drivers/net/usb/usbnet.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-)
The current source pushes skb into dev->done queue by calling
skb_queue_tail() and then pop it by calling skb_dequeue() to branch to
rx_cleanup state for freeing urb/skb in usbnet_bh(). It takes extra CPU
load, 2.21% (skb_queue_tail) as follows.
- 11.58% 0.26% swapper [k] usbnet_bh
- 11.32% usbnet_bh
- 6.43% skb_dequeue
6.34% _raw_spin_unlock_irqrestore
- 2.21% skb_queue_tail
2.19% _raw_spin_unlock_irqrestore
- 1.68% consume_skb
- 0.97% kfree_skbmem
0.80% kmem_cache_free
0.53% skb_release_data
To reduce the extra CPU load use return values jumping to rx_cleanup
state directly to free them instead of calling skb_queue_tail() and
skb_dequeue() for push/pop respectively.
- 7.87% 0.25% swapper [k] usbnet_bh
- 7.62% usbnet_bh
- 4.81% skb_dequeue
4.74% _raw_spin_unlock_irqrestore
- 1.75% consume_skb
- 0.98% kfree_skbmem
0.78% kmem_cache_free
0.58% skb_release_data
0.53% smsc95xx_rx_fixup
Signed-off-by: Leesoo Ahn <lsahn@ooseel.net>
---
v2:
- Replace goto label with return statement to reduce goto entropy
- Add CPU load information by perf in commit message
v1 at:
https://patchwork.kernel.org/project/netdevbpf/patch/20221217161851.829497-1-lsahn@ooseel.net/
---
drivers/net/usb/usbnet.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 64a9a80b2309..6e82fef90dd9 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -555,32 +555,30 @@ static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
/*-------------------------------------------------------------------------*/
-static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
+static inline int rx_process(struct usbnet *dev, struct sk_buff *skb)
{
if (dev->driver_info->rx_fixup &&
!dev->driver_info->rx_fixup (dev, skb)) {
/* With RX_ASSEMBLE, rx_fixup() must update counters */
if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
dev->net->stats.rx_errors++;
- goto done;
+ return 1;
}
// else network stack removes extra byte if we forced a short packet
/* all data was already cloned from skb inside the driver */
if (dev->driver_info->flags & FLAG_MULTI_PACKET)
- goto done;
+ return 1;
if (skb->len < ETH_HLEN) {
dev->net->stats.rx_errors++;
dev->net->stats.rx_length_errors++;
netif_dbg(dev, rx_err, dev->net, "rx length %d\n", skb->len);
- } else {
- usbnet_skb_return(dev, skb);
- return;
+ return 1;
}
-done:
- skb_queue_tail(&dev->done, skb);
+ usbnet_skb_return(dev, skb);
+ return 0;
}
/*-------------------------------------------------------------------------*/
@@ -1528,13 +1526,14 @@ static void usbnet_bh (struct timer_list *t)
entry = (struct skb_data *) skb->cb;
switch (entry->state) {
case rx_done:
- entry->state = rx_cleanup;
- rx_process (dev, skb);
+ if (rx_process(dev, skb))
+ goto cleanup;
continue;
case tx_done:
kfree(entry->urb->sg);
fallthrough;
case rx_cleanup:
+cleanup:
usb_free_urb (entry->urb);
dev_kfree_skb (skb);
continue;
--
2.34.1On Wed, Dec 21, 2022 at 01:42:30PM +0900, Leesoo Ahn wrote:
> The current source pushes skb into dev->done queue by calling
> skb_queue_tail() and then pop it by calling skb_dequeue() to branch to
> rx_cleanup state for freeing urb/skb in usbnet_bh(). It takes extra CPU
> load, 2.21% (skb_queue_tail) as follows.
>
> - 11.58% 0.26% swapper [k] usbnet_bh
> - 11.32% usbnet_bh
> - 6.43% skb_dequeue
> 6.34% _raw_spin_unlock_irqrestore
> - 2.21% skb_queue_tail
> 2.19% _raw_spin_unlock_irqrestore
> - 1.68% consume_skb
> - 0.97% kfree_skbmem
> 0.80% kmem_cache_free
> 0.53% skb_release_data
>
> To reduce the extra CPU load use return values jumping to rx_cleanup
> state directly to free them instead of calling skb_queue_tail() and
> skb_dequeue() for push/pop respectively.
