rmb                19 arch/x86/include/asm/barrier.h #define rmb() alternative("lock; addl $0,0(%%esp)", "lfence", X86_FEATURE_XMM2)
rmb                23 arch/x86/include/asm/barrier.h #define rmb()	asm volatile("lfence":::"memory")
rmb                38 include/asm-generic/barrier.h #define rmb()	mb()