Re: [PATCH net v2] net: pktgen: fix pkt_size

2016-10-03 Thread Greg 
On Sat, 2016-10-01 at 20:05 +0200, Paolo Abeni wrote:
> On Fri, 2016-09-30 at 08:39 -0700, Greg wrote:
> > On Fri, 2016-09-30 at 16:56 +0200, Paolo Abeni wrote:
> > > The commit 879c7220e828 ("net: pktgen: Observe needed_headroom
> > > of the device") increased the 'pkt_overhead' field value by
> > > LL_RESERVED_SPACE.
> > > As a side effect the generated packet size, computed as:
> > > 
> > >   /* Eth + IPh + UDPh + mpls */
> > >   datalen = pkt_dev->cur_pkt_size - 14 - 20 - 8 -
> > > pkt_dev->pkt_overhead;
> > > 
> > > is decreased by the same value.
> > > The above changed slightly the behavior of existing pktgen users,
> > > and made the procfs interface somewhat inconsistent.
> > > Fix it by restoring the previous pkt_overhead value and using
> > > LL_RESERVED_SPACE as extralen in skb allocation.
> > > Also, change pktgen_alloc_skb() to only partially reserve
> > > the headroom to allow the caller to prefetch from ll header
> > > start.
> > > 
> > > v1 -> v2:
> > >  - fixed some typos in the comments
> > > 
> > > Fixes: 879c7220e828 ("net: pktgen: Observe needed_headroom of the device")
> > > Suggested-by: Ben Greear 
> > > Signed-off-by: Paolo Abeni 
> > > ---
> > >  net/core/pktgen.c | 21 ++---
> > >  1 file changed, 10 insertions(+), 11 deletions(-)
> > > 
> > > diff --git a/net/core/pktgen.c b/net/core/pktgen.c
> > > index bbd118b..5219a9e 100644
> > > --- a/net/core/pktgen.c
> > > +++ b/net/core/pktgen.c
> > > @@ -2286,7 +2286,7 @@ out:
> > >  
> > >  static inline void set_pkt_overhead(struct pktgen_dev *pkt_dev)
> > >  {
> > > - pkt_dev->pkt_overhead = LL_RESERVED_SPACE(pkt_dev->odev);
> > > + pkt_dev->pkt_overhead = 0;
> > >   pkt_dev->pkt_overhead += pkt_dev->nr_labels*sizeof(u32);
> > >   pkt_dev->pkt_overhead += VLAN_TAG_SIZE(pkt_dev);
> > >   pkt_dev->pkt_overhead += SVLAN_TAG_SIZE(pkt_dev);
> > > @@ -2777,13 +2777,13 @@ static void pktgen_finalize_skb(struct pktgen_dev 
> > > *pkt_dev, struct sk_buff *skb,
> > >  }
> > >  
> > >  static struct sk_buff *pktgen_alloc_skb(struct net_device *dev,
> > > - struct pktgen_dev *pkt_dev,
> > > - unsigned int extralen)
> > > + struct pktgen_dev *pkt_dev)
> > >  {
> > > + unsigned int extralen = LL_RESERVED_SPACE(dev);
> > >   struct sk_buff *skb = NULL;
> > > - unsigned int size = pkt_dev->cur_pkt_size + 64 + extralen +
> > > - pkt_dev->pkt_overhead;
> > > + unsigned int size;
> > >  
> > > + size = pkt_dev->cur_pkt_size + 64 + extralen + pkt_dev->pkt_overhead;
> > >   if (pkt_dev->flags & F_NODE) {
> > >   int node = pkt_dev->node >= 0 ? pkt_dev->node : numa_node_id();
> > >  
> > > @@ -2796,8 +2796,9 @@ static struct sk_buff *pktgen_alloc_skb(struct 
> > > net_device *dev,
> > >skb = __netdev_alloc_skb(dev, size, GFP_NOWAIT);
> > >   }
> > >  
> > > + /* the caller pre-fetches from skb->data and reserves for the mac hdr */
> > >   if (likely(skb))
> > > - skb_reserve(skb, LL_RESERVED_SPACE(dev));
> > > + skb_reserve(skb, extralen - 16);
> > 
> > Is the 16 here the same as HD_DATA_MOD?
> > 
> > Magic numbers...
> 
> This magic numbers comes from the current code (the extralen argument),
> this patch just move it around. I can send a v3 using a define for it,
> if really needed, but it seems more a separated clean-up. 