>
> - 7.87% 0.25% swapper [k] usbnet_bh
> - 7.62% usbnet_bh
> - 4.81% skb_dequeue
> 4.74% _raw_spin_unlock_irqrestore
> - 1.75% consume_skb
> - 0.98% kfree_skbmem
> 0.78% kmem_cache_free
> 0.58% skb_release_data
> 0.53% smsc95xx_rx_fixup
>
> Signed-off-by: Leesoo Ahn <lsahn@ooseel.net>
> ---
> v2:
> - Replace goto label with return statement to reduce goto entropy
> - Add CPU load information by perf in commit message
>
> v1 at:
> https://patchwork.kernel.org/project/netdevbpf/patch/20221217161851.829497-1-lsahn@ooseel.net/
> ---
> drivers/net/usb/usbnet.c | 19 +++++++++----------
> 1 file changed, 9 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
> index 64a9a80b2309..6e82fef90dd9 100644
> --- a/drivers/net/usb/usbnet.c
> +++ b/drivers/net/usb/usbnet.c
> @@ -555,32 +555,30 @@ static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
>
> /*-------------------------------------------------------------------------*/
>
> -static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
> +static inline int rx_process(struct usbnet *dev, struct sk_buff *skb)
> {
> if (dev->driver_info->rx_fixup &&
> !dev->driver_info->rx_fixup (dev, skb)) {
> /* With RX_ASSEMBLE, rx_fixup() must update counters */
> if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
> dev->net->stats.rx_errors++;
> - goto done;
> + return 1;
"1" means that you processed 1 byte, not that this is an error, which is
what you want to say here, right? Please return a negative error value
like I asked this to be changed to last time :(
thanks,
greg k-h
On 22. 12. 21. 15:32, Greg KH wrote:
> On Wed, Dec 21, 2022 at 01:42:30PM +0900, Leesoo Ahn wrote:
>> The current source pushes skb into dev->done queue by calling
>> skb_queue_tail() and then pop it by calling skb_dequeue() to branch to
>> rx_cleanup state for freeing urb/skb in usbnet_bh(). It takes extra CPU
>> load, 2.21% (skb_queue_tail) as follows.
>>
>> - 11.58% 0.26% swapper [k] usbnet_bh
>> - 11.32% usbnet_bh
>> - 6.43% skb_dequeue
>> 6.34% _raw_spin_unlock_irqrestore
>> - 2.21% skb_queue_tail
>> 2.19% _raw_spin_unlock_irqrestore
>> - 1.68% consume_skb
>> - 0.97% kfree_skbmem
>> 0.80% kmem_cache_free
>> 0.53% skb_release_data
>>
>> To reduce the extra CPU load use return values jumping to rx_cleanup
>> state directly to free them instead of calling skb_queue_tail() and
>> skb_dequeue() for push/pop respectively.
>>
>> - 7.87% 0.25% swapper [k] usbnet_bh
>> - 7.62% usbnet_bh
>> - 4.81% skb_dequeue
>> 4.74% _raw_spin_unlock_irqrestore
>> - 1.75% consume_skb
>> - 0.98% kfree_skbmem
>> 0.78% kmem_cache_free
>> 0.58% skb_release_data
>> 0.53% smsc95xx_rx_fixup
>>
>> Signed-off-by: Leesoo Ahn <lsahn@ooseel.net>
>> ---
>> v2:
>> - Replace goto label with return statement to reduce goto entropy
>> - Add CPU load information by perf in commit message
>>
>> v1 at:
>> https://patchwork.kernel.org/project/netdevbpf/patch/20221217161851.829497-1-lsahn@ooseel.net/
>> ---
>> drivers/net/usb/usbnet.c | 19 +++++++++----------
>> 1 file changed, 9 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
>> index 64a9a80b2309..6e82fef90dd9 100644
>> --- a/drivers/net/usb/usbnet.c
>> +++ b/drivers/net/usb/usbnet.c
>> @@ -555,32 +555,30 @@ static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
>>
>> /*-------------------------------------------------------------------------*/
>>
>> -static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
>> +static inline int rx_process(struct usbnet *dev, struct sk_buff *skb)
>> {
>> if (dev->driver_info->rx_fixup &&
>> !dev->driver_info->rx_fixup (dev, skb)) {
>> /* With RX_ASSEMBLE, rx_fixup() must update counters */
>> if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
>> dev->net->stats.rx_errors++;
>> - goto done;
>> + return 1;
> "1" means that you processed 1 byte, not that this is an error, which is
> what you want to say here, right?
