Hello,
DESCRIPTION
this is MSG_ZEROCOPY feature support for virtio/vsock. I tried to follow
current implementation for TCP as much as possible:
1) Sender must enable SO_ZEROCOPY flag to use this feature. Without this
flag, data will be sent in "classic" copy manner and MSG_ZEROCOPY
flag will be ignored (e.g. without completion).
2) Kernel uses completions from socket's error queue. Single completion
for single tx syscall (or it can merge several completions to single
one). I used already implemented logic for MSG_ZEROCOPY support:
'msg_zerocopy_realloc()' etc.
Difference with copy way is not significant. During packet allocation,
non-linear skb is created and filled with pinned user pages.
There are also some updates for vhost and guest parts of transport - in
both cases i've added handling of non-linear skb for virtio part. vhost
copies data from such skb to the guest's rx virtio buffers. In the guest,
virtio transport fills tx virtio queue with pages from skb.
Head of this patchset is:
https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=94e86ef1b801d213dfb8543633dec86abb1a457d
This version has several limits/problems:
1) As this feature totally depends on transport, there is no way (or it
is difficult) to check whether transport is able to handle it or not
during SO_ZEROCOPY setting. Seems I need to call AF_VSOCK specific
setsockopt callback from setsockopt callback for SOL_SOCKET, but this
leads to lock problem, because both AF_VSOCK and SOL_SOCKET callback
are not considered to be called from each other. So in current version
SO_ZEROCOPY is set successfully to any type (e.g. transport) of
AF_VSOCK socket, but if transport does not support MSG_ZEROCOPY,
tx routine will fail with EOPNOTSUPP.
^^^
This is still no resolved :(
2) When MSG_ZEROCOPY is used, for each tx system call we need to enqueue
one completion. In each completion there is flag which shows how tx
was performed: zerocopy or copy. This leads that whole message must
be send in zerocopy or copy way - we can't send part of message with
copying and rest of message with zerocopy mode (or vice versa). Now,
we need to account vsock credit logic, e.g. we can't send whole data
once - only allowed number of bytes could sent at any moment. In case
of copying way there is no problem as in worst case we can send single
bytes, but zerocopy is more complex because smallest transmission
unit is single page. So if there is not enough space at peer's side
to send integer number of pages (at least one) - we will wait, thus
stalling tx side. To overcome this problem i've added simple rule -
zerocopy is possible only when there is enough space at another side
for whole message (to check, that current 'msghdr' was already used
in previous tx iterations i use 'iov_offset' field of it's iov iter).
^^^
Discussed as ok during v2. Link:
https://lore.kernel.org/netdev/23guh3txkghxpgcrcjx7h62qsoj3xgjhfzgtbmqp2slrz3rxr4@zya2z7kwt75l/
3) loopback transport is not supported, because it requires to implement
non-linear skb handling in dequeue logic (as we "send" fragged skb
and "receive" it from the same queue). I'm going to implement it in
next versions.
^^^ fixed in v2
4) Current implementation sets max length of packet to 64KB. IIUC this
is due to 'kmalloc()' allocated data buffers. I think, in case of
MSG_ZEROCOPY this value could be increased, because 'kmalloc()' is
not touched for data - user space pages are used as buffers. Also
this limit trims every message which is > 64KB, thus such messages
will be send in copy mode due to 'iov_offset' check in 2).
^^^ fixed in v2
PATCHSET STRUCTURE
Patchset has the following structure:
1) Handle non-linear skbuff on receive in virtio/vhost.
2) Handle non-linear skbuff on send in virtio/vhost.
3) Updates for AF_VSOCK.
4) Enable MSG_ZEROCOPY support on transports.
5) Tests/tools/docs updates.
PERFORMANCE
Performance: it is a little bit tricky to compare performance between
copy and zerocopy transmissions. In zerocopy way we need to wait when
user buffers will be released by kernel, so it is like synchronous
path (wait until device driver will process it), while in copy way we
can feed data to kernel as many as we want, don't care about device
driver. So I compared only time which we spend in the 'send()' syscall.
Then if this value will be combined with total number of transmitted
bytes, we can get Gbit/s parameter. Also to avoid tx stalls due to not
enough credit, receiver allocates same amount of space as sender needs.
Sender:
./vsock_perf --sender <CID> --buf-size <buf size> --bytes 256M [--zc]
Receiver:
./vsock_perf --vsk-size 256M
I run tests on two setups: desktop with Core i7 - I use this PC for
development and in this case guest is nested guest, and host is normal
guest. Another hardware is some embedded board with Atom - here I don't
have nested virtualization - host runs on hw, and guest is normal guest.
G2H transmission (values are Gbit/s):
Core i7 with nested guest. Atom with normal guest.
*-------------------------------* *-------------------------------*
| | | | | | | |
| buf size | copy | zerocopy | | buf size | copy | zerocopy |
| | | | | | | |
*-------------------------------* *-------------------------------*
| 4KB | 3 | 10 | | 4KB | 0.8 | 1.9 |
*-------------------------------* *-------------------------------*
| 32KB | 20 | 61 | | 32KB | 6.8 | 20.2 |
*-------------------------------* *-------------------------------*
| 256KB | 33 | 244 | | 256KB | 7.8 | 55 |
*-------------------------------* *-------------------------------*
| 1M | 30 | 373 | | 1M | 7 | 95 |
*-------------------------------* *-------------------------------*
| 8M | 22 | 475 | | 8M | 7 | 114 |
*-------------------------------* *-------------------------------*
H2G:
Core i7 with nested guest. Atom with normal guest.
*-------------------------------* *-------------------------------*
| | | | | | | |
| buf size | copy | zerocopy | | buf size | copy | zerocopy |
| | | | | | | |
*-------------------------------* *-------------------------------*
| 4KB | 20 | 10 | | 4KB | 4.37 | 3 |
*-------------------------------* *-------------------------------*
| 32KB | 37 | 75 | | 32KB | 11 | 18 |
*-------------------------------* *-------------------------------*
| 256KB | 44 | 299 | | 256KB | 11 | 62 |
*-------------------------------* *-------------------------------*
| 1M | 28 | 335 | | 1M | 9 | 77 |
*-------------------------------* *-------------------------------*
| 8M | 27 | 417 | | 8M | 9.35 | 115 |
*-------------------------------* *-------------------------------*
* Let's look to the first line of both tables - where copy is better
than zerocopy. I analyzed this case more deeply and found that
bottleneck is function 'vhost_work_queue()'. With 4K buffer size,
caller spends too much time in it with zerocopy mode (comparing to
copy mode). This happens only with 4K buffer size. This function just
calls 'wake_up_process()' and its internal logic does not depends on
skb, so i think potential reason (may be) is interval between two
calls of this function (e.g. how often it is called). Note, that
'vhost_work_queue()' differs from the same function at guest's side of
transport: 'virtio_transport_send_pkt()' uses 'queue_work()' which
i think is more optimized for worker purposes, than direct call to
'wake_up_process()'. But again - this is just my assumption.
Loopback:
Core i7 with nested guest. Atom with normal guest.
*-------------------------------* *-------------------------------*
| | | | | | | |
| buf size | copy | zerocopy | | buf size | copy | zerocopy |
| | | | | | | |
*-------------------------------* *-------------------------------*
| 4KB | 8 | 7 | | 4KB | 1.8 | 1.3 |
*-------------------------------* *-------------------------------*
| 32KB | 38 | 44 | | 32KB | 10 | 10 |
*-------------------------------* *-------------------------------*
| 256KB | 55 | 168 | | 256KB | 15 | 36 |
*-------------------------------* *-------------------------------*
| 1M | 53 | 250 | | 1M | 12 | 45 |
*-------------------------------* *-------------------------------*
| 8M | 40 | 344 | | 8M | 11 | 74 |
*-------------------------------* *-------------------------------*
I analyzed performace difference more deeply for the following setup:
server: ./vsock_perf --vsk-size 16M
client: ./vsock_perf --sender 2 --bytes 16M --buf-size 16K/4K [--zc]
In other words I send 16M of data from guest to host in copy/zerocopy
modes and with two different sizes of buffer - 4K and 64K. Let's see
to tx path for both modes - it consists of two steps:
copy:
1) Allocate skb of buffer's length.
2) Copy data to skb from buffer.
zerocopy:
1) Allocate skb with header space only.
2) Pin pages of the buffer and insert them to skb.
I measured average number of ns (returned by 'ktime_get()') for each
step above:
1) Skb allocation (for both copy and zerocopy modes).
2) For copy mode in 'memcpy_to_msg()' - copying.
3) For zerocopy mode in '__zerocopy_sg_from_iter()' - pinning.
Here are results for copy mode:
*-------------------------------------*
| buf | skb alloc | 'memcpy_to_msg()' |
*-------------------------------------*
| | | |
| 64K | 5000ns | 25000ns |
| | | |
*-------------------------------------*
| | | |
| 4K | 800ns | 2200ns |
| | | |
*-------------------------------------*
Here are results for zerocopy mode:
*-----------------------------------------------*
| buf | skb alloc | '__zerocopy_sg_from_iter()' |
*-----------------------------------------------*
| | | |
| 64K | 250ns | 3500ns |
| | | |
*-----------------------------------------------*
| | | |
| 4K | 250ns | 3000ns |
| | | |
*-----------------------------------------------*
I guess that reason of zerocopy performance is low overhead for page
pinning: there is big difference between 4K and 64K in case of copying
(25000 vs 2200), but in pinning case - just 3000 vs 3500.
So, zerocopy is faster than classic copy mode, but of course it requires
specific architecture of application due to user pages pinning, buffer
size and alignment.
NOTES
If host fails to send data with "Cannot allocate memory", check value
/proc/sys/net/core/optmem_max - it is accounted during completion skb
allocation. Try to update it to for example 1M and try send again:
"echo 1048576 > /proc/sys/net/core/optmem_max" (as root).
TESTING
This patchset includes set of tests for MSG_ZEROCOPY feature. I tried to
cover new code as much as possible so there are different cases for
MSG_ZEROCOPY transmissions: with disabled SO_ZEROCOPY and several io
vector types (different sizes, alignments, with unmapped pages). I also
run tests with loopback transport and run vsockmon. In v3 i've added
io_uring test as separated application.
Thanks, Arseniy
Link to v1:
https://lore.kernel.org/netdev/[email protected]/
Link to v2:
https://lore.kernel.org/netdev/[email protected]/
Changelog:
v1 -> v2:
- Replace 'get_user_pages()' with 'pin_user_pages()'.
- Loopback transport support.
v2 -> v3
- Use 'get_user_pages()' instead of 'pin_user_pages()'. I think this
is right approach, because i'm using '__zerocopy_sg_from_iter()'
function. It is already implemented and used by io_uring zerocopy
tx logic to 'pin' pages of user's buffer.
- Use 'skb_copy_datagram_iter()' to copy data from both linear and
non-linear skb to user's iov iter. It already has support for copying
data from paged part of skb (by calling 'kmap()'). In v2 i used my
own "from scratch" implemented function. With this and previous thing
I significantly reduced LOC number in kernel part.
- Add io_uring test for AF_VSOCK. It is implemented as separated util,
because it depends on liburing (i think there is no need to link
'vsock_test' with liburing, because io_uring functionality depends
on environment - both in kernel and userspace).
- Values from PERFORMANCE section are updated for all transports, but
I didn't found any significant difference with v2.
- More details in commit messages.
Arseniy Krasnov (17):
vsock/virtio: read data from non-linear skb
vhost/vsock: read data from non-linear skb
vsock/virtio: support to send non-linear skb
vsock/virtio: non-linear skb handling for tap
vsock/virtio: MSG_ZEROCOPY flag support
vsock: check error queue to set EPOLLERR
vsock: read from socket's error queue
vsock: check for MSG_ZEROCOPY support
vsock: enable SOCK_SUPPORT_ZC bit
vhost/vsock: support MSG_ZEROCOPY for transport
vsock/virtio: support MSG_ZEROCOPY for transport
vsock/loopback: support MSG_ZEROCOPY for transport
net/sock: enable setting SO_ZEROCOPY for PF_VSOCK
docs: net: description of MSG_ZEROCOPY for AF_VSOCK
test/vsock: MSG_ZEROCOPY flag tests
test/vsock: MSG_ZEROCOPY support for vsock_perf
test/vsock: io_uring rx/tx tests
Documentation/networking/msg_zerocopy.rst | 12 +-
drivers/vhost/vsock.c | 18 +-
include/linux/socket.h | 1 +
include/linux/virtio_vsock.h | 1 +
include/net/af_vsock.h | 7 +
net/core/sock.c | 4 +-
net/vmw_vsock/af_vsock.c | 19 +-
net/vmw_vsock/virtio_transport.c | 39 ++-
net/vmw_vsock/virtio_transport_common.c | 352 ++++++++++++++++----
net/vmw_vsock/vsock_loopback.c | 8 +
tools/testing/vsock/Makefile | 9 +-
tools/testing/vsock/util.c | 134 ++++++++
tools/testing/vsock/util.h | 23 ++
tools/testing/vsock/vsock_perf.c | 139 +++++++-
tools/testing/vsock/vsock_test.c | 11 +
tools/testing/vsock/vsock_test_zerocopy.c | 385 ++++++++++++++++++++++
tools/testing/vsock/vsock_test_zerocopy.h | 12 +
tools/testing/vsock/vsock_uring_test.c | 316 ++++++++++++++++++
18 files changed, 1396 insertions(+), 94 deletions(-)
create mode 100644 tools/testing/vsock/vsock_test_zerocopy.c
create mode 100644 tools/testing/vsock/vsock_test_zerocopy.h
create mode 100644 tools/testing/vsock/vsock_uring_test.c
--
2.25.1
This adds handling of MSG_ERRQUEUE input flag in receive call. This flag
is used to read socket's error queue instead of data queue. Possible
scenario of error queue usage is receiving completions for transmission
with MSG_ZEROCOPY flag.
Signed-off-by: Arseniy Krasnov <[email protected]>
---
include/linux/socket.h | 1 +
net/vmw_vsock/af_vsock.c | 5 +++++
2 files changed, 6 insertions(+)
diff --git a/include/linux/socket.h b/include/linux/socket.h
index 13c3a237b9c9..19a6f39fa014 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -379,6 +379,7 @@ struct ucred {
#define SOL_MPTCP 284
#define SOL_MCTP 285
#define SOL_SMC 286
+#define SOL_VSOCK 287
/* IPX options */
#define IPX_TYPE 1
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index eea2bcc685a2..b2da791d920b 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -110,6 +110,7 @@
#include <linux/workqueue.h>
#include <net/sock.h>
#include <net/af_vsock.h>
+#include <linux/errqueue.h>
static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr);
static void vsock_sk_destruct(struct sock *sk);
@@ -2135,6 +2136,10 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
int err;
sk = sock->sk;
+
+ if (unlikely(flags & MSG_ERRQUEUE))
+ return sock_recv_errqueue(sk, msg, len, SOL_VSOCK, 0);
+
vsk = vsock_sk(sk);
err = 0;
--
2.25.1
If socket's error queue is not empty, EPOLLERR must be set. Otherwise,
reader of error queue won't detect data in it using EPOLLERR bit.
Signed-off-by: Arseniy Krasnov <[email protected]>
---
net/vmw_vsock/af_vsock.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 413407bb646c..eea2bcc685a2 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1030,7 +1030,7 @@ static __poll_t vsock_poll(struct file *file, struct socket *sock,
poll_wait(file, sk_sleep(sk), wait);
mask = 0;
- if (sk->sk_err)
+ if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
/* Signify that there has been an error on this socket. */
mask |= EPOLLERR;
--
2.25.1
This adds handling of MSG_ZEROCOPY flag on transmission path: if this
flag is set and zerocopy transmission is possible, then non-linear skb
will be created and filled with the pages of user's buffer. Pages of
user's buffer are locked in memory by 'get_user_pages()'.
