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| author | NeilBrown <neilb@suse.de> | 2012-08-01 12:40:02 +0200 |
|---|---|---|
| committer | NeilBrown <neilb@suse.de> | 2012-08-01 12:40:02 +0200 |
| commit | bb181e2e48f8c85db08c9cb015cbba9618dbf05c (patch) | |
| tree | 191bc24dd97bcb174535cc217af082f16da3b43d /Documentation/RCU/rcubarrier.txt | |
| parent | md/RAID1: Add missing case for attempting to repair known bad blocks. (diff) | |
| parent | dm raid: move sectors_per_dev calculation (diff) | |
| download | linux-bb181e2e48f8c85db08c9cb015cbba9618dbf05c.tar.xz linux-bb181e2e48f8c85db08c9cb015cbba9618dbf05c.zip | |
Merge commit 'c039c332f23e794deb6d6f37b9f07ff3b27fb2cf' into md
Pull in pre-requisites for adding raid10 support to dm-raid.
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 |