No not at all..
> Please return a negative error value
> like I asked this to be changed to last time :(
Could you help me to decide the message type at this point please? I am
confused.
The return value totally depends on how rx_fixup() is. For instance, in
smsc95xx.c, smsc95xx_rx_fixup() function returns 0 in two cases that
1) frame size is greater than ETH_FRAME_LEN(1526 bytes) as follows
1853 /* ETH_FRAME_LEN + 4(CRC) + 2(COE) + 4(Vlan) */
1854 if (unlikely(size > (ETH_FRAME_LEN + 12))) {
1855 netif_dbg(dev, rx_err, dev->net,
1856 "size err header=0x%08x\n", header);
1857 return 0;
1858 }
2) it is failed for skb allocation, but memory?
1870 ax_skb = skb_clone(skb, GFP_ATOMIC);
1871 if (unlikely(!ax_skb)) {
1872 netdev_warn(dev->net, "Error allocating skb\n");
1873 return 0;
1874 }
I guess EPROTO or ENOMEM, one of them could be the value at the point
but I have no ideas..
Best regards,
Leesoo
On Wed, Dec 21, 2022 at 04:19:45PM +0900, Leesoo Ahn wrote:
>
> On 22. 12. 21. 15:32, Greg KH wrote:
> > On Wed, Dec 21, 2022 at 01:42:30PM +0900, Leesoo Ahn wrote:
> > > The current source pushes skb into dev->done queue by calling
> > > skb_queue_tail() and then pop it by calling skb_dequeue() to branch to
> > > rx_cleanup state for freeing urb/skb in usbnet_bh(). It takes extra CPU
> > > load, 2.21% (skb_queue_tail) as follows.
> > >
> > > - 11.58% 0.26% swapper [k] usbnet_bh
> > > - 11.32% usbnet_bh
> > > - 6.43% skb_dequeue
> > > 6.34% _raw_spin_unlock_irqrestore
> > > - 2.21% skb_queue_tail
> > > 2.19% _raw_spin_unlock_irqrestore
> > > - 1.68% consume_skb
> > > - 0.97% kfree_skbmem
> > > 0.80% kmem_cache_free
> > > 0.53% skb_release_data
> > >
> > > To reduce the extra CPU load use return values jumping to rx_cleanup
> > > state directly to free them instead of calling skb_queue_tail() and
> > > skb_dequeue() for push/pop respectively.
> > >
> > > - 7.87% 0.25% swapper [k] usbnet_bh
> > > - 7.62% usbnet_bh
> > > - 4.81% skb_dequeue
> > > 4.74% _raw_spin_unlock_irqrestore
> > > - 1.75% consume_skb
> > > - 0.98% kfree_skbmem
> > > 0.78% kmem_cache_free
> > > 0.58% skb_release_data
> > > 0.53% smsc95xx_rx_fixup
> > >
> > > Signed-off-by: Leesoo Ahn <lsahn@ooseel.net>
> > > ---
> > > v2:
> > > - Replace goto label with return statement to reduce goto entropy
> > > - Add CPU load information by perf in commit message
> > >
> > > v1 at:
> > > https://patchwork.kernel.org/project/netdevbpf/patch/20221217161851.829497-1-lsahn@ooseel.net/
> > > ---
> > > drivers/net/usb/usbnet.c | 19 +++++++++----------
> > > 1 file changed, 9 insertions(+), 10 deletions(-)
> > >
> > > diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
> > > index 64a9a80b2309..6e82fef90dd9 100644
> > > --- a/drivers/net/usb/usbnet.c
> > > +++ b/drivers/net/usb/usbnet.c
> > > @@ -555,32 +555,30 @@ static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
> > > /*-------------------------------------------------------------------------*/
> > > -static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
> > > +static inline int rx_process(struct usbnet *dev, struct sk_buff *skb)
> > > {
> > > if (dev->driver_info->rx_fixup &&
> > > !dev->driver_info->rx_fixup (dev, skb)) {
> > > /* With RX_ASSEMBLE, rx_fixup() must update counters */
> > > if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
> > > dev->net->stats.rx_errors++;
> > > - goto done;
> > > + return 1;
> > "1" means that you processed 1 byte, not that this is an error, which is
> > what you want to say here, right?
