* [PATCH] s390: more efficient smp barriers
@ 2016-01-10 11:53 Michael S. Tsirkin
2016-01-11 8:07 ` Martin Schwidefsky
0 siblings, 1 reply; 2+ messages in thread
From: Michael S. Tsirkin @ 2016-01-10 11:53 UTC (permalink / raw)
To: linux-kernel
Cc: Peter Zijlstra, Martin Schwidefsky, Heiko Carstens, Ingo Molnar,
Arnd Bergmann, Davidlohr Bueso, Andrey Konovalov,
Christian Borntraeger, linux-s390
As per: lkml.kernel.org/r/20150921112252.3c2937e1@mschwide
atomics imply a barrier on s390, so s390 should change
smp_mb__before_atomic and smp_mb__after_atomic to barrier() instead of
smp_mb() and hence should not use the generic versions.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Suggested-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
This is on top of arch barrier cleanup patchset,
will be included in v3 of that patchset.
arch/s390/include/asm/barrier.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/s390/include/asm/barrier.h b/arch/s390/include/asm/barrier.h
index 4d26fa4..5c8db3c 100644
--- a/arch/s390/include/asm/barrier.h
+++ b/arch/s390/include/asm/barrier.h
@@ -45,6 +45,9 @@ do { \
___p1; \
})
+#define __smp_mb__before_atomic() barrier()
+#define __smp_mb__after_atomic() barrier()
+
#include <asm-generic/barrier.h>
#endif /* __ASM_BARRIER_H */
--
MST
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH] s390: more efficient smp barriers
2016-01-10 11:53 [PATCH] s390: more efficient smp barriers Michael S. Tsirkin
@ 2016-01-11 8:07 ` Martin Schwidefsky
0 siblings, 0 replies; 2+ messages in thread
From: Martin Schwidefsky @ 2016-01-11 8:07 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: linux-kernel, Peter Zijlstra, Heiko Carstens, Ingo Molnar,
Arnd Bergmann, Davidlohr Bueso, Andrey Konovalov,
Christian Borntraeger, linux-s390
On Sun, 10 Jan 2016 13:53:26 +0200
"Michael S. Tsirkin" <mst@redhat.com> wrote:
> As per: lkml.kernel.org/r/20150921112252.3c2937e1@mschwide
> atomics imply a barrier on s390, so s390 should change
> smp_mb__before_atomic and smp_mb__after_atomic to barrier() instead of
> smp_mb() and hence should not use the generic versions.
>
> Suggested-by: Peter Zijlstra <peterz@infradead.org>
> Suggested-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>
> This is on top of arch barrier cleanup patchset,
> will be included in v3 of that patchset.
>
> arch/s390/include/asm/barrier.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/s390/include/asm/barrier.h b/arch/s390/include/asm/barrier.h
> index 4d26fa4..5c8db3c 100644
> --- a/arch/s390/include/asm/barrier.h
> +++ b/arch/s390/include/asm/barrier.h
> @@ -45,6 +45,9 @@ do { \
> ___p1; \
> })
>
> +#define __smp_mb__before_atomic() barrier()
> +#define __smp_mb__after_atomic() barrier()
> +
> #include <asm-generic/barrier.h>
>
> #endif /* __ASM_BARRIER_H */
Feel free to add:
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
--
blue skies,
Martin.
"Reality continues to ruin my life." - Calvin.
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