Signed-off-by: Arseniy Krasnov <[email protected]>
---
net/vmw_vsock/virtio_transport_common.c | 305 +++++++++++++++++++-----
1 file changed, 243 insertions(+), 62 deletions(-)
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 9854f48a0544..5acf824afe41 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -37,73 +37,161 @@ virtio_transport_get_ops(struct vsock_sock *vsk)
return container_of(t, struct virtio_transport, transport);
}
-/* Returns a new packet on success, otherwise returns NULL.
- *
- * If NULL is returned, errp is set to a negative errno.
- */
-static struct sk_buff *
-virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
- size_t len,
- u32 src_cid,
- u32 src_port,
- u32 dst_cid,
- u32 dst_port)
-{
- const size_t skb_len = VIRTIO_VSOCK_SKB_HEADROOM + len;
- struct virtio_vsock_hdr *hdr;
- struct sk_buff *skb;
- void *payload;
- int err;
+static bool virtio_transport_can_zcopy(struct virtio_vsock_pkt_info *info,
+ size_t max_to_send)
+{
+ struct iov_iter *iov_iter;
+ size_t max_skb_cap;
+ size_t bytes;
+ int i;
- skb = virtio_vsock_alloc_skb(skb_len, GFP_KERNEL);
- if (!skb)
- return NULL;
+ if (!info->msg)
+ return false;
- hdr = virtio_vsock_hdr(skb);
- hdr->type = cpu_to_le16(info->type);
- hdr->op = cpu_to_le16(info->op);
- hdr->src_cid = cpu_to_le64(src_cid);
- hdr->dst_cid = cpu_to_le64(dst_cid);
- hdr->src_port = cpu_to_le32(src_port);
- hdr->dst_port = cpu_to_le32(dst_port);
- hdr->flags = cpu_to_le32(info->flags);
- hdr->len = cpu_to_le32(len);
+ if (!(info->flags & MSG_ZEROCOPY) && !info->msg->msg_ubuf)
+ return false;
- if (info->msg && len > 0) {
- payload = skb_put(skb, len);
- err = memcpy_from_msg(payload, info->msg, len);
- if (err)
- goto out;
+ iov_iter = &info->msg->msg_iter;
+
+ if (iter_is_ubuf(iov_iter)) {
+ if (offset_in_page(iov_iter->ubuf))
+ return false;
+
+ return true;
+ }
+
+ if (!iter_is_iovec(iov_iter))
+ return false;
+
+ if (iov_iter->iov_offset)
+ return false;
+
+ /* We can't send whole iov. */
+ if (iov_iter->count > max_to_send)
+ return false;
+
+ for (bytes = 0, i = 0; i < iov_iter->nr_segs; i++) {
+ const struct iovec *iovec;
+ int pages_in_elem;
+
+ iovec = &iov_iter->__iov[i];
+
+ /* Base must be page aligned. */
+ if (offset_in_page(iovec->iov_base))
+ return false;
- if (msg_data_left(info->msg) == 0 &&
- info->type == VIRTIO_VSOCK_TYPE_SEQPACKET) {
- hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
+ /* Only last element could have non page aligned size. */
+ if (i != (iov_iter->nr_segs - 1)) {
+ if (offset_in_page(iovec->iov_len))
+ return false;
- if (info->msg->msg_flags & MSG_EOR)
- hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
+ pages_in_elem = iovec->iov_len >> PAGE_SHIFT;
+ } else {
+ pages_in_elem = round_up(iovec->iov_len, PAGE_SIZE);
+ pages_in_elem >>= PAGE_SHIFT;
}
+
+ bytes += (pages_in_elem * PAGE_SIZE);
}
- if (info->reply)
- virtio_vsock_skb_set_reply(skb);
+ /* How many bytes we can pack to single skb. Maximum packet
+ * buffer size is needed to allow vhost handle such packets,
+ * otherwise they will be dropped.
+ */
+ max_skb_cap = min((unsigned int)(MAX_SKB_FRAGS * PAGE_SIZE),
+ (unsigned int)VIRTIO_VSOCK_MAX_PKT_BUF_SIZE);
- trace_virtio_transport_alloc_pkt(src_cid, src_port,
- dst_cid, dst_port,
- len,
- info->type,
- info->op,
- info->flags);
+ return true;
+}
- if (info->vsk && !skb_set_owner_sk_safe(skb, sk_vsock(info->vsk))) {
- WARN_ONCE(1, "failed to allocate skb on vsock socket with sk_refcnt == 0\n");
- goto out;
+static int virtio_transport_init_zcopy_skb(struct vsock_sock *vsk,
+ struct sk_buff *skb,
+ struct msghdr *msg,
+ bool zerocopy)
+{
+ struct ubuf_info *uarg;
+
+ if (msg->msg_ubuf) {
+ uarg = msg->msg_ubuf;
+ net_zcopy_get(uarg);
+ } else {
+ struct iov_iter *iter = &msg->msg_iter;
+ struct ubuf_info_msgzc *uarg_zc;
+ int len;
+
+ /* Only ITER_IOVEC or ITER_UBUF are allowed and
+ * checked before.
+ */
+ if (iter_is_iovec(iter))
+ len = iov_length(iter->__iov, iter->nr_segs);
+ else
+ len = iter->count;
+
+ uarg = msg_zerocopy_realloc(sk_vsock(vsk),
+ len,
+ NULL);
+
+ if (!uarg)
+ return -1;
+
+ uarg_zc = uarg_to_msgzc(uarg);
+ uarg_zc->zerocopy = zerocopy ? 1 : 0;
}
- return skb;
+ skb_zcopy_init(skb, uarg);
-out:
- kfree_skb(skb);
- return NULL;
+ return 0;
+}
+
+static int virtio_transport_fill_linear_skb(struct sk_buff *skb,
+ struct vsock_sock *vsk,
+ struct virtio_vsock_pkt_info *info,
+ size_t len)
+{
+ void *payload;
+ int err;
+
+ payload = skb_put(skb, len);
+ err = memcpy_from_msg(payload, info->msg, len);
+ if (err)
+ return -1;
+
+ if (msg_data_left(info->msg))
+ return 0;
+
+ if (info->type == VIRTIO_VSOCK_TYPE_SEQPACKET) {
+ struct virtio_vsock_hdr *hdr;
+
+ hdr = virtio_vsock_hdr(skb);
+
+ hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
+
+ if (info->msg->msg_flags & MSG_EOR)
+ hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
+ }
+
+ return 0;
+}
+
+static void virtio_transport_init_hdr(struct sk_buff *skb,
+ struct virtio_vsock_pkt_info *info,
+ u32 src_cid,
+ u32 src_port,
+ u32 dst_cid,
+ u32 dst_port,
+ size_t len)
+{
+ struct virtio_vsock_hdr *hdr;
+
+ hdr = virtio_vsock_hdr(skb);
+ hdr->type = cpu_to_le16(info->type);
+ hdr->op = cpu_to_le16(info->op);
+ hdr->src_cid = cpu_to_le64(src_cid);
+ hdr->dst_cid = cpu_to_le64(dst_cid);
+ hdr->src_port = cpu_to_le32(src_port);
+ hdr->dst_port = cpu_to_le32(dst_port);
+ hdr->flags = cpu_to_le32(info->flags);
+ hdr->len = cpu_to_le32(len);
}
static void virtio_transport_copy_nonlinear_skb(struct sk_buff *skb,
@@ -214,6 +302,75 @@ static u16 virtio_transport_get_type(struct sock *sk)
return VIRTIO_VSOCK_TYPE_SEQPACKET;
}
+/* Returns a new packet on success, otherwise returns NULL.
+ *
+ * If NULL is returned, errp is set to a negative errno.
+ */
+static struct sk_buff *virtio_transport_alloc_skb(struct vsock_sock *vsk,
+ struct virtio_vsock_pkt_info *info,
+ size_t payload_len,
+ bool zcopy,
+ u32 dst_cid,
+ u32 dst_port,
+ u32 src_cid,
+ u32 src_port)
+{
+ struct sk_buff *skb;
+ size_t skb_len;
+
+ skb_len = VIRTIO_VSOCK_SKB_HEADROOM;
+
+ if (!zcopy)
+ skb_len += payload_len;
+
+ skb = virtio_vsock_alloc_skb(skb_len, GFP_KERNEL);
+ if (!skb)
+ return NULL;
+
+ virtio_transport_init_hdr(skb, info, src_cid, src_port,
+ dst_cid, dst_port,
+ payload_len);
+
+ if (info->msg && payload_len > 0) {
+ int err;
+
+ if (zcopy) {
+ struct sock *sk = sk_vsock(vsk);
+
+ err = __zerocopy_sg_from_iter(info->msg, sk, skb,
+ &info->msg->msg_iter,
+ payload_len);
+ } else {
+ err = virtio_transport_fill_linear_skb(skb, vsk, info, payload_len);
+ }
+
+ if (err)
+ goto out;
+
+ VIRTIO_VSOCK_SKB_CB(skb)->frag_off = 0;
+ }
+
+ if (info->reply)
+ virtio_vsock_skb_set_reply(skb);
+
+ trace_virtio_transport_alloc_pkt(src_cid, src_port,
+ dst_cid, dst_port,
+ payload_len,
+ info->type,
+ info->op,
+ info->flags);
+
+ if (info->vsk && !skb_set_owner_sk_safe(skb, sk_vsock(info->vsk))) {
+ WARN_ONCE(1, "failed to allocate skb on vsock socket with sk_refcnt == 0\n");
+ goto out;
+ }
+
+ return skb;
+out:
+ kfree_skb(skb);
+ return NULL;
+}
+
/* This function can only be used on connecting/connected sockets,
* since a socket assigned to a transport is required.
*
@@ -226,6 +383,8 @@ 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;
+ bool can_zcopy = false;
+ u32 max_skb_cap;
u32 rest_len;
int ret;
@@ -235,6 +394,9 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
if (unlikely(!t_ops))
return -EFAULT;
+ if (!sock_flag(sk_vsock(vsk), SOCK_ZEROCOPY))
+ info->flags &= ~MSG_ZEROCOPY;
+
src_cid = t_ops->transport.get_local_cid();
src_port = vsk->local_addr.svm_port;
if (!info->remote_cid) {
@@ -254,22 +416,40 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
return pkt_len;
+ can_zcopy = virtio_transport_can_zcopy(info, pkt_len);
+ if (can_zcopy)
+ max_skb_cap = min_t(u32, VIRTIO_VSOCK_MAX_PKT_BUF_SIZE,
+ (MAX_SKB_FRAGS * PAGE_SIZE));
+ else
+ max_skb_cap = VIRTIO_VSOCK_MAX_PKT_BUF_SIZE;
+
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_len = min(max_skb_cap, rest_len);
- skb = virtio_transport_alloc_skb(info, skb_len,
- src_cid, src_port,
- dst_cid, dst_port);
+ skb = virtio_transport_alloc_skb(vsk, info, skb_len, can_zcopy,
+ dst_cid, dst_port,
+ src_cid, src_port);
if (!skb) {
ret = -ENOMEM;
break;
}
+ if (skb_len == rest_len &&
+ info->flags & MSG_ZEROCOPY &&
+ info->op == VIRTIO_VSOCK_OP_RW) {
+ if (virtio_transport_init_zcopy_skb(vsk, skb,
+ info->msg,
+ can_zcopy)) {
+ ret = -ENOMEM;
+ break;
+ }
+ }
+
virtio_transport_inc_tx_pkt(vvs, skb);
ret = t_ops->send_pkt(skb);
@@ -884,6 +1064,7 @@ virtio_transport_stream_enqueue(struct vsock_sock *vsk,
.msg = msg,
.pkt_len = len,
.vsk = vsk,
+ .flags = msg->msg_flags,
};
return virtio_transport_send_pkt_info(vsk, &info);
@@ -935,11 +1116,11 @@ static int virtio_transport_reset_no_sock(const struct virtio_transport *t,
if (!t)
return -ENOTCONN;
- reply = virtio_transport_alloc_skb(&info, 0,
- le64_to_cpu(hdr->dst_cid),
- le32_to_cpu(hdr->dst_port),
+ reply = virtio_transport_alloc_skb(NULL, &info, 0, false,
le64_to_cpu(hdr->src_cid),
- le32_to_cpu(hdr->src_port));
+ le32_to_cpu(hdr->src_port),
+ le64_to_cpu(hdr->dst_cid),
+ le32_to_cpu(hdr->dst_port));
if (!reply)
return -ENOMEM;
--
2.25.1
Add 'msgzerocopy_allow()' callback for virtio transport.
Signed-off-by: Arseniy Krasnov <[email protected]>
---
net/vmw_vsock/virtio_transport.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 1c269c3f010d..ca12db84e053 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -433,6 +433,11 @@ static void virtio_vsock_rx_done(struct virtqueue *vq)
queue_work(virtio_vsock_workqueue, &vsock->rx_work);
}
+static bool virtio_transport_msgzerocopy_allow(void)
+{
+ return true;
+}
+
static bool virtio_transport_seqpacket_allow(u32 remote_cid);
static struct virtio_transport virtio_transport = {
@@ -479,6 +484,8 @@ static struct virtio_transport virtio_transport = {
.notify_buffer_size = virtio_transport_notify_buffer_size,
.read_skb = virtio_transport_read_skb,
+
+ .msgzerocopy_allow = virtio_transport_msgzerocopy_allow,
},
.send_pkt = virtio_transport_send_pkt,
--
2.25.1
Add 'msgzerocopy_allow()' callback for loopback transport.
Signed-off-by: Arseniy Krasnov <[email protected]>
---
net/vmw_vsock/vsock_loopback.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c
index 5c6360df1f31..a2e4aeda2d92 100644
--- a/net/vmw_vsock/vsock_loopback.c
+++ b/net/vmw_vsock/vsock_loopback.c
@@ -47,6 +47,7 @@ static int vsock_loopback_cancel_pkt(struct vsock_sock *vsk)
}
static bool vsock_loopback_seqpacket_allow(u32 remote_cid);
+static bool vsock_loopback_msgzerocopy_allow(void);
static struct virtio_transport loopback_transport = {
.transport = {
@@ -92,11 +93,18 @@ static struct virtio_transport loopback_transport = {
.notify_buffer_size = virtio_transport_notify_buffer_size,
.read_skb = virtio_transport_read_skb,
+
+ .msgzerocopy_allow = vsock_loopback_msgzerocopy_allow,
},
.send_pkt = vsock_loopback_send_pkt,
};
+static bool vsock_loopback_msgzerocopy_allow(void)
+{
+ return true;
+}
+
static bool vsock_loopback_seqpacket_allow(u32 remote_cid)
{
return true;
--
2.25.1
PF_VSOCK supports MSG_ZEROCOPY transmission, so SO_ZEROCOPY could
be enabled. PF_VSOCK implementation is a little bit special comparing to
PF_INET - MSG_ZEROCOPY support depends on transport layer of PF_VSOCK,
but here we can't "ask" its transport, so setting of this option is
always allowed, but if some transport doesn't support zerocopy tx, send
callback of PF_VSOCK will return -EOPNOTSUPP.
Signed-off-by: Arseniy Krasnov <[email protected]>
---
net/core/sock.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/core/sock.c b/net/core/sock.c
index 5440e67bcfe3..d558e541e6d7 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1452,9 +1452,11 @@ int sk_setsockopt(struct sock *sk, int level, int optname,
(sk->sk_type == SOCK_DGRAM &&
sk->sk_protocol == IPPROTO_UDP)))
ret = -EOPNOTSUPP;
- } else if (sk->sk_family != PF_RDS) {
+ } else if (sk->sk_family != PF_RDS &&
+ sk->sk_family != PF_VSOCK) {
ret = -EOPNOTSUPP;
}
+
if (!ret) {
if (val < 0 || val > 1)
ret = -EINVAL;
--
2.25.1
This adds description of MSG_ZEROCOPY flag support for AF_VSOCK type of
socket.