Sure, sounds good.  Looks like Dave applied it.

- Greg

> 
> Thank you,
> 
> Paolo
>

Re: [PATCH net v2] net: pktgen: fix pkt_size

2016-10-02 Thread David Miller 
From: Paolo Abeni 
Date: Fri, 30 Sep 2016 16:56:45 +0200

> The commit 879c7220e828 ("net: pktgen: Observe needed_headroom
> of the device") increased the 'pkt_overhead' field value by
> LL_RESERVED_SPACE.
> As a side effect the generated packet size, computed as:
> 
>   /* Eth + IPh + UDPh + mpls */
>   datalen = pkt_dev->cur_pkt_size - 14 - 20 - 8 -
> pkt_dev->pkt_overhead;
> 
> is decreased by the same value.
> The above changed slightly the behavior of existing pktgen users,
> and made the procfs interface somewhat inconsistent.
> Fix it by restoring the previous pkt_overhead value and using
> LL_RESERVED_SPACE as extralen in skb allocation.
> Also, change pktgen_alloc_skb() to only partially reserve
> the headroom to allow the caller to prefetch from ll header
> start.
> 
> v1 -> v2:
>  - fixed some typos in the comments
> 
> Fixes: 879c7220e828 ("net: pktgen: Observe needed_headroom of the device")
> Suggested-by: Ben Greear 
> Signed-off-by: Paolo Abeni 

Applied and queued up for -stable.

