[dpdk-dev] [PATCH v4]net/virtio: add mtu set in virtio
Dey, Souvik
sodey at sonusnet.com
Fri Sep 9 20:16:05 CEST 2016
Hi Mark/Liu,
Thanks to both of you for being so patient with a series of silly errors. I have tried to make it better this time. Also there were some un-used variable in the function which I have removed. Please check the new patch with all your comments incorporated. Also along with the L2_HDR_LEN and L2_CRC_LEN, I have taken in consideration the VLAN_LEN too.
One doubt though,
"9728 is the largest L2 frame size allowed by the NIC" -- this 9728 size is some constrain due to DPDK as the virtio driver in the kernel can support till mtu size of 68 to 65535, where as in DPDK pmd we are trying with 64 to 9728.
drivers/net/virtio/virtio_ethdev.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index 07d6449..da16ad4 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -653,12 +653,20 @@ virtio_dev_allmulticast_disable(struct rte_eth_dev *dev)
PMD_INIT_LOG(ERR, "Failed to disable allmulticast");
}
+#define VLAN_TAG_LEN 4 /* 802.3ac tag (not DMA'd) */
+
+static int virtio_mtu_set(struct rte_eth_dev *dev, uint16_t mtu)
+{
+ struct rte_eth_dev_info dev_info;
+ uint32_t ether_hdr_len = ETHER_HDR_LEN + ETHER_CRC_LEN + VLAN_TAG_LEN;
+ uint32_t frame_size = mtu + ether_hdr_len;
+
+ virtio_dev_info_get(dev, &dev_info);
+
+ if (mtu < dev_info.min_rx_bufsize || frame_size > dev_info.max_rx_pktlen) {
+ PMD_INIT_LOG(ERR, "MTU should be between %d and %d\n",
+ dev_info.min_rx_bufsize,
+ (dev_info.max_rx_pktlen - ether_hdr_len));
+ return -EINVAL;
+ }
+ return 0;
+}
@@ -677,7 +685,6 @@ static const struct eth_dev_ops virtio_eth_dev_ops = {
.allmulticast_enable = virtio_dev_allmulticast_enable,
.allmulticast_disable = virtio_dev_allmulticast_disable,
+ .mtu_set = virtio_mtu_set,
.dev_infos_get = virtio_dev_info_get,
.stats_get = virtio_dev_stats_get,
.xstats_get = virtio_dev_xstats_get,
--
Regards,
Souvik
-----Original Message-----
From: Kavanagh, Mark B [mailto:mark.b.kavanagh at intel.com]
Sent: Friday, September 9, 2016 11:44 AM
To: Dey, Souvik <sodey at sonusnet.com>; Yuanhan Liu <yuanhan.liu at linux.intel.com>
Cc: dev at dpdk.org; stephen at networkplumber.org
Subject: RE: [PATCH v4]net/virtio: add mtu set in virtio
>
>Hi Mark,
>
>Yes I thought I did that change. Sorry once again.. making too many mistakes. Changed it .
>Thanks.
>The MTU here is L3 MTU. Setting this will help in reducing the
>fragmented/multi-segmented packets and also in case we want to reduce
>the MTU below 1500, to support VXLAN or GRE tunnel for the packets in openstack and cloud environments.
>
>---
> drivers/net/virtio/virtio_ethdev.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
>diff --git a/drivers/net/virtio/virtio_ethdev.c
>b/drivers/net/virtio/virtio_ethdev.c
>index 07d6449..da16ad4 100644
>--- a/drivers/net/virtio/virtio_ethdev.c
>+++ b/drivers/net/virtio/virtio_ethdev.c
>
>static int virtio_dev_queue_stats_mapping_set(
> __rte_unused struct rte_eth_dev *eth_dev, @@ -652,6 +653,16 @@
>virtio_dev_allmulticast_disable(struct rte_eth_dev *dev)
> PMD_INIT_LOG(ERR, "Failed to disable allmulticast"); }
>
>+static int
>+virtio_mtu_set(struct rte_eth_dev *dev, uint16_t mtu) {
>+ struct virtio_hw *hw = dev->data->dev_private;
>+ if (mtu < VIRTIO_MIN_RX_BUFSIZE || mtu > VIRTIO_MAX_RX_PKTLEN) {
If MTU is the L3 MTU as you've indicated, then you need to take account of L2 overhead before performing the comparison above.
Say the user supplies 'mtu' as 9728 - the corresponding minimum frame size is L2_HDR_LEN + 9728 + L2_CRC_LEN = 9746 bytes, which is larger than the NIC can accommodate (note that 9728 is the largest L2 frame size allowed by the NIC, not the largest IP packet size).
