Alpha has native LL/SC instructions (LDL_L/STL_C, LDQ_L/STQ_C) that provide atomic read-modify-write capability, and already selects ARCH_HAVE_NMI_SAFE_CMPXCHG.
Selecting ARCH_SUPPORTS_ATOMIC_RMW enables MUTEX_SPIN_ON_OWNER and RWSEM_SPIN_ON_OWNER on SMP, allowing optimistic spinning on contended locks rather than immediately sleeping. Assisted-by: Claude:claude-opus-4-6 Signed-off-by: Matt Turner <[email protected]> Tested-by: Magnus Lindholm <[email protected]> Reviewed-by: Magnus Lindholm <[email protected]> --- arch/alpha/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig index 032c23f979c4..d039b7135d18 100644 --- a/arch/alpha/Kconfig +++ b/arch/alpha/Kconfig @@ -14,6 +14,7 @@ config ALPHA select ARCH_MODULE_NEEDS_WEAK_PER_CPU if SMP select ARCH_NO_PREEMPT select ARCH_NO_SG_CHAIN + select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_USE_CMPXCHG_LOCKREF select FORCE_PCI select PCI_DOMAINS if PCI -- 2.54.0
