* [PATCH] include:linux:Optimizations to __skb_push
@ 2015-01-22 18:02 Mohammad Jamal
2015-01-22 18:21 ` Tom Herbert
2015-01-23 9:05 ` David Miller
0 siblings, 2 replies; 5+ messages in thread
From: Mohammad Jamal @ 2015-01-22 18:02 UTC (permalink / raw)
To: davem, therbert, edumazet, viro, alexander.h.duyck, willemb,
hannes, linux-kernel
Cc: Mohammad Jamal
This patch optimizes __skb_push function
Signed-off-by: Mohammad Jamal <md.jamalmohiuddin@gmail.com>
---
include/linux/skbuff.h | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 85ab7d7..9acffb2 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1671,9 +1671,8 @@ static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
{
- skb->data -= len;
skb->len += len;
- return skb->data;
+ return skb->data -= len;
}
unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
--
1.7.9.5
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] include:linux:Optimizations to __skb_push
2015-01-22 18:02 [PATCH] include:linux:Optimizations to __skb_push Mohammad Jamal
@ 2015-01-22 18:21 ` Tom Herbert
2015-01-22 18:24 ` Eric Dumazet
2015-01-23 9:05 ` David Miller
1 sibling, 1 reply; 5+ messages in thread
From: Tom Herbert @ 2015-01-22 18:21 UTC (permalink / raw)
To: Mohammad Jamal
Cc: David Miller, Eric Dumazet, viro, Alexander Duyck,
Willem de Bruijn, Hannes Frederic Sowa, LKML
On Thu, Jan 22, 2015 at 10:02 AM, Mohammad Jamal
<md.jamalmohiuddin@gmail.com> wrote:
> This patch optimizes __skb_push function
>
> Signed-off-by: Mohammad Jamal <md.jamalmohiuddin@gmail.com>
> ---
> include/linux/skbuff.h | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index 85ab7d7..9acffb2 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -1671,9 +1671,8 @@ static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
> unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
> static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
> {
> - skb->data -= len;
> skb->len += len;
> - return skb->data;
> + return skb->data -= len;
> }
>
Hmm, this seems less readable to me. What is the effect of this patch?
Does the compiler even produce different assembly?
Thanks,
Tom
> unsigned char *skb_pull(struct sk_buff *skb, unsigned int len);
> --
> 1.7.9.5
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] include:linux:Optimizations to __skb_push
2015-01-22 18:21 ` Tom Herbert
@ 2015-01-22 18:24 ` Eric Dumazet
2015-01-23 1:04 ` Jamal Mohammad
0 siblings, 1 reply; 5+ messages in thread
From: Eric Dumazet @ 2015-01-22 18:24 UTC (permalink / raw)
To: Tom Herbert
Cc: Mohammad Jamal, David Miller, viro, Alexander Duyck,
Willem de Bruijn, Hannes Frederic Sowa, LKML
On Thu, Jan 22, 2015 at 10:21 AM, Tom Herbert <therbert@google.com> wrote:
> Hmm, this seems less readable to me. What is the effect of this patch?
> Does the compiler even produce different assembly?
No change at all in generated assembly, this looks not worth it.
BTW, most __skb_push() callers ignore return value.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] include:linux:Optimizations to __skb_push
2015-01-22 18:24 ` Eric Dumazet
@ 2015-01-23 1:04 ` Jamal Mohammad
0 siblings, 0 replies; 5+ messages in thread
From: Jamal Mohammad @ 2015-01-23 1:04 UTC (permalink / raw)
To: Eric Dumazet
Cc: Tom Herbert, David Miller, viro, Alexander Duyck,
Willem de Bruijn, Hannes Frederic Sowa, LKML
On Thu, Jan 22, 2015 at 11:54 PM, Eric Dumazet <edumazet@google.com> wrote:
> On Thu, Jan 22, 2015 at 10:21 AM, Tom Herbert <therbert@google.com> wrote:
>
>> Hmm, this seems less readable to me. What is the effect of this patch?
>> Does the compiler even produce different assembly?
>
> No change at all in generated assembly, this looks not worth it.
>
> BTW, most __skb_push() callers ignore return value.
it just reduces the number of lines....
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] include:linux:Optimizations to __skb_push
2015-01-22 18:02 [PATCH] include:linux:Optimizations to __skb_push Mohammad Jamal
2015-01-22 18:21 ` Tom Herbert
@ 2015-01-23 9:05 ` David Miller
1 sibling, 0 replies; 5+ messages in thread
From: David Miller @ 2015-01-23 9:05 UTC (permalink / raw)
To: md.jamalmohiuddin
Cc: therbert, edumazet, viro, alexander.h.duyck, willemb, hannes,
linux-kernel
From: Mohammad Jamal <md.jamalmohiuddin@gmail.com>
Date: Thu, 22 Jan 2015 23:32:40 +0530
> This patch optimizes __skb_push function
>
> Signed-off-by: Mohammad Jamal <md.jamalmohiuddin@gmail.com>
A patch with a commit message that doesn't even explain the
optimization, or why it is worthwhile to make that optimization,
will not be applied, sorry.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2015-01-23 9:05 UTC | newest]
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2015-01-22 18:02 [PATCH] include:linux:Optimizations to __skb_push Mohammad Jamal
2015-01-22 18:21 ` Tom Herbert
2015-01-22 18:24 ` Eric Dumazet
2015-01-23 1:04 ` Jamal Mohammad
2015-01-23 9:05 ` David Miller
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