The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=fb63bc67483ee52245d6161150702974da3d001c
commit fb63bc67483ee52245d6161150702974da3d001c Author: Mark Johnston <[email protected]> AuthorDate: 2026-08-03 14:02:33 +0000 Commit: Mark Johnston <[email protected]> CommitDate: 2026-08-03 15:22:13 +0000 atomic: Implement atomic_{set,clear}_8 in _atomic_subword.h Reimplement atomic_{set,clear}_16 using atomic_set_32. Remove emulation of these operations from vm_page.c. Reviewed by: alc, kib MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D58580 --- sys/sys/_atomic_subword.h | 54 +++++++++++++++++++++++---------- sys/vm/vm_page.c | 76 ++++++----------------------------------------- 2 files changed, 48 insertions(+), 82 deletions(-) diff --git a/sys/sys/_atomic_subword.h b/sys/sys/_atomic_subword.h index 284e2bfa340f..907fef0bb193 100644 --- a/sys/sys/_atomic_subword.h +++ b/sys/sys/_atomic_subword.h @@ -201,21 +201,42 @@ atomic_load_acq_16(const volatile uint16_t *p) } #endif -#undef _ATOMIC_WORD_ALIGNED -#undef _ATOMIC_BYTE_SHIFT -#undef _ATOMIC_HWORD_SHIFT +#ifndef atomic_set_8 +static __inline void +atomic_set_8(volatile uint8_t *p, uint8_t bit) +{ + uint32_t *addr; + int shift; + + addr = _ATOMIC_WORD_ALIGNED(p); + shift = _ATOMIC_BYTE_SHIFT(p); + atomic_set_32(addr, (uint32_t)bit << shift); +} +#endif #ifndef atomic_set_16 static __inline void atomic_set_16(volatile uint16_t *p, uint16_t bit) { - uint16_t v; + uint32_t *addr; + int shift; + + addr = _ATOMIC_WORD_ALIGNED(p); + shift = _ATOMIC_HWORD_SHIFT(p); + atomic_set_32(addr, (uint32_t)bit << shift); +} +#endif + +#ifndef atomic_clear_8 +static __inline void +atomic_clear_8(volatile uint8_t *p, uint8_t bit) +{ + uint32_t *addr; + int shift; - v = atomic_load_16(p); - for (;;) { - if (atomic_fcmpset_16(p, &v, v | bit)) - break; - } + addr = _ATOMIC_WORD_ALIGNED(p); + shift = _ATOMIC_BYTE_SHIFT(p); + atomic_clear_32(addr, (uint32_t)bit << shift); } #endif @@ -223,14 +244,17 @@ atomic_set_16(volatile uint16_t *p, uint16_t bit) static __inline void atomic_clear_16(volatile uint16_t *p, uint16_t bit) { - uint16_t v; + uint32_t *addr; + int shift; - v = atomic_load_16(p); - for (;;) { - if (atomic_fcmpset_16(p, &v, v & ~bit)) - break; - } + addr = _ATOMIC_WORD_ALIGNED(p); + shift = _ATOMIC_HWORD_SHIFT(p); + atomic_clear_32(addr, (uint32_t)bit << shift); } #endif +#undef _ATOMIC_WORD_ALIGNED +#undef _ATOMIC_BYTE_SHIFT +#undef _ATOMIC_HWORD_SHIFT + #endif /* _SYS__ATOMIC_SUBWORD_H_ */ diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c index 130d084815f6..98d0472c8487 100644 --- a/sys/vm/vm_page.c +++ b/sys/vm/vm_page.c @@ -5378,67 +5378,33 @@ vm_page_bits(int base, int size) void vm_page_bits_set(vm_page_t m, vm_page_bits_t *bits, vm_page_bits_t set) { - #if PAGE_SIZE == 32768 atomic_set_64((uint64_t *)bits, set); #elif PAGE_SIZE == 16384 atomic_set_32((uint32_t *)bits, set); -#elif (PAGE_SIZE == 8192) && defined(atomic_set_16) +#elif PAGE_SIZE == 8192 atomic_set_16((uint16_t *)bits, set); -#elif (PAGE_SIZE == 4096) && defined(atomic_set_8) +#elif PAGE_SIZE == 4096 atomic_set_8((uint8_t *)bits, set); -#else /* PAGE_SIZE <= 8192 */ - uintptr_t addr; - int shift; - - addr = (uintptr_t)bits; - /* - * Use a trick to perform a 32-bit atomic on the - * containing aligned word, to not depend on the existence - * of atomic_{set, clear}_{8, 16}. - */ - shift = addr & (sizeof(uint32_t) - 1); -#if BYTE_ORDER == BIG_ENDIAN - shift = (sizeof(uint32_t) - sizeof(vm_page_bits_t) - shift) * NBBY; #else - shift *= NBBY; +#error unhandled page size #endif - addr &= ~(sizeof(uint32_t) - 1); - atomic_set_32((uint32_t *)addr, set << shift); -#endif /* PAGE_SIZE */ } static inline void vm_page_bits_clear(vm_page_t m, vm_page_bits_t *bits, vm_page_bits_t clear) { - #if PAGE_SIZE == 32768 atomic_clear_64((uint64_t *)bits, clear); #elif PAGE_SIZE == 16384 atomic_clear_32((uint32_t *)bits, clear); -#elif (PAGE_SIZE == 8192) && defined(atomic_clear_16) +#elif PAGE_SIZE == 8192 atomic_clear_16((uint16_t *)bits, clear); -#elif (PAGE_SIZE == 4096) && defined(atomic_clear_8) +#elif PAGE_SIZE == 4096 atomic_clear_8((uint8_t *)bits, clear); -#else /* PAGE_SIZE <= 8192 */ - uintptr_t addr; - int shift; - - addr = (uintptr_t)bits; - /* - * Use a trick to perform a 32-bit atomic on the - * containing aligned word, to not depend on the existence - * of atomic_{set, clear}_{8, 16}. - */ - shift = addr & (sizeof(uint32_t) - 1); -#if BYTE_ORDER == BIG_ENDIAN - shift = (sizeof(uint32_t) - sizeof(vm_page_bits_t) - shift) * NBBY; #else - shift *= NBBY; +#error unhandled page size #endif - addr &= ~(sizeof(uint32_t) - 1); - atomic_clear_32((uint32_t *)addr, clear << shift); -#endif /* PAGE_SIZE */ } static inline vm_page_bits_t @@ -5456,45 +5422,21 @@ vm_page_bits_swap(vm_page_t m, vm_page_bits_t *bits, vm_page_bits_t newbits) old = *bits; while (atomic_fcmpset_32(bits, &old, newbits) == 0); return (old); -#elif (PAGE_SIZE == 8192) && defined(atomic_fcmpset_16) +#elif PAGE_SIZE == 8192 uint16_t old; old = *bits; while (atomic_fcmpset_16(bits, &old, newbits) == 0); return (old); -#elif (PAGE_SIZE == 4096) && defined(atomic_fcmpset_8) +#elif PAGE_SIZE == 4096 uint8_t old; old = *bits; while (atomic_fcmpset_8(bits, &old, newbits) == 0); return (old); -#else /* PAGE_SIZE <= 4096*/ - uintptr_t addr; - uint32_t old, new, mask; - int shift; - - addr = (uintptr_t)bits; - /* - * Use a trick to perform a 32-bit atomic on the - * containing aligned word, to not depend on the existence - * of atomic_{set, swap, clear}_{8, 16}. - */ - shift = addr & (sizeof(uint32_t) - 1); -#if BYTE_ORDER == BIG_ENDIAN - shift = (sizeof(uint32_t) - sizeof(vm_page_bits_t) - shift) * NBBY; #else - shift *= NBBY; +#error unhandled page size #endif - addr &= ~(sizeof(uint32_t) - 1); - mask = VM_PAGE_BITS_ALL << shift; - - old = *bits; - do { - new = old & ~mask; - new |= newbits << shift; - } while (atomic_fcmpset_32((uint32_t *)addr, &old, new) == 0); - return (old >> shift); -#endif /* PAGE_SIZE */ } /*
