Date: Mon, 13 May 1996 07:43:36 -0400 From: Tony Ardolino <tony@netcon.com> To: bugs@freebsd.org Cc: cam@solidsys.com Subject: Freebsd, mbuf cluster size MINCLSIZE Message-ID: <31972068.4DCF@netcon.com>
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We have just completed porting our NetCon product to FreeBSD this product includes among other things; a NEW IPX/SPX protocol stack, and a NEW NetWare compatible vfs file system (TFS). Both the protocol stack and file system use the MBUF subsystem. What we don't understand is why is MINCLSIZE being set to 208 bytes when it should be 100 bytes. Is there something wrong here or is that we just don't understatnd what going on. We see the following throughout the FreeBSD code: MGET(m, M_WAIT, MT_DATA); or MGETHDR(m, M_WAIT, MT_DATA); if(len >= MINCLSIZE) MCLGET(m, M_WAIT); in mbuf.h #define MINCLSIZE (MHLEN + MLEN) MINCLSIZE = 208 ((MLEN = MSIZE 128 - m_hdr 20) + (MHLEN = MLEN 108 - pkthdr 8) should MINCLSIZE == 100 not 208, and if this is a bug how come TCP/IP works so well. Our code crashes when we have packets > 100 and < 208. Can anyone shed any light on this please? Tony Ardolino
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