* [PATCH net-next v5 0/2] allocate multiple skbuffs on tx
@ 2023-03-25 22:02 Arseniy Krasnov
2023-03-25 22:03 ` [PATCH net-next v5 1/2] virtio/vsock: " Arseniy Krasnov
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Arseniy Krasnov @ 2023-03-25 22:02 UTC (permalink / raw)
To: Stefan Hajnoczi, Stefano Garzarella, David S. Miller,
Eric Dumazet, Jakub Kicinski, Paolo Abeni, Bobby Eshleman
Cc: kvm, virtualization, netdev, linux-kernel, kernel, oxffffaa, avkrasnov
This adds small optimization for tx path: instead of allocating single
skbuff on every call to transport, allocate multiple skbuff's until
credit space allows, thus trying to send as much as possible data without
return to af_vsock.c.
Also this patchset includes second patch which adds check and return from
'virtio_transport_get_credit()' and 'virtio_transport_put_credit()' when
these functions are called with 0 argument. This is needed, because zero
argument makes both functions to behave as no-effect, but both of them
always tries to acquire spinlock. Moreover, first patch always calls
function 'virtio_transport_put_credit()' with zero argument in case of
successful packet transmission.
Link to v1:
https://lore.kernel.org/netdev/2c52aa26-8181-d37a-bccd-a86bd3cbc6e1@sberdevices.ru/
Link to v2:
https://lore.kernel.org/netdev/ea5725eb-6cb5-cf15-2938-34e335a442fa@sberdevices.ru/
Link to v3:
https://lore.kernel.org/netdev/f33ef593-982e-2b3f-0986-6d537a3aaf08@sberdevices.ru/
Link to v4:
https://lore.kernel.org/netdev/0e0c1421-7cdc-2582-b120-cad6f42824bb@sberdevices.ru/
Link to v5:
https://lore.kernel.org/netdev/f0b283a1-cc63-dc3d-cc0c-0da7f684d4d2@sberdevices.ru/
Changelog:
v1 -> v2:
- If sent something, return number of bytes sent (even in
case of error). Return error only if failed to sent first
skbuff.
v2 -> v3:
- Handle case when transport callback returns unexpected value which
is not equal to 'skb->len'. Break loop.
- Don't check for zero value of 'rest_len' before calling
'virtio_transport_put_credit()'. Decided to add this check directly
to 'virtio_transport_put_credit()' in separate patch.
v3 -> v4:
- Use WARN_ONCE() to handle case when transport callback returns
unexpected value.
- Remove useless 'ret = -EFAULT;' assignment for case above.
v4 -> v5:
- Remove extra 'ret' initialization.
- Remove empty extra line before 'if (ret < 0)'.
- Add R-b tag for the first patch.
- Add second patch, thus creating patchset of 2 patches.
Arseniy Krasnov (2):
virtio/vsock: allocate multiple skbuffs on tx
virtio/vsock: check argument to avoid no effect call
net/vmw_vsock/virtio_transport_common.c | 63 +++++++++++++++++++------
1 file changed, 49 insertions(+), 14 deletions(-)
--
2.25.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH net-next v5 1/2] virtio/vsock: allocate multiple skbuffs on tx
2023-03-25 22:02 [PATCH net-next v5 0/2] allocate multiple skbuffs on tx Arseniy Krasnov
@ 2023-03-25 22:03 ` Arseniy Krasnov
2023-03-25 22:04 ` [PATCH net-next v5 2/2] virtio/vsock: check argument to avoid no effect call Arseniy Krasnov
2023-03-28 10:10 ` [PATCH net-next v5 0/2] allocate multiple skbuffs on tx patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: Arseniy Krasnov @ 2023-03-25 22:03 UTC (permalink / raw)
To: Stefan Hajnoczi, Stefano Garzarella, David S. Miller,
Eric Dumazet, Jakub Kicinski, Paolo Abeni, Bobby Eshleman
Cc: kvm, virtualization, netdev, linux-kernel, kernel, oxffffaa, avkrasnov
This adds small optimization for tx path: instead of allocating single
skbuff on every call to transport, allocate multiple skbuff's until
credit space allows, thus trying to send as much as possible data without
return to af_vsock.c.
Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
---
net/vmw_vsock/virtio_transport_common.c | 57 +++++++++++++++++++------
1 file changed, 43 insertions(+), 14 deletions(-)
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 6564192e7f20..9e87c7d4d7cf 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -196,7 +196,8 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
const struct virtio_transport *t_ops;
struct virtio_vsock_sock *vvs;
u32 pkt_len = info->pkt_len;
- struct sk_buff *skb;
+ u32 rest_len;
+ int ret;
info->type = virtio_transport_get_type(sk_vsock(vsk));
@@ -216,10 +217,6 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
vvs = vsk->trans;
- /* we can send less than pkt_len bytes */
- if (pkt_len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE)
- pkt_len = VIRTIO_VSOCK_MAX_PKT_BUF_SIZE;
-
/* virtio_transport_get_credit might return less than pkt_len credit */
pkt_len = virtio_transport_get_credit(vvs, pkt_len);
@@ -227,17 +224,49 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
return pkt_len;
- skb = virtio_transport_alloc_skb(info, pkt_len,
- src_cid, src_port,
- dst_cid, dst_port);
- if (!skb) {
- virtio_transport_put_credit(vvs, pkt_len);
- return -ENOMEM;
- }
+ rest_len = pkt_len;
+
+ do {
+ struct sk_buff *skb;
+ size_t skb_len;
+
+ skb_len = min_t(u32, VIRTIO_VSOCK_MAX_PKT_BUF_SIZE, rest_len);
+
+ skb = virtio_transport_alloc_skb(info, skb_len,
+ src_cid, src_port,
+ dst_cid, dst_port);
+ if (!skb) {
+ ret = -ENOMEM;
+ break;
+ }
- virtio_transport_inc_tx_pkt(vvs, skb);
+ virtio_transport_inc_tx_pkt(vvs, skb);
- return t_ops->send_pkt(skb);
+ ret = t_ops->send_pkt(skb);
+ if (ret < 0)
+ break;
+
+ /* Both virtio and vhost 'send_pkt()' returns 'skb_len',
+ * but for reliability use 'ret' instead of 'skb_len'.