Signed-off-by: Arseniy Krasnov <[email protected]>
---
Documentation/networking/msg_zerocopy.rst | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/Documentation/networking/msg_zerocopy.rst b/Documentation/networking/msg_zerocopy.rst
index b3ea96af9b49..34bc7ff411ce 100644
--- a/Documentation/networking/msg_zerocopy.rst
+++ b/Documentation/networking/msg_zerocopy.rst
@@ -7,7 +7,8 @@ Intro
=====
The MSG_ZEROCOPY flag enables copy avoidance for socket send calls.
-The feature is currently implemented for TCP and UDP sockets.
+The feature is currently implemented for TCP, UDP and VSOCK (with
+virtio transport) sockets.
Opportunity and Caveats
@@ -174,7 +175,7 @@ read_notification() call in the previous snippet. A notification
is encoded in the standard error format, sock_extended_err.
The level and type fields in the control data are protocol family
-specific, IP_RECVERR or IPV6_RECVERR.
+specific, IP_RECVERR or IPV6_RECVERR (for TCP or UDP socket).
Error origin is the new type SO_EE_ORIGIN_ZEROCOPY. ee_errno is zero,
as explained before, to avoid blocking read and write system calls on
@@ -201,6 +202,7 @@ undefined, bar for ee_code, as discussed below.
printf("completed: %u..%u\n", serr->ee_info, serr->ee_data);
+For VSOCK socket, cmsg_level will be SOL_VSOCK and cmsg_type will be 0.
Deferred copies
~~~~~~~~~~~~~~~
@@ -235,12 +237,15 @@ Implementation
Loopback
--------
+For TCP and UDP:
Data sent to local sockets can be queued indefinitely if the receive
process does not read its socket. Unbound notification latency is not
acceptable. For this reason all packets generated with MSG_ZEROCOPY
that are looped to a local socket will incur a deferred copy. This
includes looping onto packet sockets (e.g., tcpdump) and tun devices.
+For VSOCK:
+Data path sent to local sockets is the same as for non-local sockets.
Testing
=======
@@ -254,3 +259,6 @@ instance when run with msg_zerocopy.sh between a veth pair across
namespaces, the test will not show any improvement. For testing, the
loopback restriction can be temporarily relaxed by making
skb_orphan_frags_rx identical to skb_orphan_frags.
+
+For VSOCK type of socket example can be found in tools/testing/vsock/
+vsock_test_zerocopy.c.
--
2.25.1
This adds set of tests for MSG_ZEROCOPY flag.
Signed-off-by: Arseniy Krasnov <[email protected]>
---
tools/testing/vsock/Makefile | 2 +-
tools/testing/vsock/util.c | 134 ++++++++
tools/testing/vsock/util.h | 23 ++
tools/testing/vsock/vsock_test.c | 11 +
tools/testing/vsock/vsock_test_zerocopy.c | 385 ++++++++++++++++++++++
tools/testing/vsock/vsock_test_zerocopy.h | 12 +
6 files changed, 566 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/vsock/vsock_test_zerocopy.c
create mode 100644 tools/testing/vsock/vsock_test_zerocopy.h
diff --git a/tools/testing/vsock/Makefile b/tools/testing/vsock/Makefile
index 43a254f0e14d..0a78787d1d92 100644
--- a/tools/testing/vsock/Makefile
+++ b/tools/testing/vsock/Makefile
@@ -1,7 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
all: test vsock_perf
test: vsock_test vsock_diag_test
-vsock_test: vsock_test.o timeout.o control.o util.o
+vsock_test: vsock_test.o vsock_test_zerocopy.o timeout.o control.o util.o
vsock_diag_test: vsock_diag_test.o timeout.o control.o util.o
vsock_perf: vsock_perf.o
diff --git a/tools/testing/vsock/util.c b/tools/testing/vsock/util.c
index 01b636d3039a..ec0fbe875e2a 100644
--- a/tools/testing/vsock/util.c
+++ b/tools/testing/vsock/util.c
@@ -11,10 +11,12 @@
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
+#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <assert.h>
#include <sys/epoll.h>
+#include <sys/mman.h>
#include "timeout.h"
#include "control.h"
@@ -408,3 +410,135 @@ unsigned long hash_djb2(const void *data, size_t len)
return hash;
}
+
+void enable_so_zerocopy(int fd)
+{
+ int val = 1;
+
+ if (setsockopt(fd, SOL_SOCKET, SO_ZEROCOPY, &val, sizeof(val))) {
+ perror("mmap");
+ exit(EXIT_FAILURE);
+ }
+}
+
+static void *mmap_no_fail(size_t bytes)
+{
+ void *res;
+
+ res = mmap(NULL, bytes, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE, -1, 0);
+ if (res == MAP_FAILED) {
+ perror("mmap");
+ exit(EXIT_FAILURE);
+ }
+
+ return res;
+}
+
+size_t iovec_bytes(const struct iovec *iov, size_t iovnum)
+{
+ size_t bytes;
+ int i;
+
+ for (bytes = 0, i = 0; i < iovnum; i++)
+ bytes += iov[i].iov_len;
+
+ return bytes;
+}
+
+static void iovec_random_init(struct iovec *iov,
+ const struct vsock_test_data *test_data)
+{
+ int i;
+
+ for (i = 0; i < test_data->vecs_cnt; i++) {
+ int j;
+
+ if (test_data->vecs[i].iov_base == MAP_FAILED)
+ continue;
+
+ for (j = 0; j < iov[i].iov_len; j++)
+ ((uint8_t *)iov[i].iov_base)[j] = rand() & 0xff;
+ }
+}
+
+unsigned long iovec_hash_djb2(struct iovec *iov, size_t iovnum)
+{
+ unsigned long hash;
+ size_t iov_bytes;
+ size_t offs;
+ void *tmp;
+ int i;
+
+ iov_bytes = iovec_bytes(iov, iovnum);
+
+ tmp = malloc(iov_bytes);
+ if (!tmp) {
+ perror("malloc");
+ exit(EXIT_FAILURE);
+ }
+
+ for (offs = 0, i = 0; i < iovnum; i++) {
+ memcpy(tmp + offs, iov[i].iov_base, iov[i].iov_len);
+ offs += iov[i].iov_len;
+ }
+
+ hash = hash_djb2(tmp, iov_bytes);
+ free(tmp);
+
+ return hash;
+}
+
+struct iovec *init_iovec_from_test_data(const struct vsock_test_data *test_data)
+{
+ struct iovec *iovec;
+ int i;
+
+ iovec = malloc(sizeof(*iovec) * test_data->vecs_cnt);
+ if (!iovec) {
+ perror("malloc");
+ exit(EXIT_FAILURE);
+ }
+
+ for (i = 0; i < test_data->vecs_cnt; i++) {
+ iovec[i].iov_len = test_data->vecs[i].iov_len;
+ iovec[i].iov_base = mmap_no_fail(test_data->vecs[i].iov_len);
+
+ if (test_data->vecs[i].iov_base != MAP_FAILED &&
+ test_data->vecs[i].iov_base)
+ iovec[i].iov_base += (uintptr_t)test_data->vecs[i].iov_base;
+ }
+
+ for (i = 0; i < test_data->vecs_cnt; i++) {
+ if (test_data->vecs[i].iov_base == MAP_FAILED) {
+ if (munmap(iovec[i].iov_base, iovec[i].iov_len)) {
+ perror("munmap");
+ exit(EXIT_FAILURE);
+ }
+ }
+ }
+
+ iovec_random_init(iovec, test_data);
+
+ return iovec;
+}
+
+void free_iovec_test_data(const struct vsock_test_data *test_data,
+ struct iovec *iovec)
+{
+ int i;
+
+ for (i = 0; i < test_data->vecs_cnt; i++) {
+ if (test_data->vecs[i].iov_base != MAP_FAILED) {
+ if (test_data->vecs[i].iov_base)
+ iovec[i].iov_base -= (uintptr_t)test_data->vecs[i].iov_base;
+
+ if (munmap(iovec[i].iov_base, iovec[i].iov_len)) {
+ perror("munmap");
+ exit(EXIT_FAILURE);
+ }
+ }
+ }
+
+ free(iovec);
+}
diff --git a/tools/testing/vsock/util.h b/tools/testing/vsock/util.h
index fb99208a95ea..7f8f38671a73 100644
--- a/tools/testing/vsock/util.h
+++ b/tools/testing/vsock/util.h
@@ -2,6 +2,7 @@
#ifndef UTIL_H
#define UTIL_H
+#include <stdbool.h>
#include <sys/socket.h>
#include <linux/vm_sockets.h>
@@ -18,6 +19,18 @@ struct test_opts {
unsigned int peer_cid;
};
+#define VSOCK_TEST_DATA_MAX_IOV 4
+
+struct vsock_test_data {
+ bool zerocopied; /* Data must be zerocopied. */
+ bool use_zerocopy; /* Use zerocopy mode. */
+ bool completion; /* Need completion. */
+ int sendmsg_errno; /* 'errno' after 'sendmsg()'. */
+ ssize_t sendmsg_res; /* Return value of 'sendmsg()'. */
+ int vecs_cnt; /* Number of elements in 'vecs'. */
+ struct iovec vecs[VSOCK_TEST_DATA_MAX_IOV];
+};
+
/* A test case definition. Test functions must print failures to stderr and
* terminate with exit(EXIT_FAILURE).
*/
@@ -50,4 +63,14 @@ void list_tests(const struct test_case *test_cases);
void skip_test(struct test_case *test_cases, size_t test_cases_len,
const char *test_id_str);
unsigned long hash_djb2(const void *data, size_t len);
+
+#define SENDMSG_RES_IOV_LEN (-2)
+
+void enable_so_zerocopy(int fd);
+size_t iovec_bytes(const struct iovec *iov, size_t iovnum);
+unsigned long iovec_hash_djb2(struct iovec *iov, size_t iovnum);
+struct iovec *init_iovec_from_test_data(const struct vsock_test_data *test_data);
+void free_iovec_test_data(const struct vsock_test_data *test_data,
+ struct iovec *iovec);
+
#endif /* UTIL_H */
diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c
index ac1bd3ac1533..d9bddb643794 100644
--- a/tools/testing/vsock/vsock_test.c
+++ b/tools/testing/vsock/vsock_test.c
@@ -20,6 +20,7 @@
#include <sys/mman.h>
#include <poll.h>
+#include "vsock_test_zerocopy.h"
#include "timeout.h"
#include "control.h"
#include "util.h"
@@ -1128,6 +1129,16 @@ static struct test_case test_cases[] = {
.run_client = test_stream_virtio_skb_merge_client,
.run_server = test_stream_virtio_skb_merge_server,
},
+ {
+ .name = "SOCK_STREAM MSG_ZEROCOPY",
+ .run_client = test_stream_msg_zcopy_client,
+ .run_server = test_stream_msg_zcopy_server,
+ },
+ {
+ .name = "SOCK_STREAM MSG_ZEROCOPY empty MSG_ERRQUEUE",
+ .run_client = test_stream_msg_zcopy_empty_errq_client,
+ .run_server = test_stream_msg_zcopy_empty_errq_server,
+ },
{},
};
diff --git a/tools/testing/vsock/vsock_test_zerocopy.c b/tools/testing/vsock/vsock_test_zerocopy.c
new file mode 100644
index 000000000000..00a7fb5bda5f
--- /dev/null
+++ b/tools/testing/vsock/vsock_test_zerocopy.c
@@ -0,0 +1,385 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* MSG_ZEROCOPY feature tests for vsock
+ *
+ * Copyright (C) 2023 SberDevices.
+ *
+ * Author: Arseniy Krasnov <[email protected]>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <poll.h>
+#include <linux/errqueue.h>
+#include <linux/kernel.h>
+#include <error.h>
+#include <errno.h>
+
+#include "control.h"
+#include "vsock_test_zerocopy.h"
+
+#ifndef SOL_VSOCK
+#define SOL_VSOCK 287
+#endif
+
+#define PAGE_SIZE 4096
+#define POLL_TIMEOUT_MS 100
+
+static void do_recv_completion(int fd, bool zerocopied, bool completion)
+{
+ struct sock_extended_err *serr;
+ struct msghdr msg = { 0 };
+ struct pollfd fds = { 0 };
+ char cmsg_data[128];
+ struct cmsghdr *cm;
+ uint32_t hi, lo;
+ ssize_t res;
+
+ fds.fd = fd;
+ fds.events = 0;
+
+ if (poll(&fds, 1, POLL_TIMEOUT_MS) < 0) {
+ perror("poll");
+ exit(EXIT_FAILURE);
+ }
+
+ if (!(fds.revents & POLLERR)) {
+ if (completion) {
+ fprintf(stderr, "POLLERR expected\n");
+ exit(EXIT_FAILURE);
+ } else {
+ return;
+ }
+ }
+
+ msg.msg_control = cmsg_data;
+ msg.msg_controllen = sizeof(cmsg_data);
+
+ res = recvmsg(fd, &msg, MSG_ERRQUEUE);
+ if (res) {
+ fprintf(stderr, "failed to read error queue: %zi\n", res);
+ exit(EXIT_FAILURE);
+ }
+
+ cm = CMSG_FIRSTHDR(&msg);
+ if (!cm) {
+ fprintf(stderr, "cmsg: no cmsg\n");
+ exit(EXIT_FAILURE);
+ }
+
+ if (cm->cmsg_level != SOL_VSOCK) {
+ fprintf(stderr, "cmsg: unexpected 'cmsg_level'\n");
+ exit(EXIT_FAILURE);
+ }
+
+ if (cm->cmsg_type != 0) {
+ fprintf(stderr, "cmsg: unexpected 'cmsg_type'\n");
+ exit(EXIT_FAILURE);
+ }
+
+ serr = (void *)CMSG_DATA(cm);
+ if (serr->ee_origin != SO_EE_ORIGIN_ZEROCOPY) {
+ fprintf(stderr, "serr: wrong origin: %u\n", serr->ee_origin);
+ exit(EXIT_FAILURE);
+ }
+
+ if (serr->ee_errno) {
+ fprintf(stderr, "serr: wrong error code: %u\n", serr->ee_errno);
+ exit(EXIT_FAILURE);
+ }
+
+ hi = serr->ee_data;
+ lo = serr->ee_info;
+ if (hi != lo) {
+ fprintf(stderr, "serr: expected hi == lo\n");
+ exit(EXIT_FAILURE);
+ }
+
+ if (hi) {
+ fprintf(stderr, "serr: expected hi == lo == 0\n");
+ exit(EXIT_FAILURE);
+ }
+
+ if (zerocopied && (serr->ee_code & SO_EE_CODE_ZEROCOPY_COPIED)) {
+ fprintf(stderr, "serr: was copy instead of zerocopy\n");
+ exit(EXIT_FAILURE);
+ }
+
+ if (!zerocopied && !(serr->ee_code & SO_EE_CODE_ZEROCOPY_COPIED)) {
+ fprintf(stderr, "serr: was zerocopy instead of copy\n");
+ exit(EXIT_FAILURE);
+ }
+}
+
+static struct vsock_test_data test_data_array[] = {
+ /* Last element has non-page aligned size. */
+ {
+ .zerocopied = true,
+ .completion = true,
+ .sendmsg_errno = 0,
+ .sendmsg_res = SENDMSG_RES_IOV_LEN,
+ .vecs_cnt = 3,
+ {
+ { NULL, PAGE_SIZE },
+ { NULL, PAGE_SIZE },
+ { NULL, 200 }
+ }
+ },
+ /* All elements have page aligned base and size. */
+ {
+ .zerocopied = true,
+ .completion = true,
+ .sendmsg_errno = 0,
+ .sendmsg_res = SENDMSG_RES_IOV_LEN,
+ .vecs_cnt = 3,
+ {
+ { NULL, PAGE_SIZE },
+ { NULL, PAGE_SIZE * 2 },
+ { NULL, PAGE_SIZE * 3 }
+ }
+ },
+ /* All elements have page aligned base and size. But
+ * data length is bigger than 64Kb.
