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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2013-12-11 22:59:05 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-12-16 11:36:09 +0100 |
| commit | fb2b581968db140586e8d7db38ff278f60872313 (patch) | |
| tree | 8e47fda0c89ce87c77e8f45c33f114f81a463f10 /Documentation/memory-barriers.txt | |
| parent | Documentation/memory-barriers.txt: Add needed ACCESS_ONCE() calls to memory-b... (diff) | |
| download | linux-fb2b581968db140586e8d7db38ff278f60872313.tar.xz linux-fb2b581968db140586e8d7db38ff278f60872313.zip | |
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@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <linux-arch@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-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@kernel.org>
Diffstat (limited to 'Documentation/memory-barriers.txt')
| -rw-r--r-- | Documentation/memory-barriers.txt | 24 |
1 files 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. |