| Message ID | ea5725eb-6cb5-cf15-2938-34e335a442fa@sberdevices.ru (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RFC,v2] virtio/vsock: allocate multiple skbuffs on tx | expand |
On Sun, Mar 19, 2023 at 09:46:10PM +0300, Arseniy Krasnov 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. > >Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru> >--- > Link to v1: > https://lore.kernel.org/netdev/2c52aa26-8181-d37a-bccd-a86bd3cbc6e1@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. > > net/vmw_vsock/virtio_transport_common.c | 53 ++++++++++++++++++------- > 1 file changed, 39 insertions(+), 14 deletions(-) > >diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c >index 6564192e7f20..3fdf1433ec28 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 +224,45 @@ 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; >- } >+ ret = 0; >+ 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); >+ >+ ret = t_ops->send_pkt(skb); >+ >+ if (ret < 0) >+ break; > >- virtio_transport_inc_tx_pkt(vvs, skb); >+ rest_len -= skb_len; t_ops->send_pkt() is returning the number of bytes sent. Current implementations always return `skb_len`, so there should be no problem, but it would be better to put a comment here, or we should handle the case where ret != skb_len to avoid future issues. >+ } while (rest_len); > >- return t_ops->send_pkt(skb); >+ /* Don't call this function with zero as argument: >+ * it tries to acquire spinlock and such argument >+ * makes this call useless. Good point, can we do the same also for virtio_transport_get_credit()? (Maybe in a separate patch) I'm thinking if may be better to do it directly inside the functions, but I don't have a strong opinion on that since we only call them here. Thanks, Stefano >+ */ >+ if (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 >
On 20.03.2023 17:29, Stefano Garzarella wrote: > On Sun, Mar 19, 2023 at 09:46:10PM +0300, Arseniy Krasnov 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. >> >> Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru> >> --- >> Link to v1: >> https://lore.kernel.org/netdev/2c52aa26-8181-d37a-bccd-a86bd3cbc6e1@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. >> >> net/vmw_vsock/virtio_transport_common.c | 53 ++++++++++++++++++------- >> 1 file changed, 39 insertions(+), 14 deletions(-) >> >> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c >> index 6564192e7f20..3fdf1433ec28 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 +224,45 @@ 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; >> - } >> + ret = 0; >> + 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); >> + >> + ret = t_ops->send_pkt(skb); >> + >> + if (ret < 0) >> + break; >> >> - virtio_transport_inc_tx_pkt(vvs, skb); >> + rest_len -= skb_len; > > t_ops->send_pkt() is returning the number of bytes sent. Current > implementations always return `skb_len`, so there should be no problem, > but it would be better to put a comment here, or we should handle the > case where ret != skb_len to avoid future issues. Hello, thanks for review! I see. I think i'll handle such partial sends (ret != skb_len) as error, as it is the only thing to do - we remove 'skb_len' from user's buffer, but 'send_pkt()' returns another value, so it will be strange for me to continue this tx loop as everything is ok. Something like this: + + if (ret < 0) + break; + + if (ret != skb_len) { + ret = -EFAULT;//or may be -EIO + break; + } > >> + } while (rest_len); >> >> - return t_ops->send_pkt(skb); >> + /* Don't call this function with zero as argument: >> + * it tries to acquire spinlock and such argument >> + * makes this call useless. > > Good point, can we do the same also for virtio_transport_get_credit()? > (Maybe in a separate patch) > > I'm thinking if may be better to do it directly inside the functions, > but I don't have a strong opinion on that since we only call them here. > I think in this patch i can call 'virtio_transport_put_credit()' without if, but i'll prepare separate patch which adds zero argument check to this function. As i see, the only function suitable for such 'if' condition is 'virtio_transport_put_credit()'. Anyway - for future use this check won't be bad. Thanks, Arseniy > Thanks, > Stefano > >> + */ >> + if (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 >> >
On Mon, Mar 20, 2023 at 09:02:19PM +0300, Arseniy Krasnov wrote: > > >On 20.03.2023 17:29, Stefano Garzarella wrote: >> On Sun, Mar 19, 2023 at 09:46:10PM +0300, Arseniy Krasnov 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. >>> >>> Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru> >>> --- >>> Link to v1: >>> https://lore.kernel.org/netdev/2c52aa26-8181-d37a-bccd-a86bd3cbc6e1@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. >>> >>> net/vmw_vsock/virtio_transport_common.c | 53 ++++++++++++++++++------- >>> 1 file changed, 39 insertions(+), 14 deletions(-) >>> >>> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c >>> index 6564192e7f20..3fdf1433ec28 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 +224,45 @@ 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; >>> - } >>> + ret = 0; >>> + 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); >>> + >>> + ret = t_ops->send_pkt(skb); >>> + >>> + if (ret < 0) >>> + break; >>> >>> - virtio_transport_inc_tx_pkt(vvs, skb); >>> + rest_len -= skb_len; >> >> t_ops->send_pkt() is returning the number of bytes sent. Current >> implementations always return `skb_len`, so there should be no problem, >> but it would be better to put a comment here, or we should handle the >> case where ret != skb_len to avoid future issues. > >Hello, thanks for review! > >I see. I think i'll handle such partial sends (ret != skb_len) as error, as >it is the only thing to do - we remove 'skb_len' from user's buffer, but >'send_pkt()' returns another value, so it will be strange for me to continue >this tx loop as everything is ok. Something like this: >+ >+ if (ret < 0) >+ break; >+ >+ if (ret != skb_len) { >+ ret = -EFAULT;//or may be -EIO >+ break; >+ } Good for me. > >> >>> + } while (rest_len); >>> >>> - return t_ops->send_pkt(skb); >>> + /* Don't call this function with zero as argument: >>> + * it tries to acquire spinlock and such argument >>> + * makes this call useless. >> >> Good point, can we do the same also for virtio_transport_get_credit()? >> (Maybe in a separate patch) >> >> I'm thinking if may be better to do it directly inside the functions, >> but I don't have a strong opinion on that since we only call them here. >> > >I think in this patch i can call 'virtio_transport_put_credit()' without if, but >i'll prepare separate patch which adds zero argument check to this function. Yep, I agree. >As i see, the only function suitable for such 'if' condition is >'virtio_transport_put_credit()'. Why not even for virtio_transport_get_credit() ? When we send packets without payload (e.g. VIRTIO_VSOCK_OP_REQUEST, VIRTIO_VSOCK_OP_SHUTDOWN) we call virtio_transport_get_credit() with `credit` parameter equal to 0, then we acquire the spinlock but in the end we do nothing. >Anyway - for future use this check won't be bad. Yep, these are minor improvements ;-) Thanks, Stefano
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index 6564192e7f20..3fdf1433ec28 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 +224,45 @@ 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; - } + ret = 0; + 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); + + ret = t_ops->send_pkt(skb); + + if (ret < 0) + break; - virtio_transport_inc_tx_pkt(vvs, skb); + rest_len -= skb_len; + } while (rest_len); - return t_ops->send_pkt(skb); + /* Don't call this function with zero as argument: + * it tries to acquire spinlock and such argument + * makes this call useless. + */ + if (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,
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> --- Link to v1: https://lore.kernel.org/netdev/2c52aa26-8181-d37a-bccd-a86bd3cbc6e1@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. net/vmw_vsock/virtio_transport_common.c | 53 ++++++++++++++++++------- 1 file changed, 39 insertions(+), 14 deletions(-)