+ */
+ {
+ .zerocopied = true,
+ .completion = true,
+ .sendmsg_errno = 0,
+ .sendmsg_res = SENDMSG_RES_IOV_LEN,
+ .vecs_cnt = 3,
+ {
+ { NULL, PAGE_SIZE * 16 },
+ { NULL, PAGE_SIZE * 16 },
+ { NULL, PAGE_SIZE * 16 }
+ }
+ },
+ /* All elements have page aligned base and size. */
+ {
+ .zerocopied = true,
+ .completion = true,
+ .sendmsg_errno = 0,
+ .sendmsg_res = SENDMSG_RES_IOV_LEN,
+ .vecs_cnt = 3,
+ {
+ { NULL, PAGE_SIZE },
+ { NULL, PAGE_SIZE },
+ { NULL, PAGE_SIZE }
+ }
+ },
+ /* Middle element has non-page aligned size. */
+ {
+ .zerocopied = false,
+ .completion = true,
+ .sendmsg_errno = 0,
+ .sendmsg_res = SENDMSG_RES_IOV_LEN,
+ .vecs_cnt = 3,
+ {
+ { NULL, PAGE_SIZE },
+ { NULL, 100 },
+ { NULL, PAGE_SIZE }
+ }
+ },
+ /* Middle element has both non-page aligned base and size. */
+ {
+ .zerocopied = false,
+ .completion = true,
+ .sendmsg_errno = 0,
+ .sendmsg_res = SENDMSG_RES_IOV_LEN,
+ .vecs_cnt = 3,
+ {
+ { NULL, PAGE_SIZE },
+ { (void *)1, 100 },
+ { NULL, PAGE_SIZE }
+ }
+ },
+ /* One element has invalid base. */
+ {
+ .zerocopied = false,
+ .completion = false,
+ .sendmsg_errno = ENOMEM,
+ .sendmsg_res = -1,
+ .vecs_cnt = 3,
+ {
+ { NULL, PAGE_SIZE },
+ { MAP_FAILED, PAGE_SIZE },
+ { NULL, PAGE_SIZE }
+ }
+ },
+ /* Valid data, but SO_ZEROCOPY is off. */
+ {
+ .zerocopied = true,
+ .completion = false,
+ .sendmsg_errno = 0,
+ .sendmsg_res = SENDMSG_RES_IOV_LEN,
+ .vecs_cnt = 1,
+ {
+ { NULL, PAGE_SIZE }
+ }
+ },
+};
+
+static void __test_stream_msg_zerocopy_client(const struct test_opts *opts,
+ const struct vsock_test_data *test_data)
+{
+ struct msghdr msg = { 0 };
+ ssize_t sendmsg_res;
+ struct iovec *iovec;
+ int fd;
+
+ fd = vsock_stream_connect(opts->peer_cid, 1234);
+ if (fd < 0) {
+ perror("connect");
+ exit(EXIT_FAILURE);
+ }
+
+ if (test_data->completion)
+ enable_so_zerocopy(fd);
+
+ iovec = init_iovec_from_test_data(test_data);
+
+ msg.msg_iov = iovec;
+ msg.msg_iovlen = test_data->vecs_cnt;
+
+ errno = 0;
+
+ if (test_data->sendmsg_res == SENDMSG_RES_IOV_LEN)
+ sendmsg_res = iovec_bytes(iovec, test_data->vecs_cnt);
+ else
+ sendmsg_res = test_data->sendmsg_res;
+
+ if (sendmsg(fd, &msg, MSG_ZEROCOPY) != sendmsg_res) {
+ perror("send");
+ exit(EXIT_FAILURE);
+ }
+
+ if (errno != test_data->sendmsg_errno) {
+ fprintf(stderr, "expected 'errno' == %i, got %i\n",
+ test_data->sendmsg_errno, errno);
+ exit(EXIT_FAILURE);
+ }
+
+ do_recv_completion(fd, test_data->zerocopied, test_data->completion);
+
+ if (test_data->sendmsg_res == SENDMSG_RES_IOV_LEN)
+ control_writeulong(iovec_hash_djb2(iovec, test_data->vecs_cnt));
+ else
+ control_writeulong(0);
+
+ control_writeln("DONE");
+ free_iovec_test_data(test_data, iovec);
+ close(fd);
+}
+
+void test_stream_msg_zcopy_client(const struct test_opts *opts)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(test_data_array); i++)
+ __test_stream_msg_zerocopy_client(opts, &test_data_array[i]);
+}
+
+static void test_stream_server(const struct test_opts *opts,
+ const struct vsock_test_data *test_data)
+{
+ unsigned long remote_hash;
+ unsigned long local_hash;
+ ssize_t total_bytes_rec;
+ unsigned char *data;
+ size_t data_len;
+ int fd;
+
+ fd = vsock_stream_accept(VMADDR_CID_ANY, 1234, NULL);
+ if (fd < 0) {
+ perror("accept");
+ exit(EXIT_FAILURE);
+ }
+
+ data_len = iovec_bytes(test_data->vecs, test_data->vecs_cnt);
+
+ data = malloc(data_len);
+ if (!data) {
+ perror("malloc");
+ exit(EXIT_FAILURE);
+ }
+
+ total_bytes_rec = 0;
+
+ while (total_bytes_rec != data_len) {
+ ssize_t bytes_rec;
+
+ bytes_rec = read(fd, data + total_bytes_rec,
+ data_len - total_bytes_rec);
+ if (bytes_rec <= 0)
+ break;
+
+ total_bytes_rec += bytes_rec;
+ }
+
+ if (test_data->sendmsg_res == SENDMSG_RES_IOV_LEN)
+ local_hash = hash_djb2(data, data_len);
+ else
+ local_hash = 0;
+
+ free(data);
+
+ /* Waiting for some result. */
+ remote_hash = control_readulong();
+ if (remote_hash != local_hash) {
+ fprintf(stderr, "hash mismatch\n");
+ exit(EXIT_FAILURE);
+ }
+
+ control_expectln("DONE");
+ close(fd);
+}
+
+void test_stream_msg_zcopy_server(const struct test_opts *opts)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(test_data_array); i++)
+ test_stream_server(opts, &test_data_array[i]);
+}
+
+void test_stream_msg_zcopy_empty_errq_client(const struct test_opts *opts)
+{
+ struct msghdr msg = { 0 };
+ char cmsg_data[128];
+ ssize_t res;
+ int fd;
+
+ fd = vsock_stream_connect(opts->peer_cid, 1234);
+ if (fd < 0) {
+ perror("connect");
+ exit(EXIT_FAILURE);
+ }
+
+ msg.msg_control = cmsg_data;
+ msg.msg_controllen = sizeof(cmsg_data);
+
+ res = recvmsg(fd, &msg, MSG_ERRQUEUE);
+ if (res != -1) {
+ fprintf(stderr, "expected 'recvmsg(2)' failure, got %zi\n",
+ res);
+ exit(EXIT_FAILURE);
+ }
+
+ control_writeln("DONE");
+ close(fd);
+}
+
+void test_stream_msg_zcopy_empty_errq_server(const struct test_opts *opts)
+{
+ int fd;
+
+ fd = vsock_stream_accept(VMADDR_CID_ANY, 1234, NULL);
+ if (fd < 0) {
+ perror("accept");
+ exit(EXIT_FAILURE);
+ }
+
+ control_expectln("DONE");
+ close(fd);
+}
diff --git a/tools/testing/vsock/vsock_test_zerocopy.h b/tools/testing/vsock/vsock_test_zerocopy.h
new file mode 100644
index 000000000000..705a1e90f41a
--- /dev/null
+++ b/tools/testing/vsock/vsock_test_zerocopy.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef VSOCK_TEST_ZEROCOPY_H
+#define VSOCK_TEST_ZEROCOPY_H
+#include "util.h"
+
+void test_stream_msg_zcopy_client(const struct test_opts *opts);
+void test_stream_msg_zcopy_server(const struct test_opts *opts);
+
+void test_stream_msg_zcopy_empty_errq_client(const struct test_opts *opts);
+void test_stream_msg_zcopy_empty_errq_server(const struct test_opts *opts);
+
+#endif /* VSOCK_TEST_ZEROCOPY_H */
--
2.25.1
To use this option pass '--zc' parameter:
./vsock_perf --zc --sender <cid> --port <port> --bytes <bytes to send>
With this option MSG_ZEROCOPY flag will be passed to the 'send()' call.
Signed-off-by: Arseniy Krasnov <[email protected]>
---
tools/testing/vsock/vsock_perf.c | 139 +++++++++++++++++++++++++++++--
1 file changed, 130 insertions(+), 9 deletions(-)
diff --git a/tools/testing/vsock/vsock_perf.c b/tools/testing/vsock/vsock_perf.c
index a72520338f84..7fd76f7a3c16 100644
--- a/tools/testing/vsock/vsock_perf.c
+++ b/tools/testing/vsock/vsock_perf.c
@@ -18,6 +18,8 @@
#include <poll.h>
#include <sys/socket.h>
#include <linux/vm_sockets.h>
+#include <sys/mman.h>
+#include <linux/errqueue.h>
#define DEFAULT_BUF_SIZE_BYTES (128 * 1024)
#define DEFAULT_TO_SEND_BYTES (64 * 1024)
@@ -28,9 +30,14 @@
#define BYTES_PER_GB (1024 * 1024 * 1024ULL)
#define NSEC_PER_SEC (1000000000ULL)
+#ifndef SOL_VSOCK
+#define SOL_VSOCK 287
+#endif
+
static unsigned int port = DEFAULT_PORT;
static unsigned long buf_size_bytes = DEFAULT_BUF_SIZE_BYTES;
static unsigned long vsock_buf_bytes = DEFAULT_VSOCK_BUF_BYTES;
+static bool zerocopy;
static void error(const char *s)
{
@@ -247,15 +254,76 @@ static void run_receiver(unsigned long rcvlowat_bytes)
close(fd);
}
+static void recv_completion(int fd)
+{
+ struct sock_extended_err *serr;
+ char cmsg_data[128];
+ struct cmsghdr *cm;
+ struct msghdr msg = { 0 };
+ ssize_t ret;
+
+ msg.msg_control = cmsg_data;
+ msg.msg_controllen = sizeof(cmsg_data);
+
+ ret = recvmsg(fd, &msg, MSG_ERRQUEUE);
+ if (ret) {
+ fprintf(stderr, "recvmsg: failed to read err: %zi\n", ret);
+ return;
+ }
+
+ cm = CMSG_FIRSTHDR(&msg);
+ if (!cm) {
+ fprintf(stderr, "cmsg: no cmsg\n");
+ return;
+ }
+
+ if (cm->cmsg_level != SOL_VSOCK) {
+ fprintf(stderr, "cmsg: unexpected 'cmsg_level'\n");
+ return;
+ }
+
+ if (cm->cmsg_type) {
+ fprintf(stderr, "cmsg: unexpected 'cmsg_type'\n");
+ return;
+ }
+
+ serr = (void *)CMSG_DATA(cm);
+ if (serr->ee_origin != SO_EE_ORIGIN_ZEROCOPY) {
+ fprintf(stderr, "serr: wrong origin\n");
+ return;
+ }
+
+ if (serr->ee_errno) {
+ fprintf(stderr, "serr: wrong error code\n");
+ return;
+ }
+
+ if (zerocopy && (serr->ee_code & SO_EE_CODE_ZEROCOPY_COPIED))
+ fprintf(stderr, "warning: copy instead of zerocopy\n");
+}
+
+static void enable_so_zerocopy(int fd)
+{
+ int val = 1;
+
+ if (setsockopt(fd, SOL_SOCKET, SO_ZEROCOPY, &val, sizeof(val)))
+ error("setsockopt(SO_ZEROCOPY)");
+}
+
static void run_sender(int peer_cid, unsigned long to_send_bytes)
{
time_t tx_begin_ns;
time_t tx_total_ns;
size_t total_send;
+ time_t time_in_send;
void *data;
int fd;
- printf("Run as sender\n");
+ if (zerocopy)
+ printf("Run as sender MSG_ZEROCOPY\n");
+ else
+ printf("Run as sender\n");
+
printf("Connect to %i:%u\n", peer_cid, port);
printf("Send %lu bytes\n", to_send_bytes);
printf("TX buffer %lu bytes\n", buf_size_bytes);
@@ -265,38 +333,82 @@ static void run_sender(int peer_cid, unsigned long to_send_bytes)
if (fd < 0)
exit(EXIT_FAILURE);
- data = malloc(buf_size_bytes);
+ if (zerocopy) {
+ enable_so_zerocopy(fd);
- if (!data) {
- fprintf(stderr, "'malloc()' failed\n");
- exit(EXIT_FAILURE);
+ data = mmap(NULL, buf_size_bytes, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if (data == MAP_FAILED) {
+ perror("mmap");
+ exit(EXIT_FAILURE);
+ }
+ } else {
+ data = malloc(buf_size_bytes);
+
+ if (!data) {
+ fprintf(stderr, "'malloc()' failed\n");
+ exit(EXIT_FAILURE);
+ }
}
memset(data, 0, buf_size_bytes);
total_send = 0;
+ time_in_send = 0;
tx_begin_ns = current_nsec();
while (total_send < to_send_bytes) {
ssize_t sent;
+ size_t rest_bytes;
+ time_t before;
- sent = write(fd, data, buf_size_bytes);
+ rest_bytes = to_send_bytes - total_send;
+
+ before = current_nsec();
+ sent = send(fd, data, (rest_bytes > buf_size_bytes) ?
+ buf_size_bytes : rest_bytes,
+ zerocopy ? MSG_ZEROCOPY : 0);
+ time_in_send += (current_nsec() - before);
if (sent <= 0)
error("write");
total_send += sent;
+
+ if (zerocopy) {
+ struct pollfd fds = { 0 };
+
+ fds.fd = fd;
+
+ if (poll(&fds, 1, -1) < 0) {
+ perror("poll");
+ exit(EXIT_FAILURE);
+ }
+
+ if (!(fds.revents & POLLERR)) {
+ fprintf(stderr, "POLLERR expected\n");
+ exit(EXIT_FAILURE);
+ }
+
+ recv_completion(fd);
+ }
}
tx_total_ns = current_nsec() - tx_begin_ns;
printf("total bytes sent: %zu\n", total_send);
printf("tx performance: %f Gbits/s\n",
- get_gbps(total_send * 8, tx_total_ns));
- printf("total time in 'write()': %f sec\n",
+ get_gbps(total_send * 8, time_in_send));
+ printf("total time in tx loop: %f sec\n",
(float)tx_total_ns / NSEC_PER_SEC);
+ printf("time in 'send()': %f sec\n",
+ (float)time_in_send / NSEC_PER_SEC);
close(fd);
- free(data);
+
+ if (zerocopy)
+ munmap(data, buf_size_bytes);
+ else
+ free(data);
}
static const char optstring[] = "";
@@ -336,6 +448,11 @@ static const struct option longopts[] = {
.has_arg = required_argument,
.val = 'R',
},
+ {
+ .name = "zc",
+ .has_arg = no_argument,
+ .val = 'Z',
+ },
{},
};
@@ -351,6 +468,7 @@ static void usage(void)
" --help This message\n"
" --sender <cid> Sender mode (receiver default)\n"
" <cid> of the receiver to connect to\n"
+ " --zc Enable zerocopy\n"
" --port <port> Port (default %d)\n"
" --bytes <bytes>KMG Bytes to send (default %d)\n"
" --buf-size <bytes>KMG Data buffer size (default %d). In sender mode\n"
@@ -413,6 +531,9 @@ int main(int argc, char **argv)
case 'H': /* Help. */
usage();
break;
+ case 'Z': /* Zerocopy. */
+ zerocopy = true;
+ break;
default:
usage();
}
--
2.25.1
This is preparation patch for non-linear skbuff handling. It replaces
direct calls of 'memcpy_to_msg()' with 'skb_copy_datagram_iter()'. Main
advantage of the second one is that is can handle paged part of the skb
by using 'kmap()' on each page, but if there are no pages in the skb,
it behaves like simple copying to iov iterator. This patch also removes
'skb_pull()' calls, because it updates 'data' pointer of the skb (it is
wrong thing to do with non-linear skb). Instead of updating 'data' and
'len' fields of skb, it adds new field to the control block of the skb:
this value shows current offset to read next data from skb (no matter
that this skb is linear or not), after each read from skb this field is
incremented and once it reaches 'len', skb is considered done.
