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| author | Ingo Molnar <mingo@kernel.org> | 2012-07-31 19:05:27 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-07-31 19:05:27 +0400 |
| commit | 1f815faec46e83bc96039797151846b60875bb06 (patch) | |
| tree | 41a874f8090e3f69c8a9f13e3c85dd7a371e569b /Documentation/RCU/rcubarrier.txt | |
| parent | b44d50dcacea0d485ca2ff9140f8cc28ee22f28d (diff) | |
| parent | e2b34e311be3a57c9abcb927e37a57e38913714c (diff) | |
| download | linux-1f815faec46e83bc96039797151846b60875bb06.tar.xz | |
Merge branch 'linus' into timers/urgent
Merge in Linus's branch which already has timers/core merged.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'Documentation/RCU/rcubarrier.txt')
| -rw-r--r-- | Documentation/RCU/rcubarrier.txt | 15 |
1 files changed, 4 insertions, 11 deletions
diff --git a/Documentation/RCU/rcubarrier.txt b/Documentation/RCU/rcubarrier.txt index e439a0edee22..38428c125135 100644 --- a/Documentation/RCU/rcubarrier.txt +++ b/Documentation/RCU/rcubarrier.txt @@ -79,8 +79,6 @@ complete. Pseudo-code using rcu_barrier() is as follows: 2. Execute rcu_barrier(). 3. Allow the module to be unloaded. -Quick Quiz #1: Why is there no srcu_barrier()? - The rcutorture module makes use of rcu_barrier in its exit function as follows: @@ -162,7 +160,7 @@ for any pre-existing callbacks to complete. Then lines 55-62 print status and do operation-specific cleanup, and then return, permitting the module-unload operation to be completed. -Quick Quiz #2: Is there any other situation where rcu_barrier() might +Quick Quiz #1: Is there any other situation where rcu_barrier() might be required? Your module might have additional complications. For example, if your @@ -242,7 +240,7 @@ reaches zero, as follows: 4 complete(&rcu_barrier_completion); 5 } -Quick Quiz #3: What happens if CPU 0's rcu_barrier_func() executes +Quick Quiz #2: What happens if CPU 0's rcu_barrier_func() executes immediately (thus incrementing rcu_barrier_cpu_count to the value one), but the other CPU's rcu_barrier_func() invocations are delayed for a full grace period? Couldn't this result in @@ -259,12 +257,7 @@ so that your module may be safely unloaded. Answers to Quick Quizzes -Quick Quiz #1: Why is there no srcu_barrier()? - -Answer: Since there is no call_srcu(), there can be no outstanding SRCU - callbacks. Therefore, there is no need to wait for them. - -Quick Quiz #2: Is there any other situation where rcu_barrier() might +Quick Quiz #1: Is there any other situation where rcu_barrier() might be required? Answer: Interestingly enough, rcu_barrier() was not originally @@ -278,7 +271,7 @@ Answer: Interestingly enough, rcu_barrier() was not originally implementing rcutorture, and found that rcu_barrier() solves this problem as well. -Quick Quiz #3: What happens if CPU 0's rcu_barrier_func() executes +Quick Quiz #2: What happens if CPU 0's rcu_barrier_func() executes immediately (thus incrementing rcu_barrier_cpu_count to the value one), but the other CPU's rcu_barrier_func() invocations are delayed for a full grace period? Couldn't this result in |