initial implementation of support for native atomic ops.
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@16601 65c4cc65-6c06-0410-ace0-fbb531ad65f3
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@ -679,4 +679,50 @@ static inline int ast_cond_timedwait(ast_cond_t *cond, ast_mutex_t *t, const str
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#define pthread_create __use_ast_pthread_create_instead__
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#endif
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/*
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* Initial support for atomic instructions.
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* For platforms that have it, use the native cpu instruction to
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* implement them. For other platforms, resort to a 'slow' version
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* (defined in utils.c) that protects the atomic instruction with
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* a single lock.
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* The slow versions is always available, for testing purposes,
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* as ast_atomic_fetchadd_int_slow()
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*/
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int ast_atomic_fetchadd_int_slow(volatile int *p, int v);
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#include "asterisk/inline_api.h"
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/*! \brief Atomically add v to *pp and return * the previous value of *p.
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* This can be used to handle reference counts, and the return value
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* can be used to generate unique identifiers.
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*/
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#if defined ( __i386__)
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AST_INLINE_API(int ast_atomic_fetchadd_int(volatile int *p, int v),
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{
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__asm __volatile (
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" lock xaddl %0, %1 ; "
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: "+r" (v), /* 0 (result) */
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"=m" (*p) /* 1 */
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: "m" (*p)); /* 2 */
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return (v);
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})
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#else /* low performance version in utils.c */
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AST_INLINE_AP(int ast_atomic_fetchadd_int(volatile int *p, int v),
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{
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return ast_atomic_fetchadd_int_slow(p, v);
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})
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#endif
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/*! \brief decrement *p by 1 and return true if the variable has reached 0.
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* Useful e.g. to check if a refcount has reached 0.
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*/
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AST_INLINE_API(int ast_atomic_dec_and_test(volatile int *p),
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{
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int a = ast_atomic_fetchadd_int(p, -1);
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return a == 1; /* true if the value is 0 now (so it was 1 previously) */
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}
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)
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#endif /* _ASTERISK_LOCK_H */
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11
utils.c
11
utils.c
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@ -39,6 +39,7 @@
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ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
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#define AST_API_MODULE /* ensure that inlinable API functions will be built in lock.h if required */
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#include "asterisk/lock.h"
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#include "asterisk/io.h"
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#include "asterisk/logger.h"
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@ -1049,6 +1050,16 @@ void __ast_string_field_index_build(struct ast_string_field_mgr *mgr,
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va_end(ap2);
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}
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AST_MUTEX_DEFINE_STATIC(fetchadd_m); /* used for all fetc&add ops */
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int ast_atomic_fetchadd_int_slow(volatile int *p, int v)
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{
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int ret;
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ast_mutex_lock(&fetchadd_m);
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ret = *p;
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*p += v;
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ast_mutex_unlock(&fetchadd_m);
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return ret;
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}
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/*! \brief
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* get values from config variables.
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