Re: [PATCH net v2] net: pktgen: fix pkt_size

2016-10-01 Thread Paolo Abeni 
On Fri, 2016-09-30 at 08:39 -0700, Greg wrote:
> On Fri, 2016-09-30 at 16:56 +0200, Paolo Abeni wrote:
> > The commit 879c7220e828 ("net: pktgen: Observe needed_headroom
> > of the device") increased the 'pkt_overhead' field value by
> > LL_RESERVED_SPACE.
> > As a side effect the generated packet size, computed as:
> > 
> > /* Eth + IPh + UDPh + mpls */
> > datalen = pkt_dev->cur_pkt_size - 14 - 20 - 8 -
> >   pkt_dev->pkt_overhead;
> > 
> > is decreased by the same value.
> > The above changed slightly the behavior of existing pktgen users,
> > and made the procfs interface somewhat inconsistent.
> > Fix it by restoring the previous pkt_overhead value and using
> > LL_RESERVED_SPACE as extralen in skb allocation.
> > Also, change pktgen_alloc_skb() to only partially reserve
> > the headroom to allow the caller to prefetch from ll header
> > start.
> > 
> > v1 -> v2:
> >  - fixed some typos in the comments
> > 
> > Fixes: 879c7220e828 ("net: pktgen: Observe needed_headroom of the device")
> > Suggested-by: Ben Greear 
> > Signed-off-by: Paolo Abeni 
> > ---
> >  net/core/pktgen.c | 21 ++---
> >  1 file changed, 10 insertions(+), 11 deletions(-)
> > 
> > diff --git a/net/core/pktgen.c b/net/core/pktgen.c
> > index bbd118b..5219a9e 100644
> > --- a/net/core/pktgen.c
> > +++ b/net/core/pktgen.c
> > @@ -2286,7 +2286,7 @@ out:
> >  
> >  static inline void set_pkt_overhead(struct pktgen_dev *pkt_dev)
> >  {
> > -   pkt_dev->pkt_overhead = LL_RESERVED_SPACE(pkt_dev->odev);
> > +   pkt_dev->pkt_overhead = 0;
> > pkt_dev->pkt_overhead += pkt_dev->nr_labels*sizeof(u32);
> > pkt_dev->pkt_overhead += VLAN_TAG_SIZE(pkt_dev);
> > pkt_dev->pkt_overhead += SVLAN_TAG_SIZE(pkt_dev);
> > @@ -2777,13 +2777,13 @@ static void pktgen_finalize_skb(struct pktgen_dev 
> > *pkt_dev, struct sk_buff *skb,
> >  }
> >  
> >  static struct sk_buff *pktgen_alloc_skb(struct net_device *dev,
> > -   struct pktgen_dev *pkt_dev,
> > -   unsigned int extralen)
> > +   struct pktgen_dev *pkt_dev)
> >  {
> > +   unsigned int extralen = LL_RESERVED_SPACE(dev);
> > struct sk_buff *skb = NULL;
> > -   unsigned int size = pkt_dev->cur_pkt_size + 64 + extralen +
> > -   pkt_dev->pkt_overhead;
> > +   unsigned int size;
> >  
> > +   size = pkt_dev->cur_pkt_size + 64 + extralen + pkt_dev->pkt_overhead;
> > if (pkt_dev->flags & F_NODE) {
> > int node = pkt_dev->node >= 0 ? pkt_dev->node : numa_node_id();
> >  
> > @@ -2796,8 +2796,9 @@ static struct sk_buff *pktgen_alloc_skb(struct 
> > net_device *dev,
> >  skb = __netdev_alloc_skb(dev, size, GFP_NOWAIT);
> > }
> >  
> > +   /* the caller pre-fetches from skb->data and reserves for the mac hdr */
> > if (likely(skb))
> > -   skb_reserve(skb, LL_RESERVED_SPACE(dev));
> > +   skb_reserve(skb, extralen - 16);
> 
> Is the 16 here the same as HD_DATA_MOD?
> 
> Magic numbers...

This magic numbers comes from the current code (the extralen argument),
this patch just move it around. I can send a v3 using a define for it,
if really needed, but it seems more a separated clean-up. 