Signed-off-by: Arseniy Krasnov <[email protected]>
---
include/linux/virtio_vsock.h | 1 +
net/vmw_vsock/virtio_transport_common.c | 26 +++++++++++++++++--------
2 files changed, 19 insertions(+), 8 deletions(-)
diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index c58453699ee9..17dbb7176e37 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -12,6 +12,7 @@
struct virtio_vsock_skb_cb {
bool reply;
bool tap_delivered;
+ u32 frag_off;
};
#define VIRTIO_VSOCK_SKB_CB(skb) ((struct virtio_vsock_skb_cb *)((skb)->cb))
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index e4878551f140..16effa8d55d2 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -355,7 +355,7 @@ virtio_transport_stream_do_peek(struct vsock_sock *vsk,
spin_lock_bh(&vvs->rx_lock);
skb_queue_walk_safe(&vvs->rx_queue, skb, tmp) {
- off = 0;
+ off = VIRTIO_VSOCK_SKB_CB(skb)->frag_off;
if (total == len)
break;
@@ -370,7 +370,10 @@ virtio_transport_stream_do_peek(struct vsock_sock *vsk,
*/
spin_unlock_bh(&vvs->rx_lock);
- err = memcpy_to_msg(msg, skb->data + off, bytes);
+ err = skb_copy_datagram_iter(skb, off,
+ &msg->msg_iter,
+ bytes);
+
if (err)
goto out;
@@ -414,24 +417,28 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
skb = skb_peek(&vvs->rx_queue);
bytes = len - total;
- if (bytes > skb->len)
- bytes = skb->len;
+ if (bytes > skb->len - VIRTIO_VSOCK_SKB_CB(skb)->frag_off)
+ bytes = skb->len - VIRTIO_VSOCK_SKB_CB(skb)->frag_off;
/* sk_lock is held by caller so no one else can dequeue.
* Unlock rx_lock since memcpy_to_msg() may sleep.
*/
spin_unlock_bh(&vvs->rx_lock);
- err = memcpy_to_msg(msg, skb->data, bytes);
+ err = skb_copy_datagram_iter(skb,
+ VIRTIO_VSOCK_SKB_CB(skb)->frag_off,
+ &msg->msg_iter, bytes);
+
if (err)
goto out;
spin_lock_bh(&vvs->rx_lock);
total += bytes;
- skb_pull(skb, bytes);
- if (skb->len == 0) {
+ VIRTIO_VSOCK_SKB_CB(skb)->frag_off += bytes;
+
+ if (skb->len == VIRTIO_VSOCK_SKB_CB(skb)->frag_off) {
u32 pkt_len = le32_to_cpu(virtio_vsock_hdr(skb)->len);
virtio_transport_dec_rx_pkt(vvs, pkt_len);
@@ -503,7 +510,10 @@ static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
*/
spin_unlock_bh(&vvs->rx_lock);
- err = memcpy_to_msg(msg, skb->data, bytes_to_copy);
+ err = skb_copy_datagram_iter(skb, 0,
+ &msg->msg_iter,
+ bytes_to_copy);
+
if (err) {
/* Copy of message failed. Rest of
* fragments will be freed without copy.
--
2.25.1
This adds set of tests which use io_uring for rx/tx. This test suite is
implemented as separated util like 'vsock_test' and has the same set of
input arguments as 'vsock_test'. These tests only cover cases of data
transmission (no connect/bind/accept etc).
Signed-off-by: Arseniy Krasnov <[email protected]>
---
tools/testing/vsock/Makefile | 7 +-
tools/testing/vsock/vsock_uring_test.c | 316 +++++++++++++++++++++++++
2 files changed, 322 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/vsock/vsock_uring_test.c
diff --git a/tools/testing/vsock/Makefile b/tools/testing/vsock/Makefile
index 0a78787d1d92..8621ae73051d 100644
--- a/tools/testing/vsock/Makefile
+++ b/tools/testing/vsock/Makefile
@@ -1,12 +1,17 @@
# SPDX-License-Identifier: GPL-2.0-only
+ifeq ($(MAKECMDGOALS),vsock_uring_test)
+LDFLAGS = -luring
+endif
+
all: test vsock_perf
test: vsock_test vsock_diag_test
vsock_test: vsock_test.o vsock_test_zerocopy.o timeout.o control.o util.o
vsock_diag_test: vsock_diag_test.o timeout.o control.o util.o
vsock_perf: vsock_perf.o
+vsock_uring_test: control.o util.o vsock_uring_test.o timeout.o $(LDFLAGS)
CFLAGS += -g -O2 -Werror -Wall -I. -I../../include -I../../../usr/include -Wno-pointer-sign -fno-strict-overflow -fno-strict-aliasing -fno-common -MMD -U_FORTIFY_SOURCE -D_GNU_SOURCE
.PHONY: all test clean
clean:
- ${RM} *.o *.d vsock_test vsock_diag_test
+ ${RM} *.o *.d vsock_test vsock_diag_test vsock_uring_test
-include *.d
diff --git a/tools/testing/vsock/vsock_uring_test.c b/tools/testing/vsock/vsock_uring_test.c
new file mode 100644
index 000000000000..5d0f0f48a794
--- /dev/null
+++ b/tools/testing/vsock/vsock_uring_test.c
@@ -0,0 +1,316 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* io_uring tests for vsock
+ *
+ * Copyright (C) 2023 SberDevices.
+ *
+ * Author: Arseniy Krasnov <[email protected]>
+ */
+
+#include <getopt.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <liburing.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <linux/kernel.h>
+#include <error.h>
+
+#include "util.h"
+#include "control.h"
+
+#define PAGE_SIZE 4096
+#define RING_ENTRIES_NUM 4
+
+static struct vsock_test_data test_data_array[] = {
+ {
+ .use_zerocopy = true,
+ .vecs_cnt = 3,
+ {
+ { NULL, PAGE_SIZE },
+ { NULL, 2 * PAGE_SIZE },
+ { NULL, 3 * PAGE_SIZE },
+ }
+ },
+ {
+ .use_zerocopy = false,
+ .vecs_cnt = 3,
+ {
+ { NULL, PAGE_SIZE },
+ { NULL, 2 * PAGE_SIZE },
+ { NULL, 3 * PAGE_SIZE },
+ }
+ },
+ {
+ .use_zerocopy = true,
+ .vecs_cnt = 3,
+ {
+ { NULL, PAGE_SIZE },
+ { (void *)1, 200 },
+ { NULL, 3 * PAGE_SIZE },
+ }
+ },
+ {
+ .use_zerocopy = false,
+ .vecs_cnt = 3,
+ {
+ { NULL, PAGE_SIZE },
+ { (void *)1, 200 },
+ { NULL, 3 * PAGE_SIZE },
+ }
+ }
+};
+
+static void vsock_io_uring_client(const struct test_opts *opts,
+ const struct vsock_test_data *test_data)
+{
+ struct io_uring_sqe *sqe;
+ struct io_uring_cqe *cqe;
+ struct io_uring ring;
+ struct iovec *iovec;
+ struct msghdr msg;
+ int fd;
+
+ fd = vsock_stream_connect(opts->peer_cid, 1234);
+ if (fd < 0) {
+ perror("connect");
+ exit(EXIT_FAILURE);
+ }
+
+ enable_so_zerocopy(fd);
+
+ iovec = init_iovec_from_test_data(test_data);
+
+ if (io_uring_queue_init(RING_ENTRIES_NUM, &ring, 0))
+ error(1, errno, "io_uring_queue_init");
+
+ if (io_uring_register_buffers(&ring, iovec, test_data->vecs_cnt))
+ error(1, errno, "io_uring_register_buffers");
+
+ memset(&msg, 0, sizeof(msg));
+ msg.msg_iov = iovec;
+ msg.msg_iovlen = test_data->vecs_cnt;
+ sqe = io_uring_get_sqe(&ring);
+
+ if (test_data->use_zerocopy)
+ io_uring_prep_sendmsg_zc(sqe, fd, &msg, 0);
+ else
+ io_uring_prep_sendmsg(sqe, fd, &msg, 0);
+
+ if (io_uring_submit(&ring) != 1)
+ error(1, errno, "io_uring_submit");
+
+ if (io_uring_wait_cqe(&ring, &cqe))
+ error(1, errno, "io_uring_wait_cqe");
+
+ io_uring_cqe_seen(&ring, cqe);
+
+ control_writeulong(iovec_hash_djb2(iovec, test_data->vecs_cnt));
+
+ control_writeln("DONE");
+ io_uring_queue_exit(&ring);
+ free_iovec_test_data(test_data, iovec);
+ close(fd);
+}
+
+void test_stream_uring_client(const struct test_opts *opts)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(test_data_array); i++)
+ vsock_io_uring_client(opts, &test_data_array[i]);
+}
+
+static void vsock_io_uring_server(const struct test_opts *opts,
+ const struct vsock_test_data *test_data)
+{
+ unsigned long remote_hash;
+ unsigned long local_hash;
+ struct io_uring_sqe *sqe;
+ struct io_uring_cqe *cqe;
+ struct io_uring ring;
+ struct iovec iovec;
+ size_t data_len;
+ void *data;
+ int fd;
+
+ fd = vsock_stream_accept(VMADDR_CID_ANY, 1234, NULL);
+ if (fd < 0) {
+ perror("accept");
+ exit(EXIT_FAILURE);
+ }
+
+ data_len = iovec_bytes(test_data->vecs, test_data->vecs_cnt);
+
+ data = malloc(data_len);
+ if (!data) {
+ perror("malloc");
+ exit(EXIT_FAILURE);
+ }
+
+ if (io_uring_queue_init(RING_ENTRIES_NUM, &ring, 0))
+ error(1, errno, "io_uring_queue_init");
+
+ sqe = io_uring_get_sqe(&ring);
+ iovec.iov_base = data;
+ iovec.iov_len = data_len;
+
+ io_uring_prep_readv(sqe, fd, &iovec, 1, 0);
+
+ if (io_uring_submit(&ring) != 1)
+ error(1, errno, "io_uring_submit");
+
+ if (io_uring_wait_cqe(&ring, &cqe))
+ error(1, errno, "io_uring_wait_cqe");
+
+ if (cqe->res != data_len) {
+ fprintf(stderr, "expected %zu, got %u\n", data_len,
+ cqe->res);
+ exit(EXIT_FAILURE);
+ }
+
+ local_hash = hash_djb2(data, data_len);
+
+ remote_hash = control_readulong();
+ if (remote_hash != local_hash) {
+ fprintf(stderr, "hash mismatch\n");
+ exit(EXIT_FAILURE);
+ }
+
+ control_expectln("DONE");
+ io_uring_queue_exit(&ring);
+ free(data);
+}
+
+void test_stream_uring_server(const struct test_opts *opts)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(test_data_array); i++)
+ vsock_io_uring_server(opts, &test_data_array[i]);
+}
+
+static struct test_case test_cases[] = {
+ {
+ .name = "io_uring test",
+ .run_server = test_stream_uring_server,
+ .run_client = test_stream_uring_client,
+ },
+ {},
+};
+
+static const char optstring[] = "";
+static const struct option longopts[] = {
+ {
+ .name = "control-host",
+ .has_arg = required_argument,
+ .val = 'H',
+ },
+ {
+ .name = "control-port",
+ .has_arg = required_argument,
+ .val = 'P',
+ },
+ {
+ .name = "mode",
+ .has_arg = required_argument,
+ .val = 'm',
+ },
+ {
+ .name = "peer-cid",
+ .has_arg = required_argument,
+ .val = 'p',
+ },
+ {
+ .name = "help",
+ .has_arg = no_argument,
+ .val = '?',
+ },
+ {},
+};
+
+static void usage(void)
+{
+ fprintf(stderr, "Usage: vsock_uring_test [--help] [--control-host=<host>] --control-port=<port> --mode=client|server --peer-cid=<cid>\n"
+ "\n"
+ " Server: vsock_uring_test --control-port=1234 --mode=server --peer-cid=3\n"
+ " Client: vsock_uring_test --control-host=192.168.0.1 --control-port=1234 --mode=client --peer-cid=2\n"
+ "\n"
+ "Run transmission tests using io_uring. Usage is the same as\n"
+ "in ./vsock_test\n"
+ "\n"
+ "Options:\n"
+ " --help This help message\n"
+ " --control-host <host> Server IP address to connect to\n"
+ " --control-port <port> Server port to listen on/connect to\n"
+ " --mode client|server Server or client mode\n"
+ " --peer-cid <cid> CID of the other side\n"
+ );
+ exit(EXIT_FAILURE);
+}
+
+int main(int argc, char **argv)
+{
+ const char *control_host = NULL;
+ const char *control_port = NULL;
+ struct test_opts opts = {
+ .mode = TEST_MODE_UNSET,
+ .peer_cid = VMADDR_CID_ANY,
+ };
+
+ init_signals();
+
+ for (;;) {
+ int opt = getopt_long(argc, argv, optstring, longopts, NULL);
+
+ if (opt == -1)
+ break;
+
+ switch (opt) {
+ case 'H':
+ control_host = optarg;
+ break;
+ case 'm':
+ if (strcmp(optarg, "client") == 0) {
+ opts.mode = TEST_MODE_CLIENT;
+ } else if (strcmp(optarg, "server") == 0) {
+ opts.mode = TEST_MODE_SERVER;
+ } else {
+ fprintf(stderr, "--mode must be \"client\" or \"server\"\n");
+ return EXIT_FAILURE;
+ }
+ break;
+ case 'p':
+ opts.peer_cid = parse_cid(optarg);
+ break;
+ case 'P':
+ control_port = optarg;
+ break;
+ case '?':
+ default:
+ usage();
+ }
+ }
+
+ if (!control_port)
+ usage();
+ if (opts.mode == TEST_MODE_UNSET)
+ usage();
+ if (opts.peer_cid == VMADDR_CID_ANY)
+ usage();
+
+ if (!control_host) {
+ if (opts.mode != TEST_MODE_SERVER)
+ usage();
+ control_host = "0.0.0.0";
+ }
+
+ control_init(control_host, control_port,
+ opts.mode == TEST_MODE_SERVER);
+
+ run_tests(test_cases, &opts);
+
+ control_cleanup();
+
+ return 0;
+}
--
2.25.1
This bit is used by io_uring in case of zerocopy tx mode. io_uring code
checks, that socket has this feature. This patch sets it in two places:
1) For socket in 'connect()' call.
