From: "Jan Beulich" <jbeulich@novell.com>
To: <mingo@elte.hu>, <tglx@linutronix.de>, <hpa@zytor.com>
Cc: "Nick Piggin" <npiggin@suse.de>, <linux-kernel@vger.kernel.org>
Subject: [PATCH] x86: fix spin_is_contended()
Date: Mon, 04 Aug 2008 14:38:54 +0100 [thread overview]
Message-ID: <4897228E.76E4.0078.0@novell.com> (raw)
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)
next reply other threads:[~2008-08-04 13:38 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-04 13:38 Jan Beulich [this message]
2008-08-05 2:07 ` Nick Piggin
2008-08-15 14:26 ` Ingo Molnar
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