Commit-ID: fb2b581968db140586e8d7db38ff278f60872313 Gitweb: http://git.kernel.org/tip/fb2b581968db140586e8d7db38ff278f60872313 Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> AuthorDate: Wed, 11 Dec 2013 13:59:05 -0800 Committer: Ingo Molnar <mingo@xxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxx> Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx> Reviewed-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Cc: <linux-arch@xxxxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/1386799151-2219-2-git-send-email-paulmck@xxxxxxxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- 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. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