> No not at all..
> > Please return a negative error value
> > like I asked this to be changed to last time :(
> Could you help me to decide the message type at this point please? I am
> confused.
I do not know, pick something that seems correct and we can go from
there. The important thing is that it is a -ERR value, not a positive
one as that makes no sense for kernel functions.
thanks,
greg k-h
On 22. 12. 21. 16:30, Greg KH wrote:
> On Wed, Dec 21, 2022 at 04:19:45PM +0900, Leesoo Ahn wrote:
>> On 22. 12. 21. 15:32, Greg KH wrote:
>>> On Wed, Dec 21, 2022 at 01:42:30PM +0900, Leesoo Ahn wrote:
>>>> The current source pushes skb into dev->done queue by calling
>>>> skb_queue_tail() and then pop it by calling skb_dequeue() to branch to
>>>> rx_cleanup state for freeing urb/skb in usbnet_bh(). It takes extra CPU
>>>> load, 2.21% (skb_queue_tail) as follows.
>>>>
>>>> - 11.58% 0.26% swapper [k] usbnet_bh
>>>> - 11.32% usbnet_bh
>>>> - 6.43% skb_dequeue
>>>> 6.34% _raw_spin_unlock_irqrestore
>>>> - 2.21% skb_queue_tail
>>>> 2.19% _raw_spin_unlock_irqrestore
>>>> - 1.68% consume_skb
>>>> - 0.97% kfree_skbmem
>>>> 0.80% kmem_cache_free
>>>> 0.53% skb_release_data
>>>>
>>>> To reduce the extra CPU load use return values jumping to rx_cleanup
>>>> state directly to free them instead of calling skb_queue_tail() and
>>>> skb_dequeue() for push/pop respectively.
>>>>
>>>> - 7.87% 0.25% swapper [k] usbnet_bh
>>>> - 7.62% usbnet_bh
>>>> - 4.81% skb_dequeue
>>>> 4.74% _raw_spin_unlock_irqrestore
>>>> - 1.75% consume_skb
>>>> - 0.98% kfree_skbmem
>>>> 0.78% kmem_cache_free
>>>> 0.58% skb_release_data
>>>> 0.53% smsc95xx_rx_fixup
>>>>
>>>> Signed-off-by: Leesoo Ahn <lsahn@ooseel.net>
>>>> ---
>>>> v2:
>>>> - Replace goto label with return statement to reduce goto entropy
>>>> - Add CPU load information by perf in commit message
>>>>
>>>> v1 at:
>>>> https://patchwork.kernel.org/project/netdevbpf/patch/20221217161851.829497-1-lsahn@ooseel.net/
>>>> ---
>>>> drivers/net/usb/usbnet.c | 19 +++++++++----------
>>>> 1 file changed, 9 insertions(+), 10 deletions(-)
>>>>
>>>> diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
>>>> index 64a9a80b2309..6e82fef90dd9 100644
>>>> --- a/drivers/net/usb/usbnet.c
>>>> +++ b/drivers/net/usb/usbnet.c
>>>> @@ -555,32 +555,30 @@ static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
>>>> /*-------------------------------------------------------------------------*/
>>>> -static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
>>>> +static inline int rx_process(struct usbnet *dev, struct sk_buff *skb)
>>>> {
>>>> if (dev->driver_info->rx_fixup &&
>>>> !dev->driver_info->rx_fixup (dev, skb)) {
>>>> /* With RX_ASSEMBLE, rx_fixup() must update counters */
>>>> if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
>>>> dev->net->stats.rx_errors++;
>>>> - goto done;
>>>> + return 1;
>>> "1" means that you processed 1 byte, not that this is an error, which is
>>> what you want to say here, right?
>> No not at all..
>>> Please return a negative error value
>>> like I asked this to be changed to last time :(
>> Could you help me to decide the message type at this point please? I am
>> confused.
> I do not know, pick something that seems correct and we can go from
> there. The important thing is that it is a -ERR value, not a positive
> one as that makes no sense for kernel functions.
Thank you for reviewing, v3 will be sent soon.
Best regards,
Leesoo
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