Re: [6/6] [VIRTIO] net: Allow receiving SG packets

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Date: Tue, 22 Apr 2008 12:50:27 +1000

> But I was curious as to why the +2 in the MAX_SKB_FRAGS definition?

To be honest I have no idea.

When Alexey added the TSO changeset way back then, it had the
"+2", from the history-2.6 tree:

commit 80223d5186f73bf42a7e260c66c9cb9f7d8ec9cf
Author: Alexey Kuznetsov <kuznet@xxxxxxxxxxxxx>
Date:   Wed Aug 28 11:52:03 2002 -0700

    [NET]: Add TCP segmentation offload core infrastructure.

 ...
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index a812681..9b6e6ad 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -109,7 +109,8 @@ struct sk_buff_head {
 
 struct sk_buff;
 
-#define MAX_SKB_FRAGS 6
+/* To allow 64K frame to be packed as single skb without frag_list */
+#define MAX_SKB_FRAGS (65536/PAGE_SIZE + 2)
 
 typedef struct skb_frag_struct skb_frag_t;
 
_______________________________________________
Virtualization mailing list
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linux-foundation.org/mailman/listinfo/virtualization

[Index of Archives]     [KVM Development]     [Libvirt Development]     [Libvirt Users]     [CentOS Virtualization]     [Netdev]     [Ethernet Bridging]     [Linux Wireless]     [Kernel Newbies]     [Security]     [Linux for Hams]     [Netfilter]     [Bugtraq]     [Yosemite Forum]     [MIPS Linux]     [ARM Linux]     [Linux RAID]     [Linux Admin]     [Samba]

  Powered by Linux