>***************
>*** 172,177 ****
>--- 173,184 ----
>  #define	M_CSUM_IPv4		0x00000040	/* IPv4 header */
>  #define	M_CSUM_IPv4_BAD		0x00000080	/* IPv4 header checksum bad */
>  
>+ /*
>+  * Max # of pages we can attach to m_ext.  This is carefully chosen
>+  * to be able to handle SOSEND_LOAN_CHUNK on a 4K page size machine.
>+  */
>+ #define	M_EXT_MAXPAGES		((65536 / 4096) + 1)
>+ 
>  /* description of external storage mapped into mbuf, valid if M_EXT set */
>  struct m_ext {
>  	caddr_t	ext_buf;		/* start of buffer */

	is it a correct assumption that a page is 4K or smaller?  4096 should
	be some constant from other headers (sys/ARCH/include/BLAH), i guess?

itojun