Messages in this thread | | | Date | Tue, 5 Aug 2008 04:07:59 +0200 | From | Nick Piggin <> | Subject | Re: [PATCH] x86: fix spin_is_contended() |
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On Mon, Aug 04, 2008 at 02:38:54PM +0100, Jan Beulich wrote: > The masked difference is what needs to be compared against 1, rather > than the difference of masked values (which can be negative).
Dang, thanks.
> > Signed-off-by: Jan Beulich <jbeulich@novell.com> > Cc: Nick Piggin <npiggin@suse.de> > > --- > include/asm-x86/spinlock.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > --- linux-2.6.27-rc1/include/asm-x86/spinlock.h 2008-07-31 17:08:34.000000000 +0200 > +++ 2.6.27-rc1-x86-spin-is-contended/include/asm-x86/spinlock.h 2008-08-04 11:09:33.000000000 +0200 > @@ -65,7 +65,7 @@ static inline int __ticket_spin_is_conte > { > int tmp = ACCESS_ONCE(lock->slock); > > - return (((tmp >> 8) & 0xff) - (tmp & 0xff)) > 1; > + return (((tmp >> 8) - tmp) & 0xff) > 1; > } > > static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock) > @@ -127,7 +127,7 @@ static inline int __ticket_spin_is_conte > { > int tmp = ACCESS_ONCE(lock->slock); > > - return (((tmp >> 16) & 0xffff) - (tmp & 0xffff)) > 1; > + return (((tmp >> 16) - tmp) & 0xffff) > 1; > } > > static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock) > >
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