diff mbox

skbuff: remove unused dma_head & dma_maps fields

Message ID 20100324064049.32298.87859.stgit@localhost.localdomain
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Kirsher, Jeffrey T March 24, 2010, 6:40 a.m. UTC 
From: Alexander Duyck <alexander.h.duyck@intel.com>

The dma map fields in the skb_shared_info structure no longer has any users
and can be dropped since it is making the skb_shared_info unecessarily larger.

Running slabtop show that we were using 4K slabs for the skb->head on x86_64 w/
an allocation size of 1522.  It turns out that the dma_head and dma_maps array
made skb_shared large enough that we had crossed over the 2k boundary with
standard frames and as such we were using 4k blocks of memory for all skbs.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
---

 include/linux/skbuff.h |    6 ------
 1 files changed, 0 insertions(+), 6 deletions(-)


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Comments

Eric Dumazet March 24, 2010, 6:48 a.m. UTC | #1 
Le mardi 23 mars 2010 à 23:40 -0700, Jeff Kirsher a écrit :
> From: Alexander Duyck <alexander.h.duyck@intel.com>
> 
> The dma map fields in the skb_shared_info structure no longer has any users
> and can be dropped since it is making the skb_shared_info unecessarily larger.
> 
> Running slabtop show that we were using 4K slabs for the skb->head on x86_64 w/
> an allocation size of 1522.  It turns out that the dma_head and dma_maps array
> made skb_shared large enough that we had crossed over the 2k boundary with
> standard frames and as such we were using 4k blocks of memory for all skbs.
> 
> Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
> ---
> 

Thanks a lot for doing this cleanup !

Acked-by: Eric Dumazet <eric.dumazet@gmail.com>



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David Miller March 24, 2010, 6:13 p.m. UTC | #2 
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 24 Mar 2010 07:48:06 +0100

> Le mardi 23 mars 2010 à 23:40 -0700, Jeff Kirsher a écrit :
>> From: Alexander Duyck <alexander.h.duyck@intel.com>
>> 
>> The dma map fields in the skb_shared_info structure no longer has any users
>> and can be dropped since it is making the skb_shared_info unecessarily larger.
>> 
>> Running slabtop show that we were using 4K slabs for the skb->head on x86_64 w/
>> an allocation size of 1522.  It turns out that the dma_head and dma_maps array
>> made skb_shared large enough that we had crossed over the 2k boundary with
>> standard frames and as such we were using 4k blocks of memory for all skbs.
>> 
>> Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
>> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
>> ---
>> 
> 
> Thanks a lot for doing this cleanup !
> 
> Acked-by: Eric Dumazet <eric.dumazet@gmail.com>

Yep, thanks indeed.  Applied!
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diff mbox

Patch

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 03f816a..124f90c 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -190,9 +190,6 @@  struct skb_shared_info {
 	atomic_t	dataref;
 	unsigned short	nr_frags;
 	unsigned short	gso_size;
-#ifdef CONFIG_HAS_DMA
-	dma_addr_t	dma_head;
-#endif
 	/* Warning: this field is not always filled in (UFO)! */
 	unsigned short	gso_segs;
 	unsigned short  gso_type;
@@ -201,9 +198,6 @@  struct skb_shared_info {
 	struct sk_buff	*frag_list;
 	struct skb_shared_hwtstamps hwtstamps;
 	skb_frag_t	frags[MAX_SKB_FRAGS];
-#ifdef CONFIG_HAS_DMA
-	dma_addr_t	dma_maps[MAX_SKB_FRAGS];
-#endif
 	/* Intermediate layers must ensure that destructor_arg
 	 * remains valid until skb destructor */
 	void *		destructor_arg;