Thank you,

Paolo

Re: [PATCH net v2] net: pktgen: fix pkt_size

2016-09-30 Thread Greg 
On Fri, 2016-09-30 at 16:56 +0200, Paolo Abeni wrote:
> The commit 879c7220e828 ("net: pktgen: Observe needed_headroom
> of the device") increased the 'pkt_overhead' field value by
> LL_RESERVED_SPACE.
> As a side effect the generated packet size, computed as:
> 
>   /* Eth + IPh + UDPh + mpls */
>   datalen = pkt_dev->cur_pkt_size - 14 - 20 - 8 -
> pkt_dev->pkt_overhead;
> 
> is decreased by the same value.
> The above changed slightly the behavior of existing pktgen users,
> and made the procfs interface somewhat inconsistent.
> Fix it by restoring the previous pkt_overhead value and using
> LL_RESERVED_SPACE as extralen in skb allocation.
> Also, change pktgen_alloc_skb() to only partially reserve
> the headroom to allow the caller to prefetch from ll header
> start.
> 
> v1 -> v2:
>  - fixed some typos in the comments
> 
> Fixes: 879c7220e828 ("net: pktgen: Observe needed_headroom of the device")
> Suggested-by: Ben Greear 
> Signed-off-by: Paolo Abeni 
> ---
>  net/core/pktgen.c | 21 ++---
>  1 file changed, 10 insertions(+), 11 deletions(-)
> 
> diff --git a/net/core/pktgen.c b/net/core/pktgen.c
> index bbd118b..5219a9e 100644
> --- a/net/core/pktgen.c
> +++ b/net/core/pktgen.c
> @@ -2286,7 +2286,7 @@ out:
>  
>  static inline void set_pkt_overhead(struct pktgen_dev *pkt_dev)
>  {
> - pkt_dev->pkt_overhead = LL_RESERVED_SPACE(pkt_dev->odev);
> + pkt_dev->pkt_overhead = 0;
>   pkt_dev->pkt_overhead += pkt_dev->nr_labels*sizeof(u32);
>   pkt_dev->pkt_overhead += VLAN_TAG_SIZE(pkt_dev);
>   pkt_dev->pkt_overhead += SVLAN_TAG_SIZE(pkt_dev);
> @@ -2777,13 +2777,13 @@ static void pktgen_finalize_skb(struct pktgen_dev 
> *pkt_dev, struct sk_buff *skb,
>  }
>  
>  static struct sk_buff *pktgen_alloc_skb(struct net_device *dev,
> - struct pktgen_dev *pkt_dev,
> - unsigned int extralen)
> + struct pktgen_dev *pkt_dev)
>  {
> + unsigned int extralen = LL_RESERVED_SPACE(dev);
>   struct sk_buff *skb = NULL;
> - unsigned int size = pkt_dev->cur_pkt_size + 64 + extralen +
> - pkt_dev->pkt_overhead;
> + unsigned int size;
>  
> + size = pkt_dev->cur_pkt_size + 64 + extralen + pkt_dev->pkt_overhead;
>   if (pkt_dev->flags & F_NODE) {
>   int node = pkt_dev->node >= 0 ? pkt_dev->node : numa_node_id();
>  
> @@ -2796,8 +2796,9 @@ static struct sk_buff *pktgen_alloc_skb(struct 
> net_device *dev,
>skb = __netdev_alloc_skb(dev, size, GFP_NOWAIT);
>   }
>  
> + /* the caller pre-fetches from skb->data and reserves for the mac hdr */
>   if (likely(skb))
> - skb_reserve(skb, LL_RESERVED_SPACE(dev));
> + skb_reserve(skb, extralen - 16);

Is the 16 here the same as HD_DATA_MOD?

Magic numbers...

Thanks,

- Greg

>  
>   return skb;
>  }
> @@ -2830,16 +2831,14 @@ static struct sk_buff *fill_packet_ipv4(struct 
> net_device *odev,
>   mod_cur_headers(pkt_dev);
>   queue_map = pkt_dev->cur_queue_map;
>  
> - datalen = (odev->hard_header_len + 16) & ~0xf;
> -
> - skb = pktgen_alloc_skb(odev, pkt_dev, datalen);
> + skb = pktgen_alloc_skb(odev, pkt_dev);
>   if (!skb) {
>   sprintf(pkt_dev->result, "No memory");
>   return NULL;
>   }
>  
>   prefetchw(skb->data);
> - skb_reserve(skb, datalen);
> + skb_reserve(skb, 16);
>  
>   /*  Reserve for ethernet and IP header  */
>   eth = (__u8 *) skb_push(skb, 14);
> @@ -2959,7 +2958,7 @@ static struct sk_buff *fill_packet_ipv6(struct 
> net_device *odev,
>   mod_cur_headers(pkt_dev);
>   queue_map = pkt_dev->cur_queue_map;
>  
> - skb = pktgen_alloc_skb(odev, pkt_dev, 16);
> + skb = pktgen_alloc_skb(odev, pkt_dev);
>   if (!skb) {
>   sprintf(pkt_dev->result, "No memory");
>   return NULL;

[PATCH net v2] net: pktgen: fix pkt_size

2016-09-30 Thread Paolo Abeni 
The commit 879c7220e828 ("net: pktgen: Observe needed_headroom
of the device") increased the 'pkt_overhead' field value by
LL_RESERVED_SPACE.
As a side effect the generated packet size, computed as:

