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virtio_ring: Update weak barriers to use dma_wmb/rmb

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This change makes it so that instead of using smp_wmb/rmb which varies
depending on the kernel configuration we can can use dma_wmb/rmb which for
most architectures should be equal to or slightly more strict than
smp_wmb/rmb.

The advantage to this is that these barriers are available to uniprocessor
builds as well so the performance should improve under such a
configuration.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Alexander Duyck 2015-04-13 21:03:49 +09:30 • committed by Rusty Russell
commit 9e1a27ea42
1 changed files with 4 additions and 19 deletions
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53
include/linux/virtio_ring.h
View file

@ -21,46 +21,31 @@
* actually quite cheap. * actually quite cheap.
*/ */
#ifdef CONFIG_SMP
static inline void virtio_mb(bool weak_barriers) static inline void virtio_mb(bool weak_barriers)
{ {
#ifdef CONFIG_SMP
if (weak_barriers) if (weak_barriers)
smp_mb(); smp_mb();
else else
mb();
}
static inline void virtio_rmb(bool weak_barriers)
{
if (weak_barriers)
smp_rmb();
else
rmb();
}
static inline void virtio_wmb(bool weak_barriers)
{
if (weak_barriers)
smp_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 #endif
mb();
}
static inline void virtio_rmb(bool weak_barriers)
{
if (weak_barriers)
dma_rmb();
else
rmb();
}
static inline void virtio_wmb(bool weak_barriers)
{
if (weak_barriers)
dma_wmb();
else
wmb();
}
struct virtio_device; struct virtio_device;
struct virtqueue; struct virtqueue;