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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2012-08-04 03:41:23 +0400 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2012-09-23 18:42:23 +0400 |
| commit | 2aef619c7524d73d18ff7b102a1706066b69141d (patch) | |
| tree | da1409acbdc4baca4858af9fbc7e413fd5efa0d0 /Documentation/RCU/checklist.txt | |
| parent | 13dbf9140c726c307a9c7e2b7ff83cf95da3bb44 (diff) | |
| download | linux-2aef619c7524d73d18ff7b102a1706066b69141d.tar.xz | |
rcu: Document SRCU dead-CPU capabilities, emphasize read-side limits
The current documentation did not help someone grepping for SRCU to
learn that disabling preemption is not a replacement for srcu_read_lock(),
so upgrade the documentation to bring this out, not just for SRCU,
but also for RCU-bh. Also document the fact that SRCU readers are
respected on CPUs executing in user mode, idle CPUs, and even on
offline CPUs.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Diffstat (limited to 'Documentation/RCU/checklist.txt')
| -rw-r--r-- | Documentation/RCU/checklist.txt | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/RCU/checklist.txt b/Documentation/RCU/checklist.txt index fc103d7a0474..cdb20d41a44a 100644 --- a/Documentation/RCU/checklist.txt +++ b/Documentation/RCU/checklist.txt @@ -310,6 +310,12 @@ over a rather long period of time, but improvements are always welcome! code under the influence of preempt_disable(), you instead need to use synchronize_irq() or synchronize_sched(). + This same limitation also applies to synchronize_rcu_bh() + and synchronize_srcu(), as well as to the asynchronous and + expedited forms of the three primitives, namely call_rcu(), + call_rcu_bh(), call_srcu(), synchronize_rcu_expedited(), + synchronize_rcu_bh_expedited(), and synchronize_srcu_expedited(). + 12. Any lock acquired by an RCU callback must be acquired elsewhere with softirq disabled, e.g., via spin_lock_irqsave(), spin_lock_bh(), etc. Failing to disable irq on a given |