>+ PMD_INIT_LOG(ERR, "Mtu should be between VIRTIO_MIN_RX_BUFSIZE and
>VIRTIO_MAX_RX_PKTLEN \n");
Two things on this statement:
1) in the context of a log message, VIRTIO_XXX_RX_BUFSIZE most likely means very little, and as such is not helpful. I suggest going with the format that I included in my earlier mail, which prints the numeric value of the min and max rx defines
2) <micronit> MTU is an initialization, and should be printed as such in a log (i.e. all caps) </micronit>
Hope this helps,
Mark
>+ return -EINVAL;
>+ }
>+ return 0;
>+}
>+
> /*
> * dev_ops for virtio, bare necessities for basic operation
> */
>@@ -664,6 +675,7 @@ static const struct eth_dev_ops virtio_eth_dev_ops = {
> .promiscuous_disable = virtio_dev_promiscuous_disable,
> .allmulticast_enable = virtio_dev_allmulticast_enable,
> .allmulticast_disable = virtio_dev_allmulticast_disable,
>+ .mtu_set = virtio_mtu_set,
>
> .dev_infos_get = virtio_dev_info_get,
> .stats_get = virtio_dev_stats_get,
>--
>
>--
>Regards,
>Souvik
>-----Original Message-----
>From: Kavanagh, Mark B [mailto:mark.b.kavanagh at intel.com]
>Sent: Friday, September 9, 2016 11:05 AM
>To: Dey, Souvik <sodey at sonusnet.com<mailto:sodey at sonusnet.com>>; Yuanhan Liu
><yuanhan.liu at linux.intel.com<mailto:yuanhan.liu at linux.intel.com>>
>Cc: dev at dpdk.org<mailto:dev at dpdk.org>; stephen at networkplumber.org<mailto:stephen at networkplumber.org>
>Subject: RE: [PATCH v4]net/virtio: add mtu set in virtio
>
>>
>>Hi Liu,
>>
>>Yes agreed your comment. I will definitely remove the declaration as
>>it is not really required.
>> So the latest patch will look like this . Yes I did rush a bit to
>>submit the patch last will correct my suite. So sending the patch in a
>>reply if we have more comments we can take a look and they re-submit
>>the final reviewed
>patch. Thanks for the help though.
>>
>>---
>> drivers/net/virtio/virtio_ethdev.c | 12 ++++++++++++
>> 1 file changed, 12 insertions(+)
>>
>>diff --git a/drivers/net/virtio/virtio_ethdev.c
>>b/drivers/net/virtio/virtio_ethdev.c
>>index 07d6449..da16ad4 100644
>>--- a/drivers/net/virtio/virtio_ethdev.c
>>+++ b/drivers/net/virtio/virtio_ethdev.c
>>
>>+static int
>>+virtio_mtu_set(struct rte_eth_dev *dev, uint16_t mtu) {
>>+ struct virtio_hw *hw = dev->data->dev_private;
>>+ if (mtu < VIRTIO_MIN_RX_BUFSIZE || mtu > VIRTIO_MAX_RX_PKTLEN) {
>>+ PMD_INIT_LOG(ERR, "Mtu should be between 64 and 9728\n");
>
>Hi Souvik,
>
>Why hardcode the values in the PMD_INIT_LOG?
>
>Why not do the following: PMD_INIT_LOG(ERR, "MTU should be between %d and %d",
> VIRTIO_MIN_RX_BUFSIZE,
> VIRTIO_MAX_RX_PKTLEN);
>
>That way, if the values that the macros evaluate to change, the log
>will update correspondingly.
>
>Also, does 'MTU' in this context relate to the L2 or L3 MTU?
