RCU kernel configuration |
83 | However, work is in progress for enabling priority boosting of | 83 | parameter. However, work is in progress for enabling priority |
84 | preempted RCU read-side critical sections. This is needed if you | 84 | boosting of preempted RCU read-side critical sections. This is |
85 | have CPU-bound realtime threads. | 85 | needed if you have CPU-bound realtime threads. |
86 | 86 | ||
87 | o Where can I find more information on RCU? | 87 | o Where can I find more information on RCU? |
88 | 88 | ||
diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt index 97ded2432c59..e41a7fecf0d3 100644 --- a/Documentation/RCU/whatisRCU.txt +++ b/Documentation/RCU/whatisRCU.txt | |||
@@ -136,10 +136,10 @@ rcu_read_lock() | |||
136 | Used by a reader to inform the reclaimer that the reader is | 136 | Used by a reader to inform the reclaimer that the reader is |
137 | entering an RCU read-side critical section. It is illegal | 137 | entering an RCU read-side critical section. It is illegal |
138 | to block while in an RCU read-side critical section, though | 138 | to block while in an RCU read-side critical section, though |
139 | kernels built with CONFIG_PREEMPT_RCU can preempt RCU read-side | 139 | kernels built with CONFIG_TREE_PREEMPT_RCU can preempt RCU |
140 | critical sections. Any RCU-protected data structure accessed | 140 | read-side critical sections. Any RCU-protected data structure |
141 | during an RCU read-side critical section is guaranteed to remain | 141 | accessed during an RCU read-side critical section is guaranteed to |
142 | unreclaimed for the full duration of that critical section. | 142 | remain unreclaimed for the full duration of that critical section. |
143 | Reference counts may be used in conjunction with RCU to maintain | 143 | Reference counts may be used in conjunction with RCU to maintain |
144 | longer-term references to data structures. | 144 | longer-term references to data structures. |
145 | 145 | ||