On Tue, Jul 17, 2018 at 04:16:00PM -0400, Waiman Long wrote: > The LOCK_PREFIX macro should be used in the assembly > __raw_callee_save___pv_queued_spin_unlock code so that the lock prefix > can be patched out on UP systems.
True; but does paravirt locking realy make sense on UP guests? > Signed-off-by: Waiman Long <[email protected]> > --- > arch/x86/include/asm/qspinlock_paravirt.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/include/asm/qspinlock_paravirt.h > b/arch/x86/include/asm/qspinlock_paravirt.h > index 9ef5ee0..159622e 100644 > --- a/arch/x86/include/asm/qspinlock_paravirt.h > +++ b/arch/x86/include/asm/qspinlock_paravirt.h > @@ -43,7 +43,7 @@ > "push %rdx;" > "mov $0x1,%eax;" > "xor %edx,%edx;" > - "lock cmpxchg %dl,(%rdi);" > + LOCK_PREFIX "cmpxchg %dl,(%rdi);" > "cmp $0x1,%al;" > "jne .slowpath;" > "pop %rdx;" > -- > 1.8.3.1 >