/* Eth + IPh + UDPh + mpls */
datalen = pkt_dev->cur_pkt_size - 14 - 20 - 8 -
  pkt_dev->pkt_overhead;

is decreased by the same value.
The above changed slightly the behavior of existing pktgen users,
and made the procfs interface somewhat inconsistent.
Fix it by restoring the previous pkt_overhead value and using
LL_RESERVED_SPACE as extralen in skb allocation.
Also, change pktgen_alloc_skb() to only partially reserve
the headroom to allow the caller to prefetch from ll header
start.

v1 -> v2:
 - fixed some typos in the comments

Fixes: 879c7220e828 ("net: pktgen: Observe needed_headroom of the device")
Suggested-by: Ben Greear 
Signed-off-by: Paolo Abeni 
---
 net/core/pktgen.c | 21 ++---
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index bbd118b..5219a9e 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -2286,7 +2286,7 @@ out:
 
 static inline void set_pkt_overhead(struct pktgen_dev *pkt_dev)
 {
-   pkt_dev->pkt_overhead = LL_RESERVED_SPACE(pkt_dev->odev);
+   pkt_dev->pkt_overhead = 0;
pkt_dev->pkt_overhead += pkt_dev->nr_labels*sizeof(u32);
pkt_dev->pkt_overhead += VLAN_TAG_SIZE(pkt_dev);
pkt_dev->pkt_overhead += SVLAN_TAG_SIZE(pkt_dev);
@@ -2777,13 +2777,13 @@ static void pktgen_finalize_skb(struct pktgen_dev 
*pkt_dev, struct sk_buff *skb,
 }
 
 static struct sk_buff *pktgen_alloc_skb(struct net_device *dev,
-   struct pktgen_dev *pkt_dev,
-   unsigned int extralen)
+   struct pktgen_dev *pkt_dev)
 {
+   unsigned int extralen = LL_RESERVED_SPACE(dev);
struct sk_buff *skb = NULL;
-   unsigned int size = pkt_dev->cur_pkt_size + 64 + extralen +
-   pkt_dev->pkt_overhead;
+   unsigned int size;
 
+   size = pkt_dev->cur_pkt_size + 64 + extralen + pkt_dev->pkt_overhead;
if (pkt_dev->flags & F_NODE) {
int node = pkt_dev->node >= 0 ? pkt_dev->node : numa_node_id();
 
@@ -2796,8 +2796,9 @@ static struct sk_buff *pktgen_alloc_skb(struct net_device 
*dev,
 skb = __netdev_alloc_skb(dev, size, GFP_NOWAIT);
}
 
+   /* the caller pre-fetches from skb->data and reserves for the mac hdr */
if (likely(skb))
-   skb_reserve(skb, LL_RESERVED_SPACE(dev));
+   skb_reserve(skb, extralen - 16);
 
return skb;
 }
@@ -2830,16 +2831,14 @@ static struct sk_buff *fill_packet_ipv4(struct 
net_device *odev,
mod_cur_headers(pkt_dev);
queue_map = pkt_dev->cur_queue_map;
 
-   datalen = (odev->hard_header_len + 16) & ~0xf;
-
-   skb = pktgen_alloc_skb(odev, pkt_dev, datalen);
+   skb = pktgen_alloc_skb(odev, pkt_dev);
if (!skb) {
sprintf(pkt_dev->result, "No memory");
return NULL;
}
 
prefetchw(skb->data);
-   skb_reserve(skb, datalen);
+   skb_reserve(skb, 16);
 
/*  Reserve for ethernet and IP header  */
eth = (__u8 *) skb_push(skb, 14);
@@ -2959,7 +2958,7 @@ static struct sk_buff *fill_packet_ipv6(struct net_device 
*odev,
mod_cur_headers(pkt_dev);
queue_map = pkt_dev->cur_queue_map;
 
-   skb = pktgen_alloc_skb(odev, pkt_dev, 16);
+   skb = pktgen_alloc_skb(odev, pkt_dev);
if (!skb) {
sprintf(pkt_dev->result, "No memory");
return NULL;
-- 
1.8.3.1