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authorDavidlohr Bueso <dave@stgolabs.net>2016-04-12 08:52:55 -0700
committerIngo Molnar <mingo@kernel.org>2016-04-13 08:52:23 +0200
commit787df6383caa1338a4f6640d71917bc2d8c068b1 (patch)
tree13475ae5318f4d31cc6f6cb9bf8a034fb539fd0f /Documentation/memory-barriers.txt
parent0b6fa347dc08c6f757a35f3a180269b3ffc4cd28 (diff)
locking/Documentation: Mention smp_cond_acquire()
... do this next to smp_load_acquire() when first mentioning ACQUIRE. While this call is briefly explained and control dependencies are mentioned later, it does not hurt the reader. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: bobby.prani@gmail.com Cc: dhowells@redhat.com Cc: dipankar@in.ibm.com Cc: dvhart@linux.intel.com Cc: edumazet@google.com Cc: fweisbec@gmail.com Cc: jiangshanlai@gmail.com Cc: josh@joshtriplett.org Cc: mathieu.desnoyers@efficios.com Cc: oleg@redhat.com Cc: rostedt@goodmis.org Link: http://lkml.kernel.org/r/1460476375-27803-7-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'Documentation/memory-barriers.txt')
-rw-r--r--Documentation/memory-barriers.txt5
1 files changed, 3 insertions, 2 deletions
diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt
index 7133626a61d0..a9454b1c73bd 100644
--- a/Documentation/memory-barriers.txt
+++ b/Documentation/memory-barriers.txt
@@ -431,8 +431,9 @@ And a couple of implicit varieties:
This acts as a one-way permeable barrier. It guarantees that all memory
operations after the ACQUIRE operation will appear to happen after the
ACQUIRE operation with respect to the other components of the system.
- ACQUIRE operations include LOCK operations and smp_load_acquire()
- operations.
+ ACQUIRE operations include LOCK operations and both smp_load_acquire()
+ and smp_cond_acquire() operations. The later builds the necessary ACQUIRE
+ semantics from relying on a control dependency and smp_rmb().
Memory operations that occur before an ACQUIRE operation may appear to
happen after it completes.