#ifndef _ASM_X86_SPINLOCK_H #define _ASM_X86_SPINLOCK_H #include #include #include #include #include #include #include /* * Your basic SMP spinlocks, allowing only a single CPU anywhere * * Simple spin lock operations. There are two variants, one clears IRQ's * on the local processor, one does not. * * These are fair FIFO ticket locks, which support up to 2^16 CPUs. * * (the type definitions are in asm/spinlock_types.h) */ /* How long a lock should spin before we consider blocking */ #define SPIN_THRESHOLD (1 << 15) extern struct static_key paravirt_ticketlocks_enabled; static __always_inline bool static_key_false(struct static_key *key); #include /* * Read-write spinlocks, allowing multiple readers * but only one writer. * * NOTE! it is quite common to have readers in interrupts * but no interrupt writers. For those circumstances we * can "mix" irq-safe locks - any writer needs to get a * irq-safe write-lock, but readers can get non-irqsafe * read-locks. * * On x86, we implement read-write locks using the generic qrwlock with * x86 specific optimization. */ #include #define arch_read_lock_flags(lock, flags) arch_read_lock(lock) #define arch_write_lock_flags(lock, flags) arch_write_lock(lock) #define arch_spin_relax(lock) cpu_relax() #define arch_read_relax(lock) cpu_relax() #define arch_write_relax(lock) cpu_relax() #endif /* _ASM_X86_SPINLOCK_H */