>
>>+ return -EINVAL;
>>+ }
>>+ return 0;
>>+}
>>+
>> /*
>> * dev_ops for virtio, bare necessities for basic operation
>> */
>>@@ -664,6 +675,7 @@ static const struct eth_dev_ops virtio_eth_dev_ops = {
>> .promiscuous_disable = virtio_dev_promiscuous_disable,
>> .allmulticast_enable = virtio_dev_allmulticast_enable,
>> .allmulticast_disable = virtio_dev_allmulticast_disable,
>>+ .mtu_set = virtio_mtu_set,
>>
>> .dev_infos_get = virtio_dev_info_get,
>> .stats_get = virtio_dev_stats_get,
>>--
>>
>>--
>>Regards,
>>Souvik
>>
>>-----Original Message-----
>>From: Yuanhan Liu [mailto:yuanhan.liu at linux.intel.com]
>>Sent: Friday, September 9, 2016 3:00 AM
>>To: Dey, Souvik <sodey at sonusnet.com<mailto:sodey at sonusnet.com>>
>>Cc: dev at dpdk.org<mailto:dev at dpdk.org>; stephen at networkplumber.org<mailto:stephen at networkplumber.org>
>>Subject: Re: [PATCH v4]net/virtio: add mtu set in virtio
>>
>>On Wed, Sep 07, 2016 at 04:21:30AM +0000, Dey, Souvik wrote:
>>> Hi Liu,
>>> Submitted the version 4 of the patch as you suggested ,
>>
>>Your patch is looking much better. But not really, you ignored few of my comments.
>>
>>> and have removed the Reviewed by line.
>>> I have still kept the function definition as to follow the same suit
>>> as we have done for
>>other eth_dev_ops.
>>
>>That's because most of the method implementions are after the
>>reference, thus the declaration is needed.
>>
>>For your case, I see no good reason to do that. BTW, if you disagree
>>with my comment, you shoud made a reply, instead of rushing to sending a new version.
>>
>>> --
>>> Regards,
>>> Souvik
>>>
>>> -----Original Message-----
>>> From: Dey, Souvik
>>> Sent: Wednesday, September 7, 2016 12:19 AM
>>> To: dev at dpdk.org<mailto:dev at dpdk.org>; stephen at networkplumber.org<mailto:stephen at networkplumber.org>;
>>> yuanhan.liu at linux.intel.com<mailto:yuanhan.liu at linux.intel.com>
>>> Cc: Dey, Souvik <sodey at sonusnet.com<mailto:sodey at sonusnet.com>>
>>> Subject: [PATCH v4]net/virtio: add mtu set in virtio
>>>
>>>
>>> Virtio interfaces should also support setting of mtu, as in case of
>>> cloud it is expected to
>>have the consistent mtu across the infrastructure that the dhcp server
>>sends and not hardcoded to 1500(default).
>>>
>>> Changes in v4: Incorporated review comments.
>>> Changes in v3: Corrected few style errors as reported by sys-stv.
>>> Changes in v2: Incorporated review comments.
>>
>>DPDK prefers to put the change log to ...
>>>
>>> Signed-off-by: Souvik Dey <sodey at sonusnet.com<mailto:sodey at sonusnet.com>>
>>>
>>> ---
>>
>>... here.
>>
>>So that they will be showed in mailing list (for review), but they will be gone after apply.
>>In another word, we don't like to see those change log in git history,
>>but we'd like to see them while review.
>>
>>> drivers/net/virtio/virtio_ethdev.c | 12 ++++++++++++
>>> 1 file changed, 12 insertions(+)
>>>
>>> diff --git a/drivers/net/virtio/virtio_ethdev.c
>>> b/drivers/net/virtio/virtio_ethdev.c
>>> index 07d6449..da16ad4 100644
>>> --- a/drivers/net/virtio/virtio_ethdev.c
>>> +++ b/drivers/net/virtio/virtio_ethdev.c
>>> @@ -92,6 +92,7 @@ static void virtio_mac_addr_add(struct rte_eth_dev
>>> *dev, static void
>>virtio_mac_addr_remove(struct rte_eth_dev *dev, uint32_t index);
>>static void virtio_mac_addr_set(struct rte_eth_dev *dev,
>>> struct ether_addr *mac_addr);
>>> +static int virtio_mtu_set(struct rte_eth_dev *dev, uint16_t mtu);
>>>
>>> static int virtio_dev_queue_stats_mapping_set(
>>> __rte_unused struct rte_eth_dev *eth_dev, @@ -652,6 +653,16 @@
>>virtio_dev_allmulticast_disable(struct rte_eth_dev *dev)
>>> PMD_INIT_LOG(ERR, "Failed to disable allmulticast"); }
>>>
>>> +static int
>>> +virtio_mtu_set(struct rte_eth_dev *dev, uint16_t mtu) {
>>> + struct virtio_hw *hw = dev->data->dev_private;
>>> + if (mtu < VIRTIO_MIN_RX_BUFSIZE || mtu > VIRTIO_MAX_RX_PKTLEN) {
>>> + PMD_INIT_LOG(ERR, "Mtu should be between 64 and 9728\n");
>>
>>I still saw those numbers.
>>
>> --yliu
More information about the dev
mailing list