diff options
| author | Ingo Molnar <mingo@kernel.org> | 2013-09-03 07:41:11 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-09-03 07:41:11 +0200 |
| commit | 7d992feb7694a21ee81f22894b455dadd5d1c110 (patch) | |
| tree | d0f0961186b1c31c536a26a7f986ad7ca677453b /Documentation/RCU/rcubarrier.txt | |
| parent | 6e4664525b1db28f8c4e1130957f70a94c19213e (diff) | |
| parent | 25f27ce4a6a4995c8bdd69b4b2180465ed5ad2b8 (diff) | |
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:
"
* Update RCU documentation. These were posted to LKML at
https://lkml.org/lkml/2013/8/19/611.
* Miscellaneous fixes. These were posted to LKML at
https://lkml.org/lkml/2013/8/19/619.
* Full-system idle detection. This is for use by Frederic
Weisbecker's adaptive-ticks mechanism. Its purpose is
to allow the timekeeping CPU to shut off its tick when
all other CPUs are idle. These were posted to LKML at
https://lkml.org/lkml/2013/8/19/648.
* Improve rcutorture test coverage. These were posted to LKML at
https://lkml.org/lkml/2013/8/19/675.
"
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'Documentation/RCU/rcubarrier.txt')
| -rw-r--r-- | Documentation/RCU/rcubarrier.txt | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/Documentation/RCU/rcubarrier.txt b/Documentation/RCU/rcubarrier.txt index 2e319d1b9ef2..b10cfe711e68 100644 --- a/Documentation/RCU/rcubarrier.txt +++ b/Documentation/RCU/rcubarrier.txt @@ -70,10 +70,14 @@ in realtime kernels in order to avoid excessive scheduling latencies. rcu_barrier() -We instead need the rcu_barrier() primitive. This primitive is similar -to synchronize_rcu(), but instead of waiting solely for a grace -period to elapse, it also waits for all outstanding RCU callbacks to -complete. Pseudo-code using rcu_barrier() is as follows: +We instead need the rcu_barrier() primitive. Rather than waiting for +a grace period to elapse, rcu_barrier() waits for all outstanding RCU +callbacks to complete. Please note that rcu_barrier() does -not- imply +synchronize_rcu(), in particular, if there are no RCU callbacks queued +anywhere, rcu_barrier() is within its rights to return immediately, +without waiting for a grace period to elapse. + +Pseudo-code using rcu_barrier() is as follows: 1. Prevent any new RCU callbacks from being posted. 2. Execute rcu_barrier(). |