2) For new socket which is returned by 'accept()' call.
Signed-off-by: Arseniy Krasnov <[email protected]>
---
net/vmw_vsock/af_vsock.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index dbfe82ee7769..bee1c36dc29f 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1406,6 +1406,9 @@ static int vsock_connect(struct socket *sock, struct sockaddr *addr,
goto out;
}
+ if (vsock_msgzerocopy_allow(transport))
+ set_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags);
+
err = vsock_auto_bind(vsk);
if (err)
goto out;
@@ -1560,6 +1563,9 @@ static int vsock_accept(struct socket *sock, struct socket *newsock, int flags,
} else {
newsock->state = SS_CONNECTED;
sock_graft(connected, newsock);
+ if (vsock_msgzerocopy_allow(vconnected->transport))
+ set_bit(SOCK_SUPPORT_ZC,
+ &connected->sk_socket->flags);
}
release_sock(connected);
--
2.25.1
This feature totally depends on transport, so if transport doesn't
support it, return error.
Signed-off-by: Arseniy Krasnov <[email protected]>
---
include/net/af_vsock.h | 7 +++++++
net/vmw_vsock/af_vsock.c | 6 ++++++
2 files changed, 13 insertions(+)
diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index 0e7504a42925..ec09edc5f3a0 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -177,6 +177,9 @@ struct vsock_transport {
/* Read a single skb */
int (*read_skb)(struct vsock_sock *, skb_read_actor_t);
+
+ /* Zero-copy. */
+ bool (*msgzerocopy_allow)(void);
};
/**** CORE ****/
@@ -243,4 +246,8 @@ static inline void __init vsock_bpf_build_proto(void)
{}
#endif
+static inline bool vsock_msgzerocopy_allow(const struct vsock_transport *t)
+{
+ return t->msgzerocopy_allow && t->msgzerocopy_allow();
+}
#endif /* __AF_VSOCK_H__ */
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index b2da791d920b..dbfe82ee7769 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1824,6 +1824,12 @@ static int vsock_connectible_sendmsg(struct socket *sock, struct msghdr *msg,
goto out;
}
+ if (msg->msg_flags & MSG_ZEROCOPY &&
+ !vsock_msgzerocopy_allow(transport)) {
+ err = -EOPNOTSUPP;
+ goto out;
+ }
+
/* Wait for room in the produce queue to enqueue our user's data. */
timeout = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
--
2.25.1
Use pages of non-linear skb as buffers in virtio tx queue.
Signed-off-by: Arseniy Krasnov <[email protected]>
---
net/vmw_vsock/virtio_transport.c | 32 ++++++++++++++++++++++++++------
1 file changed, 26 insertions(+), 6 deletions(-)
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index e95df847176b..1c269c3f010d 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -100,7 +100,9 @@ virtio_transport_send_pkt_work(struct work_struct *work)
vq = vsock->vqs[VSOCK_VQ_TX];
for (;;) {
- struct scatterlist hdr, buf, *sgs[2];
+ /* +1 is for packet header. */
+ struct scatterlist *sgs[MAX_SKB_FRAGS + 1];
+ struct scatterlist bufs[MAX_SKB_FRAGS + 1];
int ret, in_sg = 0, out_sg = 0;
struct sk_buff *skb;
bool reply;
@@ -111,12 +113,30 @@ virtio_transport_send_pkt_work(struct work_struct *work)
virtio_transport_deliver_tap_pkt(skb);
reply = virtio_vsock_skb_reply(skb);
+ sg_init_one(&bufs[0], virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb)));
+ sgs[out_sg++] = &bufs[0];
+
+ if (skb_is_nonlinear(skb)) {
+ int i;
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ struct page *data_page = skb_shinfo(skb)->frags[i].bv_page;
+
+ /* We will use 'page_to_virt()' for userspace page here,
+ * because virtio layer will call 'virt_to_phys()' later
+ * to fill buffer descriptor. We don't touch memory at
+ * "virtual" address of this page.
+ */
+ sg_init_one(&bufs[i + 1],
+ page_to_virt(data_page), PAGE_SIZE);
+ sgs[out_sg++] = &bufs[i + 1];
+ }
+ } else {
+ if (skb->len > 0) {
+ sg_init_one(&bufs[1], skb->data, skb->len);
+ sgs[out_sg++] = &bufs[1];
+ }
- sg_init_one(&hdr, virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb)));
- sgs[out_sg++] = &hdr;
- if (skb->len > 0) {
- sg_init_one(&buf, skb->data, skb->len);
- sgs[out_sg++] = &buf;
}
ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL);
--
2.25.1
This adds copying to guest's virtio buffers from non-linear skbs. Such
skbs are created by protocol layer when MSG_ZEROCOPY flags is used. It
changes call of 'copy_to_iter()' to 'skb_copy_datagram_iter()'. Second
function can read data from non-linear skb.
See commit to 'net/vmw_vsock/virtio_transport_common.c' with the same
name for more details.
Signed-off-by: Arseniy Krasnov <[email protected]>
---
drivers/vhost/vsock.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 6578db78f0ae..b254aa4b756a 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -156,7 +156,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
}
iov_iter_init(&iov_iter, ITER_DEST, &vq->iov[out], in, iov_len);
- payload_len = skb->len;
+ payload_len = skb->len - VIRTIO_VSOCK_SKB_CB(skb)->frag_off;
hdr = virtio_vsock_hdr(skb);
/* If the packet is greater than the space available in the
@@ -197,8 +197,10 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
break;
}
- nbytes = copy_to_iter(skb->data, payload_len, &iov_iter);
- if (nbytes != payload_len) {
+ if (skb_copy_datagram_iter(skb,
+ VIRTIO_VSOCK_SKB_CB(skb)->frag_off,
+ &iov_iter,
+ payload_len)) {
kfree_skb(skb);
vq_err(vq, "Faulted on copying pkt buf\n");
break;
@@ -212,13 +214,13 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
vhost_add_used(vq, head, sizeof(*hdr) + payload_len);
added = true;
- skb_pull(skb, payload_len);
+ VIRTIO_VSOCK_SKB_CB(skb)->frag_off += payload_len;
total_len += payload_len;
/* If we didn't send all the payload we can requeue the packet
* to send it with the next available buffer.
*/
- if (skb->len > 0) {
+ if (VIRTIO_VSOCK_SKB_CB(skb)->frag_off < skb->len) {
hdr->flags |= cpu_to_le32(flags_to_restore);
/* We are queueing the same skb to handle
--
2.25.1
For tap device new skb is created and data from the current skb is
copied to it. This adds copying data from non-linear skb to new
the skb.
Signed-off-by: Arseniy Krasnov <[email protected]>
---
net/vmw_vsock/virtio_transport_common.c | 31 ++++++++++++++++++++++---
1 file changed, 28 insertions(+), 3 deletions(-)
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 16effa8d55d2..9854f48a0544 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -106,6 +106,27 @@ virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
return NULL;
}
+static void virtio_transport_copy_nonlinear_skb(struct sk_buff *skb,
+ void *dst,
+ size_t len)
+{
+ struct iov_iter iov_iter = { 0 };
+ struct iovec iovec;
+ size_t to_copy;
+
+ iovec.iov_base = dst;
+ iovec.iov_len = len;
+
+ iov_iter.iter_type = ITER_IOVEC;
+ iov_iter.__iov = &iovec;
+ iov_iter.nr_segs = 1;
+
+ to_copy = min_t(size_t, len, skb->len);
+
+ skb_copy_datagram_iter(skb, VIRTIO_VSOCK_SKB_CB(skb)->frag_off,
+ &iov_iter, to_copy);
+}
+
/* Packet capture */
static struct sk_buff *virtio_transport_build_skb(void *opaque)
{
@@ -114,7 +135,6 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
struct af_vsockmon_hdr *hdr;
struct sk_buff *skb;
size_t payload_len;
- void *payload_buf;
/* A packet could be split to fit the RX buffer, so we can retrieve
* the payload length from the header and the buffer pointer taking
@@ -122,7 +142,6 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
*/
pkt_hdr = virtio_vsock_hdr(pkt);
payload_len = pkt->len;
- payload_buf = pkt->data;
skb = alloc_skb(sizeof(*hdr) + sizeof(*pkt_hdr) + payload_len,
GFP_ATOMIC);
@@ -165,7 +184,13 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
skb_put_data(skb, pkt_hdr, sizeof(*pkt_hdr));
if (payload_len) {
- skb_put_data(skb, payload_buf, payload_len);
+ if (skb_is_nonlinear(pkt)) {
+ void *data = skb_put(skb, payload_len);
+
+ virtio_transport_copy_nonlinear_skb(pkt, data, payload_len);
+ } else {
+ skb_put_data(skb, pkt->data, payload_len);
+ }
}
return skb;
--
2.25.1
On Mon, May 22, 2023 at 10:39:37AM +0300, Arseniy Krasnov wrote:
> For tap device new skb is created and data from the current skb is
> copied to it. This adds copying data from non-linear skb to new
> the skb.
>
> Signed-off-by: Arseniy Krasnov <[email protected]>
> ---
> net/vmw_vsock/virtio_transport_common.c | 31 ++++++++++++++++++++++---
> 1 file changed, 28 insertions(+), 3 deletions(-)
>
> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
> index 16effa8d55d2..9854f48a0544 100644
> --- a/net/vmw_vsock/virtio_transport_common.c
> +++ b/net/vmw_vsock/virtio_transport_common.c
> @@ -106,6 +106,27 @@ virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
> return NULL;
> }
>
> +static void virtio_transport_copy_nonlinear_skb(struct sk_buff *skb,
> + void *dst,
> + size_t len)
> +{
> + struct iov_iter iov_iter = { 0 };
> + struct iovec iovec;
> + size_t to_copy;
> +
> + iovec.iov_base = dst;
Hi Arseniy,
Sparse seems unhappy about this.
Though, TBH, I'm unsure what should be done about it.
.../virtio_transport_common.c:117:24: warning: incorrect type in assignment (different address spaces)
.../virtio_transport_common.c:117:24: expected void [noderef] __user *iov_base
.../virtio_transport_common.c:117:24: got void *dst
...
On 22.05.2023 16:11, Simon Horman wrote:
> On Mon, May 22, 2023 at 10:39:38AM +0300, Arseniy Krasnov wrote:
>> This adds handling of MSG_ZEROCOPY flag on transmission path: if this
>> flag is set and zerocopy transmission is possible, then non-linear skb
>> will be created and filled with the pages of user's buffer. Pages of
>> user's buffer are locked in memory by 'get_user_pages()'.
>>
>> Signed-off-by: Arseniy Krasnov <[email protected]>
>> ---
>> net/vmw_vsock/virtio_transport_common.c | 305 +++++++++++++++++++-----
>> 1 file changed, 243 insertions(+), 62 deletions(-)
>>
>> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>> index 9854f48a0544..5acf824afe41 100644
>> --- a/net/vmw_vsock/virtio_transport_common.c
>> +++ b/net/vmw_vsock/virtio_transport_common.c
>> @@ -37,73 +37,161 @@ virtio_transport_get_ops(struct vsock_sock *vsk)
>> return container_of(t, struct virtio_transport, transport);
>> }
>>
>> -/* Returns a new packet on success, otherwise returns NULL.
>> - *
>> - * If NULL is returned, errp is set to a negative errno.
>> - */
>> -static struct sk_buff *
>> -virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
>> - size_t len,
>> - u32 src_cid,
>> - u32 src_port,
>> - u32 dst_cid,
>> - u32 dst_port)
>> -{
>> - const size_t skb_len = VIRTIO_VSOCK_SKB_HEADROOM + len;
>> - struct virtio_vsock_hdr *hdr;
>> - struct sk_buff *skb;
>> - void *payload;
>> - int err;
>> +static bool virtio_transport_can_zcopy(struct virtio_vsock_pkt_info *info,
>> + size_t max_to_send)
>> +{
>> + struct iov_iter *iov_iter;
>> + size_t max_skb_cap;
>> + size_t bytes;
>> + int i;
>>
>> - skb = virtio_vsock_alloc_skb(skb_len, GFP_KERNEL);
>> - if (!skb)
>> - return NULL;
>> + if (!info->msg)
>> + return false;
>>
>> - hdr = virtio_vsock_hdr(skb);
>> - hdr->type = cpu_to_le16(info->type);
>> - hdr->op = cpu_to_le16(info->op);
>> - hdr->src_cid = cpu_to_le64(src_cid);
>> - hdr->dst_cid = cpu_to_le64(dst_cid);
>> - hdr->src_port = cpu_to_le32(src_port);
>> - hdr->dst_port = cpu_to_le32(dst_port);
>> - hdr->flags = cpu_to_le32(info->flags);
>> - hdr->len = cpu_to_le32(len);
>> + if (!(info->flags & MSG_ZEROCOPY) && !info->msg->msg_ubuf)
>> + return false;
>>
>> - if (info->msg && len > 0) {
>> - payload = skb_put(skb, len);
>> - err = memcpy_from_msg(payload, info->msg, len);
>> - if (err)
>> - goto out;
>> + iov_iter = &info->msg->msg_iter;
>> +
>> + if (iter_is_ubuf(iov_iter)) {
>> + if (offset_in_page(iov_iter->ubuf))
>> + return false;
>> +
>> + return true;
>> + }
>> +
>> + if (!iter_is_iovec(iov_iter))
>> + return false;
>> +
>> + if (iov_iter->iov_offset)
>> + return false;
>> +
>> + /* We can't send whole iov. */
>> + if (iov_iter->count > max_to_send)
>> + return false;
>> +
>> + for (bytes = 0, i = 0; i < iov_iter->nr_segs; i++) {
>> + const struct iovec *iovec;
>> + int pages_in_elem;
>> +
>> + iovec = &iov_iter->__iov[i];
>> +
>> + /* Base must be page aligned. */
>> + if (offset_in_page(iovec->iov_base))
>> + return false;
>>
>> - if (msg_data_left(info->msg) == 0 &&
>> - info->type == VIRTIO_VSOCK_TYPE_SEQPACKET) {
>> - hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
>> + /* Only last element could have non page aligned size. */
>> + if (i != (iov_iter->nr_segs - 1)) {
>> + if (offset_in_page(iovec->iov_len))
>> + return false;
>>
>> - if (info->msg->msg_flags & MSG_EOR)
>> - hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
>> + pages_in_elem = iovec->iov_len >> PAGE_SHIFT;
>> + } else {
>> + pages_in_elem = round_up(iovec->iov_len, PAGE_SIZE);
>> + pages_in_elem >>= PAGE_SHIFT;
>> }
>> +
>> + bytes += (pages_in_elem * PAGE_SIZE);
>> }
>
> Hi Arseniy,
>
> bytes is set but the loop above, but seems otherwise unused in this function.
>
>>
>> - if (info->reply)
>> - virtio_vsock_skb_set_reply(skb);
>> + /* How many bytes we can pack to single skb. Maximum packet
>> + * buffer size is needed to allow vhost handle such packets,
>> + * otherwise they will be dropped.
>> + */
>> + max_skb_cap = min((unsigned int)(MAX_SKB_FRAGS * PAGE_SIZE),
>> + (unsigned int)VIRTIO_VSOCK_MAX_PKT_BUF_SIZE);
>
> Likewise, max_skb_cap seems to be set but unused in this function.
>
Exactly! Seems I forgot to remove it since v2. Thanks for this and above!
>>
>> - trace_virtio_transport_alloc_pkt(src_cid, src_port,
>> - dst_cid, dst_port,
>> - len,
>> - info->type,
>> - info->op,
>> - info->flags);
>> + return true;
>> +}
>
> ...
