Date: Sun, 16 Mar 2014 03:27:04 +0430 From: Hooman Fazaeli <hoomanfazaeli@gmail.com> To: Rui Paulo <rpaulo@FreeBSD.org> Cc: FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: mbuf question Message-ID: <5324DAC0.9020508@gmail.com> In-Reply-To: <5324D669.804@gmail.com> References: <53230214.7010501@gmail.com> <BBAFAB2A-F496-46A2-8FE0-224BE562EAA7@FreeBSD.org> <532405B7.2020007@gmail.com> <96659837-1FDC-421D-A339-87104A0075C7@FreeBSD.org> <5324D669.804@gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On 3/16/2014 3:08 AM, Hooman Fazaeli wrote: > On 3/15/2014 9:09 PM, Rui Paulo wrote: >> On 15 Mar 2014, at 00:48, Hooman Fazaeli <hoomanfazaeli@gmail.com> wrote: >>> What about the area started at (m->m_ext + 1) whose size is (MHLEN - sizeof(struct m_ext))? >>> Is there any known uses of this area in the stack? >> I'm not sure what you mean by m_ext + 1, but what are you trying to do? If you need to tag an mbuf, use mbuf tags. >> >> -- >> Rui Paulo > > (m->m_ext+ 1) points to the (unused?) area in m->m_dat.MHright after the space occupied by m_ext. > I am well aware of mbuf tags. I was just thinking toavoid the overhead of m_tag allocation/de-allocation > and store my little piece of data directly in mbufs. > sorry for my mistake. (m->m_ext + 1) is a totally wrong notation as m_ext is a struct. The area I was talking about is (m->m_pktdat + sizeof(m->m_ext)). Is this part of mbuf+cluster has any known uses? can we use it to store some data about the packet (instead of using mbuf tags)? -- Best regards. Hooman Fazaeli
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?5324DAC0.9020508>