diff mbox series

[RFC,v2,1/8] virtio/vsock: rework packet allocation logic

Message ID 78157286-3663-202f-da94-1a17e4ffe819@sberdevices.ru (mailing list archive)
State New, archived
Headers show
Series virtio/vsock: experimental zerocopy receive | expand

Commit Message

Arseniy Krasnov June 3, 2022, 5:31 a.m. UTC 
To support zerocopy receive, packet's buffer allocation
is changed: for buffers which could be mapped to user's
vma we can't use 'kmalloc()'(as kernel restricts to map
slab pages to user's vma) and raw buddy allocator now
called. But, for tx packets(such packets won't be mapped
to user), previous 'kmalloc()' way is used, but with special
flag in packet's structure which allows to distinguish
between 'kmalloc()' and raw pages buffers.

Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
---
 include/linux/virtio_vsock.h            | 1 +
 net/vmw_vsock/virtio_transport.c        | 8 ++++++--
 net/vmw_vsock/virtio_transport_common.c | 9 ++++++++-
 3 files changed, 15 insertions(+), 3 deletions(-)

Comments

Stefano Garzarella June 9, 2022, 8:37 a.m. UTC | #1 
On Fri, Jun 03, 2022 at 05:31:00AM +0000, Arseniy Krasnov wrote:
>To support zerocopy receive, packet's buffer allocation
>is changed: for buffers which could be mapped to user's
>vma we can't use 'kmalloc()'(as kernel restricts to map
>slab pages to user's vma) and raw buddy allocator now
>called. But, for tx packets(such packets won't be mapped
>to user), previous 'kmalloc()' way is used, but with special
>flag in packet's structure which allows to distinguish
>between 'kmalloc()' and raw pages buffers.
>
>Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
>---
> include/linux/virtio_vsock.h            | 1 +
> net/vmw_vsock/virtio_transport.c        | 8 ++++++--
> net/vmw_vsock/virtio_transport_common.c | 9 ++++++++-
> 3 files changed, 15 insertions(+), 3 deletions(-)

Each patch should as much as possible work to not break the 
bisectability, and here we are not touching vhost_vsock_alloc_pkt() that 
uses kmalloc to allocate the buffer.

I see you updated it in the next patch, that should be fine, but here 
you should set slab_buf in vhost_vsock_alloc_pkt(), or you can merge the 
two patches.

>
>diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>index 35d7eedb5e8e..d02cb7aa922f 100644
>--- a/include/linux/virtio_vsock.h
>+++ b/include/linux/virtio_vsock.h
>@@ -50,6 +50,7 @@ struct virtio_vsock_pkt {
> 	u32 off;
> 	bool reply;
> 	bool tap_delivered;
>+	bool slab_buf;
> };
>
> struct virtio_vsock_pkt_info {
>diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
>index ad64f403536a..19909c1e9ba3 100644
>--- a/net/vmw_vsock/virtio_transport.c
>+++ b/net/vmw_vsock/virtio_transport.c
>@@ -255,16 +255,20 @@ static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
> 	vq = vsock->vqs[VSOCK_VQ_RX];
>
> 	do {
>+		struct page *buf_page;
>+
> 		pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
> 		if (!pkt)
> 			break;
>
>-		pkt->buf = kmalloc(buf_len, GFP_KERNEL);
>-		if (!pkt->buf) {
>+		buf_page = alloc_page(GFP_KERNEL);
>+
>+		if (!buf_page) {
> 			virtio_transport_free_pkt(pkt);
> 			break;
> 		}
>
>+		pkt->buf = page_to_virt(buf_page);
> 		pkt->buf_len = buf_len;
> 		pkt->len = buf_len;
>
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index ec2c2afbf0d0..278567f748f2 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -69,6 +69,7 @@ virtio_transport_alloc_pkt(struct virtio_vsock_pkt_info *info,
> 		if (!pkt->buf)
> 			goto out_pkt;
>
>+		pkt->slab_buf = true;
> 		pkt->buf_len = len;
>
> 		err = memcpy_from_msg(pkt->buf, info->msg, len);
>@@ -1342,7 +1343,13 @@ EXPORT_SYMBOL_GPL(virtio_transport_recv_pkt);
>
> void virtio_transport_free_pkt(struct virtio_vsock_pkt *pkt)
> {
>-	kfree(pkt->buf);
>+	if (pkt->buf_len) {
>+		if (pkt->slab_buf)
>+			kfree(pkt->buf);
>+		else
>+			free_pages(buf, get_order(pkt->buf_len));
>+	}
>+
> 	kfree(pkt);
> }
> EXPORT_SYMBOL_GPL(virtio_transport_free_pkt);
>-- 
>2.25.1
diff mbox series

Patch

diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index 35d7eedb5e8e..d02cb7aa922f 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -50,6 +50,7 @@  struct virtio_vsock_pkt {
 	u32 off;
 	bool reply;
 	bool tap_delivered;
+	bool slab_buf;
 };
 
 struct virtio_vsock_pkt_info {
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index ad64f403536a..19909c1e9ba3 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -255,16 +255,20 @@  static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
 	vq = vsock->vqs[VSOCK_VQ_RX];
 
 	do {
+		struct page *buf_page;
+
 		pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
 		if (!pkt)
 			break;
 
-		pkt->buf = kmalloc(buf_len, GFP_KERNEL);
-		if (!pkt->buf) {
+		buf_page = alloc_page(GFP_KERNEL);
+
+		if (!buf_page) {
 			virtio_transport_free_pkt(pkt);
 			break;
 		}
 
+		pkt->buf = page_to_virt(buf_page);
 		pkt->buf_len = buf_len;
 		pkt->len = buf_len;
 
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index ec2c2afbf0d0..278567f748f2 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -69,6 +69,7 @@  virtio_transport_alloc_pkt(struct virtio_vsock_pkt_info *info,
 		if (!pkt->buf)
 			goto out_pkt;
 
+		pkt->slab_buf = true;
 		pkt->buf_len = len;
 
 		err = memcpy_from_msg(pkt->buf, info->msg, len);
@@ -1342,7 +1343,13 @@  EXPORT_SYMBOL_GPL(virtio_transport_recv_pkt);
 
 void virtio_transport_free_pkt(struct virtio_vsock_pkt *pkt)
 {
-	kfree(pkt->buf);
+	if (pkt->buf_len) {
+		if (pkt->slab_buf)
+			kfree(pkt->buf);
+		else
+			free_pages(buf, get_order(pkt->buf_len));
+	}
+
 	kfree(pkt);
 }
 EXPORT_SYMBOL_GPL(virtio_transport_free_pkt);