From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de,
peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com,
edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com,
sbw@mit.edu, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/locking 2/4] Documentation/memory-barriers.txt: Add long atomic examples to memory-barriers.txt
Date: Wed, 4 Dec 2013 14:46:57 -0800 [thread overview]
Message-ID: <1386197219-31964-2-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <1386197219-31964-1-git-send-email-paulmck@linux.vnet.ibm.com>
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Although the atomic_long_t functions are quite useful, they are a bit
obscure. This commit therefore adds the common ones alongside their
atomic_t counterparts in Documentation/memory-barriers.txt.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
---
Documentation/memory-barriers.txt | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt
index 1d067235b0bc..2d22da095a60 100644
--- a/Documentation/memory-barriers.txt
+++ b/Documentation/memory-barriers.txt
@@ -1728,21 +1728,23 @@ explicit lock operations, described later). These include:
xchg();
cmpxchg();
- atomic_xchg();
- atomic_cmpxchg();
- atomic_inc_return();
- atomic_dec_return();
- atomic_add_return();
- atomic_sub_return();
- atomic_inc_and_test();
- atomic_dec_and_test();
- atomic_sub_and_test();
- atomic_add_negative();
- atomic_add_unless(); /* when succeeds (returns 1) */
+ atomic_xchg(); atomic_long_xchg();
+ atomic_cmpxchg(); atomic_long_cmpxchg();
+ atomic_inc_return(); atomic_long_inc_return();
+ atomic_dec_return(); atomic_long_dec_return();
+ atomic_add_return(); atomic_long_add_return();
+ atomic_sub_return(); atomic_long_sub_return();
+ atomic_inc_and_test(); atomic_long_inc_and_test();
+ atomic_dec_and_test(); atomic_long_dec_and_test();
+ atomic_sub_and_test(); atomic_long_sub_and_test();
+ atomic_add_negative(); atomic_long_add_negative();
test_and_set_bit();
test_and_clear_bit();
test_and_change_bit();
+ /* when succeeds (returns 1) */
+ atomic_add_unless(); atomic_long_add_unless();
+
These are used for such things as implementing LOCK-class and UNLOCK-class
operations and adjusting reference counters towards object destruction, and as
such the implicit memory barrier effects are necessary.
--
1.8.1.5
next prev parent reply other threads:[~2013-12-04 22:47 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-04 22:46 [PATCH v4 tip/core/locking 0/4] Memory-barrier documentation updates Paul E. McKenney
2013-12-04 22:46 ` [PATCH tip/core/locking 1/4] Documentation/memory-barriers.txt: Add needed ACCESS_ONCE() calls to memory-barriers.txt Paul E. McKenney
2013-12-04 22:46 ` Paul E. McKenney [this message]
2013-12-04 22:46 ` [PATCH tip/core/locking 4/4] Documentation/memory-barriers.txt: Document ACCESS_ONCE() Paul E. McKenney
2013-12-05 9:33 ` Ingo Molnar
2013-12-05 9:52 ` Mathieu Desnoyers
2013-12-05 10:11 ` Ingo Molnar
2013-12-05 18:02 ` Paul E. McKenney
2013-12-10 13:24 ` Ingo Molnar
2013-12-10 17:36 ` Paul E. McKenney
2013-12-05 9:50 ` Ingo Molnar
2013-12-05 18:05 ` Paul E. McKenney
2013-12-05 22:47 ` Paul E. McKenney
2013-12-10 15:10 ` Ingo Molnar
2013-12-10 17:37 ` Paul E. McKenney
2013-12-05 20:21 ` Jonathan Corbet
2013-12-05 21:44 ` Paul E. McKenney
2013-12-10 15:20 ` Ingo Molnar
2013-12-10 17:44 ` Paul E. McKenney
2013-12-10 18:28 ` Ingo Molnar
2013-12-10 19:01 ` Paul E. McKenney
2013-12-10 19:46 ` Ingo Molnar
2013-12-10 20:09 ` Paul E. McKenney
2013-12-05 0:10 ` [PATCH v4 tip/core/locking 0/4] Memory-barrier documentation updates Josh Triplett
2013-12-05 10:59 ` Henrik Austad
2013-12-05 12:28 ` Ingo Molnar
2013-12-05 13:51 ` Steven Rostedt
2013-12-05 18:05 ` David Miller
2013-12-05 18:18 ` Paul E. McKenney
2013-12-05 18:44 ` David Miller
2013-12-05 19:01 ` Paul E. McKenney
2013-12-10 15:24 ` Ingo Molnar
2013-12-05 12:29 ` [PATCH v4 tip/core/locking 3/4] Documentation/memory-barriers.txt: Prohibit speculative writes Ingo Molnar
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