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[PATCH] Add atomic operations required by the new condition variable.
- From: Torvald Riegel <triegel at redhat dot com>
- To: GLIBC Devel <libc-alpha at sourceware dot org>
- Date: Thu, 26 May 2016 01:04:12 +0200
- Subject: [PATCH] Add atomic operations required by the new condition variable.
- Authentication-results: sourceware.org; auth=none
This adds just a few atomic operations required by the new condvar. Our
policy is to add atomic operations as needed, and this patch does just
that.
Tested on x86-linux and x86_64-linux using the new condvar.
2016-05-26 Torvald Riegel <triegel@redhat.com>
* include/atomic.h (atomic_exchange_relaxed, atomic_fetch_and_relaxed,
atomic_fetch_and_release, atomic_fetch_or_release,
atomic_fetch_xor_release): New.
commit ce627255c26efddbcc18f090dd4154a6740441f5
Author: Torvald Riegel <triegel@redhat.com>
Date: Thu May 26 00:57:27 2016 +0200
Add atomic operations required by the new condition variable.
* include/atomic.h (atomic_exchange_relaxed, atomic_fetch_and_relaxed,
atomic_fetch_and_release, atomic_fetch_or_release,
atomic_fetch_xor_release): New.
diff --git a/include/atomic.h b/include/atomic.h
index 5e8bfff..4e18ed0 100644
--- a/include/atomic.h
+++ b/include/atomic.h
@@ -605,6 +605,9 @@ void __atomic_link_error (void);
__atomic_compare_exchange_n ((mem), (expected), (desired), 1, \
__ATOMIC_RELEASE, __ATOMIC_RELAXED); })
+# define atomic_exchange_relaxed(mem, desired) \
+ ({ __atomic_check_size((mem)); \
+ __atomic_exchange_n ((mem), (desired), __ATOMIC_RELAXED); })
# define atomic_exchange_acquire(mem, desired) \
({ __atomic_check_size((mem)); \
__atomic_exchange_n ((mem), (desired), __ATOMIC_ACQUIRE); })
@@ -625,9 +628,15 @@ void __atomic_link_error (void);
({ __atomic_check_size((mem)); \
__atomic_fetch_add ((mem), (operand), __ATOMIC_ACQ_REL); })
+# define atomic_fetch_and_relaxed(mem, operand) \
+ ({ __atomic_check_size((mem)); \
+ __atomic_fetch_and ((mem), (operand), __ATOMIC_RELAXED); })
# define atomic_fetch_and_acquire(mem, operand) \
({ __atomic_check_size((mem)); \
__atomic_fetch_and ((mem), (operand), __ATOMIC_ACQUIRE); })
+# define atomic_fetch_and_release(mem, operand) \
+ ({ __atomic_check_size((mem)); \
+ __atomic_fetch_and ((mem), (operand), __ATOMIC_RELEASE); })
# define atomic_fetch_or_relaxed(mem, operand) \
({ __atomic_check_size((mem)); \
@@ -635,6 +644,13 @@ void __atomic_link_error (void);
# define atomic_fetch_or_acquire(mem, operand) \
({ __atomic_check_size((mem)); \
__atomic_fetch_or ((mem), (operand), __ATOMIC_ACQUIRE); })
+# define atomic_fetch_or_release(mem, operand) \
+ ({ __atomic_check_size((mem)); \
+ __atomic_fetch_or ((mem), (operand), __ATOMIC_RELEASE); })
+
+# define atomic_fetch_xor_release(mem, operand) \
+ ({ __atomic_check_size((mem)); \
+ __atomic_fetch_xor ((mem), (operand), __ATOMIC_RELEASE); })
#else /* !USE_ATOMIC_COMPILER_BUILTINS */
@@ -701,6 +717,11 @@ void __atomic_link_error (void);
*(expected) == __atg103_expected; })
# endif
+# ifndef atomic_exchange_relaxed
+/* XXX This unnecessarily has acquire MO. */
+# define atomic_exchange_relaxed(mem, val) \
+ atomic_exchange_acq ((mem), (val))
+# endif
# ifndef atomic_exchange_acquire
# define atomic_exchange_acquire(mem, val) \
atomic_exchange_acq ((mem), (val))
@@ -732,12 +753,24 @@ void __atomic_link_error (void);
atomic_exchange_and_add_acq ((mem), (operand)); })
# endif
+/* XXX Fall back to acquire MO because archs do not define a weaker
+ atomic_and_val. */
+# ifndef atomic_fetch_and_relaxed
+# define atomic_fetch_and_relaxed(mem, operand) \
+ atomic_fetch_and_acquire ((mem), (operand))
+# endif
/* XXX The default for atomic_and_val has acquire semantics, but this is not
documented. */
# ifndef atomic_fetch_and_acquire
# define atomic_fetch_and_acquire(mem, operand) \
atomic_and_val ((mem), (operand))
# endif
+# ifndef atomic_fetch_and_release
+/* XXX This unnecessarily has acquire MO. */
+# define atomic_fetch_and_release(mem, operand) \
+ ({ atomic_thread_fence_release (); \
+ atomic_and_val ((mem), (operand)); })
+# endif
/* XXX The default for atomic_or_val has acquire semantics, but this is not
documented. */
@@ -751,6 +784,28 @@ void __atomic_link_error (void);
# define atomic_fetch_or_relaxed(mem, operand) \
atomic_fetch_or_acquire ((mem), (operand))
# endif
+/* XXX Contains an unnecessary acquire MO because archs do not define a weaker
+ atomic_or_val. */
+# ifndef atomic_fetch_or_release
+# define atomic_fetch_or_release(mem, operand) \
+ ({ atomic_thread_fence_release (); \
+ atomic_fetch_or_acquire ((mem), (operand)); })
+# endif
+
+# ifndef atomic_fetch_xor_release
+# define atomic_fetch_xor_release(mem, operand) \
+ ({ __typeof (*(mem)) __atg104_old; \
+ __typeof (mem) __atg104_memp = (mem); \
+ __typeof (*(mem)) __atg104_op = (operand); \
+ \
+ do \
+ __atg104_old = (*__atg104_memp); \
+ while (__builtin_expect \
+ (atomic_compare_and_exchange_bool_rel ( \
+ __atg104_memp, __atg104_old ^ __atg104_op, __atg104_old), 0));\
+ \
+ __atg104_old; })
+#endif
#endif /* !USE_ATOMIC_COMPILER_BUILTINS */