| Message ID | 1285254414.2509.50.camel@edumazet-laptop |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Eric Dumazet <eric.dumazet@gmail.com> Date: Thu, 23 Sep 2010 17:06:54 +0200 > David > > I remember you reacted on my three years old comment about > commit a309bb072b96bfe (Page offsets and lengths need to be __u32.) > > http://www.mail-archive.com/netdev@vger.kernel.org/msg43999.html > > Could we reconsider the thing now and allow to shrink > sizeof(skb_shared_info) from 0x104 to 0xbc, considering nothing happened > about scatterlist work ? > > This saves 128 bytes on i386 because of alignments, and can be reverted > pretty fast if needed. Yes, this seems reasonable. I'll probably apply this, thanks! -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 9e8085a..9a7ea70 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -129,8 +129,13 @@ typedef struct skb_frag_struct skb_frag_t; struct skb_frag_struct { struct page *page; +#if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536) __u32 page_offset; __u32 size; +#else + __u16 page_offset; + __u16 size; +#endif }; #define HAVE_HW_TIME_STAMP
David I remember you reacted on my three years old comment about commit a309bb072b96bfe (Page offsets and lengths need to be __u32.) http://www.mail-archive.com/netdev@vger.kernel.org/msg43999.html Could we reconsider the thing now and allow to shrink sizeof(skb_shared_info) from 0x104 to 0xbc, considering nothing happened about scatterlist work ? This saves 128 bytes on i386 because of alignments, and can be reverted pretty fast if needed. Thanks ! [PATCH net-next-2.6] net: skb_frag_t can be smaller on small arches On 32bit arches, if PAGE_SIZE is smaller than 65536, we can use 16bit offset and size fields. This patch saves 72 bytes per skb on i386, or 128 bytes after rounding. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> --- include/linux/skbuff.h | 5 +++++ 1 files changed, 5 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html