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Message-ID: <tip-fb2b581968db140586e8d7db38ff278f60872313@git.kernel.org>
Date: Mon, 16 Dec 2013 02:39:45 -0800
From: "tip-bot for Paul E. McKenney" <tipbot@...or.com>
To: linux-tip-commits@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...nel.org,
torvalds@...ux-foundation.org, a.p.zijlstra@...llo.nl,
paulmck@...ux.vnet.ibm.com, akpm@...ux-foundation.org,
tglx@...utronix.de, josh@...htriplett.org,
linux-arch@...r.kernel.org
Subject: [tip:core/locking] Documentation/memory-barriers.txt:
Add long atomic examples to memory-barriers.txt
Commit-ID: fb2b581968db140586e8d7db38ff278f60872313
Gitweb: http://git.kernel.org/tip/fb2b581968db140586e8d7db38ff278f60872313
Author: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
AuthorDate: Wed, 11 Dec 2013 13:59:05 -0800
Committer: Ingo Molnar <mingo@...nel.org>
CommitDate: Mon, 16 Dec 2013 11:36:09 +0100
Documentation/memory-barriers.txt: Add long atomic examples to memory-barriers.txt
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@...ux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@...htriplett.org>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: <linux-arch@...r.kernel.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Link: http://lkml.kernel.org/r/1386799151-2219-2-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
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 1d06723..2d22da0 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.
--
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