On 22.05.2023 16:13, Simon Horman wrote:
> On Mon, May 22, 2023 at 10:39:37AM +0300, Arseniy Krasnov wrote:
>> For tap device new skb is created and data from the current skb is
>> copied to it. This adds copying data from non-linear skb to new
>> the skb.
>>
>> Signed-off-by: Arseniy Krasnov <[email protected]>
>> ---
>> net/vmw_vsock/virtio_transport_common.c | 31 ++++++++++++++++++++++---
>> 1 file changed, 28 insertions(+), 3 deletions(-)
>>
>> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>> index 16effa8d55d2..9854f48a0544 100644
>> --- a/net/vmw_vsock/virtio_transport_common.c
>> +++ b/net/vmw_vsock/virtio_transport_common.c
>> @@ -106,6 +106,27 @@ virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
>> return NULL;
>> }
>>
>> +static void virtio_transport_copy_nonlinear_skb(struct sk_buff *skb,
>> + void *dst,
>> + size_t len)
>> +{
>> + struct iov_iter iov_iter = { 0 };
>> + struct iovec iovec;
>> + size_t to_copy;
>> +
>> + iovec.iov_base = dst;
>
> Hi Arseniy,
>
> Sparse seems unhappy about this.
> Though, TBH, I'm unsure what should be done about it.
>
> .../virtio_transport_common.c:117:24: warning: incorrect type in assignment (different address spaces)
> .../virtio_transport_common.c:117:24: expected void [noderef] __user *iov_base
> .../virtio_transport_common.c:117:24: got void *dst
>
Got it, i'll check how to resolve this problem!
Thanks!
>
> ...
On Mon, May 22, 2023 at 10:39:38AM +0300, Arseniy Krasnov wrote:
> This adds handling of MSG_ZEROCOPY flag on transmission path: if this
> flag is set and zerocopy transmission is possible, then non-linear skb
> will be created and filled with the pages of user's buffer. Pages of
> user's buffer are locked in memory by 'get_user_pages()'.
>
> Signed-off-by: Arseniy Krasnov <[email protected]>
> ---
> net/vmw_vsock/virtio_transport_common.c | 305 +++++++++++++++++++-----
> 1 file changed, 243 insertions(+), 62 deletions(-)
>
> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
> index 9854f48a0544..5acf824afe41 100644
> --- a/net/vmw_vsock/virtio_transport_common.c
> +++ b/net/vmw_vsock/virtio_transport_common.c
> @@ -37,73 +37,161 @@ virtio_transport_get_ops(struct vsock_sock *vsk)
> return container_of(t, struct virtio_transport, transport);
> }
>
> -/* Returns a new packet on success, otherwise returns NULL.
> - *
> - * If NULL is returned, errp is set to a negative errno.
> - */
> -static struct sk_buff *
> -virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
> - size_t len,
> - u32 src_cid,
> - u32 src_port,
> - u32 dst_cid,
> - u32 dst_port)
> -{
> - const size_t skb_len = VIRTIO_VSOCK_SKB_HEADROOM + len;
> - struct virtio_vsock_hdr *hdr;
> - struct sk_buff *skb;
> - void *payload;
> - int err;
> +static bool virtio_transport_can_zcopy(struct virtio_vsock_pkt_info *info,
> + size_t max_to_send)
> +{
> + struct iov_iter *iov_iter;
> + size_t max_skb_cap;
> + size_t bytes;
> + int i;
>
> - skb = virtio_vsock_alloc_skb(skb_len, GFP_KERNEL);
> - if (!skb)
> - return NULL;
> + if (!info->msg)
> + return false;
>
> - hdr = virtio_vsock_hdr(skb);
> - hdr->type = cpu_to_le16(info->type);
> - hdr->op = cpu_to_le16(info->op);
> - hdr->src_cid = cpu_to_le64(src_cid);
> - hdr->dst_cid = cpu_to_le64(dst_cid);
> - hdr->src_port = cpu_to_le32(src_port);
> - hdr->dst_port = cpu_to_le32(dst_port);
> - hdr->flags = cpu_to_le32(info->flags);
> - hdr->len = cpu_to_le32(len);
> + if (!(info->flags & MSG_ZEROCOPY) && !info->msg->msg_ubuf)
> + return false;
>
> - if (info->msg && len > 0) {
> - payload = skb_put(skb, len);
> - err = memcpy_from_msg(payload, info->msg, len);
> - if (err)
> - goto out;
> + iov_iter = &info->msg->msg_iter;
> +
> + if (iter_is_ubuf(iov_iter)) {
> + if (offset_in_page(iov_iter->ubuf))
> + return false;
> +
> + return true;
> + }
> +
> + if (!iter_is_iovec(iov_iter))
> + return false;
> +
> + if (iov_iter->iov_offset)
> + return false;
> +
> + /* We can't send whole iov. */
> + if (iov_iter->count > max_to_send)
> + return false;
> +
> + for (bytes = 0, i = 0; i < iov_iter->nr_segs; i++) {
> + const struct iovec *iovec;
> + int pages_in_elem;
> +
> + iovec = &iov_iter->__iov[i];
> +
> + /* Base must be page aligned. */
> + if (offset_in_page(iovec->iov_base))
> + return false;
>
> - if (msg_data_left(info->msg) == 0 &&
> - info->type == VIRTIO_VSOCK_TYPE_SEQPACKET) {
> - hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
> + /* Only last element could have non page aligned size. */
> + if (i != (iov_iter->nr_segs - 1)) {
> + if (offset_in_page(iovec->iov_len))
> + return false;
>
> - if (info->msg->msg_flags & MSG_EOR)
> - hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
> + pages_in_elem = iovec->iov_len >> PAGE_SHIFT;
> + } else {
> + pages_in_elem = round_up(iovec->iov_len, PAGE_SIZE);
> + pages_in_elem >>= PAGE_SHIFT;
> }
> +
> + bytes += (pages_in_elem * PAGE_SIZE);
> }
Hi Arseniy,
bytes is set but the loop above, but seems otherwise unused in this function.
>
> - if (info->reply)
> - virtio_vsock_skb_set_reply(skb);
> + /* How many bytes we can pack to single skb. Maximum packet
> + * buffer size is needed to allow vhost handle such packets,
> + * otherwise they will be dropped.
> + */
> + max_skb_cap = min((unsigned int)(MAX_SKB_FRAGS * PAGE_SIZE),
> + (unsigned int)VIRTIO_VSOCK_MAX_PKT_BUF_SIZE);
Likewise, max_skb_cap seems to be set but unused in this function.
>
> - trace_virtio_transport_alloc_pkt(src_cid, src_port,
> - dst_cid, dst_port,
> - len,
> - info->type,
> - info->op,
> - info->flags);
> + return true;
> +}
...
On 22.05.2023 16:09, Arseniy Krasnov wrote:
>
>
> On 22.05.2023 16:11, Simon Horman wrote:
>> On Mon, May 22, 2023 at 10:39:38AM +0300, Arseniy Krasnov wrote:
>>> This adds handling of MSG_ZEROCOPY flag on transmission path: if this
>>> flag is set and zerocopy transmission is possible, then non-linear skb
>>> will be created and filled with the pages of user's buffer. Pages of
>>> user's buffer are locked in memory by 'get_user_pages()'.
>>>
>>> Signed-off-by: Arseniy Krasnov <[email protected]>
>>> ---
>>> net/vmw_vsock/virtio_transport_common.c | 305 +++++++++++++++++++-----
>>> 1 file changed, 243 insertions(+), 62 deletions(-)
>>>
>>> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>>> index 9854f48a0544..5acf824afe41 100644
>>> --- a/net/vmw_vsock/virtio_transport_common.c
>>> +++ b/net/vmw_vsock/virtio_transport_common.c
>>> @@ -37,73 +37,161 @@ virtio_transport_get_ops(struct vsock_sock *vsk)
>>> return container_of(t, struct virtio_transport, transport);
>>> }
>>>
>>> -/* Returns a new packet on success, otherwise returns NULL.
>>> - *
>>> - * If NULL is returned, errp is set to a negative errno.
>>> - */
>>> -static struct sk_buff *
>>> -virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
>>> - size_t len,
>>> - u32 src_cid,
>>> - u32 src_port,
>>> - u32 dst_cid,
>>> - u32 dst_port)
>>> -{
>>> - const size_t skb_len = VIRTIO_VSOCK_SKB_HEADROOM + len;
>>> - struct virtio_vsock_hdr *hdr;
>>> - struct sk_buff *skb;
>>> - void *payload;
>>> - int err;
>>> +static bool virtio_transport_can_zcopy(struct virtio_vsock_pkt_info *info,
>>> + size_t max_to_send)
>>> +{
>>> + struct iov_iter *iov_iter;
>>> + size_t max_skb_cap;
>>> + size_t bytes;
>>> + int i;
>>>
>>> - skb = virtio_vsock_alloc_skb(skb_len, GFP_KERNEL);
>>> - if (!skb)
>>> - return NULL;
>>> + if (!info->msg)
>>> + return false;
>>>
>>> - hdr = virtio_vsock_hdr(skb);
>>> - hdr->type = cpu_to_le16(info->type);
>>> - hdr->op = cpu_to_le16(info->op);
>>> - hdr->src_cid = cpu_to_le64(src_cid);
>>> - hdr->dst_cid = cpu_to_le64(dst_cid);
>>> - hdr->src_port = cpu_to_le32(src_port);
>>> - hdr->dst_port = cpu_to_le32(dst_port);
>>> - hdr->flags = cpu_to_le32(info->flags);
>>> - hdr->len = cpu_to_le32(len);
>>> + if (!(info->flags & MSG_ZEROCOPY) && !info->msg->msg_ubuf)
>>> + return false;
>>>
>>> - if (info->msg && len > 0) {
>>> - payload = skb_put(skb, len);
>>> - err = memcpy_from_msg(payload, info->msg, len);
>>> - if (err)
>>> - goto out;
>>> + iov_iter = &info->msg->msg_iter;
>>> +
>>> + if (iter_is_ubuf(iov_iter)) {
>>> + if (offset_in_page(iov_iter->ubuf))
>>> + return false;
>>> +
>>> + return true;
>>> + }
>>> +
>>> + if (!iter_is_iovec(iov_iter))
>>> + return false;
>>> +
>>> + if (iov_iter->iov_offset)
>>> + return false;
>>> +
>>> + /* We can't send whole iov. */
>>> + if (iov_iter->count > max_to_send)
>>> + return false;
>>> +
>>> + for (bytes = 0, i = 0; i < iov_iter->nr_segs; i++) {
>>> + const struct iovec *iovec;
>>> + int pages_in_elem;
>>> +
>>> + iovec = &iov_iter->__iov[i];
>>> +
>>> + /* Base must be page aligned. */
>>> + if (offset_in_page(iovec->iov_base))
>>> + return false;
>>>
>>> - if (msg_data_left(info->msg) == 0 &&
>>> - info->type == VIRTIO_VSOCK_TYPE_SEQPACKET) {
>>> - hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
>>> + /* Only last element could have non page aligned size. */
>>> + if (i != (iov_iter->nr_segs - 1)) {
>>> + if (offset_in_page(iovec->iov_len))
>>> + return false;
>>>
>>> - if (info->msg->msg_flags & MSG_EOR)
>>> - hdr->flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
>>> + pages_in_elem = iovec->iov_len >> PAGE_SHIFT;
>>> + } else {
>>> + pages_in_elem = round_up(iovec->iov_len, PAGE_SIZE);
>>> + pages_in_elem >>= PAGE_SHIFT;
>>> }
>>> +
>>> + bytes += (pages_in_elem * PAGE_SIZE);
^^^
This alignment (base and length) checks are not needed, because virtio supports unaligned buffers. I'll remove
it in v4.
Thanks, Arseniy
>>> }
>>
>> Hi Arseniy,
>>
>> bytes is set but the loop above, but seems otherwise unused in this function.
>>
>>>
>>> - if (info->reply)
>>> - virtio_vsock_skb_set_reply(skb);
>>> + /* How many bytes we can pack to single skb. Maximum packet
>>> + * buffer size is needed to allow vhost handle such packets,
>>> + * otherwise they will be dropped.
>>> + */
>>> + max_skb_cap = min((unsigned int)(MAX_SKB_FRAGS * PAGE_SIZE),
>>> + (unsigned int)VIRTIO_VSOCK_MAX_PKT_BUF_SIZE);
>>
>> Likewise, max_skb_cap seems to be set but unused in this function.
>>
>
> Exactly! Seems I forgot to remove it since v2. Thanks for this and above!
>
>>>
>>> - trace_virtio_transport_alloc_pkt(src_cid, src_port,
>>> - dst_cid, dst_port,
>>> - len,
>>> - info->type,
>>> - info->op,
>>> - info->flags);
>>> + return true;
>>> +}
>>
>> ...
On 22.05.2023 10:39, Arseniy Krasnov wrote:
This patchset is unstable with SOCK_SEQPACKET. I'll fix it.
Thanks, Arseniy
> Hello,
>
> DESCRIPTION
>
> this is MSG_ZEROCOPY feature support for virtio/vsock. I tried to follow
> current implementation for TCP as much as possible:
>
> 1) Sender must enable SO_ZEROCOPY flag to use this feature. Without this
> flag, data will be sent in "classic" copy manner and MSG_ZEROCOPY
> flag will be ignored (e.g. without completion).
>
> 2) Kernel uses completions from socket's error queue. Single completion
> for single tx syscall (or it can merge several completions to single
> one). I used already implemented logic for MSG_ZEROCOPY support:
> 'msg_zerocopy_realloc()' etc.
>
> Difference with copy way is not significant. During packet allocation,
> non-linear skb is created and filled with pinned user pages.
> There are also some updates for vhost and guest parts of transport - in
> both cases i've added handling of non-linear skb for virtio part. vhost
> copies data from such skb to the guest's rx virtio buffers. In the guest,
> virtio transport fills tx virtio queue with pages from skb.
>
> Head of this patchset is:
> https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=94e86ef1b801d213dfb8543633dec86abb1a457d
>
> This version has several limits/problems:
>
> 1) As this feature totally depends on transport, there is no way (or it
> is difficult) to check whether transport is able to handle it or not
> during SO_ZEROCOPY setting. Seems I need to call AF_VSOCK specific
> setsockopt callback from setsockopt callback for SOL_SOCKET, but this
> leads to lock problem, because both AF_VSOCK and SOL_SOCKET callback
> are not considered to be called from each other. So in current version
> SO_ZEROCOPY is set successfully to any type (e.g. transport) of
> AF_VSOCK socket, but if transport does not support MSG_ZEROCOPY,
> tx routine will fail with EOPNOTSUPP.
>
> ^^^
> This is still no resolved :(
>
> 2) When MSG_ZEROCOPY is used, for each tx system call we need to enqueue
> one completion. In each completion there is flag which shows how tx
> was performed: zerocopy or copy. This leads that whole message must
> be send in zerocopy or copy way - we can't send part of message with
> copying and rest of message with zerocopy mode (or vice versa). Now,
> we need to account vsock credit logic, e.g. we can't send whole data
> once - only allowed number of bytes could sent at any moment. In case
> of copying way there is no problem as in worst case we can send single
> bytes, but zerocopy is more complex because smallest transmission
> unit is single page. So if there is not enough space at peer's side
> to send integer number of pages (at least one) - we will wait, thus
> stalling tx side. To overcome this problem i've added simple rule -
> zerocopy is possible only when there is enough space at another side
> for whole message (to check, that current 'msghdr' was already used
> in previous tx iterations i use 'iov_offset' field of it's iov iter).
