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Groups > linux.kernel > #1299876
| From | "Michael S. Tsirkin" <mst@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v2 30/32] virtio_ring: update weak barriers to use __smp_xxx |
| Date | 2016-01-01 11:30 +0100 |
| Message-ID | <qM586-17W-7@gated-at.bofh.it> (permalink) |
| References | <qLQLL-8pu-3@gated-at.bofh.it> <qM4lH-ob-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Fri, Jan 01, 2016 at 11:39:40AM +0200, Michael S. Tsirkin wrote:
> virtio ring uses smp_wmb on SMP and wmb on !SMP,
> the reason for the later being that it might be
> talking to another kernel on the same SMP machine.
>
> This is exactly what __smp_XXX barriers do,
> so switch to these instead of homegrown ifdef hacks.
>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Alexander Duyck <alexander.duyck@gmail.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The subject and commit log should say
virt_xxx and not __smp_xxx - I fixed this up in
my tree.
> ---
> include/linux/virtio_ring.h | 25 ++++---------------------
> 1 file changed, 4 insertions(+), 21 deletions(-)
>
> diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
> index 67e06fe..f3fa55b 100644
> --- a/include/linux/virtio_ring.h
> +++ b/include/linux/virtio_ring.h
> @@ -12,7 +12,7 @@
> * anyone care?
> *
> * For virtio_pci on SMP, we don't need to order with respect to MMIO
> - * accesses through relaxed memory I/O windows, so smp_mb() et al are
> + * accesses through relaxed memory I/O windows, so virt_mb() et al are
> * sufficient.
> *
> * For using virtio to talk to real devices (eg. other heterogeneous
> @@ -21,11 +21,10 @@
> * actually quite cheap.
> */
>
> -#ifdef CONFIG_SMP
> static inline void virtio_mb(bool weak_barriers)
> {
> if (weak_barriers)
> - smp_mb();
> + virt_mb();
> else
> mb();
> }
> @@ -33,7 +32,7 @@ static inline void virtio_mb(bool weak_barriers)
> static inline void virtio_rmb(bool weak_barriers)
> {
> if (weak_barriers)
> - smp_rmb();
> + virt_rmb();
> else
> rmb();
> }
> @@ -41,26 +40,10 @@ static inline void virtio_rmb(bool weak_barriers)
> static inline void virtio_wmb(bool weak_barriers)
> {
> if (weak_barriers)
> - smp_wmb();
> + virt_wmb();
> else
> wmb();
> }
> -#else
> -static inline void virtio_mb(bool weak_barriers)
> -{
> - mb();
> -}
> -
> -static inline void virtio_rmb(bool weak_barriers)
> -{
> - rmb();
> -}
> -
> -static inline void virtio_wmb(bool weak_barriers)
> -{
> - wmb();
> -}
> -#endif
>
> struct virtio_device;
> struct virtqueue;
> --
> MST
--
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[PATCH v2 00/34] arch: barrier cleanup + barriers for virt "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:10 +0100
[PATCH v2 08/32] arm: reuse asm-generic/barrier.h "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:10 +0100
Re: [PATCH v2 08/32] arm: reuse asm-generic/barrier.h Russell King - ARM Linux <linux@arm.linux.org.uk> - 2016-01-02 12:30 +0100
[PATCH v2 27/32] x86: define __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:10 +0100
[PATCH v2 04/32] ia64: reuse asm-generic/barrier.h "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:10 +0100
[PATCH v2 22/32] s390: define __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:10 +0100
Re: [PATCH v2 22/32] s390: define __smp_xxx Peter Zijlstra <peterz@infradead.org> - 2016-01-04 14:50 +0100
Re: [PATCH v2 22/32] s390: define __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-04 21:20 +0100
Re: [PATCH v2 22/32] s390: define __smp_xxx Martin Schwidefsky <schwidefsky@de.ibm.com> - 2016-01-05 09:20 +0100
Re: [PATCH v2 22/32] s390: define __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-05 10:40 +0100
Re: [PATCH v2 22/32] s390: define __smp_xxx Martin Schwidefsky <schwidefsky@de.ibm.com> - 2016-01-05 13:10 +0100
Re: [PATCH v2 22/32] s390: define __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-05 14:10 +0100
Re: [PATCH v2 22/32] s390: define __smp_xxx Martin Schwidefsky <schwidefsky@de.ibm.com> - 2016-01-05 15:30 +0100
Re: [PATCH v2 22/32] s390: define __smp_xxx Christian Borntraeger <borntraeger@de.ibm.com> - 2016-01-05 16:50 +0100
Re: [PATCH v2 22/32] s390: define __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-05 17:10 +0100
[PATCH v2 15/32] powerpc: define __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:10 +0100
Re: [PATCH v2 15/32] powerpc: define __smp_xxx Boqun Feng <boqun.feng@gmail.com> - 2016-01-05 02:40 +0100
Re: [PATCH v2 15/32] powerpc: define __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-05 10:00 +0100
Re: [PATCH v2 15/32] powerpc: define __smp_xxx Boqun Feng <boqun.feng@gmail.com> - 2016-01-05 11:00 +0100
Re: [PATCH v2 15/32] powerpc: define __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-05 17:20 +0100
Re: [PATCH v2 15/32] powerpc: define __smp_xxx Boqun Feng <boqun.feng@gmail.com> - 2016-01-06 03:00 +0100
Re: [PATCH v2 15/32] powerpc: define __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-06 21:30 +0100
Re: [PATCH v2 15/32] powerpc: define __smp_xxx Boqun Feng <boqun.feng@gmail.com> - 2016-01-07 01:50 +0100
[PATCH v2 12/32] x86/um: reuse asm-generic/barrier.h "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:10 +0100
Re: [PATCH v2 12/32] x86/um: reuse asm-generic/barrier.h Richard Weinberger <richard@nod.at> - 2016-01-06 00:20 +0100
