diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/port/atomics.c | 109 | ||||
| -rw-r--r-- | src/include/pg_config.h.in | 3 | ||||
| -rw-r--r-- | src/include/port/atomics.h | 18 | ||||
| -rw-r--r-- | src/include/port/atomics/arch-x86.h | 8 | ||||
| -rw-r--r-- | src/include/port/atomics/fallback.h | 87 | ||||
| -rw-r--r-- | src/include/port/atomics/generic-gcc.h | 4 | ||||
| -rw-r--r-- | src/include/port/atomics/generic-msvc.h | 4 | ||||
| -rw-r--r-- | src/include/port/atomics/generic-sunpro.h | 8 |
8 files changed, 11 insertions, 230 deletions
diff --git a/src/backend/port/atomics.c b/src/backend/port/atomics.c index cd7ede96726..6f1e014d0b8 100644 --- a/src/backend/port/atomics.c +++ b/src/backend/port/atomics.c @@ -49,115 +49,6 @@ pg_extern_compiler_barrier(void) #endif -#ifdef PG_HAVE_ATOMIC_FLAG_SIMULATION - -void -pg_atomic_init_flag_impl(volatile pg_atomic_flag *ptr) -{ - StaticAssertDecl(sizeof(ptr->sema) >= sizeof(slock_t), - "size mismatch of atomic_flag vs slock_t"); - - SpinLockInit((slock_t *) &ptr->sema); - - ptr->value = false; -} - -bool -pg_atomic_test_set_flag_impl(volatile pg_atomic_flag *ptr) -{ - uint32 oldval; - - SpinLockAcquire((slock_t *) &ptr->sema); - oldval = ptr->value; - ptr->value = true; - SpinLockRelease((slock_t *) &ptr->sema); - - return oldval == 0; -} - -void -pg_atomic_clear_flag_impl(volatile pg_atomic_flag *ptr) -{ - SpinLockAcquire((slock_t *) &ptr->sema); - ptr->value = false; - SpinLockRelease((slock_t *) &ptr->sema); -} - -bool -pg_atomic_unlocked_test_flag_impl(volatile pg_atomic_flag *ptr) -{ - return ptr->value == 0; -} - -#endif /* PG_HAVE_ATOMIC_FLAG_SIMULATION */ - -#ifdef PG_HAVE_ATOMIC_U32_SIMULATION -void -pg_atomic_init_u32_impl(volatile pg_atomic_uint32 *ptr, uint32 val_) -{ - StaticAssertDecl(sizeof(ptr->sema) >= sizeof(slock_t), - "size mismatch of atomic_uint32 vs slock_t"); - - SpinLockInit((slock_t *) &ptr->sema); - ptr->value = val_; -} - -void -pg_atomic_write_u32_impl(volatile pg_atomic_uint32 *ptr, uint32 val) -{ - /* - * One might think that an unlocked write doesn't need to acquire the - * spinlock, but one would be wrong. Even an unlocked write has to cause a - * concurrent pg_atomic_compare_exchange_u32() (et al) to fail. - */ - SpinLockAcquire((slock_t *) &ptr->sema); - ptr->value = val; - SpinLockRelease((slock_t *) &ptr->sema); -} - -bool -pg_atomic_compare_exchange_u32_impl(volatile pg_atomic_uint32 *ptr, - uint32 *expected, uint32 newval) -{ - bool ret; - - /* - * Do atomic op under a spinlock. It might look like we could just skip - * the cmpxchg if the lock isn't available, but that'd just emulate a - * 'weak' compare and swap. I.e. one that allows spurious failures. Since - * several algorithms rely on a strong variant and that is efficiently - * implementable on most major architectures let's emulate it here as - * well. - */ - SpinLockAcquire((slock_t *) &ptr->sema); - - /* perform compare/exchange logic */ - ret = ptr->value == *expected; - *expected = ptr->value; - if (ret) - ptr->value = newval; - - /* and release lock */ - SpinLockRelease((slock_t *) &ptr->sema); - - return ret; -} - -uint32 -pg_atomic_fetch_add_u32_impl(volatile pg_atomic_uint32 *ptr, int32 add_) -{ - uint32 oldval; - - SpinLockAcquire((slock_t *) &ptr->sema); - oldval = ptr->value; - ptr->value += add_; - SpinLockRelease((slock_t *) &ptr->sema); - return oldval; -} - -#endif /* PG_HAVE_ATOMIC_U32_SIMULATION */ - - #ifdef PG_HAVE_ATOMIC_U64_SIMULATION void diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in index e6c06f61027..0e9b108e667 100644 --- a/src/include/pg_config.h.in +++ b/src/include/pg_config.h.in @@ -57,9 +57,6 @@ /* Define to 1 if you have the `ASN1_STRING_get0_data' function. */ #undef HAVE_ASN1_STRING_GET0_DATA -/* Define to 1 if you want to use atomics if available. */ -#undef HAVE_ATOMICS - /* Define to 1 if you have the <atomic.h> header file. */ #undef HAVE_ATOMIC_H diff --git a/src/include/port/atomics.h b/src/include/port/atomics.h index 03134e3b7bb..c2ce10a718f 100644 --- a/src/include/port/atomics.h +++ b/src/include/port/atomics.h @@ -17,7 +17,7 @@ * There exist generic, hardware independent, implementations for several * compilers which might be sufficient, although possibly not optimal, for a * new platform. If no such generic implementation is available spinlocks will - * be used to implement the API. + * be used to implement the 64-bit parts of the API. * * Implement _u64 atomics if and only if your platform can use them * efficiently (and obviously correctly). @@ -91,17 +91,17 @@ #elif defined(__SUNPRO_C) && !defined(__GNUC__) #include "port/atomics/generic-sunpro.h" #else -/* - * Unsupported compiler, we'll likely use slower fallbacks... At least - * compiler barriers should really be provided. - */ +/* Unknown compiler. */ +#endif + +/* Fail if we couldn't find implementations of required facilities. */ +#if !defined(PG_HAVE_ATOMIC_U32_SUPPORT) +#error "could not find an implementation of pg_atomic_uint32" #endif /* - * Provide a full fallback of the pg_*_barrier(), pg_atomic**_flag and - * pg_atomic_* APIs for platforms without sufficient spinlock and/or atomics - * support. In the case of spinlock backed atomics the emulation is expected - * to be efficient, although less so than native atomics support. + * Provide a spinlock-based implementation of the 64 bit variants, if + * necessary. */ #include "port/atomics/fallback.h" diff --git a/src/include/port/atomics/arch-x86.h b/src/include/port/atomics/arch-x86.h index 2a8eca30fcf..c12f8a60697 100644 --- a/src/include/port/atomics/arch-x86.h +++ b/src/include/port/atomics/arch-x86.h @@ -49,8 +49,6 @@ * nice to support older gcc's and the compare/exchange implementation here is * actually more efficient than the * __sync variant. */ -#if defined(HAVE_ATOMICS) - #if defined(__GNUC__) || defined(__INTEL_COMPILER) #define PG_HAVE_ATOMIC_FLAG_SUPPORT @@ -80,8 +78,6 @@ typedef struct pg_atomic_uint64 #endif /* defined(__GNUC__) || defined(__INTEL_COMPILER) */ -#endif /* defined(HAVE_ATOMICS) */ - #if !defined(PG_HAVE_SPIN_DELAY) /* * This sequence is equivalent to the PAUSE instruction ("rep" is @@ -132,8 +128,6 @@ pg_spin_delay_impl(void) #endif /* !defined(PG_HAVE_SPIN_DELAY) */ -#if defined(HAVE_ATOMICS) - #if defined(__GNUC__) || defined(__INTEL_COMPILER) #define