Messages in this thread Patch in this message | | | Date | Mon, 04 Aug 2008 14:38:54 +0100 | From | "Jan Beulich" <> | Subject | [PATCH] x86: fix spin_is_contended() |
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The masked difference is what needs to be compared against 1, rather than the difference of masked values (which can be negative).
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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