[PATCH v2 10/32] metag: reuse asm-generic/barrier.h "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:10 +0100
Re: [PATCH v2 10/32] metag: reuse asm-generic/barrier.h James Hogan <james.hogan@imgtec.com> - 2016-01-05 00:30 +0100
[PATCH v2 16/32] arm64: define __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:10 +0100
[PATCH v2 03/32] ia64: rename nop->iosapic_nop "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:10 +0100
[PATCH v2 06/32] s390: reuse asm-generic/barrier.h "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:10 +0100
Re: [PATCH v2 06/32] s390: reuse asm-generic/barrier.h Peter Zijlstra <peterz@infradead.org> - 2016-01-04 14:30 +0100
Re: [PATCH v2 06/32] s390: reuse asm-generic/barrier.h Martin Schwidefsky <schwidefsky@de.ibm.com> - 2016-01-04 16:10 +0100
Re: [PATCH v2 06/32] s390: reuse asm-generic/barrier.h "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-04 21:50 +0100
Re: [PATCH v2 06/32] s390: reuse asm-generic/barrier.h Martin Schwidefsky <schwidefsky@de.ibm.com> - 2016-01-05 09:10 +0100
Re: [PATCH v2 06/32] s390: reuse asm-generic/barrier.h "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-04 21:40 +0100
[PATCH v2 21/32] mips: define __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:20 +0100
[PATCH v2 09/32] arm64: reuse asm-generic/barrier.h "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:20 +0100
[PATCH v2 32/32] virtio_ring: use virt_store_mb "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:20 +0100
Re: [PATCH v2 32/32] virtio_ring: use virt_store_mb Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> - 2016-01-01 18:30 +0100
Re: [PATCH v2 32/32] virtio_ring: use virt_store_mb "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-03 10:10 +0100
[PATCH v2 31/32] sh: support a 2-byte smp_store_mb "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:20 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb Peter Zijlstra <peterz@infradead.org> - 2016-01-04 15:10 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb Rich Felker <dalias@libc.org> - 2016-01-06 00:40 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-06 12:20 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb Peter Zijlstra <peterz@infradead.org> - 2016-01-06 12:50 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-06 13:00 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb Peter Zijlstra <peterz@infradead.org> - 2016-01-06 15:40 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb Rob Landley <rob@landley.net> - 2016-01-06 16:50 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb Peter Zijlstra <peterz@infradead.org> - 2016-01-06 18:00 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb Rob Landley <rob@landley.net> - 2016-01-06 21:30 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb Geert Uytterhoeven <geert@linux-m68k.org> - 2016-01-06 20:00 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb Rich Felker <dalias@libc.org> - 2016-01-06 19:30 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-06 21:30 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb Rich Felker <dalias@libc.org> - 2016-01-07 01:00 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb Peter Zijlstra <peterz@infradead.org> - 2016-01-07 14:40 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb Rich Felker <dalias@libc.org> - 2016-01-07 20:10 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-07 17:00 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-07 18:50 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb Rich Felker <dalias@libc.org> - 2016-01-07 20:20 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-07 23:50 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb Rich Felker <dalias@libc.org> - 2016-01-08 05:30 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-08 08:30 +0100
Re: [PATCH v2 31/32] sh: support a 2-byte smp_store_mb "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-06 23:20 +0100
[PATCH v2 33/34] xenbus: use virt_xxx barriers "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:20 +0100
Re: [Xen-devel] [PATCH v2 33/34] xenbus: use virt_xxx barriers David Vrabel <david.vrabel@citrix.com> - 2016-01-04 12:40 +0100
Re: [PATCH v2 33/34] xenbus: use virt_xxx barriers Stefano Stabellini <stefano.stabellini@eu.citrix.com> - 2016-01-04 13:10 +0100
Re: [PATCH v2 33/34] xenbus: use virt_xxx barriers Peter Zijlstra <peterz@infradead.org> - 2016-01-04 15:20 +0100
[PATCH v2 26/32] xtensa: define __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:20 +0100
[PATCH v2 34/34] xen/io: use virt_xxx barriers "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:20 +0100
Re: [Xen-devel] [PATCH v2 34/34] xen/io: use virt_xxx barriers David Vrabel <david.vrabel@citrix.com> - 2016-01-04 12:40 +0100
Re: [PATCH v2 34/34] xen/io: use virt_xxx barriers Stefano Stabellini <stefano.stabellini@eu.citrix.com> - 2016-01-04 13:10 +0100
[PATCH v2 02/32] asm-generic: guard smp_store_release/load_acquire "Michael S. Tsirkin" <mst@redhat.com> - 2015-12-31 20:20 +0100
[PATCH v2 30/32] virtio_ring: update weak barriers to use __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-01 10:40 +0100
Re: [PATCH v2 30/32] virtio_ring: update weak barriers to use __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-01 11:30 +0100
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