>
> ^^^
> Discussed as ok during v2. Link:
> https://lore.kernel.org/netdev/23guh3txkghxpgcrcjx7h62qsoj3xgjhfzgtbmqp2slrz3rxr4@zya2z7kwt75l/
>
> 3) loopback transport is not supported, because it requires to implement
> non-linear skb handling in dequeue logic (as we "send" fragged skb
> and "receive" it from the same queue). I'm going to implement it in
> next versions.
>
> ^^^ fixed in v2
>
> 4) Current implementation sets max length of packet to 64KB. IIUC this
> is due to 'kmalloc()' allocated data buffers. I think, in case of
> MSG_ZEROCOPY this value could be increased, because 'kmalloc()' is
> not touched for data - user space pages are used as buffers. Also
> this limit trims every message which is > 64KB, thus such messages
> will be send in copy mode due to 'iov_offset' check in 2).
>
> ^^^ fixed in v2
>
> PATCHSET STRUCTURE
>
> Patchset has the following structure:
> 1) Handle non-linear skbuff on receive in virtio/vhost.
> 2) Handle non-linear skbuff on send in virtio/vhost.
> 3) Updates for AF_VSOCK.
> 4) Enable MSG_ZEROCOPY support on transports.
> 5) Tests/tools/docs updates.
>
> PERFORMANCE
>
> Performance: it is a little bit tricky to compare performance between
> copy and zerocopy transmissions. In zerocopy way we need to wait when
> user buffers will be released by kernel, so it is like synchronous
> path (wait until device driver will process it), while in copy way we
> can feed data to kernel as many as we want, don't care about device
> driver. So I compared only time which we spend in the 'send()' syscall.
> Then if this value will be combined with total number of transmitted
> bytes, we can get Gbit/s parameter. Also to avoid tx stalls due to not
> enough credit, receiver allocates same amount of space as sender needs.
>
> Sender:
> ./vsock_perf --sender <CID> --buf-size <buf size> --bytes 256M [--zc]
>
> Receiver:
> ./vsock_perf --vsk-size 256M
>
> I run tests on two setups: desktop with Core i7 - I use this PC for
> development and in this case guest is nested guest, and host is normal
> guest. Another hardware is some embedded board with Atom - here I don't
> have nested virtualization - host runs on hw, and guest is normal guest.
>
> G2H transmission (values are Gbit/s):
>
> Core i7 with nested guest. Atom with normal guest.
>
> *-------------------------------* *-------------------------------*
> | | | | | | | |
> | buf size | copy | zerocopy | | buf size | copy | zerocopy |
> | | | | | | | |
> *-------------------------------* *-------------------------------*
> | 4KB | 3 | 10 | | 4KB | 0.8 | 1.9 |
> *-------------------------------* *-------------------------------*
> | 32KB | 20 | 61 | | 32KB | 6.8 | 20.2 |
> *-------------------------------* *-------------------------------*
> | 256KB | 33 | 244 | | 256KB | 7.8 | 55 |
> *-------------------------------* *-------------------------------*
> | 1M | 30 | 373 | | 1M | 7 | 95 |
> *-------------------------------* *-------------------------------*
> | 8M | 22 | 475 | | 8M | 7 | 114 |
> *-------------------------------* *-------------------------------*
>
> H2G:
>
> Core i7 with nested guest. Atom with normal guest.
>
> *-------------------------------* *-------------------------------*
> | | | | | | | |
> | buf size | copy | zerocopy | | buf size | copy | zerocopy |
> | | | | | | | |
> *-------------------------------* *-------------------------------*
> | 4KB | 20 | 10 | | 4KB | 4.37 | 3 |
> *-------------------------------* *-------------------------------*
> | 32KB | 37 | 75 | | 32KB | 11 | 18 |
> *-------------------------------* *-------------------------------*
> | 256KB | 44 | 299 | | 256KB | 11 | 62 |
> *-------------------------------* *-------------------------------*
> | 1M | 28 | 335 | | 1M | 9 | 77 |
> *-------------------------------* *-------------------------------*
> | 8M | 27 | 417 | | 8M | 9.35 | 115 |
> *-------------------------------* *-------------------------------*
>
> * Let's look to the first line of both tables - where copy is better
> than zerocopy. I analyzed this case more deeply and found that
> bottleneck is function 'vhost_work_queue()'. With 4K buffer size,
> caller spends too much time in it with zerocopy mode (comparing to
> copy mode). This happens only with 4K buffer size. This function just
> calls 'wake_up_process()' and its internal logic does not depends on
> skb, so i think potential reason (may be) is interval between two
> calls of this function (e.g. how often it is called). Note, that
> 'vhost_work_queue()' differs from the same function at guest's side of
> transport: 'virtio_transport_send_pkt()' uses 'queue_work()' which
> i think is more optimized for worker purposes, than direct call to
> 'wake_up_process()'. But again - this is just my assumption.
>
> Loopback:
>
> Core i7 with nested guest. Atom with normal guest.
>
> *-------------------------------* *-------------------------------*
> | | | | | | | |
> | buf size | copy | zerocopy | | buf size | copy | zerocopy |
> | | | | | | | |
> *-------------------------------* *-------------------------------*
> | 4KB | 8 | 7 | | 4KB | 1.8 | 1.3 |
> *-------------------------------* *-------------------------------*
> | 32KB | 38 | 44 | | 32KB | 10 | 10 |
> *-------------------------------* *-------------------------------*
> | 256KB | 55 | 168 | | 256KB | 15 | 36 |
> *-------------------------------* *-------------------------------*
> | 1M | 53 | 250 | | 1M | 12 | 45 |
> *-------------------------------* *-------------------------------*
> | 8M | 40 | 344 | | 8M | 11 | 74 |
> *-------------------------------* *-------------------------------*
>
> I analyzed performace difference more deeply for the following setup:
> server: ./vsock_perf --vsk-size 16M
> client: ./vsock_perf --sender 2 --bytes 16M --buf-size 16K/4K [--zc]
>
> In other words I send 16M of data from guest to host in copy/zerocopy
> modes and with two different sizes of buffer - 4K and 64K. Let's see
> to tx path for both modes - it consists of two steps:
>
> copy:
> 1) Allocate skb of buffer's length.
> 2) Copy data to skb from buffer.
>
> zerocopy:
> 1) Allocate skb with header space only.
> 2) Pin pages of the buffer and insert them to skb.
>
> I measured average number of ns (returned by 'ktime_get()') for each
> step above:
> 1) Skb allocation (for both copy and zerocopy modes).
> 2) For copy mode in 'memcpy_to_msg()' - copying.
> 3) For zerocopy mode in '__zerocopy_sg_from_iter()' - pinning.
>
> Here are results for copy mode:
> *-------------------------------------*
> | buf | skb alloc | 'memcpy_to_msg()' |
> *-------------------------------------*
> | | | |
> | 64K | 5000ns | 25000ns |
> | | | |
> *-------------------------------------*
> | | | |
> | 4K | 800ns | 2200ns |
> | | | |
> *-------------------------------------*
>
> Here are results for zerocopy mode:
> *-----------------------------------------------*
> | buf | skb alloc | '__zerocopy_sg_from_iter()' |
> *-----------------------------------------------*
> | | | |
> | 64K | 250ns | 3500ns |
> | | | |
> *-----------------------------------------------*
> | | | |
> | 4K | 250ns | 3000ns |
> | | | |
> *-----------------------------------------------*
>
> I guess that reason of zerocopy performance is low overhead for page
> pinning: there is big difference between 4K and 64K in case of copying
> (25000 vs 2200), but in pinning case - just 3000 vs 3500.
>
> So, zerocopy is faster than classic copy mode, but of course it requires
> specific architecture of application due to user pages pinning, buffer
> size and alignment.
>
> NOTES
>
> If host fails to send data with "Cannot allocate memory", check value
> /proc/sys/net/core/optmem_max - it is accounted during completion skb
> allocation. Try to update it to for example 1M and try send again:
> "echo 1048576 > /proc/sys/net/core/optmem_max" (as root).
>
> TESTING
>
> This patchset includes set of tests for MSG_ZEROCOPY feature. I tried to
> cover new code as much as possible so there are different cases for
> MSG_ZEROCOPY transmissions: with disabled SO_ZEROCOPY and several io
> vector types (different sizes, alignments, with unmapped pages). I also
> run tests with loopback transport and run vsockmon. In v3 i've added
> io_uring test as separated application.
>
> Thanks, Arseniy
>
> Link to v1:
> https://lore.kernel.org/netdev/[email protected]/
> Link to v2:
> https://lore.kernel.org/netdev/[email protected]/
>
> Changelog:
> v1 -> v2:
> - Replace 'get_user_pages()' with 'pin_user_pages()'.
> - Loopback transport support.
>
> v2 -> v3
> - Use 'get_user_pages()' instead of 'pin_user_pages()'. I think this
> is right approach, because i'm using '__zerocopy_sg_from_iter()'
> function. It is already implemented and used by io_uring zerocopy
> tx logic to 'pin' pages of user's buffer.
>
> - Use 'skb_copy_datagram_iter()' to copy data from both linear and
> non-linear skb to user's iov iter. It already has support for copying
> data from paged part of skb (by calling 'kmap()'). In v2 i used my
> own "from scratch" implemented function. With this and previous thing
> I significantly reduced LOC number in kernel part.
>
> - Add io_uring test for AF_VSOCK. It is implemented as separated util,
> because it depends on liburing (i think there is no need to link
> 'vsock_test' with liburing, because io_uring functionality depends
> on environment - both in kernel and userspace).
>
> - Values from PERFORMANCE section are updated for all transports, but
> I didn't found any significant difference with v2.
>
> - More details in commit messages.
>
> Arseniy Krasnov (17):
> vsock/virtio: read data from non-linear skb
> vhost/vsock: read data from non-linear skb
> vsock/virtio: support to send non-linear skb
> vsock/virtio: non-linear skb handling for tap
> vsock/virtio: MSG_ZEROCOPY flag support
> vsock: check error queue to set EPOLLERR
> vsock: read from socket's error queue
> vsock: check for MSG_ZEROCOPY support
> vsock: enable SOCK_SUPPORT_ZC bit
> vhost/vsock: support MSG_ZEROCOPY for transport
> vsock/virtio: support MSG_ZEROCOPY for transport
> vsock/loopback: support MSG_ZEROCOPY for transport
> net/sock: enable setting SO_ZEROCOPY for PF_VSOCK
> docs: net: description of MSG_ZEROCOPY for AF_VSOCK
> test/vsock: MSG_ZEROCOPY flag tests
> test/vsock: MSG_ZEROCOPY support for vsock_perf
> test/vsock: io_uring rx/tx tests
>
> Documentation/networking/msg_zerocopy.rst | 12 +-
> drivers/vhost/vsock.c | 18 +-
> include/linux/socket.h | 1 +
> include/linux/virtio_vsock.h | 1 +
> include/net/af_vsock.h | 7 +
> net/core/sock.c | 4 +-
> net/vmw_vsock/af_vsock.c | 19 +-
> net/vmw_vsock/virtio_transport.c | 39 ++-
> net/vmw_vsock/virtio_transport_common.c | 352 ++++++++++++++++----
> net/vmw_vsock/vsock_loopback.c | 8 +
> tools/testing/vsock/Makefile | 9 +-
> tools/testing/vsock/util.c | 134 ++++++++
> tools/testing/vsock/util.h | 23 ++
> tools/testing/vsock/vsock_perf.c | 139 +++++++-
> tools/testing/vsock/vsock_test.c | 11 +
> tools/testing/vsock/vsock_test_zerocopy.c | 385 ++++++++++++++++++++++
> tools/testing/vsock/vsock_test_zerocopy.h | 12 +
> tools/testing/vsock/vsock_uring_test.c | 316 ++++++++++++++++++
> 18 files changed, 1396 insertions(+), 94 deletions(-)
> create mode 100644 tools/testing/vsock/vsock_test_zerocopy.c
> create mode 100644 tools/testing/vsock/vsock_test_zerocopy.h
> create mode 100644 tools/testing/vsock/vsock_uring_test.c
>
On Thu, May 25, 2023 at 06:56:42PM +0300, Arseniy Krasnov wrote:
>
>
>On 22.05.2023 10:39, Arseniy Krasnov wrote:
>
>This patchset is unstable with SOCK_SEQPACKET. I'll fix it.
Thanks for let us know!
I'm thinking if we should start split this series in two, because it
becomes too big.
But let keep this for RFC, we can decide later. An idea is to send
the first 7 patches with a preparation series, and the next ones with a
second series.
Thanks,
Stefano
On 26.05.2023 13:30, Stefano Garzarella wrote:
> On Thu, May 25, 2023 at 06:56:42PM +0300, Arseniy Krasnov wrote:
>>
>>
>> On 22.05.2023 10:39, Arseniy Krasnov wrote:
>>
>> This patchset is unstable with SOCK_SEQPACKET. I'll fix it.
>
> Thanks for let us know!
>
> I'm thinking if we should start split this series in two, because it
> becomes too big.
>
> But let keep this for RFC, we can decide later. An idea is to send
> the first 7 patches with a preparation series, and the next ones with a
> second series.
Hello, ok! So i'll split patchset in the following way:
1) Patches which adds new fields/flags and checks. But all of this is not used,
as it is preparation.
2) Second part starts to use it and also carries tests.
Thanks, Arseniy
>
> Thanks,
> Stefano
>
On Fri, May 26, 2023 at 02:36:17PM +0300, Arseniy Krasnov wrote:
>
>
>On 26.05.2023 13:30, Stefano Garzarella wrote:
>> On Thu, May 25, 2023 at 06:56:42PM +0300, Arseniy Krasnov wrote:
>>>
>>>
>>> On 22.05.2023 10:39, Arseniy Krasnov wrote:
>>>
>>> This patchset is unstable with SOCK_SEQPACKET. I'll fix it.
>>
>> Thanks for let us know!
>>
>> I'm thinking if we should start split this series in two, because it
>> becomes too big.
>>
>> But let keep this for RFC, we can decide later. An idea is to send
>> the first 7 patches with a preparation series, and the next ones with a
>> second series.
>
>Hello, ok! So i'll split patchset in the following way:
>1) Patches which adds new fields/flags and checks. But all of this is not used,
> as it is preparation.
>2) Second part starts to use it and also carries tests.
As long as they're RFCs, maybe you can keep them together if they're
related, possibly specifying in the cover letter where you'd like to
split them. When we agree that we are in good shape, we can split it.
Thanks,
Stefano
On 26.05.2023 15:23, Stefano Garzarella wrote:
> On Fri, May 26, 2023 at 02:36:17PM +0300, Arseniy Krasnov wrote:
>>
>>
>> On 26.05.2023 13:30, Stefano Garzarella wrote:
>>> On Thu, May 25, 2023 at 06:56:42PM +0300, Arseniy Krasnov wrote:
>>>>
>>>>
>>>> On 22.05.2023 10:39, Arseniy Krasnov wrote:
>>>>
>>>> This patchset is unstable with SOCK_SEQPACKET. I'll fix it.
>>>
>>> Thanks for let us know!
>>>
>>> I'm thinking if we should start split this series in two, because it
>>> becomes too big.
>>>
>>> But let keep this for RFC, we can decide later. An idea is to send
>>> the first 7 patches with a preparation series, and the next ones with a
>>> second series.
>>
>> Hello, ok! So i'll split patchset in the following way:
>> 1) Patches which adds new fields/flags and checks. But all of this is not used,
>> as it is preparation.
>> 2) Second part starts to use it and also carries tests.
>
> As long as they're RFCs, maybe you can keep them together if they're
> related, possibly specifying in the cover letter where you'd like to
> split them. When we agree that we are in good shape, we can split it.
Sure! I'll add this information in cover letter of v4
Thanks, Arseniy
> > Thanks,
> Stefano
>