On 2018年04月20日 01:35, Michael S. Tsirkin wrote:
virtio is using barriers to order memory accesses, thus dma_wmb/rmb is a good match. Build-tested on x86: Before [mst@tuck linux]$ size drivers/virtio/virtio_ring.o text data bss dec hex filename 11392 820 0 12212 2fb4 drivers/virtio/virtio_ring.o After mst@tuck linux]$ size drivers/virtio/virtio_ring.o text data bss dec hex filename 11284 820 0 12104 2f48 drivers/virtio/virtio_ring.o Cc: Ohad Ben-Cohen <[email protected]> Cc: Bjorn Andersson <[email protected]> Cc: [email protected] Signed-off-by: Michael S. Tsirkin <[email protected]> --- It's good in theory, but could one of RPMSG maintainers please review and ack this patch? Or even better test it? All these barriers are useless on Intel anyway ... include/linux/virtio_ring.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h index bbf3252..fab0213 100644 --- a/include/linux/virtio_ring.h +++ b/include/linux/virtio_ring.h @@ -35,7 +35,7 @@ static inline void virtio_rmb(bool weak_barriers) if (weak_barriers) virt_rmb(); else - rmb(); + dma_rmb(); }static inline void virtio_wmb(bool weak_barriers)@@ -43,7 +43,7 @@ static inline void virtio_wmb(bool weak_barriers) if (weak_barriers) virt_wmb(); else - wmb(); + dma_wmb(); }static inline void virtio_store_mb(bool weak_barriers,
Acked-by: Jason Wang <[email protected]>