PG_HAVE_ATOMIC_TEST_SET_FLAG @@ -250,5 +244,3 @@ pg_atomic_fetch_add_u64_impl(volatile pg_atomic_uint64 *ptr, int64 add_) defined(__x86_64__) || defined(__x86_64) || defined(_M_X64) /* gcc, sunpro, msvc */ #define PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY #endif /* 8 byte single-copy atomicity */ - -#endif /* HAVE_ATOMICS */ diff --git a/src/include/port/atomics/fallback.h b/src/include/port/atomics/fallback.h index 2e3eef4acaf..8ffd1a8fd32 100644 --- a/src/include/port/atomics/fallback.h +++ b/src/include/port/atomics/fallback.h @@ -1,7 +1,7 @@ /*------------------------------------------------------------------------- * * fallback.h - * Fallback for platforms without spinlock and/or atomics support. Slower + * Fallback for platforms without 64 bit atomics support. Slower * than native atomics support, but not unusably slow. * * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group @@ -49,50 +49,6 @@ extern void pg_extern_compiler_barrier(void); #endif -/* - * If we have atomics implementation for this platform, fall back to providing - * the atomics API using a spinlock to protect the internal state. Possibly - * the spinlock implementation uses semaphores internally... - * - * We have to be a bit careful here, as it's not guaranteed that atomic - * variables are mapped to the same address in every process (e.g. dynamic - * shared memory segments). We can't just hash the address and use that to map - * to a spinlock. Instead assign a spinlock on initialization of the atomic - * variable. - */ -#if !defined(PG_HAVE_ATOMIC_FLAG_SUPPORT) && !defined(PG_HAVE_ATOMIC_U32_SUPPORT) - -#define PG_HAVE_ATOMIC_FLAG_SIMULATION -#define PG_HAVE_ATOMIC_FLAG_SUPPORT - -typedef struct pg_atomic_flag -{ - /* - * To avoid circular includes we can't use s_lock as a type here. Instead - * just reserve enough space for all spinlock types. Some platforms would - * be content with just one byte instead of 4, but that's not too much - * waste. - */ - int sema; - volatile bool value; -} pg_atomic_flag; - -#endif /* PG_HAVE_ATOMIC_FLAG_SUPPORT */ - -#if !defined(PG_HAVE_ATOMIC_U32_SUPPORT) - -#define PG_HAVE_ATOMIC_U32_SIMULATION - -#define PG_HAVE_ATOMIC_U32_SUPPORT -typedef struct pg_atomic_uint32 -{ - /* Check pg_atomic_flag's definition above for an explanation */ - int sema; - volatile uint32 value; -} pg_atomic_uint32; - -#endif /* PG_HAVE_ATOMIC_U32_SUPPORT */ - #if !defined(PG_HAVE_ATOMIC_U64_SUPPORT) #define PG_HAVE_ATOMIC_U64_SIMULATION @@ -100,49 +56,10 @@ typedef struct pg_atomic_uint32 #define PG_HAVE_ATOMIC_U64_SUPPORT typedef struct pg_atomic_uint64 { - /* Check pg_atomic_flag's definition above for an explanation */ int sema; volatile uint64 value; } pg_atomic_uint64; -#endif /* PG_HAVE_ATOMIC_U64_SUPPORT */ - -#ifdef PG_HAVE_ATOMIC_FLAG_SIMULATION - -#define PG_HAVE_ATOMIC_INIT_FLAG -extern void pg_atomic_init_flag_impl(volatile pg_atomic_flag *ptr); - -#define PG_HAVE_ATOMIC_TEST_SET_FLAG -extern bool pg_atomic_test_set_flag_impl(volatile pg_atomic_flag *ptr); - -#define PG_HAVE_ATOMIC_CLEAR_FLAG -extern void pg_atomic_clear_flag_impl(volatile pg_atomic_flag *ptr); - -#define PG_HAVE_ATOMIC_UNLOCKED_TEST_FLAG -extern bool pg_atomic_unlocked_test_flag_impl(volatile pg_atomic_flag *ptr); - -#endif /* PG_HAVE_ATOMIC_FLAG_SIMULATION */ - -#ifdef PG_HAVE_ATOMIC_U32_SIMULATION - -#define PG_HAVE_ATOMIC_INIT_U32 -extern void pg_atomic_init_u32_impl(volatile pg_atomic_uint32 *ptr, uint32 val_); - -#define PG_HAVE_ATOMIC_WRITE_U32 -extern void pg_atomic_write_u32_impl(volatile pg_atomic_uint32 *ptr, uint32 val); - -#define PG_HAVE_ATOMIC_COMPARE_EXCHANGE_U32 -extern bool pg_atomic_compare_exchange_u32_impl(volatile pg_atomic_uint32 *ptr, - uint32 *expected, uint32 newval); - -#define PG_HAVE_ATOMIC_FETCH_ADD_U32 -extern uint32 pg_atomic_fetch_add_u32_impl(volatile pg_atomic_uint32 *ptr, int32 add_); - -#endif /* PG_HAVE_ATOMIC_U32_SIMULATION */ - - -#ifdef PG_HAVE_ATOMIC_U64_SIMULATION - #define PG_HAVE_ATOMIC_INIT_U64 extern void pg_atomic_init_u64_impl(volatile pg_atomic_uint64 *ptr, uint64 val_); @@ -153,4 +70,4 @@ extern bool pg_atomic_compare_exchange_u64_impl(volatile pg_atomic_uint64 *ptr, #define PG_HAVE_ATOMIC_FETCH_ADD_U64 extern uint64 pg_atomic_fetch_add_u64_impl(volatile pg_atomic_uint64 *ptr, int64 add_); -#endif /* PG_HAVE_ATOMIC_U64_SIMULATION */ +#endif /* PG_HAVE_ATOMIC_U64_SUPPORT */ diff --git a/src/include/port/atomics/generic-gcc.h b/src/include/port/atomics/generic-gcc.h index 872d2f02af4..cfbcbe0fff7 100644 --- a/src/include/port/atomics/generic-gcc.h +++ b/src/include/port/atomics/generic-gcc.h @@ -53,8 +53,6 @@ #endif -#ifdef HAVE_ATOMICS - /* generic gcc based atomic flag implementation */ #if !defined(PG_HAVE_ATOMIC_FLAG_SUPPORT) \ && (defined(HAVE_GCC__SYNC_INT32_TAS) || defined(HAVE_GCC__SYNC_CHAR_TAS)) @@ -319,5 +317,3 @@ pg_atomic_fetch_or_u64_impl(volatile pg_atomic_uint64 *ptr, uint64 or_) #endif #endif /* !defined(PG_DISABLE_64_BIT_ATOMICS) */ - -#endif /* defined(HAVE_ATOMICS) */ diff --git a/src/include/port/atomics/generic-msvc.h b/src/include/port/atomics/generic-msvc.h index c013aca5e7c..677436f2601 100644 --- a/src/include/port/atomics/generic-msvc.h +++ b/src/include/port/atomics/generic-msvc.h @@ -30,8 +30,6 @@ #define pg_memory_barrier_impl() MemoryBarrier() #endif -#if defined(HAVE_ATOMICS) - #define PG_HAVE_ATOMIC_U32_SUPPORT typedef struct pg_atomic_uint32 { @@ -115,5 +113,3 @@ pg_atomic_fetch_add_u64_impl(volatile pg_atomic_uint64 *ptr, int64 add_) } #endif /* _WIN64 */ - -#endif /* HAVE_ATOMICS */ diff --git a/src/include/port/atomics/generic-sunpro.h b/src/include/port/atomics/generic-sunpro.h index 840a45e7788..08f093ed2c1 100644 --- a/src/include/port/atomics/generic-sunpro.h +++ b/src/include/port/atomics/generic-sunpro.h @@ -17,8 +17,6 @@ * ------------------------------------------------------------------------- */ -#if defined(HAVE_ATOMICS) - #ifdef HAVE_MBARRIER_H #include <mbarrier.h> @@ -66,10 +64,6 @@ typedef struct pg_atomic_uint64 #endif /* HAVE_ATOMIC_H */ -#endif /* defined(HAVE_ATOMICS) */ - - -#if defined(HAVE_ATOMICS) #ifdef HAVE_ATOMIC_H @@ -117,5 +111,3 @@ pg_atomic_exchange_u64_impl(volatile pg_atomic_uint64 *ptr, uint64 newval) } #endif /* HAVE_ATOMIC_H */ - -#endif /* defined(HAVE_ATOMICS) */ |