similar to: [PATCH] virtio: use smp_XX barriers

virtio is communicating with a virtual "device" that actually runs on another host processor. Thus SMP barriers can be used to control memory access ordering. Where possible, we should use SMP barriers which are more lightweight than mandatory barriers, because mandatory barriers also control MMIO effects on accesses through relaxed memory I/O windows (which virtio does not use)

virtio is communicating with a virtual "device" that actually runs on another host processor. Thus SMP barriers can be used to control memory access ordering. Where possible, we should use SMP barriers which are more lightweight than mandatory barriers, because mandatory barriers also control MMIO effects on accesses through relaxed memory I/O windows (which virtio does not use)

vhost-net only uses memory barriers to control SMP effects (communication with userspace potentially running on a different CPU), so it should use SMP barriers and not mandatory barriers for memory access ordering, as suggested by Documentation/memory-barriers.txt Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/vhost/vhost.c | 10 +++++----- 1 files changed, 5

vhost-net only uses memory barriers to control SMP effects (communication with userspace potentially running on a different CPU), so it should use SMP barriers and not mandatory barriers for memory access ordering, as suggested by Documentation/memory-barriers.txt Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/vhost/vhost.c | 10 +++++----- 1 files changed, 5

Paolo Bonzini <pbonzini at redhat.com> writes: > Il 19/06/2013 10:24, Michael S. Tsirkin ha scritto: >>> > 2) We introduce VIRTIO_NET_F_ANY_LAYOUT and VIRTIO_BLK_F_ANY_LAYOUT >>> > specifically for net and block (note the new names). > > So why not a transport feature? Is it just because the SCSI commands > for virtio-blk also require a config space

Il 20/06/2013 04:40, Rusty Russell ha scritto: > Paolo Bonzini <pbonzini at redhat.com> writes: >> Il 19/06/2013 10:24, Michael S. Tsirkin ha scritto: >>>>> 2) We introduce VIRTIO_NET_F_ANY_LAYOUT and VIRTIO_BLK_F_ANY_LAYOUT >>>>> specifically for net and block (note the new names). >> >> So why not a transport feature? Is it just

Il 20/06/2013 04:40, Rusty Russell ha scritto: > Paolo Bonzini <pbonzini at redhat.com> writes: >> Il 19/06/2013 10:24, Michael S. Tsirkin ha scritto: >>>>> 2) We introduce VIRTIO_NET_F_ANY_LAYOUT and VIRTIO_BLK_F_ANY_LAYOUT >>>>> specifically for net and block (note the new names). >> >> So why not a transport feature? Is it just

From: Rusty Russell <rusty at rustcorp.com.au> Add a linked list of all virtqueues for a virtio device: this helps for debugging and is also needed for upcoming interface change. Also, add a "name" field for clearer debug messages. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> --- including this Rusty's patch here for completeness.

From: Rusty Russell <rusty at rustcorp.com.au> Add a linked list of all virtqueues for a virtio device: this helps for debugging and is also needed for upcoming interface change. Also, add a "name" field for clearer debug messages. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> --- including this Rusty's patch here for completeness.

Virtio is using memory barriers to control the ordering of references to the vrings on SMP systems. When the guest is compiled with SMP support, virtio is only using SMP barriers in order to avoid incurring the overhead involved with mandatory barriers. Lately, though, virtio is being increasingly used with inter-processor communication scenarios too, which involve running two (separate)

Virtio is using memory barriers to control the ordering of references to the vrings on SMP systems. When the guest is compiled with SMP support, virtio is only using SMP barriers in order to avoid incurring the overhead involved with mandatory barriers. Lately, though, virtio is being increasingly used with inter-processor communication scenarios too, which involve running two (separate)

Add a new vq, cmdq, to handle requests between the device and driver. This patch implements two commands sent from the device and handled in the driver. 1) VIRTIO_BALLOON_CMDQ_REPORT_STATS: this command is used to report the guest memory statistics to the host. The stats_vq mechanism is not used when the cmdq mechanism is enabled. 2) VIRTIO_BALLOON_CMDQ_REPORT_UNUSED_PAGES: this command is used

This helper returns 1 if a call to add_buf will not fail with -ENOSPC. This will help callers that do while(1) { alloc() if (add_buf()) { free(); break; } } This will result in one less alloc/free exercise. Signed-off-by: Amit Shah <amit.shah at redhat.com> --- v2: return true/false instead of 1/0 drivers/virtio/virtio_ring.c | 8 ++++++++ include/linux/virtio.h |

This helper returns 1 if a call to add_buf will not fail with -ENOSPC. This will help callers that do while(1) { alloc() if (add_buf()) { free(); break; } } This will result in one less alloc/free exercise. Signed-off-by: Amit Shah <amit.shah at redhat.com> --- v2: return true/false instead of 1/0 drivers/virtio/virtio_ring.c | 8 ++++++++ include/linux/virtio.h |

On Wed, Jul 12, 2017 at 08:40:21PM +0800, Wei Wang wrote: > Add a new vq, cmdq, to handle requests between the device and driver. > > This patch implements two commands sent from the device and handled in > the driver. > 1) VIRTIO_BALLOON_CMDQ_REPORT_STATS: this command is used to report > the guest memory statistics to the host. The stats_vq mechanism is not > used when the

On Wed, Jul 12, 2017 at 08:40:21PM +0800, Wei Wang wrote: > Add a new vq, cmdq, to handle requests between the device and driver. > > This patch implements two commands sent from the device and handled in > the driver. > 1) VIRTIO_BALLOON_CMDQ_REPORT_STATS: this command is used to report > the guest memory statistics to the host. The stats_vq mechanism is not > used when the

This helper returns 1 if a call to add_buf will not fail with -ENOSPC. This will help callers that do while(1) { alloc() if (add_buf()) { free(); break; } } This will result in one less alloc/free exercise. Signed-off-by: Amit Shah <amit.shah at redhat.com> --- drivers/virtio/virtio_ring.c | 8 ++++++++ include/linux/virtio.h | 5 +++++ 2 files changed, 13

This helper returns 1 if a call to add_buf will not fail with -ENOSPC. This will help callers that do while(1) { alloc() if (add_buf()) { free(); break; } } This will result in one less alloc/free exercise. Signed-off-by: Amit Shah <amit.shah at redhat.com> --- drivers/virtio/virtio_ring.c | 8 ++++++++ include/linux/virtio.h | 5 +++++ 2 files changed, 13

Add documentation for indirect descriptors Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- virtio-spec.lyx | 118 +++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 files changed, 114 insertions(+), 4 deletions(-) diff --git a/virtio-spec.lyx b/virtio-spec.lyx index 8062e11..b5a8fbd 100644 --- a/virtio-spec.lyx +++ b/virtio-spec.lyx @@ -1,4 +1,4 @@ -#LyX 1.6.4 created

Add documentation for indirect descriptors Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- virtio-spec.lyx | 118 +++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 files changed, 114 insertions(+), 4 deletions(-) diff --git a/virtio-spec.lyx b/virtio-spec.lyx index 8062e11..b5a8fbd 100644 --- a/virtio-spec.lyx +++ b/virtio-spec.lyx @@ -1,4 +1,4 @@ -#LyX 1.6.4 created