[Patch v1] skbuff: Hide GFP_ATOMIC page allocation failures for dropped packets

[Patch v1] skbuff: Hide GFP_ATOMIC page allocation failures for dropped packets

[atomlin]

From: Aaron Tomlin <atomlin@redhat.com>

Failed GFP_ATOMIC allocations by the network stack result in dropped
packets, which will be received on a subsequent retransmit, and an
unnecessary, noisy warning with a kernel backtrace.

These warnings are harmless, but they still cause users to panic and
file bug reports over dropped packets. It would be better to hide the
failed allocation warnings and backtraces, and let retransmits handle
dropped packets quietly.

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
---
 net/core/skbuff.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index af9185d..02139d6 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -236,7 +236,7 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
 		? skbuff_fclone_cache : skbuff_head_cache;
 
 	if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX))
-		gfp_mask |= __GFP_MEMALLOC;
+		gfp_mask |= (__GFP_MEMALLOC|__GFP_NOWARN);
 
 	/* Get the HEAD */
 	skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
-- 
1.8.1.4

Re: [Patch v1] skbuff: Hide GFP_ATOMIC page allocation failures for dropped packets

[Sergei Shtylyov]

Hello.

On 26-05-2013 17:17, atomlin@redhat.com wrote:

> From: Aaron Tomlin <atomlin@redhat.com>

> Failed GFP_ATOMIC allocations by the network stack result in dropped
> packets, which will be received on a subsequent retransmit, and an
> unnecessary, noisy warning with a kernel backtrace.

> These warnings are harmless, but they still cause users to panic and
> file bug reports over dropped packets. It would be better to hide the
> failed allocation warnings and backtraces, and let retransmits handle
> dropped packets quietly.

> Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
> ---
>   net/core/skbuff.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index af9185d..02139d6 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -236,7 +236,7 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
>   		? skbuff_fclone_cache : skbuff_head_cache;
>
>   	if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX))
> -		gfp_mask |= __GFP_MEMALLOC;
> +		gfp_mask |= (__GFP_MEMALLOC|__GFP_NOWARN);

    Parens not needed here.

WBR, Sergei

Re: [Patch v1] skbuff: Hide GFP_ATOMIC page allocation failures for dropped packets

[Joe Perches]

On Sun, 2013-05-26 at 20:28 +0400, Sergei Shtylyov wrote:
> On 26-05-2013 17:17, atomlin@redhat.com wrote:
> > Failed GFP_ATOMIC allocations by the network stack result in dropped
> > packets, which will be received on a subsequent retransmit, and an
> > unnecessary, noisy warning with a kernel backtrace.
> 
> > These warnings are harmless, but they still cause users to panic and
> > file bug reports over dropped packets. It would be better to hide the
> > failed allocation warnings and backtraces, and let retransmits handle
> > dropped packets quietly.

> > diff --git a/net/core/skbuff.c b/net/core/skbuff.c
[]
> > @@ -236,7 +236,7 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
> >   		? skbuff_fclone_cache : skbuff_head_cache;
> >
> >   	if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX))
> > -		gfp_mask |= __GFP_MEMALLOC;
> > +		gfp_mask |= (__GFP_MEMALLOC|__GFP_NOWARN);
> 
>     Parens not needed here.

Maybe add a pr_debug before the goto out instead.

Re: [Patch v1] skbuff: Hide GFP_ATOMIC page allocation failures for dropped packets

[Sergei Shtylyov]

Hello.

On 26-05-2013 20:28, Sergei Shtylyov wrote:

>> From: Aaron Tomlin <atomlin@redhat.com>

>> Failed GFP_ATOMIC allocations by the network stack result in dropped
>> packets, which will be received on a subsequent retransmit, and an
>> unnecessary, noisy warning with a kernel backtrace.

>> These warnings are harmless, but they still cause users to panic and
>> file bug reports over dropped packets. It would be better to hide the
>> failed allocation warnings and backtraces, and let retransmits handle
>> dropped packets quietly.

>> Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
>> ---
>>   net/core/skbuff.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)

>> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
>> index af9185d..02139d6 100644
>> --- a/net/core/skbuff.c
>> +++ b/net/core/skbuff.c
>> @@ -236,7 +236,7 @@ struct sk_buff *__alloc_skb(unsigned int size,
>> gfp_t gfp_mask,
>>           ? skbuff_fclone_cache : skbuff_head_cache;
>>
>>       if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX))
>> -        gfp_mask |= __GFP_MEMALLOC;
>> +        gfp_mask |= (__GFP_MEMALLOC|__GFP_NOWARN);

>     Parens not needed here.

    And add spaces around | please, to be consistent with other code.

WBR, Sergei