* [PATCH] x86: fix spin_is_contended()
@ 2008-08-04 13:38 Jan Beulich
2008-08-05 2:07 ` Nick Piggin
0 siblings, 1 reply; 3+ messages in thread
From: Jan Beulich @ 2008-08-04 13:38 UTC (permalink / raw)
To: mingo, tglx, hpa; +Cc: Nick Piggin, linux-kernel
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)
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] x86: fix spin_is_contended()
2008-08-04 13:38 [PATCH] x86: fix spin_is_contended() Jan Beulich
@ 2008-08-05 2:07 ` Nick Piggin
2008-08-15 14:26 ` Ingo Molnar
0 siblings, 1 reply; 3+ messages in thread
From: Nick Piggin @ 2008-08-05 2:07 UTC (permalink / raw)
To: Jan Beulich; +Cc: mingo, tglx, hpa, linux-kernel
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)
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] x86: fix spin_is_contended()
2008-08-05 2:07 ` Nick Piggin
@ 2008-08-15 14:26 ` Ingo Molnar
0 siblings, 0 replies; 3+ messages in thread
From: Ingo Molnar @ 2008-08-15 14:26 UTC (permalink / raw)
To: Nick Piggin; +Cc: Jan Beulich, tglx, hpa, linux-kernel
* Nick Piggin <npiggin@suse.de> wrote:
> 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.
applied to tip/x86/urgent, with your:
Acked-by: Nick Piggin <npiggin@suse.de>
thanks Jan.
Ingo
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2008-08-15 14:26 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2008-08-04 13:38 [PATCH] x86: fix spin_is_contended() Jan Beulich
2008-08-05 2:07 ` Nick Piggin
2008-08-15 14:26 ` Ingo Molnar
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