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author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2013-03-13 00:54:14 +0100 |
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committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2013-06-10 22:45:25 +0200 |
commit | 99f88919f8fa8a8b01b5306c59c9977b94604df8 (patch) | |
tree | 8e92937651258199944fed1ae2b612f0f693be00 /Documentation/RCU/whatisRCU.txt | |
parent | rcu: Convert rcutree_plugin.h printk calls (diff) | |
download | linux-99f88919f8fa8a8b01b5306c59c9977b94604df8.tar.xz linux-99f88919f8fa8a8b01b5306c59c9977b94604df8.zip |
rcu: Remove srcu_read_lock_raw() and srcu_read_unlock_raw().
These interfaces never did get used, so this commit removes them,
their rcutorture tests, and documentation referencing them.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'Documentation/RCU/whatisRCU.txt')
-rw-r--r-- | Documentation/RCU/whatisRCU.txt | 22 |
1 files changed, 7 insertions, 15 deletions
diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt index 10df0b82f459..0f0fb7c432c2 100644 --- a/Documentation/RCU/whatisRCU.txt +++ b/Documentation/RCU/whatisRCU.txt @@ -842,9 +842,7 @@ SRCU: Critical sections Grace period Barrier srcu_read_lock synchronize_srcu srcu_barrier srcu_read_unlock call_srcu - srcu_read_lock_raw synchronize_srcu_expedited - srcu_read_unlock_raw - srcu_dereference + srcu_dereference synchronize_srcu_expedited SRCU: Initialization/cleanup init_srcu_struct @@ -865,38 +863,32 @@ list can be helpful: a. Will readers need to block? If so, you need SRCU. -b. Is it necessary to start a read-side critical section in a - hardirq handler or exception handler, and then to complete - this read-side critical section in the task that was - interrupted? If so, you need SRCU's srcu_read_lock_raw() and - srcu_read_unlock_raw() primitives. - -c. What about the -rt patchset? If readers would need to block +b. What about the -rt patchset? If readers would need to block in an non-rt kernel, you need SRCU. If readers would block in a -rt kernel, but not in a non-rt kernel, SRCU is not necessary. -d. Do you need to treat NMI handlers, hardirq handlers, +c. Do you need to treat NMI handlers, hardirq handlers, and code segments with preemption disabled (whether via preempt_disable(), local_irq_save(), local_bh_disable(), or some other mechanism) as if they were explicit RCU readers? If so, RCU-sched is the only choice that will work for you. -e. Do you need RCU grace periods to complete even in the face +d. Do you need RCU grace periods to complete even in the face of softirq monopolization of one or more of the CPUs? For example, is your code subject to network-based denial-of-service attacks? If so, you need RCU-bh. -f. Is your workload too update-intensive for normal use of +e. Is your workload too update-intensive for normal use of RCU, but inappropriate for other synchronization mechanisms? If so, consider SLAB_DESTROY_BY_RCU. But please be careful! -g. Do you need read-side critical sections that are respected +f. Do you need read-side critical sections that are respected even though they are in the middle of the idle loop, during user-mode execution, or on an offlined CPU? If so, SRCU is the only choice that will work for you. -h. Otherwise, use RCU. +g. Otherwise, use RCU. Of course, this all assumes that you have determined that RCU is in fact the right tool for your job. |