diff options
Diffstat (limited to 'include/my_atomic.h')
| -rw-r--r-- | include/my_atomic.h | 200 |
1 files changed, 150 insertions, 50 deletions
diff --git a/include/my_atomic.h b/include/my_atomic.h index a1347d26401..5fe7e521c19 100644 --- a/include/my_atomic.h +++ b/include/my_atomic.h @@ -13,6 +13,40 @@ along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ +/* + This header defines five atomic operations: + + my_atomic_add#(&var, what) + add 'what' to *var, and return the old value of *var + + my_atomic_fas#(&var, what) + 'Fetch And Store' + store 'what' in *var, and return the old value of *var + + my_atomic_cas#(&var, &old, new) + 'Compare And Swap' + if *var is equal to *old, then store 'new' in *var, and return TRUE + otherwise store *var in *old, and return FALSE + + my_atomic_load#(&var) + return *var + + my_atomic_store#(&var, what) + store 'what' in *var + + '#' is substituted by a size suffix - 8, 16, 32, or ptr + (e.g. my_atomic_add8, my_atomic_fas32, my_atomic_casptr). + + NOTE This operations are not always atomic, so they always must be + enclosed in my_atomic_rwlock_rdlock(lock)/my_atomic_rwlock_rdunlock(lock) + or my_atomic_rwlock_wrlock(lock)/my_atomic_rwlock_wrunlock(lock). + Hint: if a code block makes intensive use of atomic ops, it make sense + to take/release rwlock once for the whole block, not for every statement. + + On architectures where these operations are really atomic, rwlocks will + be optimized away. +*/ + #ifndef my_atomic_rwlock_init #define intptr void * @@ -26,70 +60,115 @@ #endif #ifndef make_atomic_add_body -#define make_atomic_add_body(S) \ +#define make_atomic_add_body(S) \ int ## S tmp=*a; \ while (!my_atomic_cas ## S(a, &tmp, tmp+v)); \ v=tmp; #endif +#ifdef __GNUC__ +/* + we want to be able to use my_atomic_xxx functions with + both signed and unsigned integers. But gcc will issue a warning + "passing arg N of `my_atomic_XXX' as [un]signed due to prototype" + if the signedness of the argument doesn't match the prototype, or + "pointer targets in passing argument N of my_atomic_XXX differ in signedness" + if int* is used where uint* is expected (or vice versa). + Let's shut these warnings up +*/ +#define make_transparent_unions(S) \ + typedef union { \ + int ## S i; \ + uint ## S u; \ + } U_ ## S __attribute__ ((transparent_union)); \ + typedef union { \ + int ## S volatile *i; \ + uint ## S volatile *u; \ + } Uv_ ## S __attribute__ ((transparent_union)); +#define uintptr intptr +make_transparent_unions(8) +make_transparent_unions(16) +make_transparent_unions(32) +make_transparent_unions(ptr) +#undef uintptr +#undef make_transparent_unions +#define a U_a.i +#define cmp U_cmp.i +#define v U_v.i +#define set U_set.i +#else +#define U_8 int8 +#define U_16 int16 +#define U_32 int32 +#define U_ptr intptr +#define Uv_8 int8 +#define Uv_16 int16 +#define Uv_32 int32 +#define Uv_ptr intptr +#define U_a volatile *a +#define U_cmp *cmp +#define U_v v +#define U_set set +#endif /* __GCC__ transparent_union magic */ + #ifdef HAVE_INLINE -#define make_atomic_add(S) \ -static inline int ## S my_atomic_add ## S( \ - int ## S volatile *a, int ## S v) \ -{ \ - make_atomic_add_body(S); \ - return v; \ +#define make_atomic_add(S) \ +STATIC_INLINE int ## S my_atomic_add ## S( \ + Uv_ ## S U_a, U_ ## S U_v) \ +{ \ + make_atomic_add_body(S); \ + return v; \ } -#define make_atomic_swap(S) \ -static inline int ## S my_atomic_swap ## S( \ - int ## S volatile *a, int ## S v) \ -{ \ - make_atomic_swap_body(S); \ - return v; \ +#define make_atomic_fas(S) \ +STATIC_INLINE int ## S my_atomic_fas ## S( \ + Uv_ ## S U_a, U_ ## S U_v) \ +{ \ + make_atomic_fas_body(S); \ + return v; \ } -#define make_atomic_cas(S) \ -static inline int my_atomic_cas ## S(int ## S volatile *a, \ - int ## S *cmp, int ## S set) \ -{ \ - int8 ret; \ - make_atomic_cas_body(S); \ - return ret; \ +#define make_atomic_cas(S) \ +STATIC_INLINE int my_atomic_cas ## S(Uv_ ## S U_a, \ + Uv_ ## S U_cmp, U_ ## S U_set) \ +{ \ + int8 ret; \ + make_atomic_cas_body(S); \ + return ret; \ } -#define make_atomic_load(S) \ -static inline int ## S my_atomic_load ## S(int ## S volatile *a) \ -{ \ - int ## S ret; \ - make_atomic_load_body(S); \ - return ret; \ +#define make_atomic_load(S) \ +STATIC_INLINE int ## S my_atomic_load ## S(Uv_ ## S U_a) \ +{ \ + int ## S ret; \ + make_atomic_load_body(S); \ + return ret; \ } -#define make_atomic_store(S) \ -static inline void my_atomic_store ## S( \ - int ## S volatile *a, int ## S v) \ -{ \ - make_atomic_store_body(S); \ +#define make_atomic_store(S) \ +STATIC_INLINE void my_atomic_store ## S( \ + Uv_ ## S U_a, U_ ## S U_v) \ +{ \ + make_atomic_store_body(S); \ } #else /* no inline functions */ -#define make_atomic_add(S) \ -extern int ## S my_atomic_add ## S(int ## S volatile *a, int ## S v); +#define make_atomic_add(S) \ +extern int ## S my_atomic_add ## S(Uv_ ## S, U_ ## S); -#define make_atomic_swap(S) \ -extern int ## S my_atomic_swap ## S(int ## S volatile *a, int ## S v); +#define make_atomic_fas(S) \ +extern int ## S my_atomic_fas ## S(Uv_ ## S, U_ ## S); -#define make_atomic_cas(S) \ -extern int my_atomic_cas ## S(int ## S volatile *a, int ## S *cmp, int ## S set); +#define make_atomic_cas(S) \ +extern int my_atomic_cas ## S(Uv_ ## S, Uv_ ## S, U_ ## S); -#define make_atomic_load(S) \ -extern int ## S my_atomic_load ## S(int ## S volatile *a); +#define make_atomic_load(S) \ +extern int ## S my_atomic_load ## S(Uv_ ## S); -#define make_atomic_store(S) \ -extern void my_atomic_store ## S(int ## S volatile *a, int ## S v); +#define make_atomic_store(S) \ +extern void my_atomic_store ## S(Uv_ ## S, U_ ## S); #endif @@ -112,26 +191,47 @@ make_atomic_store(16) make_atomic_store(32) make_atomic_store(ptr) -make_atomic_swap( 8) -make_atomic_swap(16) -make_atomic_swap(32) -make_atomic_swap(ptr) +make_atomic_fas( 8) +make_atomic_fas(16) +make_atomic_fas(32) +make_atomic_fas(ptr) +#ifdef _atomic_h_cleanup_ +#include _atomic_h_cleanup_ +#undef _atomic_h_cleanup_ +#endif + +#undef U_8 +#undef U_16 +#undef U_32 +#undef U_ptr +#undef a +#undef cmp +#undef v +#undef set +#undef U_a +#undef U_cmp +#undef U_v +#undef U_set #undef make_atomic_add #undef make_atomic_cas #undef make_atomic_load #undef make_atomic_store -#undef make_atomic_swap +#undef make_atomic_fas #undef make_atomic_add_body #undef make_atomic_cas_body #undef make_atomic_load_body #undef make_atomic_store_body -#undef make_atomic_swap_body +#undef make_atomic_fas_body #undef intptr -#ifdef _atomic_h_cleanup_ -#include _atomic_h_cleanup_ -#undef _atomic_h_cleanup_ +/* + the macro below defines (as an expression) the code that + will be run in spin-loops. Intel manuals recummend to have PAUSE there. + It is expected to be defined in include/atomic/ *.h files +*/ +#ifndef LF_BACKOFF +#define LF_BACKOFF (1) #endif #define MY_ATOMIC_OK 0 |