+ * Also if partial send happens (e.g. 'ret' != 'skb_len')
+ * somehow, we break this loop, but account such returned
+ * value in 'virtio_transport_put_credit()'.
+ */
+ rest_len -= ret;
+
+ if (WARN_ONCE(ret != skb_len,
+ "'send_pkt()' returns %i, but %zu expected\n",
+ ret, skb_len))
+ break;
+ } while (rest_len);
+
+ virtio_transport_put_credit(vvs, rest_len);
+
+ /* Return number of bytes, if any data has been sent. */
+ if (rest_len != pkt_len)
+ ret = pkt_len - rest_len;
+
+ return ret;
}
static bool virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs,
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH net-next v5 2/2] virtio/vsock: check argument to avoid no effect call
2023-03-25 22:02 [PATCH net-next v5 0/2] allocate multiple skbuffs on tx Arseniy Krasnov
2023-03-25 22:03 ` [PATCH net-next v5 1/2] virtio/vsock: " Arseniy Krasnov
@ 2023-03-25 22:04 ` Arseniy Krasnov
2023-03-28 10:10 ` [PATCH net-next v5 0/2] allocate multiple skbuffs on tx patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: Arseniy Krasnov @ 2023-03-25 22:04 UTC (permalink / raw)
To: Stefan Hajnoczi, Stefano Garzarella, David S. Miller,
Eric Dumazet, Jakub Kicinski, Paolo Abeni, Bobby Eshleman
Cc: kvm, virtualization, netdev, linux-kernel, kernel, oxffffaa, avkrasnov
Both of these functions have no effect when input argument is 0, so to
avoid useless spinlock access, check argument before it.
Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
---
net/vmw_vsock/virtio_transport_common.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 9e87c7d4d7cf..312658c176bd 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -302,6 +302,9 @@ u32 virtio_transport_get_credit(struct virtio_vsock_sock *vvs, u32 credit)
{
u32 ret;
+ if (!credit)
+ return 0;
+
spin_lock_bh(&vvs->tx_lock);
ret = vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
if (ret > credit)
@@ -315,6 +318,9 @@ EXPORT_SYMBOL_GPL(virtio_transport_get_credit);
void virtio_transport_put_credit(struct virtio_vsock_sock *vvs, u32 credit)
{
+ if (!credit)
+ return;
+
spin_lock_bh(&vvs->tx_lock);
vvs->tx_cnt -= credit;
spin_unlock_bh(&vvs->tx_lock);
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH net-next v5 0/2] allocate multiple skbuffs on tx
2023-03-25 22:02 [PATCH net-next v5 0/2] allocate multiple skbuffs on tx Arseniy Krasnov
2023-03-25 22:03 ` [PATCH net-next v5 1/2] virtio/vsock: " Arseniy Krasnov
2023-03-25 22:04 ` [PATCH net-next v5 2/2] virtio/vsock: check argument to avoid no effect call Arseniy Krasnov
@ 2023-03-28 10:10 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: patchwork-bot+netdevbpf @ 2023-03-28 10:10 UTC (permalink / raw)
To: Arseniy Krasnov
Cc: stefanha, sgarzare, davem, edumazet, kuba, pabeni,
bobby.eshleman, kvm, virtualization, netdev, linux-kernel,
kernel, oxffffaa, avkrasnov
Hello:
This series was applied to netdev/net-next.git (main)
by Paolo Abeni <pabeni@redhat.com>:
On Sun, 26 Mar 2023 01:02:43 +0300 you wrote:
> This adds small optimization for tx path: instead of allocating single
> skbuff on every call to transport, allocate multiple skbuff's until
> credit space allows, thus trying to send as much as possible data without
> return to af_vsock.c.
>
> Also this patchset includes second patch which adds check and return from
> 'virtio_transport_get_credit()' and 'virtio_transport_put_credit()' when
> these functions are called with 0 argument. This is needed, because zero
> argument makes both functions to behave as no-effect, but both of them
> always tries to acquire spinlock. Moreover, first patch always calls
> function 'virtio_transport_put_credit()' with zero argument in case of
> successful packet transmission.
>
> [...]
Here is the summary with links:
- [net-next,v5,1/2] virtio/vsock: allocate multiple skbuffs on tx
https://git.kernel.org/netdev/net-next/c/b68ffb1b3bee
- [net-next,v5,2/2] virtio/vsock: check argument to avoid no effect call
https://git.kernel.org/netdev/net-next/c/e3ec366eb0d1
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-03-28 10:10 UTC | newest]
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2023-03-25 22:02 [PATCH net-next v5 0/2] allocate multiple skbuffs on tx Arseniy Krasnov
2023-03-25 22:03 ` [PATCH net-next v5 1/2] virtio/vsock: " Arseniy Krasnov
2023-03-25 22:04 ` [PATCH net-next v5 2/2] virtio/vsock: check argument to avoid no effect call Arseniy Krasnov
2023-03-28 10:10 ` [PATCH net-next v5 0/2] allocate multiple skbuffs on tx patchwork-bot+netdevbpf
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