Date: Wed, 6 Feb 2013 11:41:32 -0800 From: Lino Sanfilippo <lsanfil@marvell.com> To: Jacques Fourie <jacques.fourie@gmail.com>, John Baldwin <jhb@freebsd.org> Cc: Hackers freeBSD <freebsd-hackers@freebsd.org>, Axel Fischer <afischer@marvell.com>, Ralf Assmann <rassmann@marvell.com>, Markus Althoff <malthoff@marvell.com> Subject: RE: Mbuf memory handling Message-ID: <175CCF5F49938B4D99B2E3EF7F558EBE1C73F4038E@SC-VEXCH4.marvell.com> In-Reply-To: <CALX0vxCKqMm2PdK_5t1SdOO91LjpZ1bHz-oDskx6pEj5FPhvtg@mail.gmail.com> References: <175CCF5F49938B4D99B2E3EF7F558EBE1C73F401F3@SC-VEXCH4.marvell.com> <201302060836.55404.jhb@freebsd.org> <CALX0vxADMfWe1-_mOYnx0C-9cRxf-ETv6wOPn=%2B34NATNUbbKA@mail.gmail.com> <201302061137.35651.jhb@freebsd.org> <CALX0vxCKqMm2PdK_5t1SdOO91LjpZ1bHz-oDskx6pEj5FPhvtg@mail.gmail.com>
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John, Jacques, thank you very much for your help. An mbuf cluster seems to be the right di= rection. So I would have to do something like mbuf =3D m_getjcl(how, MT_DATA, M_PKTHDR, MJUMPAGESIZE); left_for_next_rcv =3D m_split(mbuf, chunksize); if_input(ifp, mbuf); right? >I agree that read-only buffers may be ok in this case but would like to po= int out that the M_WRITABLE() macro will evaluate to 0 if the refcount on t= he cluster is >1 The fact that the resulting mbufs returned by m_split() are not writeable a= ny more is indeed a problem: What I would like to do is keep the 'left_for_next_rcv' mbuf until the next= packet arrives and then fill it with the next packets data only up to 'chunksize', split it ag= ain to pass the new mbuf to the protocol stack and so on until 'left_for_next_rcv' becomes too small to= be splitted further. Only then I would want to allocate a new "fresh" jumbo sized mbuf. Is it po= ssible to realize this with cluster mbufs? Thx, Lino
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